Fix: After clicking "cancel" button while sending a print job

the connection is disconnected
CURA-4960

cura/PrinterOutput/NetworkedPrinterOutputDevice.py

@@ -219,6 +219,9 @@ class NetworkedPrinterOutputDevice(PrinterOutputDevice):
             reply.uploadProgress.connect(onProgress)
         self._registerOnFinishedCallback(reply, onFinished)
 
+
+        return reply
+
     def postForm(self, target: str, header_data: str, body_data: bytes, onFinished: Optional[Callable[[Any, QNetworkReply], None]], onProgress: Callable = None) -> None:
         post_part = QHttpPart()
         post_part.setHeader(QNetworkRequest.ContentDispositionHeader, header_data)

plugins/UM3NetworkPrinting/ClusterUM3OutputDevice.py

@@ -77,6 +77,9 @@ class ClusterUM3OutputDevice(NetworkedPrinterOutputDevice):
 
         self._cluster_size = int(properties.get(b"cluster_size", 0))
 
+        self._latest_reply_handler = None
+
+
     def requestWrite(self, nodes, file_name=None, filter_by_machine=False, file_handler=None, **kwargs):
         self.writeStarted.emit(self)
 
@@ -147,7 +150,7 @@ class ClusterUM3OutputDevice(NetworkedPrinterOutputDevice):
 
         parts.append(self._createFormPart("name=\"file\"; filename=\"%s\"" % file_name, compressed_gcode))
 
-        self.postFormWithParts("print_jobs/", parts, onFinished=self._onPostPrintJobFinished, onProgress=self._onUploadPrintJobProgress)
+        self._latest_reply_handler = self.postFormWithParts("print_jobs/", parts, onFinished=self._onPostPrintJobFinished, onProgress=self._onUploadPrintJobProgress)
 
     @pyqtProperty(QObject, notify=activePrinterChanged)
     def activePrinter(self) -> Optional["PrinterOutputModel"]:
@@ -187,6 +190,12 @@ class ClusterUM3OutputDevice(NetworkedPrinterOutputDevice):
             self._sending_gcode = False
             Application.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()
+
+
     @pyqtSlot()
     def openPrintJobControlPanel(self):
         Logger.log("d", "Opening print job control panel...")