Organize files better

First things first... organize!

plugins/UM3NetworkPrinting/src/ClusterUM3OutputDevice.py

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+# Copyright (c) 2018 Ultimaker B.V.
+# Cura is released under the terms of the LGPLv3 or higher.
+
+from typing import Any, cast, Optional, Set, Tuple, Union
+
+from UM.FileHandler.FileHandler import FileHandler
+from UM.FileHandler.FileWriter import FileWriter  # To choose based on the output file mode (text vs. binary).
+from UM.FileHandler.WriteFileJob import WriteFileJob  # To call the file writer asynchronously.
+from UM.Logger import Logger
+from UM.Settings.ContainerRegistry import ContainerRegistry
+from UM.i18n import i18nCatalog
+
+from UM.Message import Message
+from UM.Qt.Duration import Duration, DurationFormat
+from UM.OutputDevice import OutputDeviceError  # To show that something went wrong when writing.
+from UM.Scene.SceneNode import SceneNode  # For typing.
+from UM.Version import Version  # To check against firmware versions for support.
+
+from cura.CuraApplication import CuraApplication
+from cura.PrinterOutput.ConfigurationModel import ConfigurationModel
+from cura.PrinterOutput.ExtruderConfigurationModel import ExtruderConfigurationModel
+from cura.PrinterOutput.NetworkedPrinterOutputDevice import NetworkedPrinterOutputDevice, AuthState
+from cura.PrinterOutput.PrinterOutputModel import PrinterOutputModel
+from cura.PrinterOutput.PrintJobOutputModel import PrintJobOutputModel
+from cura.PrinterOutput.MaterialOutputModel import MaterialOutputModel
+from cura.PrinterOutput.NetworkCamera import NetworkCamera
+
+from .ClusterUM3PrinterOutputController import ClusterUM3PrinterOutputController
+from .SendMaterialJob import SendMaterialJob
+
+from PyQt5.QtNetwork import QNetworkRequest, QNetworkReply
+from PyQt5.QtGui import QDesktopServices, QImage
+from PyQt5.QtCore import pyqtSlot, QUrl, pyqtSignal, pyqtProperty, QObject
+
+from time import time
+from datetime import datetime
+from typing import Optional, Dict, List
+
+import io  # To create the correct buffers for sending data to the printer.
+import json
+import os
+
+i18n_catalog = i18nCatalog("cura")
+
+
+class ClusterUM3OutputDevice(NetworkedPrinterOutputDevice):
+    printJobsChanged = pyqtSignal()
+    activePrinterChanged = pyqtSignal()
+    activeCameraChanged = pyqtSignal()
+
+    # This is a bit of a hack, as the notify can only use signals that are defined by the class that they are in.
+    # Inheritance doesn't seem to work. Tying them together does work, but i'm open for better suggestions.
+    clusterPrintersChanged = pyqtSignal()
+
+    def __init__(self, device_id, address, properties, parent = None) -> None:
+        super().__init__(device_id = device_id, address = address, properties=properties, parent = parent)
+        self._api_prefix = "/cluster-api/v1/"
+
+        self._number_of_extruders = 2
+
+        self._dummy_lambdas = ("", {}, io.BytesIO()) #type: Tuple[str, Dict, Union[io.StringIO, io.BytesIO]]
+
+        self._print_jobs = [] # type: List[PrintJobOutputModel]
+
+        self._monitor_view_qml_path = os.path.join(os.path.dirname(os.path.abspath(__file__)), "../resources/qml/ClusterMonitorItem.qml")
+        self._control_view_qml_path = os.path.join(os.path.dirname(os.path.abspath(__file__)), "../resources/qml/ClusterControlItem.qml")
+
+        # See comments about this hack with the clusterPrintersChanged signal
+        self.printersChanged.connect(self.clusterPrintersChanged)
+
+        self._accepts_commands = True  # type: bool
+
+        # Cluster does not have authentication, so default to authenticated
+        self._authentication_state = AuthState.Authenticated
+
+        self._error_message = None  # type: Optional[Message]
+        self._write_job_progress_message = None  # type: Optional[Message]
+        self._progress_message = None  # type: Optional[Message]
+
+        self._active_printer = None  # type: Optional[PrinterOutputModel]
+
+        self._printer_selection_dialog = None  # type: QObject
+
+        self.setPriority(3)  # Make sure the output device gets selected above local file output
+        self.setName(self._id)
+        self.setShortDescription(i18n_catalog.i18nc("@action:button Preceded by 'Ready to'.", "Print over network"))
+        self.setDescription(i18n_catalog.i18nc("@properties:tooltip", "Print over network"))
+
+        self.setConnectionText(i18n_catalog.i18nc("@info:status", "Connected over the network"))
+
+        self._printer_uuid_to_unique_name_mapping = {}  # type: Dict[str, str]
+
+        self._finished_jobs = []  # type: List[PrintJobOutputModel]
+
+        self._cluster_size = int(properties.get(b"cluster_size", 0))  # type: int
+
+        self._latest_reply_handler = None  # type: Optional[QNetworkReply]
+        self._sending_job = None
+
+        self._active_camera = None # type: Optional[NetworkCamera]
+
+    def requestWrite(self, nodes: List[SceneNode], file_name: Optional[str] = None, limit_mimetypes: bool = False, file_handler: Optional[FileHandler] = None, **kwargs: str) -> None:
+        self.writeStarted.emit(self)
+
+        self.sendMaterialProfiles()
+
+        # Formats supported by this application (file types that we can actually write).
+        if file_handler:
+            file_formats = file_handler.getSupportedFileTypesWrite()
+        else:
+            file_formats = CuraApplication.getInstance().getMeshFileHandler().getSupportedFileTypesWrite()
+
+        global_stack = CuraApplication.getInstance().getGlobalContainerStack()
+        # Create a list from the supported file formats string.
+        if not global_stack:
+            Logger.log("e", "Missing global stack!")
+            return
+
+        machine_file_formats = global_stack.getMetaDataEntry("file_formats").split(";")
+        machine_file_formats = [file_type.strip() for file_type in machine_file_formats]
+        # Exception for UM3 firmware version >=4.4: UFP is now supported and should be the preferred file format.
+        if "application/x-ufp" not in machine_file_formats and Version(self.firmwareVersion) >= Version("4.4"):
+            machine_file_formats = ["application/x-ufp"] + machine_file_formats
+
+        # Take the intersection between file_formats and machine_file_formats.
+        format_by_mimetype = {format["mime_type"]: format for format in file_formats}
+        file_formats = [format_by_mimetype[mimetype] for mimetype in machine_file_formats] #Keep them ordered according to the preference in machine_file_formats.
+
+        if len(file_formats) == 0:
+            Logger.log("e", "There are no file formats available to write with!")
+            raise OutputDeviceError.WriteRequestFailedError(i18n_catalog.i18nc("@info:status", "There are no file formats available to write with!"))
+        preferred_format = file_formats[0]
+
+        # Just take the first file format available.
+        if file_handler is not None:
+            writer = file_handler.getWriterByMimeType(cast(str, preferred_format["mime_type"]))
+        else:
+            writer = CuraApplication.getInstance().getMeshFileHandler().getWriterByMimeType(cast(str, preferred_format["mime_type"]))
+
+        if not writer:
+            Logger.log("e", "Unexpected error when trying to get the FileWriter")
+            return
+
+        # This function pauses with the yield, waiting on instructions on which printer it needs to print with.
+        if not writer:
+            Logger.log("e", "Missing file or mesh writer!")
+            return
+        self._sending_job = self._sendPrintJob(writer, preferred_format, nodes)
+        if self._sending_job is not None:
+            self._sending_job.send(None)  # Start the generator.
+
+            if len(self._printers) > 1:  # We need to ask the user.
+                self._spawnPrinterSelectionDialog()
+                is_job_sent = True
+            else:  # Just immediately continue.
+                self._sending_job.send("")  # No specifically selected printer.
+                is_job_sent = self._sending_job.send(None)
+
+    def _spawnPrinterSelectionDialog(self):
+        if self._printer_selection_dialog is None:
+            path = os.path.join(os.path.dirname(os.path.abspath(__file__)), "../resources/qml/PrintWindow.qml")
+            self._printer_selection_dialog = CuraApplication.getInstance().createQmlComponent(path, {"OutputDevice": self})
+        if self._printer_selection_dialog is not None:
+            self._printer_selection_dialog.show()
+
+    @pyqtProperty(int, constant=True)
+    def clusterSize(self) -> int:
+        return self._cluster_size
+
+    ##  Allows the user to choose a printer to print with from the printer
+    #   selection dialogue.
+    #   \param target_printer The name of the printer to target.
+    @pyqtSlot(str)
+    def selectPrinter(self, target_printer: str = "") -> None:
+        if self._sending_job is not None:
+            self._sending_job.send(target_printer)
+
+    @pyqtSlot()
+    def cancelPrintSelection(self) -> None:
+        self._sending_gcode = False
+
+    ##  Greenlet to send a job to the printer over the network.
+    #
+    #   This greenlet gets called asynchronously in requestWrite. It is a
+    #   greenlet in order to optionally wait for selectPrinter() to select a
+    #   printer.
+    #   The greenlet yields exactly three times: First time None,
+    #   \param writer The file writer to use to create the data.
+    #   \param preferred_format A dictionary containing some information about
+    #   what format to write to. This is necessary to create the correct buffer
+    #   types and file extension and such.
+    def _sendPrintJob(self, writer: FileWriter, preferred_format: Dict, nodes: List[SceneNode]):
+        Logger.log("i", "Sending print job to printer.")
+        if self._sending_gcode:
+            self._error_message = Message(
+                i18n_catalog.i18nc("@info:status",
+                                   "Sending new jobs (temporarily) blocked, still sending the previous print job."))
+            self._error_message.show()
+            yield #Wait on the user to select a target printer.
+            yield #Wait for the write job to be finished.
+            yield False #Return whether this was a success or not.
+            yield #Prevent StopIteration.
+
+        self._sending_gcode = True
+
+        target_printer = yield #Potentially wait on the user to select a target printer.
+
+        # Using buffering greatly reduces the write time for many lines of gcode
+
+        stream = io.BytesIO() # type: Union[io.BytesIO, io.StringIO]# Binary mode.
+        if preferred_format["mode"] == FileWriter.OutputMode.TextMode:
+            stream = io.StringIO()
+
+        job = WriteFileJob(writer, stream, nodes, preferred_format["mode"])
+
+        self._write_job_progress_message = Message(i18n_catalog.i18nc("@info:status", "Sending data to printer"), lifetime = 0, dismissable = False, progress = -1,
+                                                   title = i18n_catalog.i18nc("@info:title", "Sending Data"), use_inactivity_timer = False)
