seance/functions.js

const r2 = require('r2')
const path = require('path')
const fs = require('fs')
const { once } = require('events')
const getPost = require('mediumexporter').getPost
const { createClient } = require('webdav')
const readline = require('readline')
const { markdown } = require('markdown')
const GhostAdminAPI = require('@tryghost/admin-api')
const Rembrandt = require('rembrandt')

const config = require('./config')

class Seance {
  constructor(...args) {
    this.MEDIUM_IMG_CDN = 'https://miro.medium.com/fit/c/'

    try {
      this.ghostAdmin = new GhostAdminAPI({
        url: config.ghost.url,
        version: config.ghost.version,
        key: config.ghost.admin_key,
      })
    } catch(err) {
      console.error('Your Ghost isn\'t configured. Please run `seance setup` to fix this!')
    }

    /**
     * function [fetchFromMedium]
     * @returns [string] status
    */
  }

    async fetchFromMedium (mediumUrl, options = {
        json: null,
      }) {
      console.info(`Fetching: ${mediumUrl}`);
      var output = path.join(process.env.PWD, 'content')

      var json

      if (!options.json) {
        json = await this.fetchMediumJSON(mediumUrl)
      } else {
        json = options.json
      }

      // use mediumexporter's getPost function to fetch a Medium post
      const post = await getPost(mediumUrl, {
          returnObject: true,
          output: output,
          postJSON: json
        }).catch((err) => {
          return {
            error: err,
          }
        })

      // set output folder path
      // this is based on what mediumexporter chooses as the output folder
      var outputFolder = path.join(output, post.slug)

      console.info(`Saving to: ${outputFolder}`)

      if (!fs.existsSync(path.join(outputFolder, post.slug))) {
        fs.mkdirSync(outputFolder, { recursive: true })
      }

      // mediumexporter writes a plain .md file if the post has no media
      // if that is the case, we should create the subfolder manually
      // and copy the data there.
      if (fs.existsSync(path.join(output, post.slug + '.md'))) {
        fs.renameSync(
          path.join(output, post.slug + '.md'),
          path.join(outputFolder, 'index.md')
        )
      }

      // generate metadata
      const metadata = JSON.stringify({
        title: post.title,
        subtitle: post.subtitle,
        author: post.author || "",
        authors: post.authors || [],
        date: new Date(post.date),
        tags: post.tags,
        url: post.url,
        slug: post.slug,
        images: post.images,
        featuredImage: post.featuredImage,
      })

      // write metadata to output folder
      await fs.promises.writeFile(path.join(outputFolder, 'metadata.json'), metadata)
      return post
    };


  /**
   * function [pushToGhost]
   * @returns [string] status
  */
  async pushToGhost (postSlug) {
    console.info('Pushing: ' + postSlug);

    // Decide working path
    var postFolder = path.resolve('content/' + postSlug)

    // Verify file exists
    if (!fs.existsSync(postFolder)) {
      console.error('Could not find post folder! Is it fetched?')
      return false
    }

    // Decide file
    const postContent = path.join(postFolder, 'index.md')
    const postOutput = path.join(postFolder, 'ghost.md')

    // Verify post exists
    if (!fs.existsSync(postContent)) {
      console.error("Could not find 'index.md' in " + postSlug + "! Is it fetched?")
      return false
    }

    // Decide WebDAV upload path
    var current_date = new Date()

    const uploadPath = path.join(
      current_date.getUTCFullYear().toString(),
      (current_date.getUTCMonth() + 1).toString(),
      postSlug
    )

    // Path where WebDAV files will be placed (eg. https://example.com:2078)
    const davPath = path.join(config.webdav.path_prefix, uploadPath)

    // Public path to upload those files (eg. https://media.example.com/uploads)
    // We'll do it directly since path.join mangles the protocol
    const uploadedPath = config.webdav.uploaded_path_prefix + '/' + uploadPath

    // load metadata file
    console.debug('Loading metadata')

    var postMetaFile = path.join(postFolder, 'metadata.json')
    let postMeta = await JSON.parse(await fs.promises.readFile(postMetaFile))

    // Process lines
    const readInterface = readline.createInterface({
      input: fs.createReadStream(postContent),
      output: process.stdout,
      terminal: false
    })

    const outStream = fs.createWriteStream(postOutput, { encoding: 'utf-8' })

    var titleSkipped = false;

    let reImage = new RegExp('^!\\[(.*)\\]\\((\\S+?)\\)(.*)')
    let reTitle = new RegExp('^#\ .*')

