lemmy-bot

Library to make it easier to make bots for Lemmy, the fediverse forum/link aggregator.

Features

• Respond to different events that happen in lemmy, such as posts, comments, and modlog actions
• Perform actions on a schedule
• Supports most actions a regular Lemmy account can make, including moderator and admin actions

Installation

Run

npm install lemmy-bot

or

yarn add lemmy-bot

or

pnpm install lemmy-bot

Lemmy Versions

For lemmy versions 0.17.x, use lemmy-bot 0.3.9 and lower. For lemmy versions 0.18.x, use lemmy-bot 0.4.0 and up

Documentation

LemmyBot

Create a bot by newing up a LemmyBot

import LemmyBot from 'lemmy-bot';

const bot = new LemmyBot({
  // Pass configuration options here
});

Calling bot.start() will start the bot. Calling bot.stop() will stop it.

---

LemmyBotOptions

What your bot does is determined by the options passed to the constructor. They are as follows:

credentials

Log in credentials for the bot. Accepts an object with username and password properties. If not provided, the bot can still poll the instance for items like posts, comments, and modlog actions, but it will not be able to perform actions that require an account.

instance REQUIRED

The Lemmy instance your bot will connect to. Only pass the domain name of the instance, e.g. if the bot is supposed to be on lemmy.ml, pass 'lemmy.ml', not 'https://lemmy.ml'.

connection

Options for the bot's connection. It is an object with the following properties:

• minutesBeforeRetryConnection: If the bot's connection closes, the bot will wait this many minutes before opening another connection and trying again. Default value is 5. If you don't want the bot to attempt to reconnect, pass in false.
• secondsBetweenPolls: Number of seconds between HTTP requests the bot will make to check for items to handle. Default value is 30.
• minutesUntilReprocess: If the bot can to potentially handle the same item more than once (e.g. polling posts by top day every minute and replying to any with more than 25 points), minutesUntilReprocess specifies how many minutes must pass until an item is valid for reprocessing. If this value is undefined, items will not be reprocessed at all. Default value is undefined. NOTE: It is possible that an item that is valid for reprocessing will not be handled again. Taking the example from before and polling every day instead of every minute, a post from the day before that is valid for reprocessing might not show up in the current day's top posts.

handlers

Options that control what the bot does when encountering a certain item. The following is a simple example to show how handlers work:

import LemmyBot from 'lemmy-bot';

const bot = new LemmyBot({
  handlers: {
    post: (res) => {
      console.log(res.postView.post.name);
    }
  }
});

bot.start();

In the previous example, the bot polls the instance for posts and logs the name of each one.

Each handler can accept an object with the following properties:

• handle: Function to run to handle an item. Acccepts the item being handled as an argument.
• secondsBetweenPolls: Does the same thing as the one from connection. Any value provided will override the value set in connection for handling items of a given type.
• minutesUntilReprocess: Does the same thing as the one from connection. Any value provided will override the value set in connection for handling items of a given type.

Some handlers accept more options.

If using the default values for secondsBetweenPolling and minutesUntilReprocess, the handle function can be used instead of the object.

The handle function receives an object that has the following props as an argument:

• botActions: Different actions the bot can perform. More on bot actions in the bot actions sections.
• preventReprocess: Call if the item being handled should not be handled again, even if minutesUntilReprocess is set.
• reprocess: Mark the item being handled as able to be reprocessed, even if minutesUntilReprocess is not set.
• item (property name varies depending on handler): The item being handled.

The following are the properties that can be set on handlers:

• comment: Handle function has commentView in the argument object. Handler options also accept sort property of type CommentSortType.
• post: Handle function has postView in the argument object. Handler options also accept sort property of type SortType.
• privateMessage: Handle function has messageView in the argument object.
• comment: Handle function has commentView in the argument object.
• registrationApplication: Handle function has applicationView in the argument object.
• mention: Handle function has mentionView in the argument object.
• reply: Handle function has replyView in the argument object.
• commentReport: Handle function has reportView in the argument object.
• postReport: Handle function has reportView in the argument object.
• privateMessageReport: Handle function has reportView in the argument object.
• modRemovePost: Handle function has removedPostView in the argument object.
• modLockPost: Handle function has lockedPostView in the argument object.
• modFeaturePost: Handle function has featurePostView in the argument object.
• modRemoveComment: Handle function has removedCommentView in the argument object.
• modRemoveCommunity: Handle function has removedCommunityView in the argument object.
• modBanFromCommunity: Handle function has banView in the argument object.
• modAddModToCommunity: Handle function has modAddedToCommunityView in the argument object.
• modTransferCommunity: Handle function has modTransferredToCommunityView in the argument object.
• modAddAdmin: Handle function has addedAdminView in the argument object.
• modBanFromSite: Handle function has banView in the argument object.

federation

Options for handling federated instances. Can be one of:

• 'local': Only handle items on the bot's local instance. This is the default setting.
• 'all': Handle items on any instance, both local and federated.
• object with the following properties:
  • allowList: List of instances the bot is allowed to handle items from.
  • blockList: List of instances the bot is not allowed to handle ites from.

A bot cannot set both a block list and an allow list. Entries allowList and blockList can either be strings or objects. If the entry is a string, all items on the instance named by the string will be allowed/blocked. If an object, it must have the following shape:

• instance: Domain name of the instance to allow/block from.
• communities: List of community names on the instance that should be allowed/blocked.

schedule

Task object or list of task objects. Task objects have the following properties:

• cronExpression: String expression that controls when the task runs. See node-cron for valid expression syntax.
• doTask: Run the task. Takes bot actions as an argument.
• timezone: String stating the timezone the schedule should be in. See here for supported timezones.
• runAtStart: Boolean value for whether or not the task should be run immediately. Defaults to false.

dbFile

The bot tracks which items it has handled already in a SQLite database. Accepts a string path to the file to use a database: will create the file if it does not already exist. If this option is not specified, the bot will store the SQLite DB in memory. This can be useful during development, but it is recommended to use a file when running in production.

markAsBot

If true, the bot will automatically mark its own account as a bot. If false, make sure to remember to mark the bot's account as a bot in the account's settings.

Default value is true.

---

Bot Actions

When handling an item or running a scheduled task, the bot will have access to several actions it can perform as an argument.

The actions are as follows, grouped by access level in ascending order:

No login required

• getCommunityId(options: string | SearchOptions): Retrieves a community ID based on name; returns undefined if not found. If passed a string, the bot will look for the community name on the local instance. Can also be passed a SearchOptions object with the following propertied:
  • instance: Instance the community is on.
  • name: Name of the community.
• getUserId(options: string | SearchOptions): Retrieves a user ID based on name; returns undefined if not found. Like getCommunityId, accepts either a string to search for a user by name on the local instance, or a SearchOptions object to search on another instance, only the name refers to a user instead of a community.
• getPost(postId: number): Retrieve a post based on its ID.
• getComment(commentId: number): Retrieve a comment based on its ID.
• getParentOfComment(form: Comment): Retrieves the parent of a comment. Accepts a comment object, which is returned from handlers that deal with comments (e.g. comment handler, mention handler, reply handler, etc.). Returns an object with the following properties:
  • type "post" or "comment"
  • data PostView | CommentView
• isCommunityMod(form: {community_id: number, person_id: number}): Returns whether or not a person is a moderator of a given community.

Regular account

• createComment(form: CreateComment): Create a comment. Accepts an object with the following properties:
  • content string
  • post_id number
  • parent_id optional number
  • language_id optional number
• reportComment(form: ReportComment): Report a comment. Accepts an object with the following properties:
  • comment_id number
  • reason string
• reportPost(form: ReportPost): Report a post. Accepts an object with the following properties:
  • post_id number
  • reason string
• votePost(form: VotePost): Vote on a post. Accepts an object with the following properties:
  • post_id number
  • vote Vote
• voteComment(form: VoteComment): Vote on a comment. Accepts an object with the following properties:
  • comment_id number
  • vote Vote
• createPost(form: CreatePost): Create a post. form has the following properties:
  • name string
  • url optional string
  • body optional string
  • nsfw optional boolean
  • language_id optional number
  • community_id number
  • honeypot optional string
• sendPrivateMessage(form: SendPrivateMessage): Send a private message to a user. Accepts an object with the following properties:
  • recipient_id number
  • content string
• reportPrivateMessage(form: ReportPrivateMessage): Report a private message. Accepts an object with the following properties:
  • privateMessage_id number
  • reason string
• uploadImage(image: Buffer): Upload an image to pictrs. Returns a promise with an UploadImageResponse.
• resolveObject(form: string | { community: string, instance: string }): Resolves an object on a remote instance. Use this to federate with communities that aren't showing up on your local instance yet. Note: If passing in a string, make sure it is in the format "!'community name'@'instance domain'".
• followCommunity(community_id: number): Make your bot subscribe to a community.
• editPost(form: EditPost): Edit a post that was made previously by the bot. The form argument has the following properties:
  • post_id number
  • name optional string
  • url optional string
  • body optional string
  • nsfw optional boolean
  • language_id optional number
• editComment(form: EditComment): Edit a comment previously made by the bot. The form argument has the following properties:
  • comment_id number
  • content optional string
  • language_id optional number

Community moderator

• banFromCommunity(form: BanFromCommunity): Ban a user from a community. Accepts an object with the following properties:
  • community_id number
  • personId number
  • days_until_expires optional number
  • reason optional string
  • remove_data optional boolean
• removeBanFromCommunity(form: BanFromCommunity): Undoes ban from community. Takes same argument type as banFromCommunity.
• removePost(form: RemovePost): Remove a post. Accepts an object with the following properties:
  • post_id number
  • reason optional string
• removeComment(form: RemoveComment): Remove a comment. Accepts an object with the following properties:
  • comment_id number
  • reason optional string
• resolveCommentReport(commentReportId: number): Resolve a comment report.
• resolvePostReport(postReportId: number): Resolve a post report.
• resolveMessageReport(privateMessageReportId: number): Resolve a private message report.
• featurePost(form: FeaturePost): Feature a post. Accepts an object with the following properties:
  • post_id number
  • feature_type: PostFeatureType
  • featured: boolean
• lockPost(postId: number, locked: boolean): Lock/unlock a post. Accepts an object with the following properties:
  • pst_id number
  • locked boolean

Admin

• banFromSite(form: BanFromSite): Ban a user from the instance. Accepts an object with the following properties:
  • person_id number
  • days_until_expires optional number
  • reason optional string
  • remove_data optional boolean
• removeBanFromSite(form: BanFromSite): Unbans a user from the site. Argument type is the same that is passed to banFromSite
• approveRegistrationApplication(applicationId: number): Approve the creation of an account.
• rejectRegistrationApplication(applicationId: number, denyReason?: string): Deny a request to create an account on the instance.

Examples

Live Examples

• Translator bot
• OCR scanner bot
• AI art bot
• Piped link bot

Like Me Bot

This example bot will like users' posts and comments on request. Users can subscribe and unsubscribe to the liking by messaging the bot.

import LemmyBot, { Vote } from 'lemmy-bot';

const usersToLike: number[] = [];

const bot = new LemmyBot({
  instance: 'instance.xyz',
  credentials: {
    username: 'LikeMeBot',
    password: 'password'
  },
  federation: 'all',
  dbFile: 'db.sqlite3',
  handlers: {
    post: {
      handle: ({
        postView: {
          post: { creator_id, id }
        },
        botActions: { votePost }
      }) => {
        if (usersToLike.includes(creator_id)) {
          votePost({
            post_id: id,
            vote: Vote.Upvote
          });
        }
      }
    },
    comment: ({
      commentView: {
        comment: { creator_id, id }
      },
      botActions: { voteComment }
    }) => {
      if (usersToLike.includes(creator_id)) {
        voteComment({
          comment_id: id,
          vote: Vote.Upvote
        });
      }
    },
    privateMessage: ({
      messageView: {
        private_message: { content, creator_id }
      },
      botActions: { sendPrivateMessage }
    }) => {
      const lcContent = content.toLowerCase();
      if (lcContent.includes('like me')) {
        if (usersToLike.includes(creator_id)) {
          sendPrivateMessage({
            recipient_id: creator_id,
            content:
              'I am already liking your posts. Message "Stop" to unsubscribe.'
          });
        } else {
          usersToLike.push(creator_id);
          sendPrivateMessage({
            recipient_id: creator_id,
            content: 'You are now subscribed! I will like anything you post'
          });
        }
      } else if (lcContent.includes('stop')) {
        if (!usersToLike.includes(creator_id)) {
          sendPrivateMessage({
            recipient_id: creator_id,
            content: 'You are already unsubscribed from my likes'
          });
        } else {
          for (let i = 0; i < usersToLike.length; ++i) {
            if (usersToLike[i] === creator_id) {
              usersToLike.splice(i, 1);
              break;
            }
          }
        }
      } else {
        sendPrivateMessage({
          recipient_id: creator_id,
          content:
            'Command not recognized. Send a message to me that says "Like me" if you want me to like your posts. If you don\'t want me to like your posts anymore, message me "Stop"'
        });
      }
    }
  }
});

bot.start();

Congratulator Bot

This bot will comment a cringy congratulations whenever a post on certain communities receives a score or 25 or more. Posts are valid to be handled after 10 minutes, but if a post ist congratulated it will no longer be eligible to be processed (due to preventReprocess being called). Posts that it's polling will be sorted by hot, and the bot will only be able to check posts in the shrek or tv communities on instance.xyz or the fediverse, cringe, and cooking communities on fediplace.ml.

import LemmyBot from 'lemmy-bot';

const bot = new LemmyBot({
  instance: 'instance.xyz',
  credentials: {
    username: 'CongratulatorBot',
    password: 'password'
  },
  connection: {
    minutesUntilReprocess: 10,
    secondsBetweenPolls: 120
  },
  dbFile: 'db.sqlite3',
  federation: {
    allowList: [
      {
        instance: 'instance.xyz',
        communities: ['shrek', 'tv']
      },
      {
        instance: 'fediplace.ml',
        communities: ['fediverse', 'cringe', 'cooking']
      }
    ]
  },
  handlers: {
    post: {
      sort: 'Hot',
      handle: ({
        postView: {
          counts: { score },
          post: { id }
        },
        botActions: { createComment },
        preventReprocess
      }) => {
        if (score > 25) {
          createComment({
            post_id: id,
            content:
              'WOW, 25+ score!?!?! Das a lot of score-arinos!!!!! Congratulations fedizen! :)'
          });
          preventReprocess();
        }
      }
    }
  }
});

bot.start();

Cringe username rejector

This bot will reject registration applications of anyone with a cringy username. The bot must have admin privileges to work.

import LemmyBot from 'lemmy-bot';

const cringeNameRegex = /(^(x|X)+.+(x|X)+$)|69|420/;

const bot = new LemmyBot({
  instance: 'instance.ml',
  credentials: {
    username: 'CringeRejector',
    password: 'password'
  },
  handlers: {
    registrationApplication: ({
      applicationView: {
        creator: { name },
        registration_application: { id }
      },
      botActions: { rejectRegistrationApplication }
    }) => {
      if (cringeNameRegex.test(name)) {
        rejectRegistrationApplication({
          id,
          deny_reason: 'No cringy usernames allowed'
        });
      }
    }
  }
});

bot.start();

Credits

Logo made by Andy Cuccaro (@andycuccaro) under the CC-BY-SA 4.0 license.