+        self._write_job_progress_message.show()
+
+        self._dummy_lambdas = (target_printer, preferred_format, stream)
+        job.finished.connect(self._sendPrintJobWaitOnWriteJobFinished)
+
+        job.start()
+
+        yield True  # Return that we had success!
+        yield  # To prevent having to catch the StopIteration exception.
+
+    def _sendPrintJobWaitOnWriteJobFinished(self, job: WriteFileJob) -> None:
+        if self._write_job_progress_message:
+            self._write_job_progress_message.hide()
+
+        self._progress_message = Message(i18n_catalog.i18nc("@info:status", "Sending data to printer"), lifetime = 0, dismissable = False, progress = -1,
+                                         title = i18n_catalog.i18nc("@info:title", "Sending Data"))
+        self._progress_message.addAction("Abort", i18n_catalog.i18nc("@action:button", "Cancel"), icon = None, description = "")
+        self._progress_message.actionTriggered.connect(self._progressMessageActionTriggered)
+        self._progress_message.show()
+        parts = []
+
+        target_printer, preferred_format, stream = self._dummy_lambdas
+
+        # If a specific printer was selected, it should be printed with that machine.
+        if target_printer:
+            target_printer = self._printer_uuid_to_unique_name_mapping[target_printer]
+            parts.append(self._createFormPart("name=require_printer_name", bytes(target_printer, "utf-8"), "text/plain"))
+
+        # Add user name to the print_job
+        parts.append(self._createFormPart("name=owner", bytes(self._getUserName(), "utf-8"), "text/plain"))
+
+        file_name = CuraApplication.getInstance().getPrintInformation().jobName + "." + preferred_format["extension"]
+
+        output = stream.getvalue()  # Either str or bytes depending on the output mode.
+        if isinstance(stream, io.StringIO):
+            output = cast(str, output).encode("utf-8")
+        output = cast(bytes, output)
+
+        parts.append(self._createFormPart("name=\"file\"; filename=\"%s\"" % file_name, output))
+
+        self._latest_reply_handler = self.postFormWithParts("print_jobs/", parts, on_finished = self._onPostPrintJobFinished, on_progress = self._onUploadPrintJobProgress)
+
+    @pyqtProperty(QObject, notify = activePrinterChanged)
+    def activePrinter(self) -> Optional[PrinterOutputModel]:
+        return self._active_printer
+
+    @pyqtProperty(QObject, notify=activeCameraChanged)
+    def activeCamera(self) -> Optional[NetworkCamera]:
+        return self._active_camera
+
+    @pyqtSlot(QObject)
+    def setActivePrinter(self, printer: Optional[PrinterOutputModel]) -> None:
+        if self._active_printer != printer:
+            if self._active_printer and self._active_printer.camera:
+                self._active_printer.camera.stop()
+            self._active_printer = printer
+            self.activePrinterChanged.emit()
+
+    @pyqtSlot(QObject)
+    def setActiveCamera(self, camera: Optional[NetworkCamera]) -> None:
+        if self._active_camera != camera:
+            if self._active_camera:
+                self._active_camera.stop()
+
+            self._active_camera = camera
+
+            if self._active_camera:
+                self._active_camera.start()
+
+            self.activeCameraChanged.emit()
+
+    def _onPostPrintJobFinished(self, reply: QNetworkReply) -> None:
+        if self._progress_message:
+            self._progress_message.hide()
+        self._compressing_gcode = False
+        self._sending_gcode = False
+
+    def _onUploadPrintJobProgress(self, bytes_sent: int, bytes_total: int) -> None:
+        if bytes_total > 0:
+            new_progress = bytes_sent / bytes_total * 100
+            # Treat upload progress as response. Uploading can take more than 10 seconds, so if we don't, we can get
+            # timeout responses if this happens.
+            self._last_response_time = time()
+            if self._progress_message and new_progress > self._progress_message.getProgress():
+                self._progress_message.show()  # Ensure that the message is visible.
+                self._progress_message.setProgress(bytes_sent / bytes_total * 100)
+
+            # If successfully sent:
+            if bytes_sent == bytes_total:
+                # Show a confirmation to the user so they know the job was sucessful and provide the option to switch to
+                # the monitor tab.
+                self._success_message = Message(
+                    i18n_catalog.i18nc("@info:status", "Print job was successfully sent to the printer."),
+                    lifetime=5, dismissable=True,
+                    title=i18n_catalog.i18nc("@info:title", "Data Sent"))
+                self._success_message.addAction("View", i18n_catalog.i18nc("@action:button", "View in Monitor"), icon=None,
+                                                description="")
+                self._success_message.actionTriggered.connect(self._successMessageActionTriggered)
+                self._success_message.show()
+        else:
+            if self._progress_message is not None:
+                self._progress_message.setProgress(0)
+                self._progress_message.hide()
+
+    def _progressMessageActionTriggered(self, message_id: Optional[str] = None, action_id: Optional[str] = None) -> None:
+        if action_id == "Abort":
+            Logger.log("d", "User aborted sending print to remote.")
+            if self._progress_message is not None:
+                self._progress_message.hide()
+            self._compressing_gcode = False
+            self._sending_gcode = False
+            CuraApplication.getInstance().getController().setActiveStage("PrepareStage")
+
+            # After compressing the sliced model Cura sends data to printer, to stop receiving updates from the request
+            # the "reply" should be disconnected
+            if self._latest_reply_handler:
+                self._latest_reply_handler.disconnect()
+                self._latest_reply_handler = None
+
+    def _successMessageActionTriggered(self, message_id: Optional[str] = None, action_id: Optional[str] = None) -> None:
+        if action_id == "View":
+            CuraApplication.getInstance().getController().setActiveStage("MonitorStage")
+
+    @pyqtSlot()
+    def openPrintJobControlPanel(self) -> None:
+        Logger.log("d", "Opening print job control panel...")
+        QDesktopServices.openUrl(QUrl("http://" + self._address + "/print_jobs"))
+
+    @pyqtSlot()
+    def openPrinterControlPanel(self) -> None:
+        Logger.log("d", "Opening printer control panel...")
+        QDesktopServices.openUrl(QUrl("http://" + self._address + "/printers"))
+
+    @pyqtProperty("QVariantList", notify = printJobsChanged)
+    def printJobs(self)-> List[PrintJobOutputModel]:
+        return self._print_jobs
+
+    @pyqtProperty("QVariantList", notify = printJobsChanged)
+    def queuedPrintJobs(self) -> List[PrintJobOutputModel]:
+        return [print_job for print_job in self._print_jobs if print_job.state == "queued" or print_job.state == "error"]
+
+    @pyqtProperty("QVariantList", notify = printJobsChanged)
+    def activePrintJobs(self) -> List[PrintJobOutputModel]:
+        return [print_job for print_job in self._print_jobs if print_job.assignedPrinter is not None and print_job.state != "queued"]
+
+    @pyqtProperty("QVariantList", notify = clusterPrintersChanged)
+    def connectedPrintersTypeCount(self) -> List[Dict[str, str]]:
+        printer_count = {} # type: Dict[str, int]
+        for printer in self._printers:
+            if printer.type in printer_count:
+                printer_count[printer.type] += 1
+            else:
+                printer_count[printer.type] = 1
+        result = []
+        for machine_type in printer_count:
+            result.append({"machine_type": machine_type, "count": str(printer_count[machine_type])})
+        return result
+
+    @pyqtProperty("QVariantList", notify=clusterPrintersChanged)
+    def printers(self):
+        return self._printers
+
+    @pyqtSlot(int, result = str)
+    def formatDuration(self, seconds: int) -> str:
+        return Duration(seconds).getDisplayString(DurationFormat.Format.Short)
+
+    @pyqtSlot(int, result = str)
+    def getTimeCompleted(self, time_remaining: int) -> str:
+        current_time = time()
+        datetime_completed = datetime.fromtimestamp(current_time + time_remaining)
+        return "{hour:02d}:{minute:02d}".format(hour=datetime_completed.hour, minute=datetime_completed.minute)
+
+    @pyqtSlot(int, result = str)
+    def getDateCompleted(self, time_remaining: int) -> str:
+        current_time = time()
+        datetime_completed = datetime.fromtimestamp(current_time + time_remaining)
+        return (datetime_completed.strftime("%a %b ") + "{day}".format(day=datetime_completed.day)).upper()
+
+    @pyqtSlot(str)
+    def sendJobToTop(self, print_job_uuid: str) -> None:
+        # This function is part of the output device (and not of the printjob output model) as this type of operation
+        # is a modification of the cluster queue and not of the actual job.
+        data = "{\"to_position\": 0}"
+        self.put("print_jobs/{uuid}/move_to_position".format(uuid = print_job_uuid), data, on_finished=None)
+
+    @pyqtSlot(str)
+    def deleteJobFromQueue(self, print_job_uuid: str) -> None:
+        # This function is part of the output device (and not of the printjob output model) as this type of operation
+        # is a modification of the cluster queue and not of the actual job.
+        self.delete("print_jobs/{uuid}".format(uuid = print_job_uuid), on_finished=None)
+
+    def _printJobStateChanged(self) -> None:
+        username = self._getUserName()
+
+        if username is None:
+            return  # We only want to show notifications if username is set.
+
+        finished_jobs = [job for job in self._print_jobs if job.state == "wait_cleanup"]
+
+        newly_finished_jobs = [job for job in finished_jobs if job not in self._finished_jobs and job.owner == username]
+        for job in newly_finished_jobs:
+            if job.assignedPrinter:
+                job_completed_text = i18n_catalog.i18nc("@info:status", "Printer '{printer_name}' has finished printing '{job_name}'.".format(printer_name=job.assignedPrinter.name, job_name = job.name))
+            else:
+                job_completed_text =  i18n_catalog.i18nc("@info:status", "The print job '{job_name}' was finished.".format(job_name = job.name))
+            job_completed_message = Message(text=job_completed_text, title = i18n_catalog.i18nc("@info:status", "Print finished"))
+            job_completed_message.show()
+
+        # Ensure UI gets updated
+        self.printJobsChanged.emit()
+
+        # Keep a list of all completed jobs so we know if something changed next time.
+        self._finished_jobs = finished_jobs
+
+    ##  Called when the connection to the cluster changes.
+    def connect(self) -> None:
