Printer can now actually be linked

CURA-336

DiscoverUM3Action.py

@@ -30,3 +30,12 @@ class DiscoverUM3Action(MachineAction):
             return [printers[printer] for printer in printers]
         else:
             return []
+
+    @pyqtSlot(str)
+    def setKey(self, key):
+        global_container_stack = Application.getInstance().getGlobalContainerStack()
+        if global_container_stack:
+            if "key" in global_container_stack.getMetaData():
+                global_container_stack.setMetaDataEntry("key", key)
+            else:
+                global_container_stack.addMetaDataEntry("key", key)

DiscoverUM3Action.qml

@@ -145,4 +145,26 @@ Cura.MachineAction
             }
         }
     }
+    Button
+    {
+        text: catalog.i18nc("@action:button", "Ok")
+        anchors.right: cancelButton.left
+        anchors.bottom: parent.bottom
+        onClicked:
+        {
+            manager.setKey(base.selectedPrinter.getKey())
+            completed()
+        }
+    }
+    Button
+    {
+        id: cancelButton
+        text: catalog.i18nc("@action:button", "Cancel")
+        anchors.right: discoverUM3Action.right
+        anchors.bottom: parent.bottom
+        onClicked:
+        {
+            completed()
+        }
+    }
 }

NetworkPrinterOutputDevice.py

@@ -8,8 +8,8 @@ from UM.Message import Message
 from cura.PrinterOutputDevice import PrinterOutputDevice, ConnectionState
 
 from PyQt5.QtNetwork import QHttpMultiPart, QHttpPart, QNetworkRequest, QNetworkAccessManager
-from PyQt5.QtCore import QUrl, QTimer, pyqtSignal, pyqtProperty
-from PyQt5.QtGui import QPixmap, QImage
+from PyQt5.QtCore import QUrl, QTimer, pyqtSignal, pyqtProperty, pyqtSlot
+from PyQt5.QtGui import QImage
 
 import json
 
@@ -89,6 +89,7 @@ class NetworkPrinterOutputDevice(PrinterOutputDevice):
 
     ##  Get the unique key of this machine
     #   \return key String containing the key of the machine.
+    @pyqtSlot(result = str)
     def getKey(self):
         return self._key