Slack bridge: Update Slack bridge with Events API.

zulip/integrations/bridge_with_slack/README.md

@@ -1,33 +1,51 @@
 # Slack <--> Zulip bridge
 
-This is a bridge between Slack and Zulip.
+This integration is a bridge with Slack, delivering messages from
+Zulip into Slack. It is designed for bidirectional bridging, with the
+[Slack integration](https://zulip.com/integrations/doc/slack) used to
+deliver messages from Slack into Zulip.
+
+Note that using these integrations together for bidirectional bridging
+requires the updated version of the Slack integration included in
+Zulip 9.4+.
 
 ## Usage
 
 ### 1. Zulip endpoint
-1. Create a generic Zulip bot, with a full name like `Slack Bot`.
-2. (Important) Subscribe the bot user to the Zulip stream you'd like to bridge your Slack
-   channel into.
-3. In the `zulip` section of the configuration file, enter the bot's `zuliprc`
-   details (`email`, `api_key`, and `site`).
-4. In the same section, also enter the Zulip `stream` and `topic`.
+
+1. Create a generic Zulip bot, with a full name like `Slack Bridge`.
+
+2. [Subscribe](https://zulip.com/help/manage-user-channel-subscriptions#subscribe-a-user-to-a-channel)
+   the bot user to the Zulip channel(s) you'd like to bridge with
+   Slack.
+
+3. Create a [Slack webhook integration bot](https://zulip.com/integrations/doc/slack)
+   to get messages from Slack to Zulip. Make sure to follow the additional instruction
+   for setting up a Slack bridge.
+
+4. In the `zulip` section of the `bridge_with_slack_config.py`
+   configuration file, the bot's `zuliprc` details (`email`,
+   `api_key`, and `site`).
+
+5. In the `channel_mapping` section, enter the Zulip `channel` and
+   `topic` that you'd like to use for each Slack channel.  Make sure
+   that they match the same `channel` and `topic` you configured in
+   steps 2 and 3.
 
 ### 2. Slack endpoint
-1. Make sure Websocket isn't blocked in the computer where you run this bridge.
-   Test it at https://www.websocket.org/echo.html.
-2. Go to https://api.slack.com/apps?new_classic_app=1 and create a new classic
-   app (note: must be a classic app). Choose a bot name that will be put into
-   bridge_with_slack_config.py, e.g. "zulip_mirror". In the process of doing
-   this, you need to add oauth token scope. Simply choose `bot`. Slack will say
-   that this is a legacy scope, but we still need to use it anyway. The reason
-   why we need the legacy scope is because otherwise the RTM API wouldn't work.
-   We might remove the RTM API usage in newer version of this bot. Make sure to
-   install the app to the workspace. When successful, you should see a token
-   that starts with "xoxb-...". There is also a token that starts with
-   "xoxp-...", we need the "xoxb-..." one.
-3. Go to "App Home", click the button "Add Legacy Bot User".
-4. (Important) Make sure the bot is subscribed to the channel. You can do this by typing e.g. `/invite @zulip_mirror` in the relevant channel.
-5. In the `slack` section of the Zulip-Slack bridge configuration file, enter the bot name (e.g. "zulip_mirror") and token, and the channel ID (note: must be ID, not name).
+
+1. Go to the [Slack Apps menu](https://api.slack.com/apps) and open the same Slack app
+   that you used to set up the Slack Webhook integration previously.
+
+2. Navigate to the "OAuth & Permissions" menu and scroll down to the "Scopes"
+   section in the same page. Make sure "Bot Token Scopes" includes: `chat:write`
+
+3. Next, also in the same menu find and note down the "Bot User OAuth Token".
+   It starts with "xoxb-..." and not "xoxp".
+
+4. In the `slack` section of `bridge_with_slack_config.py`, enter the
+   bot name (e.g "slack_bridge"), token (e.g xoxb-...), and the
+   channel ID (note: must be ID, not name).
 
 ### Running the bridge
 

zulip/integrations/bridge_with_slack/bridge_with_slack_config.py

@@ -13,8 +13,8 @@
     "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
@@ -65,31 +74,28 @@ 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 is_message_from_slack(self, msg: Dict[str, Any]) -> bool:
+        # Check whether or not this message is from Slack to prevent
+        # them from being tossed back to Zulip.
+        return msg["sender_email"] == self.zulip_config.get("email")
 
     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(
                 msg, self.zulip_to_slack_map, self.zulip_config["email"]
             )
-            if slack_channel is not None:
+
+            if slack_channel is not None and not self.is_message_from_slack(msg):
                 self.wrap_slack_mention_with_bracket(msg)
                 slack_text = SLACK_MESSAGE_TEMPLATE.format(
                     username=msg["sender_full_name"], message=msg["content"]
@@ -101,36 +107,6 @@ 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 +118,8 @@ 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 +128,11 @@ 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 +141,14 @@ 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()