    // Note down uploaded images
    var uploadedImages = []

    for await (const line of readInterface) {
      // Line to output
      // Default is to make it same as input
      var newLine = line

      // Skip the header
      if (!titleSkipped && await reTitle.exec(line)) {
        titleSkipped = true
      }

      // check for images
      var m = await reImage.exec(line)
      if (m) {
        // Get image name
        var imageAlt = m[1]
        var imageName = m[2].replace('*', '')
        var imagePath = path.join(postFolder, 'images', imageName)

        if (!fs.existsSync(imagePath)) {
          console.warn('Skipping missing image: ' + imageName)
        } else {
          // check for separator image
          var isScissors = await this.checkScissors(imagePath)
          if (isScissors) {
            newLine = '\n---\n'
          } else {
            // upload pic to server
            console.debug(`Adding to upload queue: ${imageName}`)
            uploadedImages.push(imageName)
            this.uploadDav(davPath, imagePath)

            newLine = '![' + imageAlt + '](' + uploadedPath + '/' + imageName + ')'
          }
        }
      }

      outStream.write(newLine + '\n')
    }

    // Upload feature_image, if required
    var featuredImagePath
    if (!!postMeta.featuredImage) {
      var imageName = postMeta.featuredImage.replace('*', '')

      // if the image is listed in postMeta.images, it would have
      // already been uploaded
      if (uploadedImages.indexOf(imageName) != -1) {
        console.log(`Skipping feature image ${imageName}: already listed for upload`)
      } else {
        var imagePath = path.join(postFolder, 'images', imageName)

        // We can only upload if the file exists!
        if (!fs.existsSync(imagePath)) {
          console.warn(`Skipping feature image "${imageName}": file not found`)
        } else {
          console.log(`Uploading feature image: ${imageName}`)
          this.uploadDav(davPath, imagePath)
          featuredImagePath = uploadedPath + '/' + imageName
        }
      }
    }

    // calculate users
    let users = []
    postMeta.authors.forEach((user) => {
      users.push({slug: user.username})
    })

    // This will happen once all the line reading is finished
    // Uploads will continue in paralell though
    console.debug('Adding to Ghost')

    this.ghostAdmin.posts.add({
      title: postMeta.title,
      custom_excerpt: postMeta.subtitle || null,
      tags: postMeta.tags,
      authors: users,
      html: markdown.toHTML(await fs.promises.readFile(postOutput, 'utf-8')),
      feature_image: featuredImagePath
    }, {source: 'html'})
    .then((res) => {
      // Check if user was added
      if (res.primary_author.id == 1) {
        console.warn(`WARNING: The admin editor, "${res.primary_author.name}", is set as author for this post. If this is incorrect, there was some problem matching usernames. Please check and set it manually.`)
      }
      console.log('Post conveyed successfully.')
    })
  };


  /**
   * function [mediumToGhost]
   * @returns [string] status
  */
  mediumToGhost (mediumUrl) {
    console.info('Copying: ' + mediumUrl);
  }


  async fetchMediumJSON(mediumUrl) {
    var json
    var text

    if (mediumUrl.match(/^http/i)) {
      // add ?json attribute
      mediumUrl = mediumUrl.replace(/#.*$/, '')
      mediumUrl= `${mediumUrl}?format=json`
      const response = await fetch(mediumUrl)
      text = await response.text()
    } else if (fs.existsSync(mediumUrl)) {
      text = (await fs.promises.readFile(mediumUrl)).toString()
    } else {
      throw { error: 'URL must be a Medium URL or existing JSON file' }
    }

    try {
      json = await JSON.parse(text.substr(text.indexOf('{')))
    } catch(err) {
      throw { error: 'You JSON seems to be malformed' }
    }

    return json;
  }

  /**
   * function [checkScissors]
   * @returns [boolean] matchStatus
  */

  async checkScissors (imagePath) {
    // Decide "separator" image
    // If set, images matching this will be ignored and replaced
    // with a horizontal-rule ("---" in markdown) instead.
    let scissors = config.scissors

      // if scissors not set, return false
    // (it's never a scissors since it never matches)
    if (!scissors) {
      console.warn('[scissors] No scissors set, so rejecting all images')
      return false
    } else {

      // Check if given image matches the scissors
      try {
        let isScissors = new Rembrandt({
          imageA: scissors,
          imageB: imagePath,
          thresholdType: Rembrandt.THRESHOLD_PERCENT,
          maxThreshold: 0.1
        })
        let result = await isScissors.compare()
        return result.passed
      } catch (err) {
        console.warn('[scissors] Skipping scissors check:', err.message)
        return false
      }
    }
  }

