tweb-i2p/src/lib/files/downloadStorage.ts

/*
 * https://github.com/morethanwords/tweb
 * Copyright (C) 2019-2021 Eduard Kuzmenko
 * https://github.com/morethanwords/tweb/blob/master/LICENSE
 */

import deferredPromise from '../../helpers/cancellablePromise';
import makeError from '../../helpers/makeError';
import fileNameRFC from '../../helpers/string/fileNameRFC';
import {getServiceMessagePort} from '../mtproto/mtproto.worker';
import DownloadWriter from './downloadWriter';
import FileStorage from './fileStorage';
import StreamWriter from './streamWriter';

export default class DownloadStorage implements FileStorage {
  public getFile(fileName: string): Promise<any> {
    return Promise.reject(makeError('NO_ENTRY_FOUND'));
  }

  public prepareWriting({fileName, downloadId, size}: {
    fileName: string,
    downloadId: string,
    size: number
  }) {
    const headers = {
      'Content-Type': 'application/octet-stream; charset=utf-8',
      'Content-Disposition': 'attachment; filename*=UTF-8\'\'' + fileNameRFC(fileName),
      ...(size ? {'Content-Length': size} : {})
    };

    const serviceMessagePort = getServiceMessagePort();
    const promise = serviceMessagePort.invoke('download', {
      headers,
      id: downloadId
    });

    const deferred = deferredPromise<void>();
    deferred.cancel = () => {
      deferred.reject(makeError('DOWNLOAD_CANCELED'));
    };

    deferred.catch(() => {
      getServiceMessagePort().invoke('downloadCancel', downloadId);
    });

    promise.then(deferred.resolve, deferred.reject);

    return {
      deferred,
      getWriter: () => {
        return new DownloadWriter(serviceMessagePort, downloadId);
      }
    };
  }
}