pdfjs-dist/lib/core/network.js

/* Copyright 2017 Mozilla Foundation
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
'use strict';
var sharedUtil = require('../shared/util.js');
var coreWorker = require('./worker.js');
var globalScope = sharedUtil.globalScope;
var OK_RESPONSE = 200;
var PARTIAL_CONTENT_RESPONSE = 206;
function NetworkManager(url, args) {
 this.url = url;
 args = args || {};
 this.isHttp = /^https?:/i.test(url);
 this.httpHeaders = this.isHttp && args.httpHeaders || {};
 this.withCredentials = args.withCredentials || false;
 this.getXhr = args.getXhr || function NetworkManager_getXhr() {
  return new XMLHttpRequest();
 };
 this.currXhrId = 0;
 this.pendingRequests = Object.create(null);
 this.loadedRequests = Object.create(null);
}
function getArrayBuffer(xhr) {
 var data = xhr.response;
 if (typeof data !== 'string') {
  return data;
 }
 var length = data.length;
 var array = new Uint8Array(length);
 for (var i = 0; i < length; i++) {
  array[i] = data.charCodeAt(i) & 0xFF;
 }
 return array.buffer;
}
var supportsMozChunked = function supportsMozChunkedClosure() {
 try {
  var x = new XMLHttpRequest();
  x.open('GET', globalScope.location.href);
  x.responseType = 'moz-chunked-arraybuffer';
  return x.responseType === 'moz-chunked-arraybuffer';
 } catch (e) {
  return false;
 }
}();
NetworkManager.prototype = {
 requestRange: function NetworkManager_requestRange(begin, end, listeners) {
  var args = {
   begin: begin,
   end: end
  };
  for (var prop in listeners) {
   args[prop] = listeners[prop];
  }
  return this.request(args);
 },
 requestFull: function NetworkManager_requestFull(listeners) {
  return this.request(listeners);
 },
 request: function NetworkManager_request(args) {
  var xhr = this.getXhr();
  var xhrId = this.currXhrId++;
  var pendingRequest = this.pendingRequests[xhrId] = { xhr: xhr };
  xhr.open('GET', this.url);
  xhr.withCredentials = this.withCredentials;
  for (var property in this.httpHeaders) {
   var value = this.httpHeaders[property];
   if (typeof value === 'undefined') {
    continue;
   }
   xhr.setRequestHeader(property, value);
  }
  if (this.isHttp && 'begin' in args && 'end' in args) {
   var rangeStr = args.begin + '-' + (args.end - 1);
   xhr.setRequestHeader('Range', 'bytes=' + rangeStr);
   pendingRequest.expectedStatus = 206;
  } else {
   pendingRequest.expectedStatus = 200;
  }
  var useMozChunkedLoading = supportsMozChunked && !!args.onProgressiveData;
  if (useMozChunkedLoading) {
   xhr.responseType = 'moz-chunked-arraybuffer';
   pendingRequest.onProgressiveData = args.onProgressiveData;
   pendingRequest.mozChunked = true;
  } else {
   xhr.responseType = 'arraybuffer';
  }
  if (args.onError) {
   xhr.onerror = function (evt) {
    args.onError(xhr.status);
   };
  }
  xhr.onreadystatechange = this.onStateChange.bind(this, xhrId);
  xhr.onprogress = this.onProgress.bind(this, xhrId);
  pendingRequest.onHeadersReceived = args.onHeadersReceived;
  pendingRequest.onDone = args.onDone;
  pendingRequest.onError = args.onError;
  pendingRequest.onProgress = args.onProgress;
  xhr.send(null);
  return xhrId;
 },
 onProgress: function NetworkManager_onProgress(xhrId, evt) {
  var pendingRequest = this.pendingRequests[xhrId];
  if (!pendingRequest) {
   return;
  }
  if (pendingRequest.mozChunked) {
   var chunk = getArrayBuffer(pendingRequest.xhr);
   pendingRequest.onProgressiveData(chunk);
  }
  var onProgress = pendingRequest.onProgress;
  if (onProgress) {
   onProgress(evt);
  }
 },
 onStateChange: function NetworkManager_onStateChange(xhrId, evt) {
  var pendingRequest = this.pendingRequests[xhrId];
  if (!pendingRequest) {
   return;
  }
  var xhr = pendingRequest.xhr;
  if (xhr.readyState >= 2 && pendingRequest.onHeadersReceived) {
   pendingRequest.onHeadersReceived();
   delete pendingRequest.onHeadersReceived;
  }
  if (xhr.readyState !== 4) {
   return;
  }
  if (!(xhrId in this.pendingRequests)) {
   return;
  }
  delete this.pendingRequests[xhrId];
  if (xhr.status === 0 && this.isHttp) {
   if (pendingRequest.onError) {
    pendingRequest.onError(xhr.status);
   }
   return;
  }
  var xhrStatus = xhr.status || OK_RESPONSE;
  var ok_response_on_range_request = xhrStatus === OK_RESPONSE && pendingRequest.expectedStatus === PARTIAL_CONTENT_RESPONSE;
  if (!ok_response_on_range_request && xhrStatus !== pendingRequest.expectedStatus) {
   if (pendingRequest.onError) {
    pendingRequest.onError(xhr.status);
   }
   return;
  }
  this.loadedRequests[xhrId] = true;
  var chunk = getArrayBuffer(xhr);
  if (xhrStatus === PARTIAL_CONTENT_RESPONSE) {
   var rangeHeader = xhr.getResponseHeader('Content-Range');
   var matches = /bytes (\d+)-(\d+)\/(\d+)/.exec(rangeHeader);
   var begin = parseInt(matches[1], 10);
   pendingRequest.onDone({
    begin: begin,
    chunk: chunk
   });
  } else if (pendingRequest.onProgressiveData) {
   pendingRequest.onDone(null);
  } else if (chunk) {
   pendingRequest.onDone({
    begin: 0,
    chunk: chunk
   });
  } else if (pendingRequest.onError) {
   pendingRequest.onError(xhr.status);
  }
 },
 hasPendingRequests: function NetworkManager_hasPendingRequests() {
  for (var xhrId in this.pendingRequests) {
   return true;
  }
  return false;
 },
 getRequestXhr: function NetworkManager_getXhr(xhrId) {
  return this.pendingRequests[xhrId].xhr;
 },
 isStreamingRequest: function NetworkManager_isStreamingRequest(xhrId) {
  return !!this.pendingRequests[xhrId].onProgressiveData;
 },
 isPendingRequest: function NetworkManager_isPendingRequest(xhrId) {
  return xhrId in this.pendingRequests;
 },
 isLoadedRequest: function NetworkManager_isLoadedRequest(xhrId) {
  return xhrId in this.loadedRequests;
 },
 abortAllRequests: function NetworkManager_abortAllRequests() {
  for (var xhrId in this.pendingRequests) {
   this.abortRequest(xhrId | 0);
  }
 },
 abortRequest: function NetworkManager_abortRequest(xhrId) {
  var xhr = this.pendingRequests[xhrId].xhr;
  delete this.pendingRequests[xhrId];
  xhr.abort();
 }
};
var assert = sharedUtil.assert;
var createPromiseCapability = sharedUtil.createPromiseCapability;
var isInt = sharedUtil.isInt;
var MissingPDFException = sharedUtil.MissingPDFException;
var UnexpectedResponseException = sharedUtil.UnexpectedResponseException;
function PDFNetworkStream(options) {
 this._options = options;
 var source = options.source;
 this._manager = new NetworkManager(source.url, {
  httpHeaders: source.httpHeaders,
  withCredentials: source.withCredentials
 });
 this._rangeChunkSize = source.rangeChunkSize;
 this._fullRequestReader = null;
 this._rangeRequestReaders = [];
}
PDFNetworkStream.prototype = {
 _onRangeRequestReaderClosed: function PDFNetworkStream_onRangeRequestReaderClosed(reader) {
  var i = this._rangeRequestReaders.indexOf(reader);
  if (i >= 0) {
