Added a simple echo bot example

examples/echobot/echobot.py

@@ -0,0 +1,95 @@
+#!/usr/bin/env python3
+
+# Copyright (c) 2022 Marc Ordinas i Llopis
+#
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+# A simple Matrix echo bot to show the usage of mautrix-python.
+#
+# To use it, you'll need an access token and a device ID.
+# If you don't have those, first create a user (for example, 'echobot') in your homeserver. Then,
+# log it in with
+#      curl -XPOST -d '{"type":"m.login.password", "user":"echobot", "password":"echobot"}' \
+#      http://localhost:8008/_matrix/client/v3/login
+# This will return the device ID and token necessaries. Fill in the Echobot static vars and run.
+#
+# Once connected, invite the bot to a room and send a message starting with "!echo". You should get
+# a notice from the bot.
+
+
+import asyncio
+
+from mautrix.client import Client
+from mautrix.types import EventType, MessageEvent, StrippedStateEvent, Membership, \
+    TextMessageEventContent, MessageType, Format
+
+
+class EchoBot:
+    # Change to the correct user and homeserver.
+    user_id = "@echobot:localhost"
+    base_url = "http://localhost:8008"
+
+    # Fill in with the login result.
+    token = "<token>"
+    device_id = "<device ID>"
+
+    def __init__(self):
+        # Create the client to access Matrix.
+        self.client = Client(mxid=EchoBot.user_id,
+                             device_id=EchoBot.device_id,
+                             base_url=EchoBot.base_url,
+                             token=EchoBot.token)
+        # As we aren't passing any :class:SyncStore or :class:StateStore, just ignore anything sent
+        # before we connect.
+        self.client.ignore_initial_sync = True
+        self.client.ignore_first_sync = True
+
+        # Register two handlers, one for room memberships (invites) and another for room messages.
+        self.client.add_event_handler(EventType.ROOM_MEMBER, self.handle_invite)
+        self.client.add_event_handler(EventType.ROOM_MESSAGE, self.handle_message)
+
+    async def handle_invite(self, event: StrippedStateEvent) -> None:
+        # Ignore the message if it's not an invitation for us.
+        if event.state_key == self.user_id and event.content.membership == Membership.INVITE:
+            # If it is, join the room.
+            await self.client.join_room(event.room_id)
+
+    async def handle_message(self, event: MessageEvent) -> None:
+        if event.sender == self.user_id:
+            # Ignore our own messages
+            return
+
+        if event.content.relates_to:
+            # Don't echo replies to other messages
+            return
+
+        body = event.content.body
+        if body.startswith("!echo"):
+            response = TextMessageEventContent(
+                msgtype=MessageType.NOTICE,
+                body=body[5:].strip()
+            )
+            # If there's HTML-formatted content, echo that too
+            if event.content.format == Format.HTML:
+                response.format = Format.HTML
+                response.formatted_body = event.content.formatted_body[5:].strip()
+
+            # Send back the notice
+            await self.client.send_message(event.room_id, response)
+
+    async def start(self):
+        print("Starting EchoBot")
+        whoami = await self.client.whoami()
+        print(f"\tConnected, I'm {whoami.user_id} using {whoami.device_id}")
+        await self.client.start(None)
+
+
+async def main():
+    bot = EchoBot()
+    await bot.start()
+
+
+if __name__ == '__main__':
+    asyncio.run(main())