slack bridge: Remove the legacy RTM API based bridge.

Slack Bridge now uses the Slack Webhook integration
to get messages accross from Slack instead of the
legacy RTM API based connection our Slack Bridge
use.

Author: PieterCK

zulip/integrations/bridge_with_slack/bridge_with_slack_config.py

@@ -6,15 +6,15 @@
     },
     "slack": {
         "username": "slack_username",
-        "token": "xoxb-your-slack-token",
+        "token": "xoxp-your-slack-token",
     },
     # Mapping between Slack channels and Zulip stream-topic's.
     # You can specify multiple pairs.
     "channel_mapping": {
         # Slack channel; must be channel ID
         "C5Z5N7R8A": {
-            # Zulip stream
-            "stream": "test here",
+            # Zulip channel
+            "channel": "test here",
             # Zulip topic
             "topic": "<- slack-bridge",
         },

zulip/integrations/bridge_with_slack/run-slack-bridge

@@ -8,13 +8,11 @@ import traceback
 from typing import Any, Callable, Dict, Optional, Tuple
 
 import bridge_with_slack_config
-import slack_sdk
-from slack_sdk.rtm_v2 import RTMClient
+from slack_sdk.web.client import WebClient
 
 import zulip
 
 # change these templates to change the format of displayed message
-ZULIP_MESSAGE_TEMPLATE = "**{username}**: {message}"
 SLACK_MESSAGE_TEMPLATE = "<{username}> {message}"
 
 StreamTopicT = Tuple[str, str]
@@ -41,15 +39,26 @@ def get_slack_channel_for_zulip_message(
     return zulip_to_slack_map[stream_topic]
 
 
+def check_token_access(token: str) -> None:
+    if token.startswith("xoxp-"):
+        print(
+            "--- Warning! ---\n"
+            "You entered a Slack user token, please copy the token under\n"
+            "'Bot User OAuth Token' which starts with 'xoxb-...'."
+        )
+        sys.exit(1)
+    elif token.startswith("xoxb-"):
+        return
+
+
 class SlackBridge:
     def __init__(self, config: Dict[str, Any]) -> None:
         self.config = config
         self.zulip_config = config["zulip"]
         self.slack_config = config["slack"]
 
-        self.slack_to_zulip_map: Dict[str, Dict[str, str]] = config["channel_mapping"]
         self.zulip_to_slack_map: Dict[StreamTopicT, str] = {
-            (z["stream"], z["topic"]): s for s, z in config["channel_mapping"].items()
+            (z["channel"], z["topic"]): s for s, z in config["channel_mapping"].items()
         }
 
         # zulip-specific
@@ -65,25 +74,16 @@ class SlackBridge:
         # https://github.com/zulip/python-zulip-api/issues/761 is fixed.
         self.zulip_client_constructor = zulip_client_constructor
 
-        # slack-specific
-        self.slack_client = rtm
         # Spawn a non-websocket client for getting the users
         # list and for posting messages in Slack.
-        self.slack_webclient = slack_sdk.WebClient(token=self.slack_config["token"])
+        self.slack_webclient = WebClient(token=self.slack_config["token"])
 
     def wrap_slack_mention_with_bracket(self, zulip_msg: Dict[str, Any]) -> None:
         words = zulip_msg["content"].split(" ")
         for w in words:
             if w.startswith("@"):
                 zulip_msg["content"] = zulip_msg["content"].replace(w, "<" + w + ">")
 
-    def replace_slack_id_with_name(self, msg: Dict[str, Any]) -> None:
-        words = msg["text"].split(" ")
-        for w in words:
-            if w.startswith("<@") and w.endswith(">"):
-                _id = w[2:-1]
-                msg["text"] = msg["text"].replace(_id, self.slack_id_to_name[_id])
-
     def zulip_to_slack(self) -> Callable[[Dict[str, Any]], None]:
         def _zulip_to_slack(msg: Dict[str, Any]) -> None:
             slack_channel = get_slack_channel_for_zulip_message(
@@ -101,36 +101,6 @@ class SlackBridge:
 
         return _zulip_to_slack
 
-    def run_slack_listener(self) -> None:
-        members = self.slack_webclient.users_list()["members"]
-        # See also https://api.slack.com/changelog/2017-09-the-one-about-usernames
-        self.slack_id_to_name: Dict[str, str] = {
-            u["id"]: u["profile"].get("display_name", u["profile"]["real_name"]) for u in members
-        }
-        self.slack_name_to_id = {v: k for k, v in self.slack_id_to_name.items()}
-
-        @rtm.on("message")
-        def slack_to_zulip(client: RTMClient, event: Dict[str, Any]) -> None:
-            if event["channel"] not in self.slack_to_zulip_map:
-                return
-            user_id = event["user"]
-            user = self.slack_id_to_name[user_id]
-            from_bot = user == self.slack_config["username"]
-            if from_bot:
-                return
-            self.replace_slack_id_with_name(event)
-            content = ZULIP_MESSAGE_TEMPLATE.format(username=user, message=event["text"])
-            zulip_endpoint = self.slack_to_zulip_map[event["channel"]]
-            msg_data = dict(
-                type="stream",
-                to=zulip_endpoint["stream"],
-                subject=zulip_endpoint["topic"],
-                content=content,
-            )
-            self.zulip_client_constructor().send_message(msg_data)
-
-        self.slack_client.start()
-
 
 if __name__ == "__main__":
     usage = """run-slack-bridge
@@ -142,6 +112,8 @@ if __name__ == "__main__":
     sys.path.append(os.path.join(os.path.dirname(__file__), ".."))
     parser = argparse.ArgumentParser(usage=usage)
 
+    args = parser.parse_args()
+
     config: Dict[str, Any] = bridge_with_slack_config.config
     if "channel_mapping" not in config:
         print(
@@ -150,12 +122,11 @@ if __name__ == "__main__":
         )
         sys.exit(1)
 
+    check_token_access(config["slack"]["token"])
+
     print("Starting slack mirroring bot")
     print("MAKE SURE THE BOT IS SUBSCRIBED TO THE RELEVANT ZULIP STREAM(S) & SLACK CHANNEL(S)!")
 
-    # We have to define rtm outside of SlackBridge because the rtm variable is used as a method decorator.
-    rtm = RTMClient(token=config["slack"]["token"])
-
     backoff = zulip.RandomExponentialBackoff(timeout_success_equivalent=300)
     while backoff.keep_going():
         try:
@@ -164,14 +135,14 @@ if __name__ == "__main__":
             zp = threading.Thread(
                 target=sb.zulip_client.call_on_each_message, args=(sb.zulip_to_slack(),)
             )
-            sp = threading.Thread(target=sb.run_slack_listener, args=())
             print("Starting message handler on Zulip client")
             zp.start()
-            print("Starting message handler on Slack client")
-            sp.start()
 
+            print(
+                "Make sure your Slack Webhook integration is running\n"
+                "to receive messages from Slack."
+            )
             zp.join()
-            sp.join()
         except Exception:
             traceback.print_exc()
         backoff.fail()