Download facebook messages by js

facebook message downloader.js

(async function (globalOptions) {
  let batch = 1;
  window['finalResult'] = {
    user_id: '',
    requestToken: '',
    messages: [],
    friend: {id: globalOptions.friend_id || 0, name: ''}
  };

  if (!finalResult.friend.id) {
    finalResult.friend = getFriend();
  }
  if (!finalResult.friend.id) {
    alert('Không tìm thấy friend id.');
    return;
  }
  const {requestToken, user_id} = getRequestToken();
  if (!requestToken) {
    alert('Không tìm thấy request token.');
    return;
  }
  finalResult.user_id = user_id;
  finalResult.requestToken = requestToken;
  await fetchMessage({...finalResult, ...globalOptions});
  console.info('Done', finalResult);

  function set(obj, keys, val, safe) {
    if (safe && typeof val === 'undefined') {
      return;
    }
    if (typeof keys === 'string') {
      keys = keys.split('.');
    }
    let index = 0;
    const length = keys.length;
    let temp = obj;
    let x;
    for (; index < length; ++index) {
      x = temp[keys[index]];
      temp = temp[keys[index]] = (index === length - 1 ? val : (x == null ? {} : x));
    }
  }

  function get(data, key, defValue) {
    if (typeof data !== 'object') {
      return defValue;
    }
    let result = defValue;
    key.replace(/([^a-zA-Z_\.]+)/g, '').split('.')
      .every(function (objKey) {
        if (data[objKey]) {
          result = data[objKey];
          data = data[objKey];
          return true;
        }
        result = defValue;
        return false;
      });
    return typeof result === 'function' ? result() : result;
  }

  function pick(obj, keys) {
    const result = {};
    keys.forEach(key => {
      set(result, key, get(obj, key));
    });

    return result;
  }

  function queryStringify(obj) {
    const items = [];
    for (let prop in obj) {
      if (obj.hasOwnProperty(prop)) {
        items.push(`${prop}=${encodeURIComponent(obj[prop] + '')}`);
      }
    }
    return items.join('&');
  }

  function request(options) {
    return new Promise((resolve, reject) => {
      const xhttp = new XMLHttpRequest();
      xhttp.onreadystatechange = function () {
        if (this.readyState === 4) {
          try {
            const rawData = xhttp.responseText.match(/^([^\n]+)\n(.*)$/m)[1];
            const data = JSON.parse(rawData);
            const rawMessages = get(data, 'buzz.data.message_thread.messages.nodes');
            if (!Array.isArray(rawMessages)) {
              return resolve({has_previous_page: false});
            }
            options.before = rawMessages[0].timestamp_precise;
            rawMessages.reverse();
            rawMessages.some(item => {
              if (options.after && item.timestamp_precise < options.after) {
                window['buzz_cancel'] = 'stop by after';
                return true;
              }
              if (options.maxMessages && options.messages.length === options.maxMessages) {
                window['buzz_cancel'] = 'stop by max message';
                return true;
              }
              const message = pick(item, ['__typename', 'message.text', 'message_sender.id', 'timestamp_precise']);
              if (item.__typename !== 'UserMessage') {
                if (['VoiceCallMessage', 'VideoCallMessage'].indexOf(item.__typename) > -1) {
                  message.snippet = item.snippet;
                  options.messages.push(message);
                }
                return;
              }
              if (item.sticker) {
                message.sticker = pick(item.sticker, ['label', 'url', 'width', 'height']);
              }
              if (item.extensible_attachment) {
                message.extensible_attachment = pick(item.extensible_attachment.story_attachment, [
                  'description.text',
                  'url'
                ]);
              }
              if (item.blob_attachments[0]) {
                message.blob_attachments = item.blob_attachments.map(blob_attachment => {
                  let result;
                  switch (blob_attachment.__typename) {
                    case 'MessageAnimatedImage':
                      result = pick(blob_attachment.animated_image, ['uri', 'height', 'width']);
                      result.__typename = blob_attachment.__typename;
                      result.filename = blob_attachment.filename;
                      break;
                    case 'MessageImage':
                      result = pick(blob_attachment.large_preview, ['uri', 'height', 'width']);
                      result.thumbnail = blob_attachment.thumbnail.uri;
                      result.filename = blob_attachment.filename;
                      result.__typename = blob_attachment.__typename;
                      break;
                    case 'MessageFile':
                      result = pick(blob_attachment, ['filename', 'url']);
                      result.__typename = blob_attachment.__typename;
                      break;
                    case 'MessageVideo':
                    case 'MessageAudio':
                      result = pick(blob_attachment, ['filename', 'playable_url', 'playable_duration_in_ms']);
                      result.__typename = blob_attachment.__typename;
                      break;
                  }
                  return result;
                })
                  .filter(item => !!item);
              }
              options.messages.push(message);
            });
            return resolve({
              has_previous_page: !!get(data, 'buzz.data.message_thread.messages.page_info.has_previous_page', false)
            });
          } catch (error) {
            return reject(error);
          }
        }
      };
      xhttp.open('POST', location.origin + '/api/graphqlbatch/?dpr=1', true);
      xhttp.setRequestHeader('content-type', 'application/x-www-form-urlencoded, application/x-www-form-urlencoded');
      xhttp.setRequestHeader('x-msgr-region', 'SGP');