   this._rangeRequestReaders.splice(i, 1);
  }
 },
 getFullReader: function PDFNetworkStream_getFullReader() {
  assert(!this._fullRequestReader);
  this._fullRequestReader = new PDFNetworkStreamFullRequestReader(this._manager, this._options);
  return this._fullRequestReader;
 },
 getRangeReader: function PDFNetworkStream_getRangeReader(begin, end) {
  var reader = new PDFNetworkStreamRangeRequestReader(this._manager, begin, end);
  reader.onClosed = this._onRangeRequestReaderClosed.bind(this);
  this._rangeRequestReaders.push(reader);
  return reader;
 },
 cancelAllRequests: function PDFNetworkStream_cancelAllRequests(reason) {
  if (this._fullRequestReader) {
   this._fullRequestReader.cancel(reason);
  }
  var readers = this._rangeRequestReaders.slice(0);
  readers.forEach(function (reader) {
   reader.cancel(reason);
  });
 }
};
function PDFNetworkStreamFullRequestReader(manager, options) {
 this._manager = manager;
 var source = options.source;
 var args = {
  onHeadersReceived: this._onHeadersReceived.bind(this),
  onProgressiveData: source.disableStream ? null : this._onProgressiveData.bind(this),
  onDone: this._onDone.bind(this),
  onError: this._onError.bind(this),
  onProgress: this._onProgress.bind(this)
 };
 this._url = source.url;
 this._fullRequestId = manager.requestFull(args);
 this._headersReceivedCapability = createPromiseCapability();
 this._disableRange = options.disableRange || false;
 this._contentLength = source.length;
 this._rangeChunkSize = source.rangeChunkSize;
 if (!this._rangeChunkSize && !this._disableRange) {
  this._disableRange = true;
 }
 this._isStreamingSupported = false;
 this._isRangeSupported = false;
 this._cachedChunks = [];
 this._requests = [];
 this._done = false;
 this._storedError = undefined;
 this.onProgress = null;
}
PDFNetworkStreamFullRequestReader.prototype = {
 _validateRangeRequestCapabilities: function PDFNetworkStreamFullRequestReader_validateRangeRequestCapabilities() {
  if (this._disableRange) {
   return false;
  }
  var networkManager = this._manager;
  if (!networkManager.isHttp) {
   return false;
  }
  var fullRequestXhrId = this._fullRequestId;
  var fullRequestXhr = networkManager.getRequestXhr(fullRequestXhrId);
  if (fullRequestXhr.getResponseHeader('Accept-Ranges') !== 'bytes') {
   return false;
  }
  var contentEncoding = fullRequestXhr.getResponseHeader('Content-Encoding') || 'identity';
  if (contentEncoding !== 'identity') {
   return false;
  }
  var length = fullRequestXhr.getResponseHeader('Content-Length');
  length = parseInt(length, 10);
  if (!isInt(length)) {
   return false;
  }
  this._contentLength = length;
  if (length <= 2 * this._rangeChunkSize) {
   return false;
  }
  return true;
 },
 _onHeadersReceived: function PDFNetworkStreamFullRequestReader_onHeadersReceived() {
  if (this._validateRangeRequestCapabilities()) {
   this._isRangeSupported = true;
  }
  var networkManager = this._manager;
  var fullRequestXhrId = this._fullRequestId;
  if (networkManager.isStreamingRequest(fullRequestXhrId)) {
   this._isStreamingSupported = true;
  } else if (this._isRangeSupported) {
   networkManager.abortRequest(fullRequestXhrId);
  }
  this._headersReceivedCapability.resolve();
 },
 _onProgressiveData: function PDFNetworkStreamFullRequestReader_onProgressiveData(chunk) {
  if (this._requests.length > 0) {
   var requestCapability = this._requests.shift();
   requestCapability.resolve({
