BlobManager.js

/**
 * Copyright (c) 2013-present, Facebook, Inc.
 *
 * This source code is licensed under the MIT license found in the
 * LICENSE file in the root directory of this source tree.
 *
 * @providesModule BlobManager
 * @flow
 * @format
 */

'use strict';

const Blob = require('Blob');
const BlobRegistry = require('BlobRegistry');
const {BlobModule} = require('NativeModules');

import type {BlobData, BlobOptions} from 'BlobTypes';

/*eslint-disable no-bitwise */
/*eslint-disable eqeqeq */

/**
 * Based on the rfc4122-compliant solution posted at
 * http://stackoverflow.com/questions/105034
 */
function uuidv4(): string {
  return 'xxxxxxxx-xxxx-4xxx-yxxx-xxxxxxxxxxxx'.replace(/[xy]/g, c => {
    const r = (Math.random() * 16) | 0,
      v = c == 'x' ? r : (r & 0x3) | 0x8;
    return v.toString(16);
  });
}

/**
 * Module to manage blobs. Wrapper around the native blob module.
 */
class BlobManager {
  /**
   * If the native blob module is available.
   */
  static isAvailable = !!BlobModule;

  /**
   * Create blob from existing array of blobs.
   */
  static createFromParts(
    parts: Array<Blob | string>,
    options?: BlobOptions,
  ): Blob {
    const blobId = uuidv4();
    const items = parts.map(part => {
      if (
        part instanceof ArrayBuffer ||
        (global.ArrayBufferView && part instanceof global.ArrayBufferView)
      ) {
        throw new Error(
          "Creating blobs from 'ArrayBuffer' and 'ArrayBufferView' are not supported",
        );
      }
      if (part instanceof Blob) {
        return {
          data: part.data,
          type: 'blob',
        };
      } else {
        return {
          data: String(part),
          type: 'string',
        };
      }
    });
    const size = items.reduce((acc, curr) => {
      if (curr.type === 'string') {
        return acc + global.unescape(encodeURI(curr.data)).length;
      } else {
        return acc + curr.data.size;
      }
    }, 0);

    BlobModule.createFromParts(items, blobId);

    return BlobManager.createFromOptions({
      blobId,
      offset: 0,
      size,
      type: options ? options.type : '',
      lastModified: options ? options.lastModified : Date.now(),
    });
  }

  /**
   * Create blob instance from blob data from native.
   * Used internally by modules like XHR, WebSocket, etc.
   */
  static createFromOptions(options: BlobData): Blob {
    BlobRegistry.register(options.blobId);
    return Object.assign(Object.create(Blob.prototype), {data: options});
  }

  /**
   * Deallocate resources for a blob.
   */
  static release(blobId: string): void {
    BlobRegistry.unregister(blobId);
    if (BlobRegistry.has(blobId)) {
      return;
    }
    BlobModule.release(blobId);
  }

  /**
   * Inject the blob content handler in the networking module to support blob
   * requests and responses.
   */
  static addNetworkingHandler(): void {
    BlobModule.addNetworkingHandler();
  }

  /**
   * Indicate the websocket should return a blob for incoming binary
   * messages.
   */
  static addWebSocketHandler(socketId: number): void {
    BlobModule.addWebSocketHandler(socketId);
  }

  /**
   * Indicate the websocket should no longer return a blob for incoming
   * binary messages.
   */
  static removeWebSocketHandler(socketId: number): void {
    BlobModule.removeWebSocketHandler(socketId);
  }

  /**
   * Send a blob message to a websocket.
   */
  static sendOverSocket(blob: Blob, socketId: number): void {
    BlobModule.sendOverSocket(blob.data, socketId);
  }
}

module.exports = BlobManager;