+        super().connect()
+        self.sendMaterialProfiles()
+
+    def _onGetPreviewImageFinished(self, reply: QNetworkReply) -> None:
+        reply_url = reply.url().toString()
+
+        uuid = reply_url[reply_url.find("print_jobs/")+len("print_jobs/"):reply_url.rfind("/preview_image")]
+
+        print_job = findByKey(self._print_jobs, uuid)
+        if print_job:
+            image = QImage()
+            image.loadFromData(reply.readAll())
+            print_job.updatePreviewImage(image)
+
+    def _update(self) -> None:
+        super()._update()
+        self.get("printers/", on_finished = self._onGetPrintersDataFinished)
+        self.get("print_jobs/", on_finished = self._onGetPrintJobsFinished)
+
+        for print_job in self._print_jobs:
+            if print_job.getPreviewImage() is None:
+                self.get("print_jobs/{uuid}/preview_image".format(uuid=print_job.key), on_finished=self._onGetPreviewImageFinished)
+
+    def _onGetPrintJobsFinished(self, reply: QNetworkReply) -> None:
+        if not checkValidGetReply(reply):
+            return
+
+        result = loadJsonFromReply(reply)
+        if result is None:
+            return
+
+        print_jobs_seen = []
+        job_list_changed = False
+        for idx, print_job_data in enumerate(result):
+            print_job = findByKey(self._print_jobs, print_job_data["uuid"])
+            if print_job is None:
+                print_job = self._createPrintJobModel(print_job_data)
+                job_list_changed = True
+            elif not job_list_changed:
+                # Check if the order of the jobs has changed since the last check
+                if self._print_jobs.index(print_job) != idx:
+                    job_list_changed = True
+
+            self._updatePrintJob(print_job, print_job_data)
+
+            if print_job.state != "queued" and print_job.state != "error":  # Print job should be assigned to a printer.
+                if print_job.state in ["failed", "finished", "aborted", "none"]:
+                    # Print job was already completed, so don't attach it to a printer.
+                    printer = None
+                else:
+                    printer = self._getPrinterByKey(print_job_data["printer_uuid"])
+            else:  # The job can "reserve" a printer if some changes are required.
+                printer = self._getPrinterByKey(print_job_data["assigned_to"])
+
+            if printer:
+                printer.updateActivePrintJob(print_job)
+
+            print_jobs_seen.append(print_job)
+
+        # Check what jobs need to be removed.
+        removed_jobs = [print_job for print_job in self._print_jobs if print_job not in print_jobs_seen]
+
+        for removed_job in removed_jobs:
+            job_list_changed = job_list_changed or self._removeJob(removed_job)
+
+        if job_list_changed:
+            # Override the old list with the new list (either because jobs were removed / added or order changed)
+            self._print_jobs = print_jobs_seen
+            self.printJobsChanged.emit()  # Do a single emit for all print job changes.
+
+    def _onGetPrintersDataFinished(self, reply: QNetworkReply) -> None:
+        if not checkValidGetReply(reply):
+            return
+
+        result = loadJsonFromReply(reply)
+        if result is None:
+            return
+
+        printer_list_changed = False
+        printers_seen = []
+
+        for printer_data in result:
+            printer = findByKey(self._printers, printer_data["uuid"])
+
+            if printer is None:
+                printer = self._createPrinterModel(printer_data)
+                printer_list_changed = True
+
+            printers_seen.append(printer)
+
+            self._updatePrinter(printer, printer_data)
+
+        removed_printers = [printer for printer in self._printers if printer not in printers_seen]
+        for printer in removed_printers:
+            self._removePrinter(printer)
+
+        if removed_printers or printer_list_changed:
+            self.printersChanged.emit()
+
+    def _createPrinterModel(self, data: Dict[str, Any]) -> PrinterOutputModel:
+        printer = PrinterOutputModel(output_controller = ClusterUM3PrinterOutputController(self),
+                                     number_of_extruders = self._number_of_extruders)
+        printer.setCamera(NetworkCamera("http://" + data["ip_address"] + ":8080/?action=stream"))
+        self._printers.append(printer)
+        return printer
+
+    def _createPrintJobModel(self, data: Dict[str, Any]) -> PrintJobOutputModel:
+        print_job = PrintJobOutputModel(output_controller=ClusterUM3PrinterOutputController(self),
+                                        key=data["uuid"], name= data["name"])
+
+        configuration = ConfigurationModel()
+        extruders = [ExtruderConfigurationModel(position = idx) for idx in range(0, self._number_of_extruders)]
+        for index in range(0, self._number_of_extruders):
+            try:
+                extruder_data = data["configuration"][index]
+            except IndexError:
+                continue
+            extruder = extruders[int(data["configuration"][index]["extruder_index"])]
+            extruder.setHotendID(extruder_data.get("print_core_id", ""))
+            extruder.setMaterial(self._createMaterialOutputModel(extruder_data.get("material", {})))
+
+        configuration.setExtruderConfigurations(extruders)
+        print_job.updateConfiguration(configuration)
+        print_job.setCompatibleMachineFamilies(data.get("compatible_machine_families", []))
+        print_job.stateChanged.connect(self._printJobStateChanged)
+        return print_job
+
+    def _updatePrintJob(self, print_job: PrintJobOutputModel, data: Dict[str, Any]) -> None:
+        print_job.updateTimeTotal(data["time_total"])
+        print_job.updateTimeElapsed(data["time_elapsed"])
+        impediments_to_printing = data.get("impediments_to_printing", [])
+        print_job.updateOwner(data["owner"])
+
+        status_set_by_impediment = False
+        for impediment in impediments_to_printing:
+            if impediment["severity"] == "UNFIXABLE":
+                status_set_by_impediment = True
+                print_job.updateState("error")
+                break
+
+        if not status_set_by_impediment:
+            print_job.updateState(data["status"])
+
+
+    def _createMaterialOutputModel(self, material_data) -> MaterialOutputModel:
+        containers = ContainerRegistry.getInstance().findInstanceContainers(type="material", GUID=material_data["guid"])
+        if containers:
+            color = containers[0].getMetaDataEntry("color_code")
+            brand = containers[0].getMetaDataEntry("brand")
+            material_type = containers[0].getMetaDataEntry("material")
+            name = containers[0].getName()
+        else:
+            Logger.log("w",
+                       "Unable to find material with guid {guid}. Using data as provided by cluster".format(
+                           guid=material_data["guid"]))
+            color = material_data["color"]
+            brand = material_data["brand"]
+            material_type = material_data["material"]
+            name = "Empty" if material_data["material"] == "empty" else "Unknown"
+        return MaterialOutputModel(guid=material_data["guid"], type=material_type,
+                                       brand=brand, color=color, name=name)
+
+    def _updatePrinter(self, printer: PrinterOutputModel, data: Dict[str, Any]) -> None:
+        # For some unknown reason the cluster wants UUID for everything, except for sending a job directly to a printer.
+        # Then we suddenly need the unique name. So in order to not have to mess up all the other code, we save a mapping.
+        self._printer_uuid_to_unique_name_mapping[data["uuid"]] = data["unique_name"]
+
+        definitions = ContainerRegistry.getInstance().findDefinitionContainers(name = data["machine_variant"])
+        if not definitions:
+            Logger.log("w", "Unable to find definition for machine variant %s", data["machine_variant"])
+            return
+
+        machine_definition = definitions[0]
+
+        printer.updateName(data["friendly_name"])
+        printer.updateKey(data["uuid"])
+        printer.updateType(data["machine_variant"])
+
+        # Do not store the build plate information that comes from connect if the current printer has not build plate information
+        if "build_plate" in data and machine_definition.getMetaDataEntry("has_variant_buildplates", False):
+            printer.updateBuildplateName(data["build_plate"]["type"])
+        if not data["enabled"]:
+            printer.updateState("disabled")
+        else:
+            printer.updateState(data["status"])
+
+        for index in range(0, self._number_of_extruders):
+            extruder = printer.extruders[index]
+            try:
+                extruder_data = data["configuration"][index]
+            except IndexError:
+                break
+
+            extruder.updateHotendID(extruder_data.get("print_core_id", ""))
+
+            material_data = extruder_data["material"]
+            if extruder.activeMaterial is None or extruder.activeMaterial.guid != material_data["guid"]:
+                material = self._createMaterialOutputModel(material_data)
+                extruder.updateActiveMaterial(material)
+
+    def _removeJob(self, job: PrintJobOutputModel) -> bool:
+        if job not in self._print_jobs:
+            return False
+
+        if job.assignedPrinter:
+            job.assignedPrinter.updateActivePrintJob(None)
+            job.stateChanged.disconnect(self._printJobStateChanged)
+        self._print_jobs.remove(job)
+
+        return True
+
+    def _removePrinter(self, printer: PrinterOutputModel) -> None:
+        self._printers.remove(printer)
+        if self._active_printer == printer:
+            self._active_printer = None
+            self.activePrinterChanged.emit()
+
+    ##  Sync the material profiles in Cura with the printer.
+    #
+    #   This gets called when connecting to a printer as well as when sending a
+    #   print.
+    def sendMaterialProfiles(self) -> None:
+        job = SendMaterialJob(device = self)
+        job.run()
+
+
+def loadJsonFromReply(reply: QNetworkReply) -> Optional[List[Dict[str, Any]]]:
+    try:
+        result = json.loads(bytes(reply.readAll()).decode("utf-8"))
+    except json.decoder.JSONDecodeError:
+        Logger.logException("w", "Unable to decode JSON from reply.")
+        return None
+    return result
+
+
+def checkValidGetReply(reply: QNetworkReply) -> bool:
+    status_code = reply.attribute(QNetworkRequest.HttpStatusCodeAttribute)
+
+    if status_code != 200:
+        Logger.log("w", "Got status code {status_code} while trying to get data".format(status_code=status_code))
+        return False
+    return True
+
+
+def findByKey(lst: List[Union[PrintJobOutputModel, PrinterOutputModel]], key: str) -> Optional[PrintJobOutputModel]:
+    for item in lst:
+        if item.key == key:
+            return item
+    return None

