onion_message: add callback for unsolicited onionmsg_tlv.message payl…

…oads and display received text message on Qt client console

electrum/gui/qt/console.py

@@ -13,7 +13,7 @@
 from electrum import util
 from electrum.i18n import _
 
-from .util import MONOSPACE_FONT, font_height
+from .util import MONOSPACE_FONT, font_height, QtEventListener, qt_event_listener
 
 # sys.ps1 and sys.ps2 are only declared if an interpreter is in interactive mode.
 sys.ps1 = '>>> '
@@ -47,9 +47,10 @@ def on_resize(self, w):
         self.setFixedWidth(w - padding)
 
 
-class Console(QtWidgets.QPlainTextEdit):
+class Console(QtWidgets.QPlainTextEdit, QtEventListener):
     def __init__(self, parent=None):
         QtWidgets.QPlainTextEdit.__init__(self, parent)
+        QtEventListener.__init__(self)
 
         self.history = []
         self.namespace = {}
@@ -72,6 +73,16 @@ def __init__(self, parent=None):
         )
         self.messageOverlay = OverlayLabel(warning_text, self)
 
+        self.register_callbacks()
+        self.destroyed.connect(lambda: self.on_destroy())
+
+    def on_destroy(self):
+        self.unregister_callbacks()
+
+    @qt_event_listener
+    def on_event_onion_message_textmessage(self, text):
+        self.showMessage(f'ONION_MESSAGE text message received: {text}')
+
     def resizeEvent(self, e):
         super().resizeEvent(e)
         vertical_scrollbar_width = self.verticalScrollBar().width() * self.verticalScrollBar().isVisible()

electrum/onion_message.py

@@ -34,7 +34,7 @@
 from electrum.lnonion import (get_shared_secrets_along_route2, get_bolt04_onion_key, OnionPacket, process_onion_packet,
                               OnionHopsDataSingle, new_onion_packet2)
 from electrum.lnutil import get_ecdh
-from electrum.util import OldTaskGroup, now
+from electrum.util import OldTaskGroup, now, trigger_callback
 
 if TYPE_CHECKING:
     from electrum.lnworker import LNWallet
@@ -222,6 +222,8 @@ def on_onion_message_received_unsolicited(self, recipient_data, payload):
 
         self.logger.info(f'onion message with text received: {text}')
 
+        trigger_callback('onion_message_textmessage', text)
+
     def on_onion_message(self, payload):
         blinding = payload.get('blinding')
         if not blinding: