wafrn / packages / backend / utils / activitypub / handlePostRequest.ts

import { SignedRequest } from '../../interfaces/fediverse/signedRequest.js'
import { Response } from 'express'
import { getPostAndUserFromPostId } from '../cacheGetters/getPostAndUserFromPostId.js'
import { getFollowerRemoteIds } from '../cacheGetters/getFollowerRemoteIds.js'
import { logger } from '../logger.js'
import { postToJSONLD } from './postToJSONLD.js'
import { getRemoteActor } from './getRemoteActor.js'
import { Queue } from 'bullmq'
import { completeEnvironment } from '../backendOptions.js'
import { FederatedHost, Follows, User } from '../../models/index.js'
import { Op } from 'sequelize'
import { Privacy } from '../../models/post.js'

const processPostViewQueue = new Queue('processRemoteView', {
  connection: completeEnvironment.bullmqConnection,
  defaultJobOptions: {
    removeOnComplete: true,
    attempts: 3,
    backoff: {
      type: 'exponential',
      delay: 25000
    },
    removeOnFail: true
  }
})

async function handlePostRequest(req: SignedRequest, res: Response) {
  if (req.params?.id) {
    const cachePost = await getPostAndUserFromPostId(req.params.id)
    const post = cachePost.data
    if (post) {
      // we get remote user async-ly
      const fediData = req.fediData as {
        fediHost: string
        remoteUserUrl: string
        valid: boolean
      }
      const user = post.user
      if (user.isRemoteUser) {
        // EXTERNAL USER
        if (post.remotePostId) {
          res.redirect(post.remotePostId)
        } else {
          // bsky post
          res.sendStatus(404)
        }
        return
      }
      if (user.banned) {
        res.sendStatus(410)
        return
      }
      const remoteActor = await getRemoteActor(fediData.remoteUserUrl, cachePost.data.user, false)
      if (!remoteActor) {
        logger.debug({
          message: `remote actor not found`,
          fedidata: fediData
        })
        return res.sendStatus(500)
      } else {
        const federatedHost = await remoteActor.getFederatedHost()
        await processPostViewQueue.add('processPost', {
          postId: post.id,
          federatedHostId: federatedHost && federatedHost.publicInbox ? federatedHost.id : '',
          userId: federatedHost?.publicInbox ? '' : remoteActor.id
        })
      }
      if (post.privacy === Privacy.DirectMessage) {
        res.sendStatus(403)
        return
      }
      if (post.privacy === Privacy.FollowersOnly) {
        const followerIds = await getFollowerRemoteIds(user.id)
        try {
          if (remoteActor) {
            const followerServers = (
              await User.findAll({
                include: [FederatedHost],
                where: {
                  id: {
                    [Op.in]: (
                      await Follows.findAll({
                        where: {
                          followedId: user.id
                        }
                      })
                    ).map((elem: any) => elem.followerId)
                  }
                }
              })
            ).map((elem: any) => elem.federatedHostId)
            if (
              !(followerIds.includes(remoteActor.remoteId) || followerServers.includes(remoteActor.federatedHostId))
            ) {
              res.sendStatus(403)
              return
            }
          } else {
            res.sendStatus(403)
            return
          }
        } catch (error) {
          logger.warn({
            message: 'Error on post',
            postId: post.id,
            fediData: req.fediData,
            user: user.id,
            error: error
          })
          res.sendStatus(500)
          return
        }
      }
      const response = await postToJSONLD(post.id)
      if (!response) {
        return res.sendStatus(404)
      }
      res.set({
        'content-type': 'application/activity+json'
      })
      res.send({
        ...response.object,
        '@context': response['@context']
      })
    } else {
      res.sendStatus(404)
    }
  } else {
    res.sendStatus(404)
  }
  res.end()
}

export { handlePostRequest }