plugins/UM3NetworkPrinting/src/ClusterUM3PrinterOutputController.py

@@ -0,0 +1,21 @@
+# Copyright (c) 2017 Ultimaker B.V.
+# Cura is released under the terms of the LGPLv3 or higher.
+
+from cura.PrinterOutput.PrinterOutputController import PrinterOutputController
+
+MYPY = False
+if MYPY:
+    from cura.PrinterOutput.PrintJobOutputModel import PrintJobOutputModel
+
+class ClusterUM3PrinterOutputController(PrinterOutputController):
+    def __init__(self, output_device):
+        super().__init__(output_device)
+        self.can_pre_heat_bed = False
+        self.can_pre_heat_hotends = False
+        self.can_control_manually = False
+        self.can_send_raw_gcode = False
+
+    def setJobState(self, job: "PrintJobOutputModel", state: str):
+        data = "{\"action\": \"%s\"}" % state
+        self._output_device.put("print_jobs/%s/action" % job.key, data, on_finished=None)
+

plugins/UM3NetworkPrinting/src/DiscoverUM3Action.py

@@ -0,0 +1,185 @@
+# Copyright (c) 2018 Ultimaker B.V.
+# Cura is released under the terms of the LGPLv3 or higher.
+
+import os.path
+import time
+from typing import cast, Optional
+
+from PyQt5.QtCore import pyqtSignal, pyqtProperty, pyqtSlot, QObject
+
+from UM.PluginRegistry import PluginRegistry
+from UM.Logger import Logger
+from UM.i18n import i18nCatalog
+
+from cura.CuraApplication import CuraApplication
+from cura.MachineAction import MachineAction
+
+from .UM3OutputDevicePlugin import UM3OutputDevicePlugin
+
+catalog = i18nCatalog("cura")
+
+
+class DiscoverUM3Action(MachineAction):
+    discoveredDevicesChanged = pyqtSignal()
+
+    def __init__(self) -> None:
+        super().__init__("DiscoverUM3Action", catalog.i18nc("@action","Connect via Network"))
+        self._qml_url = "../resources/qml/DiscoverUM3Action.qml"
+
+        self._network_plugin = None #type: Optional[UM3OutputDevicePlugin]
+
+        self.__additional_components_view = None #type: Optional[QObject]
+
+        CuraApplication.getInstance().engineCreatedSignal.connect(self._createAdditionalComponentsView)
+
+        self._last_zero_conf_event_time = time.time() #type: float
+
+        # Time to wait after a zero-conf service change before allowing a zeroconf reset
+        self._zero_conf_change_grace_period = 0.25 #type: float
+
+    @pyqtSlot()
+    def startDiscovery(self):
+        if not self._network_plugin:
+            Logger.log("d", "Starting device discovery.")
+            self._network_plugin = CuraApplication.getInstance().getOutputDeviceManager().getOutputDevicePlugin("UM3NetworkPrinting")
+            self._network_plugin.discoveredDevicesChanged.connect(self._onDeviceDiscoveryChanged)
+            self.discoveredDevicesChanged.emit()
+
+    ##  Re-filters the list of devices.
+    @pyqtSlot()
+    def reset(self):
+        Logger.log("d", "Reset the list of found devices.")
+        if self._network_plugin:
+            self._network_plugin.resetLastManualDevice()
+        self.discoveredDevicesChanged.emit()
+
+    @pyqtSlot()
+    def restartDiscovery(self):
+        # Ensure that there is a bit of time after a printer has been discovered.
+        # This is a work around for an issue with Qt 5.5.1 up to Qt 5.7 which can segfault if we do this too often.
+        # It's most likely that the QML engine is still creating delegates, where the python side already deleted or
+        # garbage collected the data.
+        # Whatever the case, waiting a bit ensures that it doesn't crash.
+        if time.time() - self._last_zero_conf_event_time > self._zero_conf_change_grace_period:
+            if not self._network_plugin:
+                self.startDiscovery()
+            else:
+                self._network_plugin.startDiscovery()
+
+    @pyqtSlot(str, str)
+    def removeManualDevice(self, key, address):
+        if not self._network_plugin:
+            return
+
+        self._network_plugin.removeManualDevice(key, address)
+
+    @pyqtSlot(str, str)
+    def setManualDevice(self, key, address):
+        if key != "":
+            # This manual printer replaces a current manual printer
+            self._network_plugin.removeManualDevice(key)
+
+        if address != "":
+            self._network_plugin.addManualDevice(address)
+
+    def _onDeviceDiscoveryChanged(self, *args):
+        self._last_zero_conf_event_time = time.time()
+        self.discoveredDevicesChanged.emit()
+
+    @pyqtProperty("QVariantList", notify = discoveredDevicesChanged)
+    def foundDevices(self):
+        if self._network_plugin:
+
+            printers = list(self._network_plugin.getDiscoveredDevices().values())
+            printers.sort(key = lambda k: k.name)
+            return printers
+        else:
+            return []
+
+    @pyqtSlot(str)
+    def setGroupName(self, group_name: str) -> None:
+        Logger.log("d", "Attempting to set the group name of the active machine to %s", group_name)
+        global_container_stack = CuraApplication.getInstance().getGlobalContainerStack()
+        if global_container_stack:
+            meta_data = global_container_stack.getMetaData()
+            if "connect_group_name" in meta_data:
+                previous_connect_group_name = meta_data["connect_group_name"]
+                global_container_stack.setMetaDataEntry("connect_group_name", group_name)
+                # Find all the places where there is the same group name and change it accordingly
+                CuraApplication.getInstance().getMachineManager().replaceContainersMetadata(key = "connect_group_name", value = previous_connect_group_name, new_value = group_name)
+            else:
+                global_container_stack.setMetaDataEntry("connect_group_name", group_name)
+            # Set the default value for "hidden", which is used when you have a group with multiple types of printers
+            global_container_stack.setMetaDataEntry("hidden", False)
+
+        if self._network_plugin:
+            # Ensure that the connection states are refreshed.
+            self._network_plugin.reCheckConnections()
+
+    @pyqtSlot(str)
+    def setKey(self, key: str) -> None:
+        Logger.log("d", "Attempting to set the network key of the active machine to %s", key)
+        global_container_stack = CuraApplication.getInstance().getGlobalContainerStack()
+        if global_container_stack:
+            meta_data = global_container_stack.getMetaData()
+            if "um_network_key" in meta_data:
+                previous_network_key= meta_data["um_network_key"]
+                global_container_stack.setMetaDataEntry("um_network_key", key)
+                # Delete old authentication data.
+                Logger.log("d", "Removing old authentication id %s for device %s", global_container_stack.getMetaDataEntry("network_authentication_id", None), key)
+                global_container_stack.removeMetaDataEntry("network_authentication_id")
+                global_container_stack.removeMetaDataEntry("network_authentication_key")
+                CuraApplication.getInstance().getMachineManager().replaceContainersMetadata(key = "um_network_key", value = previous_network_key, new_value = key)
+            else:
+                global_container_stack.setMetaDataEntry("um_network_key", key)
+
+        if self._network_plugin:
+            # Ensure that the connection states are refreshed.
+            self._network_plugin.reCheckConnections()
+
+    @pyqtSlot(result = str)
+    def getStoredKey(self) -> str:
+        global_container_stack = CuraApplication.getInstance().getGlobalContainerStack()
+        if global_container_stack:
+            meta_data = global_container_stack.getMetaData()
+            if "um_network_key" in meta_data:
+                return global_container_stack.getMetaDataEntry("um_network_key")
+
+        return ""
+
+    @pyqtSlot(result = str)
+    def getLastManualEntryKey(self) -> str:
+        if self._network_plugin:
+            return self._network_plugin.getLastManualDevice()
+        return ""
+
+    @pyqtSlot(str, result = bool)
+    def existsKey(self, key: str) -> bool:
+        return CuraApplication.getInstance().getMachineManager().existNetworkInstances(network_key = key)
+
+    @pyqtSlot()
+    def loadConfigurationFromPrinter(self) -> None:
+        machine_manager = CuraApplication.getInstance().getMachineManager()
+        hotend_ids = machine_manager.printerOutputDevices[0].hotendIds
+        for index in range(len(hotend_ids)):
+            machine_manager.printerOutputDevices[0].hotendIdChanged.emit(index, hotend_ids[index])
+        material_ids = machine_manager.printerOutputDevices[0].materialIds
+        for index in range(len(material_ids)):
+            machine_manager.printerOutputDevices[0].materialIdChanged.emit(index, material_ids[index])
+
+    def _createAdditionalComponentsView(self) -> None:
+        Logger.log("d", "Creating additional ui components for UM3.")
+
+        # Create networking dialog
+        plugin_path = PluginRegistry.getInstance().getPluginPath("UM3NetworkPrinting")
+        if not plugin_path:
+            return
+        path = os.path.join(plugin_path, "resources/qml/UM3InfoComponents.qml")
+        self.__additional_components_view = CuraApplication.getInstance().createQmlComponent(path, {"manager": self})
+        if not self.__additional_components_view:
+            Logger.log("w", "Could not create ui components for UM3.")
+            return
+
+        # Create extra components
+        CuraApplication.getInstance().addAdditionalComponent("monitorButtons", self.__additional_components_view.findChild(QObject, "networkPrinterConnectButton"))
+        CuraApplication.getInstance().addAdditionalComponent("machinesDetailPane", self.__additional_components_view.findChild(QObject, "networkPrinterConnectionInfo"))

