def send_message(self, message, callback=None):
"""
Attempt to send a message to the previously running instance of the
application. Returns True if the message is sent successfully, or False
otherwise.
Alternatively, if a callback is provided the function will return
immediately and the boolean will be sent to the callback instead.
"""
message = json.dumps(message)
if sys.version_info.major == 3:
packedLen = struct.pack("!I", len(message)).decode()
else:
packedLen = struct.pack("!I", len(message))
message = packedLen + message
# Create a socket.
sock = QLocalSocket(self)
# Build our helper functions.
def error(err):
""" Return False to the callback. """
callback(False)
def connected():
""" Send our message. """
sock.writeData(message, len(message))
def bytesWritten(bytes):
""" If we've written everything, close and return True. """
if not sock.bytesToWrite():
sock.close()
callback(True)
if callback:
sock.error.connect(error)
sock.connect.connect(connected)
sock.bytesWritten.connect(bytesWritten)
# Now connect.
sock.connectToServer(self._app_id)
if not callback:
# Do things synchronously.
connected = sock.waitForConnected(5000)
if not connected:
return False
# Write it.
sock.writeData(message, len(message))
# Wait until we've written everything.
while sock.bytesToWrite():
success = sock.waitForBytesWritten(5000)
if not success:
sock.close()
return False
sock.close()
return True
