CURA-1923: SliceInfo: Sending data threaded

The idea is to make the sending process, so it won't block the UI until the data is sent or the timeout has reached.
This commit does the following:
* Increasing the timeout to 5s
-> As we are sending our data threaded now this won't hurt. At least for clients in slow networks.
* Moving section for "sending data to info_url" into a seperate thread.
* Starting the thread instead and collecting all threads in a list
* Removing all threads from the list, if they have already finished their work.
* When the SliceInfo Extension gets __del__'d, it will wait for the threads until they finish.

Contributes to CURA-1923

plugins/SliceInfoPlugin/SliceInfo.py

@@ -12,10 +12,7 @@ from UM.Logger import Logger
 from UM.Platform import Platform
 from UM.Qt.Duration import DurationFormat
 
-import collections
-import json
-import os.path
-import copy
+from threading import Thread
 import platform
 import math
 import urllib.request
@@ -24,6 +21,33 @@ import ssl
 
 catalog = i18nCatalog("cura")
 
+class SliceInfoThread(Thread):
+    data = None
+    url = None
+
+    def __init__(self, url, data):
+        Thread.__init__(self)
+        self.url = url
+        self.data = data
+
+    def run(self):
+        if not self.url or not self.data:
+            Logger.log("e", "URL or DATA for sending slice info was not set!")
+
+        # Submit data
+        kwoptions = {"data" : self.data,
+                     "timeout" : 5
+                     }
+
+        if Platform.isOSX():
+            kwoptions["context"] = ssl._create_unverified_context()
+
+        try:
+            f = urllib.request.urlopen(self.url, **kwoptions)
+            Logger.log("i", "Sent anonymous slice info to %s", self.url)
+            f.close()
+        except Exception:
+            Logger.logException("e", "An exception occurred while trying to send slice information")
 
 ##      This Extension runs in the background and sends several bits of information to the Ultimaker servers.
 #       The data is only sent when the user in question gave permission to do so. All data is anonymous and
@@ -43,11 +67,25 @@ class SliceInfo(Extension):
             self.send_slice_info_message.actionTriggered.connect(self.messageActionTriggered)
             self.send_slice_info_message.show()
 
+        self.runningThreads = []
+
+    def __del__(self):
+        for thread in self.threadedReports:
+            if thread.is_alive():
+                thread.join() # Wait for threads - shouldn't take much more time than the timeout. See above..
+
+    def _removeFinishedThreads(self):
+        for process in self.runningThreads:
+            if not process.is_alive():
+                self.runningThreads.remove(process) # Remove finished threads
+
     def messageActionTriggered(self, message_id, action_id):
         self.send_slice_info_message.hide()
         Preferences.getInstance().setValue("info/asked_send_slice_info", True)
 
     def _onWriteStarted(self, output_device):
+        self._removeFinishedThreads()
+
         try:
             if not Preferences.getInstance().getValue("info/send_slice_info"):
                 Logger.log("d", "'info/send_slice_info' is turned off.")
@@ -112,19 +150,11 @@ class SliceInfo(Extension):
             submitted_data = urllib.parse.urlencode(submitted_data)
             binary_data = submitted_data.encode("utf-8")
 
-            # Submit data
-            kwoptions = {"data" : binary_data,
-                         "timeout" : 1
-                         }
-            if Platform.isOSX():
-                kwoptions["context"] = ssl._create_unverified_context()
-            try:
-                f = urllib.request.urlopen(self.info_url, **kwoptions)
-                Logger.log("i", "Sent anonymous slice info to %s", self.info_url)
-                f.close()
-            except Exception as e:
-                Logger.logException("e", "An exception occurred while trying to send slice information")
+            # Sending slice info non-blocking
+            reportThread = SliceInfoThread(self.info_url, binary_data)
+            self.runningThreads.append(reportThread)
+            reportThread.start()
         except:
             # We really can't afford to have a mistake here, as this would break the sending of g-code to a device
             # (Either saving or directly to a printer). The functionality of the slice data is not *that* important.
-            pass
+            Logger.logException("e", "Exception raised while sending slice info") # But we should be notified about these problems of course.