plugins/UM3NetworkPrinting/src/LegacyUM3OutputDevice.py

@@ -0,0 +1,640 @@
+from typing import List, Optional
+
+from UM.FileHandler.FileHandler import FileHandler
+from UM.Scene.SceneNode import SceneNode
+from cura.CuraApplication import CuraApplication
+from cura.PrinterOutput.NetworkedPrinterOutputDevice import NetworkedPrinterOutputDevice, AuthState
+from cura.PrinterOutput.PrinterOutputModel import PrinterOutputModel
+from cura.PrinterOutput.PrintJobOutputModel import PrintJobOutputModel
+from cura.PrinterOutput.MaterialOutputModel import MaterialOutputModel
+from cura.PrinterOutput.NetworkCamera import NetworkCamera
+
+from cura.Settings.ContainerManager import ContainerManager
+from cura.Settings.ExtruderManager import ExtruderManager
+
+from UM.Logger import Logger
+from UM.Settings.ContainerRegistry import ContainerRegistry
+from UM.i18n import i18nCatalog
+from UM.Message import Message
+
+from PyQt5.QtNetwork import QNetworkRequest
+from PyQt5.QtCore import QTimer
+from PyQt5.QtWidgets import QMessageBox
+
+from .LegacyUM3PrinterOutputController import LegacyUM3PrinterOutputController
+
+from time import time
+
+import json
+import os
+
+
+i18n_catalog = i18nCatalog("cura")
+
+
+##  This is the output device for the "Legacy" API of the UM3. All firmware before 4.0.1 uses this API.
+#   Everything after that firmware uses the ClusterUM3Output.
+#   The Legacy output device can only have one printer (whereas the cluster can have 0 to n).
+#
+#   Authentication is done in a number of steps;
+#   1. Request an id / key pair by sending the application & user name. (state = authRequested)
+#   2. Machine sends this back and will display an approve / deny message on screen. (state = AuthReceived)
+#   3. OutputDevice will poll if the button was pressed.
+#   4. At this point the machine either has the state Authenticated or AuthenticationDenied.
+#   5. As a final step, we verify the authentication, as this forces the QT manager to setup the authenticator.
+class LegacyUM3OutputDevice(NetworkedPrinterOutputDevice):
+    def __init__(self, device_id, address: str, properties, parent = None) -> None:
+        super().__init__(device_id = device_id, address = address, properties = properties, parent = parent)
+        self._api_prefix = "/api/v1/"
+        self._number_of_extruders = 2
+
+        self._authentication_id = None
+        self._authentication_key = None
+
+        self._authentication_counter = 0
+        self._max_authentication_counter = 5 * 60  # Number of attempts before authentication timed out (5 min)
+
+        self._authentication_timer = QTimer()
+        self._authentication_timer.setInterval(1000)  # TODO; Add preference for update interval
+        self._authentication_timer.setSingleShot(False)
+
+        self._authentication_timer.timeout.connect(self._onAuthenticationTimer)
+
+        # The messages are created when connect is called the first time.
+        # This ensures that the messages are only created for devices that actually want to connect.
+        self._authentication_requested_message = None
+        self._authentication_failed_message = None
+        self._authentication_succeeded_message = None
+        self._not_authenticated_message = None
+
+        self.authenticationStateChanged.connect(self._onAuthenticationStateChanged)
+
+        self.setPriority(3)  # Make sure the output device gets selected above local file output
+        self.setName(self._id)
+        self.setShortDescription(i18n_catalog.i18nc("@action:button Preceded by 'Ready to'.", "Print over network"))
+        self.setDescription(i18n_catalog.i18nc("@properties:tooltip", "Print over network"))
+
+        self.setIconName("print")
+
+        self._monitor_view_qml_path = os.path.join(os.path.dirname(os.path.abspath(__file__)), "../resources/qml/MonitorItem.qml")
+
+        self._output_controller = LegacyUM3PrinterOutputController(self)
+
+    def _onAuthenticationStateChanged(self):
+        # We only accept commands if we are authenticated.
+        self._setAcceptsCommands(self._authentication_state == AuthState.Authenticated)
+
+        if self._authentication_state == AuthState.Authenticated:
+            self.setConnectionText(i18n_catalog.i18nc("@info:status", "Connected over the network."))
+        elif self._authentication_state == AuthState.AuthenticationRequested:
+            self.setConnectionText(i18n_catalog.i18nc("@info:status",
+                                                      "Connected over the network. Please approve the access request on the printer."))
+        elif self._authentication_state == AuthState.AuthenticationDenied:
+            self.setConnectionText(i18n_catalog.i18nc("@info:status", "Connected over the network. No access to control the printer."))
+
+
+    def _setupMessages(self):
+        self._authentication_requested_message = Message(i18n_catalog.i18nc("@info:status",
+                                                                            "Access to the printer requested. Please approve the request on the printer"),
+                                                         lifetime=0, dismissable=False, progress=0,
+                                                         title=i18n_catalog.i18nc("@info:title",
+                                                                                  "Authentication status"))
+
+        self._authentication_failed_message = Message(i18n_catalog.i18nc("@info:status", ""),
+                                                      title=i18n_catalog.i18nc("@info:title", "Authentication Status"))
+        self._authentication_failed_message.addAction("Retry", i18n_catalog.i18nc("@action:button", "Retry"), None,
+                                                      i18n_catalog.i18nc("@info:tooltip", "Re-send the access request"))
+        self._authentication_failed_message.actionTriggered.connect(self._messageCallback)
+        self._authentication_succeeded_message = Message(
+            i18n_catalog.i18nc("@info:status", "Access to the printer accepted"),
+            title=i18n_catalog.i18nc("@info:title", "Authentication Status"))
+
+        self._not_authenticated_message = Message(
+            i18n_catalog.i18nc("@info:status", "No access to print with this printer. Unable to send print job."),
+            title=i18n_catalog.i18nc("@info:title", "Authentication Status"))
+        self._not_authenticated_message.addAction("Request", i18n_catalog.i18nc("@action:button", "Request Access"),
+                                                  None, i18n_catalog.i18nc("@info:tooltip",
+                                                                           "Send access request to the printer"))
+        self._not_authenticated_message.actionTriggered.connect(self._messageCallback)
+
+    def _messageCallback(self, message_id=None, action_id="Retry"):
+        if action_id == "Request" or action_id == "Retry":
+            if self._authentication_failed_message:
+                self._authentication_failed_message.hide()
+            if self._not_authenticated_message:
+                self._not_authenticated_message.hide()
+
+            self._requestAuthentication()
+
+    def connect(self):
+        super().connect()
+        self._setupMessages()
+        global_container = CuraApplication.getInstance().getGlobalContainerStack()
+        if global_container:
+            self._authentication_id = global_container.getMetaDataEntry("network_authentication_id", None)
+            self._authentication_key = global_container.getMetaDataEntry("network_authentication_key", None)
+
+    def close(self):
+        super().close()
+        if self._authentication_requested_message:
+            self._authentication_requested_message.hide()
+        if self._authentication_failed_message:
+            self._authentication_failed_message.hide()
+        if self._authentication_succeeded_message:
+            self._authentication_succeeded_message.hide()
+        self._sending_gcode = False
+        self._compressing_gcode = False
+        self._authentication_timer.stop()
+
+    ##  Send all material profiles to the printer.
+    def _sendMaterialProfiles(self):
+        Logger.log("i", "Sending material profiles to printer")
+
+        # TODO: Might want to move this to a job...
+        for container in ContainerRegistry.getInstance().findInstanceContainers(type="material"):
+            try:
+                xml_data = container.serialize()
+                if xml_data == "" or xml_data is None:
+                    continue
+
+                names = ContainerManager.getInstance().getLinkedMaterials(container.getId())
+                if names:
+                    # There are other materials that share this GUID.
+                    if not container.isReadOnly():
+                        continue  # If it's not readonly, it's created by user, so skip it.
+
+                file_name = "none.xml"
+
+                self.postForm("materials", "form-data; name=\"file\";filename=\"%s\"" % file_name, xml_data.encode(), on_finished=None)
+
+            except NotImplementedError:
+                # If the material container is not the most "generic" one it can't be serialized an will raise a
+                # NotImplementedError. We can simply ignore these.
+                pass
+
+    def requestWrite(self, nodes: List[SceneNode], file_name: Optional[str] = None, limit_mimetypes: bool = False, file_handler: Optional[FileHandler] = None, **kwargs: str) -> None:
+        if not self.activePrinter:
+            # No active printer. Unable to write
+            return
+
+        if self.activePrinter.state not in ["idle", ""]:
+            # Printer is not able to accept commands.
+            return
+
+        if self._authentication_state != AuthState.Authenticated:
+            # Not authenticated, so unable to send job.
+            return
+
+        self.writeStarted.emit(self)
+
+        gcode_dict = getattr(CuraApplication.getInstance().getController().getScene(), "gcode_dict", [])
+        active_build_plate_id = CuraApplication.getInstance().getMultiBuildPlateModel().activeBuildPlate
+        gcode_list = gcode_dict[active_build_plate_id]
+
+        if not gcode_list:
+            # Unable to find g-code. Nothing to send
+            return
+
+        self._gcode = gcode_list
+
+        errors = self._checkForErrors()
+        if errors:
+            text = i18n_catalog.i18nc("@label", "Unable to start a new print job.")
+            informative_text = i18n_catalog.i18nc("@label",
+                                                  "There is an issue with the configuration of your Ultimaker, which makes it impossible to start the print. "
+                                                  "Please resolve this issues before continuing.")
+            detailed_text = ""
+            for error in errors:
+                detailed_text += error + "\n"
+
+            CuraApplication.getInstance().messageBox(i18n_catalog.i18nc("@window:title", "Mismatched configuration"),
+                                                 text,
+                                                 informative_text,
+                                                 detailed_text,
+                                                 buttons=QMessageBox.Ok,
+                                                 icon=QMessageBox.Critical,
+                                                callback = self._messageBoxCallback
+                                                 )
+            return  # Don't continue; Errors must block sending the job to the printer.
+
+        # There might be multiple things wrong with the configuration. Check these before starting.
+        warnings = self._checkForWarnings()
+
+        if warnings:
+            text = i18n_catalog.i18nc("@label", "Are you sure you wish to print with the selected configuration?")
+            informative_text = i18n_catalog.i18nc("@label",
+                                                  "There is a mismatch between the configuration or calibration of the printer and Cura. "
+                                                  "For the best result, always slice for the PrintCores and materials that are inserted in your printer.")
+            detailed_text = ""
+            for warning in warnings:
+                detailed_text += warning + "\n"
+
+            CuraApplication.getInstance().messageBox(i18n_catalog.i18nc("@window:title", "Mismatched configuration"),
+                                                 text,
+                                                 informative_text,
+                                                 detailed_text,
+                                                 buttons=QMessageBox.Yes + QMessageBox.No,
+                                                 icon=QMessageBox.Question,
+                                                 callback=self._messageBoxCallback
+                                                 )
+            return
+
+        # No warnings or errors, so we're good to go.
+        self._startPrint()
+
+        # Notify the UI that a switch to the print monitor should happen
+        CuraApplication.getInstance().getController().setActiveStage("MonitorStage")
+
+    def _startPrint(self):
+        Logger.log("i", "Sending print job to printer.")
+        if self._sending_gcode:
+            self._error_message = Message(
+                i18n_catalog.i18nc("@info:status",
+                                   "Sending new jobs (temporarily) blocked, still sending the previous print job."))
+            self._error_message.show()
+            return
+
+        self._sending_gcode = True
+
+        self._send_gcode_start = time()
+        self._progress_message = Message(i18n_catalog.i18nc("@info:status", "Sending data to printer"), 0, False, -1,
+                                         i18n_catalog.i18nc("@info:title", "Sending Data"))
+        self._progress_message.addAction("Abort", i18n_catalog.i18nc("@action:button", "Cancel"), None, "")
+        self._progress_message.actionTriggered.connect(self._progressMessageActionTriggered)
+        self._progress_message.show()
+        
+        compressed_gcode = self._compressGCode()
+        if compressed_gcode is None:
+            # Abort was called.
+            return
+
+        file_name = "%s.gcode.gz" % CuraApplication.getInstance().getPrintInformation().jobName
+        self.postForm("print_job", "form-data; name=\"file\";filename=\"%s\"" % file_name, compressed_gcode,
+                      on_finished=self._onPostPrintJobFinished)
+
+        return
+
+    def _progressMessageActionTriggered(self, message_id=None, action_id=None):
+        if action_id == "Abort":
+            Logger.log("d", "User aborted sending print to remote.")
+            self._progress_message.hide()
+            self._compressing_gcode = False
+            self._sending_gcode = False
+            CuraApplication.getInstance().getController().setActiveStage("PrepareStage")
+
+    def _onPostPrintJobFinished(self, reply):
+        self._progress_message.hide()
+        self._sending_gcode = False
+
+    def _onUploadPrintJobProgress(self, bytes_sent, bytes_total):
+        if bytes_total > 0:
+            new_progress = bytes_sent / bytes_total * 100
+            # Treat upload progress as response. Uploading can take more than 10 seconds, so if we don't, we can get
+            # timeout responses if this happens.
+            self._last_response_time = time()
+            if new_progress > self._progress_message.getProgress():
+                self._progress_message.show()  # Ensure that the message is visible.
+                self._progress_message.setProgress(bytes_sent / bytes_total * 100)
+        else:
+            self._progress_message.setProgress(0)
+
+            self._progress_message.hide()
+
+    def _messageBoxCallback(self, button):
+        def delayedCallback():
+            if button == QMessageBox.Yes:
+                self._startPrint()
+            else:
+                CuraApplication.getInstance().getController().setActiveStage("PrepareStage")
+                # For some unknown reason Cura on OSX will hang if we do the call back code
+                # immediately without first returning and leaving QML's event system.
+
+        QTimer.singleShot(100, delayedCallback)
+
+    def _checkForErrors(self):
+        errors = []
+        print_information = CuraApplication.getInstance().getPrintInformation()
+        if not print_information.materialLengths:
+            Logger.log("w", "There is no material length information. Unable to check for errors.")
+            return errors
+
+        for index, extruder in enumerate(self.activePrinter.extruders):
+            # Due to airflow issues, both slots must be loaded, regardless if they are actually used or not.
+            if extruder.hotendID == "":
+                # No Printcore loaded.
+                errors.append(i18n_catalog.i18nc("@info:status", "No Printcore loaded in slot {slot_number}".format(slot_number=index + 1)))
+
+            if index < len(print_information.materialLengths) and print_information.materialLengths[index] != 0:
+                # The extruder is by this print.
+                if extruder.activeMaterial is None:
+                    # No active material
