Initial basic version of this feature.

CURA-3335

cura/CuraApplication.py

@@ -1,5 +1,9 @@
 # Copyright (c) 2015 Ultimaker B.V.
 # Cura is released under the terms of the AGPLv3 or higher.
+import json
+
+from PyQt5.QtCore import QTextStream
+from PyQt5.QtNetwork import QLocalServer
 
 from UM.Qt.QtApplication import QtApplication
 from UM.Scene.SceneNode import SceneNode
@@ -420,13 +424,44 @@ class CuraApplication(QtApplication):
 
         self._plugins_loaded = True
 
+    @classmethod
     def addCommandLineOptions(self, parser):
         super().addCommandLineOptions(parser)
         parser.add_argument("file", nargs="*", help="Files to load after starting the application.")
+        parser.add_argument("--single-instance", action="store_true", default=False)
+
+    def _setUpSingleInstanceServer(self):
+        if self.getCommandLineOption("single_instance", False):
+            self.__single_instance_server = QLocalServer()
+            self.__single_instance_server.newConnection.connect(self._singleInstanceServerNewConnection)
+            self.__single_instance_server.listen("ultimaker-cura")
+
+    def _singleInstanceServerNewConnection(self):
+        Logger.log('d', 'Saw something on the single instance server')
+        other_cura_connection = self.__single_instance_server.nextPendingConnection()
+        if other_cura_connection is not None:
+            def readyRead():
+                while other_cura_connection.canReadLine():
+                    line = other_cura_connection.readLine()
+                    payload = json.loads(str(line, encoding="ASCII").strip())
+                    command = payload["command"]
+                    if command == "clear-all":
+                        self.deleteAll()
+
+                    elif command == "open":
+                        self.deleteAll()
+                        self._openFile(payload["filePath"])
+
+                    elif command == "focus":
+                        self.focusWindow()
+
+            other_cura_connection.readyRead.connect(readyRead)
 
     def run(self):
         self.showSplashMessage(self._i18n_catalog.i18nc("@info:progress", "Setting up scene..."))
 
+        self._setUpSingleInstanceServer()
+
         controller = self.getController()
 
         controller.setActiveView("SolidView")

cura_app.py

@@ -2,11 +2,14 @@
 
 # Copyright (c) 2015 Ultimaker B.V.
 # Cura is released under the terms of the AGPLv3 or higher.
-
+import argparse
+import json
 import os
 import sys
 import platform
+import time
 
+from PyQt5.QtNetwork import QLocalSocket
 from UM.Platform import Platform
 
 #WORKAROUND: GITHUB-88 GITHUB-385 GITHUB-612
@@ -58,5 +61,36 @@ if Platform.isWindows() and hasattr(sys, "frozen"):
 # Force an instance of CuraContainerRegistry to be created and reused later.
 cura.Settings.CuraContainerRegistry.getInstance()
 
+# Peek the arguments and look for the 'single-instance' flag.
+parser = argparse.ArgumentParser(prog="cura")  # pylint: disable=bad-whitespace
+cura.CuraApplication.CuraApplication.addCommandLineOptions(parser)
+parsed_command_line = vars(parser.parse_args())
+
+if "single_instance" in parsed_command_line and parsed_command_line["single_instance"]:
+    print("Check for single instance")
+    single_instance_socket = QLocalSocket()
+    single_instance_socket.connectToServer("ultimaker-cura")
+    single_instance_socket.waitForConnected()
+    if single_instance_socket.state() == QLocalSocket.ConnectedState:
+        print("Connected to the other Cura instance.")
+        print(repr(parsed_command_line))
+
+        payload = {"command": "clear-all"}
+        single_instance_socket.write(bytes(json.dumps(payload) + "\n", encoding="ASCII"))
+
+        payload = {"command": "focus"}
+        single_instance_socket.write(bytes(json.dumps(payload) + "\n", encoding="ASCII"))
+
+        if len(parsed_command_line["file"]) != 0:
+            for filename in parsed_command_line["file"]:
+                payload = { "command": "open", "filePath": filename }
+                single_instance_socket.write(bytes(json.dumps(payload) + "\n", encoding="ASCII"))
+
+        single_instance_socket.flush()
+
+
+        single_instance_socket.close()
+        sys.exit(0)
+
 app = cura.CuraApplication.CuraApplication.getInstance()
 app.run()