WebSocket support

client.py

@@ -0,0 +1,54 @@
+"""
+This is a test-client for the transit-relay that uses TCP. It
+doesn't send any data, only prints out data that is received. Uses a
+fixed token of 64 'a' characters. Always connects on localhost:4001
+"""
+
+
+from twisted.internet import endpoints
+from twisted.internet.defer import (
+    Deferred,
+)
+from twisted.internet.task import react
+from twisted.internet.error import (
+    ConnectionDone,
+)
+from twisted.internet.protocol import (
+    Protocol,
+    Factory,
+)
+
+
+class RelayEchoClient(Protocol):
+    """
+    Speaks the version1 magic wormhole transit relay protocol (as a client)
+    """
+
+    def connectionMade(self):
+        print(">CONNECT")
+        self.data = b""
+        self.transport.write(u"please relay {}\n".format(self.factory.token).encode("ascii"))
+
+    def dataReceived(self, data):
+        print(">RECV {} bytes".format(len(data)))
+        print(data.decode("ascii"))
+        self.data += data
+        if data == "ok\n":
+            self.transport.write("ding\n")
+
+    def connectionLost(self, reason):
+        if isinstance(reason.value, ConnectionDone):
+            self.factory.done.callback(None)
+        else:
+            print(">DISCONNCT: {}".format(reason))
+            self.factory.done.callback(reason)
+
+
+@react
+def main(reactor):
+    ep = endpoints.clientFromString(reactor, "tcp:localhost:4001")
+    f = Factory.forProtocol(RelayEchoClient)
+    f.token = "a" * 64
+    f.done = Deferred()
+    ep.connect(f)
+    return f.done

docs/running.md

@@ -50,6 +50,15 @@ The relevant arguments are:
 * ``--usage-db=``: maintains a SQLite database with current and historical usage data
 * ``--blur-usage=``: round logged timestamps and data sizes
 
+For WebSockets support, two additional arguments:
+
+* ``--websocket``: the endpoint to listen for websocket connections
+  on, like ``tcp:4002``
+* ``--websocket-url``: the URL of the WebSocket connection. This may
+  be different from the listening endpoint because of port-forwarding
+  and so forth. By default it will be ``ws://localhost:<port>`` if not
+  provided
+
 When you use ``twist``, the relay runs in the foreground, so it will
 generally exit as soon as the controlling terminal exits. For persistent
 environments, you should daemonize the server.

setup.py

@@ -18,7 +18,8 @@
                 ],
       package_data={"wormhole_transit_relay": ["db-schemas/*.sql"]},
       install_requires=[
-          "twisted >= 17.5.0",
+          "twisted >= 21.2.0",
+          "autobahn >= 21.3.1",
       ],
       extras_require={
           ':sys_platform=="win32"': ["pypiwin32"],