      xhttp.send(queryStringify({
        'batch_name': 'MessengerGraphQLThreadFetcher',
        '__user': options.user_id,
        '__a': '1',
        'fb_dtsg': options.requestToken,
        'queries': JSON.stringify({
          'buzz': {
            'doc_id': '2294242067312755',
            'query_params': {
              'id': options.friend.id,
              'message_limit': options.perPage,
              'load_messages': true,
              'load_read_receipts': true,
              'load_delivery_receipts': true,
              'before': options.before
            }
          }
        })
      }));
    });
  }

  async function fetchMessage(options) {
    if (window['buzz_cancel']) {
      console.warn(window['buzz_cancel']);
      return;
    }
    if (options.before instanceof Date) {
      options.before = options.before.getTime();
    }
    if (options.after instanceof Date) {
      options.after = options.after.getTime();
    }
    const result = await request(options);
    console.info(`Batch ${batch++} completed`);
    if (result.has_previous_page) {
      await fetchMessage(options);
    }
  }

  function getFriend() {
    const currentTab = document.querySelector('[id^=row_header_id_user]>a[tabindex="0"]')
      || document.querySelector('[id^=row_header_id_thread]>a[tabindex="0"]');

    if (!currentTab) {
      return 0;
    }
    return {
      id: currentTab.parentNode.id.replace(/(^[^:]+):([0-9]+)$/g, '$2'),
      name: currentTab.querySelector('[data-tooltip-content]').getAttribute('data-tooltip-content')
    };
  }

  function getRequestToken() {
    const result = {requestToken: '', user_id: ''};
    Array.prototype.some.call(document.querySelectorAll('script'), script => {
      if (!script.textContent) {
        return false;
      }
      if (!result.requestToken) {
        const token = script.textContent.match(/"token":"([^"]+)"/);
        if (token) {
          result.requestToken = token[1];
        }
      }

      if (!result.user_id) {
        const user_id = script.textContent.match(/"USER_ID":"([^"]+)"/);
        if (user_id) {
          result.user_id = user_id[1];
        }
      }

      return result.requestToken && result.user_id;
    });

    return result;
  }
})({
  perPage: 100,
  maxMessages: Infinity,
  friend_id: 0
  // before: new Date(year, month (0-11), day, hours, minutes, seconds, milliseconds),
  // after: new Date(year, month (0-11), day, hours, minutes, seconds, milliseconds),
});

1. Open messenger screen on https://www.facebook.com/messages/t/01234567890 or https://www.messenger.com/t/01234567890
2. Enable console by Ctrl + Shift + J
3. Open console tab and paste above code
4. Finally, type to console finalResult, it is json result