rocket.chat web-hook to post messages silently

readme.md

This is a Rocket.Chat incoming web hook. Hook gets an array of "messages" and silently creates chat messages directly in the Rocket's database without disturbing users with notifications or alerts - messages just appear in the channels. Messages appear silently even if the user has the channel openned: no refresh or re-enter is required (this is not this script's feature, it's how Rocket works).

This script can post messages to channels and groups by name (if message destination set to #name), or by api roomId (no prefixes in destination). And it can post DM to a user (if destination is set to @username). Please note, in this case DM between message author and destination user must already be created.

This hook expects request.content: ISilentMessage[];

ISilentMessage {
  // Message body.
  text: string;

  // User to set as message author.
  // No leading @, user must be registered.
  author: string;

  // Channel to post message to.
  // It may be "#channeg_or_group_name", "@username", or "room_id".
  // NOTE: in case of "@username", the DM between this user and message
  // author must exists, this script doesn't create one
  // (greatly complicates everything).
  destination: string;

  // An array of message attachments. Optional, may be omitted.
  attachments: [];
}

Pyhton

with requests.sessions.Session() as session:
  session.post(
    'https://CHAT.URL/hooks/WEBHOOK/TOKEN',
    json=[
      {
        'text': 'Multiline\nmessage\nto #channel_by_name',
        'author': 'admin',
        'destination': '#channel_by_name',
      },
      {
        'text': 'Message to abc123abc123abc123 (roomId)',
        'author': 'admin',
        'destination': 'abc123abc123abc123',
      },
      {
        'text': 'DM to user `user` (by username)',
        'author': 'admin',
        'destination': '@user',
      },
      {
        'text': 'Message with attachments to #channel_by_name',
        'author': 'admin',
        'destination': '#channel_by_name',
        'attachments': [
          {
            "title": "Rocket.Chat",
            "title_link": "https://rocket.chat",
            "text": "Rocket.Chat, the best open source chat",
            "image_url": "/images/integration-attachment-example.png",
            "color": "#764FA5"
          }
        ]
      },
    ])

curl

curl -X POST -H 'Content-Type: application/json' \
     --data '[ { "text": "Multiline\\nmessage\\nto #channel_by_name", "author": "admin", "destination": "#channel_by_name" }, { "text": "Message to abc123abc123abc123 (roomId)", "author": "admin", "destination": "abc123abc123abc123" }, { "text": "DM to user `user` (by username)", "author": "admin", "destination": "@user" }]' \
     https://chat.url/hooks/WEBHOOK/TOKEN

silent-post-whs.js

class Script {
  knownRoomIds = new Map();
  knownUserIds = new Map();

  process_incoming_request({request}) {
    /*
    * This hook expects
    * request.content: ISilentMessage[];
    * ISilentMessage {
    *   // Message body.
    *   text: string;
    *
    *   // User to set as message author.
    *   // No leading @, user must be registered.
    *   author: string;
    *
    *   // Channel to post message to.
    *   // It may be "#channeg_or_group_name", "@username", or "room_id".
    *   // NOTE: in case of "@username", the DM between this user and message
    *   // author must exists, this script doesn't create one
    *   // (greatly complicates everything).
    *   destination: string;
    *
    *   // An array of message attachments. Optional, may be omitted.
    *   attachments: [];
    * }
    * */

    for (const message of request.content) {
      authorId = this.findUser(message.author)
      if (!authorId) {
        continue;
      }

      rid = this.findDestination(message.destination, authorId);
      if (!rid) {
        continue;
      }

      this.postMessageSilent(
        rid, authorId, message.author,
        message.text, message.attachments);
    }
    return {
      content: null,
    };
  }

  findDestination(dest, authorId) {
    if (this.knownRoomIds.has(dest)) {
      return this.knownRoomIds.get(dest);
    }

    let rid = null;
    if (dest[0] === '#') {
      const room = Rooms.findOneByName(dest.slice(1));
      if (!room) {
        return null;
      }
      rid = room._id;
    } else if (dest[0] === '@') {
      userId = this.findUser(dest.slice(1), knownUserIds);
      if (!userId) {
        return null;
      }
      rid = [authorId, userId].sort().join('');
      const room = Rooms.findOneById(rid);
      if (!room) {
        return null;
      }
      rid = room._id;
    } else {
      rid = dest;
    }

    this.knownRoomIds.set(dest, rid);
    return rid;
  }

  findUser(username) {
    if (this.knownUserIds.has(username)) {
      return this.knownUserIds.get(username);
    }

    const user = Users.findOneByUsername(username);
    if (!user) {
      return null;
    }
    this.knownUserIds.set(username, user._id);
    return user._id;
  }

  postMessageSilent(rid, authorId, authorName, text, attachments) {
    const record = {
      t: 'p',
      rid: rid,
      ts: new Date(),
      msg: text,
      u: {
        _id: authorId,
        username: authorName,
      },
      groupable: false,
      unread: true,
    };

    if (attachments && attachments.length) {
      record.attachments = attachments;
    }

    Messages.insertOrUpsert(record);
  }
}