  /**
   * function [createUser]
   * @returns [object] ghost data json
  */
  async generateUserData (mediumUsername, email) {
    console.debug('Creating: @' + mediumUsername + '(email: ' + email + ')');
    const mediumUrl = `https://medium.com/@${mediumUsername}/?format=json`;
    const json = await fetchMediumJSON(mediumUrl);

    if (!json.success) {
      console.error(`Error: ${json.error}`)
      return false
    }

    console.debug(`Name: ${json.payload.user.name}`)
    console.debug(`Bio: ${json.payload.user.bio}`)

    // Download and upload image

    let imageId = json.payload.user.imageId
    console.log(`Image: ${imageId}`)

    let imagePath = MEDIUM_IMG_CDN + '256/256/' + imageId
    let filetype = imageId.split('.')[imageId.split('.').length - 1]
    let fileName = `${mediumUsername}.${filetype}`
    let filePath = path.join(process.env.PWD, fileName)

    console.log(`Fetching: ${imagePath}`)

    const response = await (await r2.get(imagePath).response).buffer()
    await await fs.promises.writeFile(filePath, response, 'base64')

    console.log("Uploading to server")

    await this.uploadDav(path.join(config.webdav.path_prefix,'avatars'),
      filePath)

    // Generate Ghost JSON

    const ghostData = {
      data: {
        users: [
          {
            id: 1,
            slug: json.payload.user.username,
            bio: json.payload.user.bio,
            email: email,
            name: json.payload.user.name,
            profile_image: config.webdav.uploaded_path_prefix + '/avatars/' + fileName
          }
        ]
      },
      meta: {
        exported_on: new Date,
        version: '2.14.0'
      }
    }

    return(JSON.stringify(ghostData))
  };

  async createDirIfNotExist (client, folder) {
    // recursively create subfolders if they don't exist.

    //safety: don't touch directories outside WEBDAV_PATH_PREFIX
    if (!folder.startsWith(config.webdav.path_prefix)) {
      throw new Error(`Cannot create directories outside ${config.webdav.path_prefix}`)
    }

    // check the folder
    await client.stat(folder)
    .catch(async (err) => {
      if (!err.response) {
        // no response! Maybe a network error or something :P
        console.error(`[dav-upload:folder] Error creating folder "${folder}"`)
        console.error(`[dav-upload:folder] ${err.toJSON().message}`)
        console.error('[dav-upload:folder] Please check your Internet connection and try again')
        return false
      } else if (err.response.status == 404) {

        // it's a 404, so we'll create the directory
        console.debug(`Noting missing subdirectory: ${folder}`)

        // first, create the parent directory (if required)
        if (!await this.createDirIfNotExist(client, path.dirname(folder))) {
          // if not created, we fail too :-/
          return false
        }

        console.debug(`Creating missing subdirectory: ${folder}`)
        // then, create the current directory
        await client.createDirectory(folder)
        .catch(async (err) => {
          if (err.response.status == 405) { // Method Not Allowed
            // Maybe the directory's already been created in the meantime?
            await client.stat(folder)
            .catch((err2) => {
              // Bad guess. Panic (and raise the original error)
              console.error(`Error: ${err.toJSON().message}`)
              console.error("We're not sure what went wrong. Help!")
              throw err
            })
          } else {
            // what's this? Panic!
            console.error(`Error: ${err.toJSON().message}`)
            console.error("We're not sure what went wrong. Help!")
            throw err
          }
        })
      } else {

        // it's not a 404; we don't know how to handle this. Panic!
        console.error(err.toJSON())
        throw err
      }
    })
    return true
  }

  /**
   * function [uploadDav]
   * @returns [string] status
  */
  async uploadDav (dirPath, filePath) {

    // connect to webdav
    const client = createClient(
      config.webdav.server_url,
      {
        username: config.webdav.username,
        password: config.webdav.password,
        digest: config.webdav.use_digest
      })

    // create directory if not exists
    console.debug(`[dav-upload] Loading ${dirPath}`)
    if (!await this.createDirIfNotExist(client, dirPath)) {
      console.error(`[dav-upload] Could not upload ${path.basename(filePath)} :(`)
      return false
    }

    // upload a file
    console.debug('Uploading file')
    const outStream = client.createWriteStream(
      path.join(dirPath, path.basename(filePath))
    )
    outStream.on('finish', () => console.debug('Uploaded successfully.'))

    const inStream = fs.createReadStream(filePath)
    .pipe(outStream)

    return true
  }

}

module.exports = {
  Seance
}