+                    errors.append(i18n_catalog.i18nc("@info:status", "No material loaded in slot {slot_number}".format(slot_number=index + 1)))
+        return errors
+
+    def _checkForWarnings(self):
+        warnings = []
+        print_information = CuraApplication.getInstance().getPrintInformation()
+
+        if not print_information.materialLengths:
+            Logger.log("w", "There is no material length information. Unable to check for warnings.")
+            return warnings
+
+        extruder_manager = ExtruderManager.getInstance()
+
+        for index, extruder in enumerate(self.activePrinter.extruders):
+            if index < len(print_information.materialLengths) and print_information.materialLengths[index] != 0:
+                # The extruder is by this print.
+
+                # TODO: material length check
+
+                # Check if the right Printcore is active.
+                variant = extruder_manager.getExtruderStack(index).findContainer({"type": "variant"})
+                if variant:
+                    if variant.getName() != extruder.hotendID:
+                        warnings.append(i18n_catalog.i18nc("@label", "Different PrintCore (Cura: {cura_printcore_name}, Printer: {remote_printcore_name}) selected for extruder {extruder_id}".format(cura_printcore_name = variant.getName(), remote_printcore_name = extruder.hotendID, extruder_id = index + 1)))
+                else:
+                    Logger.log("w", "Unable to find variant.")
+
+                # Check if the right material is loaded.
+                local_material = extruder_manager.getExtruderStack(index).findContainer({"type": "material"})
+                if local_material:
+                    if extruder.activeMaterial.guid != local_material.getMetaDataEntry("GUID"):
+                        Logger.log("w", "Extruder %s has a different material (%s) as Cura (%s)", index + 1, extruder.activeMaterial.guid, local_material.getMetaDataEntry("GUID"))
+                        warnings.append(i18n_catalog.i18nc("@label", "Different material (Cura: {0}, Printer: {1}) selected for extruder {2}").format(local_material.getName(), extruder.activeMaterial.name, index + 1))
+                else:
+                    Logger.log("w", "Unable to find material.")
+
+        return warnings
+
+    def _update(self):
+        if not super()._update():
+            return
+        if self._authentication_state == AuthState.NotAuthenticated:
+            if self._authentication_id is None and self._authentication_key is None:
+                # This machine doesn't have any authentication, so request it.
+                self._requestAuthentication()
+            elif self._authentication_id is not None and self._authentication_key is not None:
+                # We have authentication info, but we haven't checked it out yet. Do so now.
+                self._verifyAuthentication()
+        elif self._authentication_state == AuthState.AuthenticationReceived:
+            # We have an authentication, but it's not confirmed yet.
+            self._checkAuthentication()
+
+        # We don't need authentication for requesting info, so we can go right ahead with requesting this.
+        self.get("printer", on_finished=self._onGetPrinterDataFinished)
+        self.get("print_job", on_finished=self._onGetPrintJobFinished)
+
+    def _resetAuthenticationRequestedMessage(self):
+        if self._authentication_requested_message:
+            self._authentication_requested_message.hide()
+        self._authentication_timer.stop()
+        self._authentication_counter = 0
+
+    def _onAuthenticationTimer(self):
+        self._authentication_counter += 1
+        self._authentication_requested_message.setProgress(
+            self._authentication_counter / self._max_authentication_counter * 100)
+        if self._authentication_counter > self._max_authentication_counter:
+            self._authentication_timer.stop()
+            Logger.log("i", "Authentication timer ended. Setting authentication to denied for printer: %s" % self._id)
+            self.setAuthenticationState(AuthState.AuthenticationDenied)
+            self._resetAuthenticationRequestedMessage()
+            self._authentication_failed_message.show()
+
+    def _verifyAuthentication(self):
+        Logger.log("d", "Attempting to verify authentication")
+        # This will ensure that the "_onAuthenticationRequired" is triggered, which will setup the authenticator.
+        self.get("auth/verify", on_finished=self._onVerifyAuthenticationCompleted)
+
+    def _onVerifyAuthenticationCompleted(self, reply):
+        status_code = reply.attribute(QNetworkRequest.HttpStatusCodeAttribute)
+        if status_code == 401:
+            # Something went wrong; We somehow tried to verify authentication without having one.
+            Logger.log("d", "Attempted to verify auth without having one.")
+            self._authentication_id = None
+            self._authentication_key = None
+            self.setAuthenticationState(AuthState.NotAuthenticated)
+        elif status_code == 403 and self._authentication_state != AuthState.Authenticated:
+            # If we were already authenticated, we probably got an older message back all of the sudden. Drop that.
+            Logger.log("d",
+                       "While trying to verify the authentication state, we got a forbidden response. Our own auth state was %s. ",
+                       self._authentication_state)
+            self.setAuthenticationState(AuthState.AuthenticationDenied)
+            self._authentication_failed_message.show()
+        elif status_code == 200:
+            self.setAuthenticationState(AuthState.Authenticated)
+
+    def _checkAuthentication(self):
+        Logger.log("d", "Checking if authentication is correct for id %s and key %s", self._authentication_id, self._getSafeAuthKey())
+        self.get("auth/check/" + str(self._authentication_id), on_finished=self._onCheckAuthenticationFinished)
+
+    def _onCheckAuthenticationFinished(self, reply):
+        if str(self._authentication_id) not in reply.url().toString():
+            Logger.log("w", "Got an old id response.")
+            # Got response for old authentication ID.
+            return
+        try:
+            data = json.loads(bytes(reply.readAll()).decode("utf-8"))
+        except json.decoder.JSONDecodeError:
+            Logger.log("w", "Received an invalid authentication check from printer: Not valid JSON.")
+            return
+
+        if data.get("message", "") == "authorized":
+            Logger.log("i", "Authentication was approved")
+            self.setAuthenticationState(AuthState.Authenticated)
+            self._saveAuthentication()
+
+            # Double check that everything went well.
+            self._verifyAuthentication()
+
+            # Notify the user.
+            self._resetAuthenticationRequestedMessage()
+            self._authentication_succeeded_message.show()
+        elif data.get("message", "") == "unauthorized":
+            Logger.log("i", "Authentication was denied.")
+            self.setAuthenticationState(AuthState.AuthenticationDenied)
+            self._authentication_failed_message.show()
+
+    def _saveAuthentication(self) -> None:
+        global_container_stack = CuraApplication.getInstance().getGlobalContainerStack()
+        if self._authentication_key is None:
+            Logger.log("e", "Authentication key is None, nothing to save.")
+            return
+        if self._authentication_id is None:
+            Logger.log("e", "Authentication id is None, nothing to save.")
+            return
+        if global_container_stack:
+            global_container_stack.setMetaDataEntry("network_authentication_key", self._authentication_key)
+
+            global_container_stack.setMetaDataEntry("network_authentication_id", self._authentication_id)
+
+            # Force save so we are sure the data is not lost.
+            CuraApplication.getInstance().saveStack(global_container_stack)
+            Logger.log("i", "Authentication succeeded for id %s and key %s", self._authentication_id,
+                       self._getSafeAuthKey())
+        else:
+            Logger.log("e", "Unable to save authentication for id %s and key %s", self._authentication_id,
+                       self._getSafeAuthKey())
+
+    def _onRequestAuthenticationFinished(self, reply):
+        try:
+            data = json.loads(bytes(reply.readAll()).decode("utf-8"))
+        except json.decoder.JSONDecodeError:
+            Logger.log("w", "Received an invalid authentication request reply from printer: Not valid JSON.")
+            self.setAuthenticationState(AuthState.NotAuthenticated)
+            return
+
+        self.setAuthenticationState(AuthState.AuthenticationReceived)
+        self._authentication_id = data["id"]
+        self._authentication_key = data["key"]
+        Logger.log("i", "Got a new authentication ID (%s) and KEY (%s). Waiting for authorization.",
+                   self._authentication_id, self._getSafeAuthKey())
+
+    def _requestAuthentication(self):
+        self._authentication_requested_message.show()
+        self._authentication_timer.start()
+
+        # Reset any previous authentication info. If this isn't done, the "Retry" action on the failed message might
+        # give issues.
+        self._authentication_key = None
+        self._authentication_id = None
+
+        self.post("auth/request",
+                  json.dumps({"application":  "Cura-" + CuraApplication.getInstance().getVersion(),
+                                               "user": self._getUserName()}).encode(),
+                  on_finished=self._onRequestAuthenticationFinished)
+
+        self.setAuthenticationState(AuthState.AuthenticationRequested)
+
+    def _onAuthenticationRequired(self, reply, authenticator):
+        if self._authentication_id is not None and self._authentication_key is not None:
+            Logger.log("d",
+                       "Authentication was required for printer: %s. Setting up authenticator with ID %s and key %s",
+                       self._id, self._authentication_id, self._getSafeAuthKey())
+            authenticator.setUser(self._authentication_id)
+            authenticator.setPassword(self._authentication_key)
+        else:
+            Logger.log("d", "No authentication is available to use for %s, but we did got a request for it.", self._id)
+
+    def _onGetPrintJobFinished(self, reply):
+        status_code = reply.attribute(QNetworkRequest.HttpStatusCodeAttribute)
+
+        if not self._printers:
+            return  # Ignore the data for now, we don't have info about a printer yet.
+        printer = self._printers[0]
+
+        if status_code == 200:
+            try:
+                result = json.loads(bytes(reply.readAll()).decode("utf-8"))
+            except json.decoder.JSONDecodeError:
+                Logger.log("w", "Received an invalid print job state message: Not valid JSON.")
+                return
+            if printer.activePrintJob is None:
+                print_job = PrintJobOutputModel(output_controller=self._output_controller)
+                printer.updateActivePrintJob(print_job)
+            else:
+                print_job = printer.activePrintJob
+            print_job.updateState(result["state"])
+            print_job.updateTimeElapsed(result["time_elapsed"])
+            print_job.updateTimeTotal(result["time_total"])
+            print_job.updateName(result["name"])
+        elif status_code == 404:
+            # No job found, so delete the active print job (if any!)
+            printer.updateActivePrintJob(None)
+        else:
+            Logger.log("w",
+                       "Got status code {status_code} while trying to get printer data".format(status_code=status_code))
+
+    def materialHotendChangedMessage(self, callback):
+        CuraApplication.getInstance().messageBox(i18n_catalog.i18nc("@window:title", "Sync with your printer"),
+                                             i18n_catalog.i18nc("@label",
+                                                                "Would you like to use your current printer configuration in Cura?"),
+                                             i18n_catalog.i18nc("@label",
+                                                                "The PrintCores and/or materials on your printer differ from those within your current project. For the best result, always slice for the PrintCores and materials that are inserted in your printer."),
+                                             buttons=QMessageBox.Yes + QMessageBox.No,
+                                             icon=QMessageBox.Question,
+                                             callback=callback
+                                             )
+
+    def _onGetPrinterDataFinished(self, reply):
+        status_code = reply.attribute(QNetworkRequest.HttpStatusCodeAttribute)
+        if status_code == 200:
+            try:
+                result = json.loads(bytes(reply.readAll()).decode("utf-8"))
+            except json.decoder.JSONDecodeError:
+                Logger.log("w", "Received an invalid printer state message: Not valid JSON.")
+                return
+
+            if not self._printers:
+                # Quickest way to get the firmware version is to grab it from the zeroconf.
+                firmware_version = self._properties.get(b"firmware_version", b"").decode("utf-8")
+                self._printers = [PrinterOutputModel(output_controller=self._output_controller, number_of_extruders=self._number_of_extruders, firmware_version=firmware_version)]
+                self._printers[0].setCamera(NetworkCamera("http://" + self._address + ":8080/?action=stream"))
+                for extruder in self._printers[0].extruders:
+                    extruder.activeMaterialChanged.connect(self.materialIdChanged)
+                    extruder.hotendIDChanged.connect(self.hotendIdChanged)
+                self.printersChanged.emit()
+
+            # LegacyUM3 always has a single printer.
+            printer = self._printers[0]
+            printer.updateBedTemperature(result["bed"]["temperature"]["current"])
+            printer.updateTargetBedTemperature(result["bed"]["temperature"]["target"])
+            printer.updateState(result["status"])
+
+            try:
+                # If we're still handling the request, we should ignore remote for a bit.
+                if not printer.getController().isPreheatRequestInProgress():
+                    printer.updateIsPreheating(result["bed"]["pre_heat"]["active"])
+            except KeyError:
+                # Older firmwares don't support preheating, so we need to fake it.
+                pass
+
+            head_position = result["heads"][0]["position"]
+            printer.updateHeadPosition(head_position["x"], head_position["y"], head_position["z"])
+
+            for index in range(0, self._number_of_extruders):
+                temperatures = result["heads"][0]["extruders"][index]["hotend"]["temperature"]
+                extruder = printer.extruders[index]
+                extruder.updateTargetHotendTemperature(temperatures["target"])
+                extruder.updateHotendTemperature(temperatures["current"])
+
+                material_guid = result["heads"][0]["extruders"][index]["active_material"]["guid"]
+
+                if extruder.activeMaterial is None or extruder.activeMaterial.guid != material_guid:
+                    # Find matching material (as we need to set brand, type & color)
+                    containers = ContainerRegistry.getInstance().findInstanceContainers(type="material",
+                                                                                        GUID=material_guid)
+                    if containers:
+                        color = containers[0].getMetaDataEntry("color_code")
+                        brand = containers[0].getMetaDataEntry("brand")
+                        material_type = containers[0].getMetaDataEntry("material")
+                        name = containers[0].getName()
+                    else:
+                        # Unknown material.
+                        color = "#00000000"
+                        brand = "Unknown"
+                        material_type = "Unknown"
+                        name = "Unknown"
+                    material = MaterialOutputModel(guid=material_guid, type=material_type,
+                                                   brand=brand, color=color, name = name)
+                    extruder.updateActiveMaterial(material)
+
+                try:
+                    hotend_id = result["heads"][0]["extruders"][index]["hotend"]["id"]
+                except KeyError:
+                    hotend_id = ""
+                printer.extruders[index].updateHotendID(hotend_id)
+
+        else:
+            Logger.log("w",
+                       "Got status code {status_code} while trying to get printer data".format(status_code = status_code))
+
+    ##  Convenience function to "blur" out all but the last 5 characters of the auth key.
+    #   This can be used to debug print the key, without it compromising the security.
+    def _getSafeAuthKey(self):
+        if self._authentication_key is not None:
+            result = self._authentication_key[-5:]
+            result = "********" + result
+            return result
+
+        return self._authentication_key

plugins/UM3NetworkPrinting/src/LegacyUM3PrinterOutputController.py

@@ -0,0 +1,96 @@
+# Copyright (c) 2017 Ultimaker B.V.
+# Cura is released under the terms of the LGPLv3 or higher.
+
+from cura.PrinterOutput.PrinterOutputController import PrinterOutputController
+from PyQt5.QtCore import QTimer
+from UM.Version import Version
+
+MYPY = False
+if MYPY:
+    from cura.PrinterOutput.PrintJobOutputModel import PrintJobOutputModel
+    from cura.PrinterOutput.PrinterOutputModel import PrinterOutputModel
+
+
+class LegacyUM3PrinterOutputController(PrinterOutputController):
+    def __init__(self, output_device):
+        super().__init__(output_device)
+        self._preheat_bed_timer = QTimer()
+        self._preheat_bed_timer.setSingleShot(True)
+        self._preheat_bed_timer.timeout.connect(self._onPreheatBedTimerFinished)
+        self._preheat_printer = None
+
+        self.can_control_manually = False
+        self.can_send_raw_gcode = False
+
+        # Are we still waiting for a response about preheat?
+        # We need this so we can already update buttons, so it feels more snappy.
+        self._preheat_request_in_progress = False
+
+    def isPreheatRequestInProgress(self):
+        return self._preheat_request_in_progress
+
+    def setJobState(self, job: "PrintJobOutputModel", state: str):
+        data = "{\"target\": \"%s\"}" % state
+        self._output_device.put("print_job/state", data, on_finished=None)
+
+    def setTargetBedTemperature(self, printer: "PrinterOutputModel", temperature: int):
+        data = str(temperature)
+        self._output_device.put("printer/bed/temperature/target", data, on_finished=self._onPutBedTemperatureCompleted)
+
+    def _onPutBedTemperatureCompleted(self, reply):
+        if Version(self._preheat_printer.firmwareVersion) < Version("3.5.92"):
+            # If it was handling a preheat, it isn't anymore.
+            self._preheat_request_in_progress = False
+
+    def _onPutPreheatBedCompleted(self, reply):
+        self._preheat_request_in_progress = False
+
+    def moveHead(self, printer: "PrinterOutputModel", x, y, z, speed):
+        head_pos = printer._head_position
+        new_x = head_pos.x + x
+        new_y = head_pos.y + y
+        new_z = head_pos.z + z
+        data = "{\n\"x\":%s,\n\"y\":%s,\n\"z\":%s\n}" %(new_x, new_y, new_z)
+        self._output_device.put("printer/heads/0/position", data, on_finished=None)
+
+    def homeBed(self, printer):
+        self._output_device.put("printer/heads/0/position/z", "0", on_finished=None)
+
+    def _onPreheatBedTimerFinished(self):
+        self.setTargetBedTemperature(self._preheat_printer, 0)
+        self._preheat_printer.updateIsPreheating(False)
+        self._preheat_request_in_progress = True
+
+    def cancelPreheatBed(self, printer: "PrinterOutputModel"):
+        self.preheatBed(printer, temperature=0, duration=0)
+        self._preheat_bed_timer.stop()
+        printer.updateIsPreheating(False)
+
+    def preheatBed(self, printer: "PrinterOutputModel", temperature, duration):
+        try:
+            temperature = round(temperature)  # The API doesn't allow floating point.
+            duration = round(duration)
+        except ValueError:
+            return  # Got invalid values, can't pre-heat.
+
+        if duration > 0:
+            data = """{"temperature": "%i", "timeout": "%i"}""" % (temperature, duration)
+        else:
+            data = """{"temperature": "%i"}""" % temperature
+
+        # Real bed pre-heating support is implemented from 3.5.92 and up.
+
+        if Version(printer.firmwareVersion) < Version("3.5.92"):
+            # No firmware-side duration support then, so just set target bed temp and set a timer.
+            self.setTargetBedTemperature(printer, temperature=temperature)
+            self._preheat_bed_timer.setInterval(duration * 1000)
+            self._preheat_bed_timer.start()
+            self._preheat_printer = printer
+            printer.updateIsPreheating(True)
+            return
+
+        self._output_device.put("printer/bed/pre_heat", data, on_finished = self._onPutPreheatBedCompleted)
+        printer.updateIsPreheating(True)
+        self._preheat_request_in_progress = True
+
+

plugins/UM3NetworkPrinting/src/SendMaterialJob.py

@@ -0,0 +1,99 @@
+# Copyright (c) 2018 Ultimaker B.V.
+# Cura is released under the terms of the LGPLv3 or higher.
+
+import json #To understand the list of materials from the printer reply.
+import os #To walk over material files.
+import os.path #To filter on material files.
+from PyQt5.QtNetwork import QNetworkReply, QNetworkRequest #To listen to the reply from the printer.
+from typing import Any, Dict, Set, TYPE_CHECKING
+import urllib.parse #For getting material IDs from their file names.
+
+from UM.Job import Job #The interface we're implementing.
+from UM.Logger import Logger
+from UM.MimeTypeDatabase import MimeTypeDatabase #To strip the extensions of the material profile files.
+from UM.Resources import Resources
+from UM.Settings.ContainerRegistry import ContainerRegistry #To find the GUIDs of materials.
+
+from cura.CuraApplication import CuraApplication #For the resource types.
+
+if TYPE_CHECKING:
+    from .ClusterUM3OutputDevice import ClusterUM3OutputDevice
+
+##  Asynchronous job to send material profiles to the printer.
+#
+#   This way it won't freeze up the interface while sending those materials.
+class SendMaterialJob(Job):
+    def __init__(self, device: "ClusterUM3OutputDevice") -> None:
+        super().__init__()
+        self.device = device #type: ClusterUM3OutputDevice
+
+    def run(self) -> None:
+        self.device.get("materials/", on_finished = self.sendMissingMaterials)
+
+    def sendMissingMaterials(self, reply: QNetworkReply) -> None:
+        if reply.attribute(QNetworkRequest.HttpStatusCodeAttribute) != 200: #Got an error from the HTTP request.
+            Logger.log("e", "Couldn't request current material storage on printer. Not syncing materials.")
+            return
+
+        remote_materials_list = reply.readAll().data().decode("utf-8")
+        try:
+            remote_materials_list = json.loads(remote_materials_list)
+        except json.JSONDecodeError:
+            Logger.log("e", "Request material storage on printer: I didn't understand the printer's answer.")
+            return
+        try:
+            remote_materials_by_guid = {material["guid"]: material for material in remote_materials_list} #Index by GUID.
+        except KeyError:
+            Logger.log("e", "Request material storage on printer: Printer's answer was missing GUIDs.")
+            return
+
+        container_registry = ContainerRegistry.getInstance()
+        local_materials_list = filter(lambda material: ("GUID" in material and "version" in material and "id" in material), container_registry.findContainersMetadata(type = "material"))
+        local_materials_by_guid = {material["GUID"]: material for material in local_materials_list if material["id"] == material["base_file"]}
+        for material in local_materials_list: #For each GUID get the material with the highest version number.
+            try:
+                if int(material["version"]) > local_materials_by_guid[material["GUID"]]["version"]:
+                    local_materials_by_guid[material["GUID"]] = material
+            except ValueError:
+                Logger.log("e", "Material {material_id} has invalid version number {number}.".format(material_id = material["id"], number = material["version"]))
+                continue
+
+        materials_to_send = set() #type: Set[Dict[str, Any]]
+        for guid, material in local_materials_by_guid.items():
+            if guid not in remote_materials_by_guid:
+                materials_to_send.add(material["id"])
+                continue
+            try:
+                if int(material["version"]) > remote_materials_by_guid[guid]["version"]:
+                    materials_to_send.add(material["id"])
+                    continue
+            except KeyError:
+                Logger.log("e", "Current material storage on printer was an invalid reply (missing version).")
+                return
+
+        for file_path in Resources.getAllResourcesOfType(CuraApplication.ResourceTypes.MaterialInstanceContainer):
+            try:
+                mime_type = MimeTypeDatabase.getMimeTypeForFile(file_path)
+            except MimeTypeDatabase.MimeTypeNotFoundError:
+                continue #Not the sort of file we'd like to send then.
+            _, file_name = os.path.split(file_path)
+            material_id = urllib.parse.unquote_plus(mime_type.stripExtension(file_name))
+            if material_id not in materials_to_send:
+                continue
+
+            parts = []
+            with open(file_path, "rb") as f:
+                parts.append(self.device._createFormPart("name=\"file\"; filename=\"{file_name}\"".format(file_name = file_name), f.read()))
+            signature_file_path = file_path + ".sig"
+            if os.path.exists(signature_file_path):
+                _, signature_file_name = os.path.split(signature_file_path)
+                with open(signature_file_path, "rb") as f:
+                    parts.append(self.device._createFormPart("name=\"signature_file\"; filename=\"{file_name}\"".format(file_name = signature_file_name), f.read()))
+
+            Logger.log("d", "Syncing material {material_id} with cluster.".format(material_id = material_id))
+            self.device.postFormWithParts(target = "materials/", parts = parts, on_finished = self.sendingFinished)
+
+    def sendingFinished(self, reply: QNetworkReply):
+        if reply.attribute(QNetworkRequest.HttpStatusCodeAttribute) != 200:
+            Logger.log("e", "Received error code from printer when syncing material: {code}".format(code = reply.attribute(QNetworkRequest.HttpStatusCodeAttribute)))
+            Logger.log("e", reply.readAll().data().decode("utf-8"))

plugins/UM3NetworkPrinting/src/UM3OutputDevicePlugin.py

@@ -0,0 +1,352 @@
+# Copyright (c) 2017 Ultimaker B.V.
+# Cura is released under the terms of the LGPLv3 or higher.
+
+from UM.OutputDevice.OutputDevicePlugin import OutputDevicePlugin
+from UM.Logger import Logger
+from UM.Application import Application
+from UM.Signal import Signal, signalemitter
+from UM.Version import Version
+
+from . import ClusterUM3OutputDevice, LegacyUM3OutputDevice
+
+from PyQt5.QtNetwork import QNetworkRequest, QNetworkAccessManager
+from PyQt5.QtCore import QUrl
+
+from zeroconf import Zeroconf, ServiceBrowser, ServiceStateChange, ServiceInfo
+from queue import Queue
+from threading import Event, Thread
+from time import time
+
+import json
+
+
+##      This plugin handles the connection detection & creation of output device objects for the UM3 printer.
+#       Zero-Conf is used to detect printers, which are saved in a dict.
+#       If we discover a printer that has the same key as the active machine instance a connection is made.
+@signalemitter
+class UM3OutputDevicePlugin(OutputDevicePlugin):
+    addDeviceSignal = Signal()
+    removeDeviceSignal = Signal()
+    discoveredDevicesChanged = Signal()
+
+    def __init__(self):
+        super().__init__()
+        self._zero_conf = None
+        self._zero_conf_browser = None
+
+        # Because the model needs to be created in the same thread as the QMLEngine, we use a signal.
+        self.addDeviceSignal.connect(self._onAddDevice)
+        self.removeDeviceSignal.connect(self._onRemoveDevice)
+
+        Application.getInstance().globalContainerStackChanged.connect(self.reCheckConnections)
+
+        self._discovered_devices = {}
+        
+        self._network_manager = QNetworkAccessManager()
+        self._network_manager.finished.connect(self._onNetworkRequestFinished)
+
+        self._min_cluster_version = Version("4.0.0")
+
+        self._api_version = "1"
+        self._api_prefix = "/api/v" + self._api_version + "/"
+        self._cluster_api_version = "1"
+        self._cluster_api_prefix = "/cluster-api/v" + self._cluster_api_version + "/"
+
+        # Get list of manual instances from preferences
+        self._preferences = Application.getInstance().getPreferences()
+        self._preferences.addPreference("um3networkprinting/manual_instances",
+                                        "")  # A comma-separated list of ip adresses or hostnames
+
+        self._manual_instances = self._preferences.getValue("um3networkprinting/manual_instances").split(",")
+
+        # Store the last manual entry key
+        self._last_manual_entry_key = "" # type: str
+
+        # The zero-conf service changed requests are handled in a separate thread, so we can re-schedule the requests
+        # which fail to get detailed service info.
+        # Any new or re-scheduled requests will be appended to the request queue, and the handling thread will pick
+        # them up and process them.
+        self._service_changed_request_queue = Queue()
+        self._service_changed_request_event = Event()
+        self._service_changed_request_thread = Thread(target=self._handleOnServiceChangedRequests, daemon=True)
+        self._service_changed_request_thread.start()
+
+    def getDiscoveredDevices(self):
+        return self._discovered_devices
+
+    def getLastManualDevice(self) -> str:
+        return self._last_manual_entry_key
+
+    def resetLastManualDevice(self) -> None:
+        self._last_manual_entry_key = ""
+
+    ##  Start looking for devices on network.
+    def start(self):
+        self.startDiscovery()
+
+    def startDiscovery(self):
+        self.stop()
+        if self._zero_conf_browser:
+            self._zero_conf_browser.cancel()
+            self._zero_conf_browser = None  # Force the old ServiceBrowser to be destroyed.
+
+        for instance_name in list(self._discovered_devices):
+            self._onRemoveDevice(instance_name)
+
+        self._zero_conf = Zeroconf()
+        self._zero_conf_browser = ServiceBrowser(self._zero_conf, u'_ultimaker._tcp.local.',
+                                                 [self._appendServiceChangedRequest])
+
+        # Look for manual instances from preference
+        for address in self._manual_instances:
+            if address:
+                self.addManualDevice(address)
+        self.resetLastManualDevice()
+
+    def reCheckConnections(self):
+        active_machine = Application.getInstance().getGlobalContainerStack()
+        if not active_machine:
+            return
+
+        um_network_key = active_machine.getMetaDataEntry("um_network_key")
+
+        for key in self._discovered_devices:
+            if key == um_network_key:
+                if not self._discovered_devices[key].isConnected():
+                    Logger.log("d", "Attempting to connect with [%s]" % key)
+                    self._discovered_devices[key].connect()
+                    self._discovered_devices[key].connectionStateChanged.connect(self._onDeviceConnectionStateChanged)
+                else:
+                    self._onDeviceConnectionStateChanged(key)
+            else:
+                if self._discovered_devices[key].isConnected():
+                    Logger.log("d", "Attempting to close connection with [%s]" % key)
+                    self._discovered_devices[key].close()
+                    self._discovered_devices[key].connectionStateChanged.disconnect(self._onDeviceConnectionStateChanged)
+
+    def _onDeviceConnectionStateChanged(self, key):
+        if key not in self._discovered_devices:
+            return
+        if self._discovered_devices[key].isConnected():
+            # Sometimes the status changes after changing the global container and maybe the device doesn't belong to this machine
+            um_network_key = Application.getInstance().getGlobalContainerStack().getMetaDataEntry("um_network_key")
+            if key == um_network_key:
+                self.getOutputDeviceManager().addOutputDevice(self._discovered_devices[key])
+        else:
+            self.getOutputDeviceManager().removeOutputDevice(key)
+
+    def stop(self):
+        if self._zero_conf is not None:
+            Logger.log("d", "zeroconf close...")
+            self._zero_conf.close()
+
+    def removeManualDevice(self, key, address = None):
+        if key in self._discovered_devices:
+            if not address:
+                address = self._discovered_devices[key].ipAddress
+            self._onRemoveDevice(key)
+            self.resetLastManualDevice()
+
+        if address in self._manual_instances:
+            self._manual_instances.remove(address)
+            self._preferences.setValue("um3networkprinting/manual_instances", ",".join(self._manual_instances))
+
+    def addManualDevice(self, address):
+        if address not in self._manual_instances:
+            self._manual_instances.append(address)
+            self._preferences.setValue("um3networkprinting/manual_instances", ",".join(self._manual_instances))
+
+        instance_name = "manual:%s" % address
+        properties = {
+            b"name": address.encode("utf-8"),
+            b"address": address.encode("utf-8"),
+            b"manual": b"true",
+            b"incomplete": b"true",
+            b"temporary": b"true"   # Still a temporary device until all the info is retrieved in _onNetworkRequestFinished
+        }
+
+        if instance_name not in self._discovered_devices:
+            # Add a preliminary printer instance
+            self._onAddDevice(instance_name, address, properties)
+        self._last_manual_entry_key = instance_name
+
+        self._checkManualDevice(address)
+
+    def _checkManualDevice(self, address):
+        # Check if a UM3 family device exists at this address.
+        # If a printer responds, it will replace the preliminary printer created above
+        # origin=manual is for tracking back the origin of the call
+        url = QUrl("http://" + address + self._api_prefix + "system")
+        name_request = QNetworkRequest(url)
+        self._network_manager.get(name_request)
+
+    def _onNetworkRequestFinished(self, reply):
+        reply_url = reply.url().toString()
+
+        if "system" in reply_url:
+            if reply.attribute(QNetworkRequest.HttpStatusCodeAttribute) != 200:
+                # Something went wrong with checking the firmware version!
+                return
+
+            try:
+                system_info = json.loads(bytes(reply.readAll()).decode("utf-8"))
+            except:
+                Logger.log("e", "Something went wrong converting the JSON.")
+                return
+
+            address = reply.url().host()
+            has_cluster_capable_firmware = Version(system_info["firmware"]) > self._min_cluster_version
+            instance_name = "manual:%s" % address
+            properties = {
+                b"name": (system_info["name"] + " (manual)").encode("utf-8"),
+                b"address": address.encode("utf-8"),
+                b"firmware_version": system_info["firmware"].encode("utf-8"),
+                b"manual": b"true",
+                b"machine": str(system_info['hardware']["typeid"]).encode("utf-8")
+            }
+
+            if has_cluster_capable_firmware:
+                # Cluster needs an additional request, before it's completed.
+                properties[b"incomplete"] = b"true"
+
+            # Check if the device is still in the list & re-add it with the updated
+            # information.
+            if instance_name in self._discovered_devices:
+                self._onRemoveDevice(instance_name)
+                self._onAddDevice(instance_name, address, properties)
+
+            if has_cluster_capable_firmware:
+                # We need to request more info in order to figure out the size of the cluster.
+                cluster_url = QUrl("http://" + address + self._cluster_api_prefix + "printers/")
+                cluster_request = QNetworkRequest(cluster_url)
+                self._network_manager.get(cluster_request)
+
+        elif "printers" in reply_url:
+            if reply.attribute(QNetworkRequest.HttpStatusCodeAttribute) != 200:
+                # Something went wrong with checking the amount of printers the cluster has!
+                return
+            # So we confirmed that the device is in fact a cluster printer, and we should now know how big it is.
+            try:
+                cluster_printers_list = json.loads(bytes(reply.readAll()).decode("utf-8"))
+            except:
+                Logger.log("e", "Something went wrong converting the JSON.")
+                return
+            address = reply.url().host()
+            instance_name = "manual:%s" % address
+            if instance_name in self._discovered_devices:
+                device = self._discovered_devices[instance_name]
+                properties = device.getProperties().copy()
+                if b"incomplete" in properties:
+                    del properties[b"incomplete"]
+                properties[b'cluster_size'] = len(cluster_printers_list)
+                self._onRemoveDevice(instance_name)
+                self._onAddDevice(instance_name, address, properties)
+
+    def _onRemoveDevice(self, device_id):
+        device = self._discovered_devices.pop(device_id, None)
+        if device:
+            if device.isConnected():
+                device.disconnect()
+                try:
+                    device.connectionStateChanged.disconnect(self._onDeviceConnectionStateChanged)
+                except TypeError:
+                    # Disconnect already happened.
+                    pass
+
+            self.discoveredDevicesChanged.emit()
+
+    def _onAddDevice(self, name, address, properties):
+        # Check what kind of device we need to add; Depending on the firmware we either add a "Connect"/"Cluster"
+        # or "Legacy" UM3 device.
+        cluster_size = int(properties.get(b"cluster_size", -1))
+
+        if cluster_size >= 0:
+            device = ClusterUM3OutputDevice.ClusterUM3OutputDevice(name, address, properties)
+        else:
+            device = LegacyUM3OutputDevice.LegacyUM3OutputDevice(name, address, properties)
+
+        self._discovered_devices[device.getId()] = device
+        self.discoveredDevicesChanged.emit()
+
+        global_container_stack = Application.getInstance().getGlobalContainerStack()
+        if global_container_stack and device.getId() == global_container_stack.getMetaDataEntry("um_network_key"):
+            device.connect()
+            device.connectionStateChanged.connect(self._onDeviceConnectionStateChanged)
+
+    ##  Appends a service changed request so later the handling thread will pick it up and processes it.
+    def _appendServiceChangedRequest(self, zeroconf, service_type, name, state_change):
+        # append the request and set the event so the event handling thread can pick it up
+        item = (zeroconf, service_type, name, state_change)
+        self._service_changed_request_queue.put(item)
+        self._service_changed_request_event.set()
+
+    def _handleOnServiceChangedRequests(self):
+        while True:
+            # Wait for the event to be set
+            self._service_changed_request_event.wait(timeout = 5.0)
+
+            # Stop if the application is shutting down
+            if Application.getInstance().isShuttingDown():
+                return
+
+            self._service_changed_request_event.clear()
+
+            # Handle all pending requests
+            reschedule_requests = []  # A list of requests that have failed so later they will get re-scheduled
+            while not self._service_changed_request_queue.empty():
+                request = self._service_changed_request_queue.get()
+                zeroconf, service_type, name, state_change = request
+                try:
+                    result = self._onServiceChanged(zeroconf, service_type, name, state_change)
+                    if not result:
+                        reschedule_requests.append(request)
+                except Exception:
+                    Logger.logException("e", "Failed to get service info for [%s] [%s], the request will be rescheduled",
+                                        service_type, name)
+                    reschedule_requests.append(request)
+
+            # Re-schedule the failed requests if any
+            if reschedule_requests:
+                for request in reschedule_requests:
+                    self._service_changed_request_queue.put(request)
+
+    ##  Handler for zeroConf detection.
+    #   Return True or False indicating if the process succeeded.
+    #   Note that this function can take over 3 seconds to complete. Be carefull calling it from the main thread.
+    def _onServiceChanged(self, zero_conf, service_type, name, state_change):
+        if state_change == ServiceStateChange.Added:
+            Logger.log("d", "Bonjour service added: %s" % name)
+
+            # First try getting info from zero-conf cache
+            info = ServiceInfo(service_type, name, properties={})
+            for record in zero_conf.cache.entries_with_name(name.lower()):
+                info.update_record(zero_conf, time(), record)
+
+            for record in zero_conf.cache.entries_with_name(info.server):
+                info.update_record(zero_conf, time(), record)
+                if info.address:
+                    break
+
+            # Request more data if info is not complete
+            if not info.address:
+                Logger.log("d", "Trying to get address of %s", name)
+                info = zero_conf.get_service_info(service_type, name)
+
+            if info:
+                type_of_device = info.properties.get(b"type", None)
+                if type_of_device:
+                    if type_of_device == b"printer":
+                        address = '.'.join(map(lambda n: str(n), info.address))
+                        self.addDeviceSignal.emit(str(name), address, info.properties)
+                    else:
+                        Logger.log("w",
+                                   "The type of the found device is '%s', not 'printer'! Ignoring.." % type_of_device)
+            else:
+                Logger.log("w", "Could not get information about %s" % name)
+                return False
+
+        elif state_change == ServiceStateChange.Removed:
+            Logger.log("d", "Bonjour service removed: %s" % name)
+            self.removeDeviceSignal.emit(str(name))
+
+        return True