    value: chunk,
    done: false
   });
  } else {
   this._cachedChunks.push(chunk);
  }
 },
 _onDone: function PDFNetworkStreamFullRequestReader_onDone(args) {
  if (args) {
   this._onProgressiveData(args.chunk);
  }
  this._done = true;
  if (this._cachedChunks.length > 0) {
   return;
  }
  this._requests.forEach(function (requestCapability) {
   requestCapability.resolve({
    value: undefined,
    done: true
   });
  });
  this._requests = [];
 },
 _onError: function PDFNetworkStreamFullRequestReader_onError(status) {
  var url = this._url;
  var exception;
  if (status === 404 || status === 0 && /^file:/.test(url)) {
   exception = new MissingPDFException('Missing PDF "' + url + '".');
  } else {
   exception = new UnexpectedResponseException('Unexpected server response (' + status + ') while retrieving PDF "' + url + '".', status);
  }
  this._storedError = exception;
  this._headersReceivedCapability.reject(exception);
  this._requests.forEach(function (requestCapability) {
   requestCapability.reject(exception);
  });
  this._requests = [];
  this._cachedChunks = [];
 },
 _onProgress: function PDFNetworkStreamFullRequestReader_onProgress(data) {
  if (this.onProgress) {
   this.onProgress({
    loaded: data.loaded,
    total: data.lengthComputable ? data.total : this._contentLength
   });
  }
 },
 get isRangeSupported() {
  return this._isRangeSupported;
 },
 get isStreamingSupported() {
  return this._isStreamingSupported;
 },
 get contentLength() {
  return this._contentLength;
 },
 get headersReady() {
  return this._headersReceivedCapability.promise;
 },
 read: function PDFNetworkStreamFullRequestReader_read() {
  if (this._storedError) {
   return Promise.reject(this._storedError);
  }
  if (this._cachedChunks.length > 0) {
   var chunk = this._cachedChunks.shift();
   return Promise.resolve(chunk);
  }
  if (this._done) {
   return Promise.resolve({
    value: undefined,
    done: true
   });
  }
  var requestCapability = createPromiseCapability();
  this._requests.push(requestCapability);
  return requestCapability.promise;
 },
 cancel: function PDFNetworkStreamFullRequestReader_cancel(reason) {
  this._done = true;
  this._headersReceivedCapability.reject(reason);
  this._requests.forEach(function (requestCapability) {
   requestCapability.resolve({
    value: undefined,
    done: true
   });
  });
  this._requests = [];
  if (this._manager.isPendingRequest(this._fullRequestId)) {
   this._manager.abortRequest(this._fullRequestId);
  }
  this._fullRequestReader = null;
 }
};
function PDFNetworkStreamRangeRequestReader(manager, begin, end) {
 this._manager = manager;
 var args = {
  onDone: this._onDone.bind(this),
  onProgress: this._onProgress.bind(this)
 };
 this._requestId = manager.requestRange(begin, end, args);
 this._requests = [];
 this._queuedChunk = null;
 this._done = false;
 this.onProgress = null;
 this.onClosed = null;
}
PDFNetworkStreamRangeRequestReader.prototype = {
 _close: function PDFNetworkStreamRangeRequestReader_close() {
  if (this.onClosed) {
   this.onClosed(this);
  }
 },
 _onDone: function PDFNetworkStreamRangeRequestReader_onDone(data) {
  var chunk = data.chunk;
  if (this._requests.length > 0) {
   var requestCapability = this._requests.shift();
   requestCapability.resolve({
    value: chunk,
    done: false
   });
  } else {
   this._queuedChunk = chunk;
  }
  this._done = true;
  this._requests.forEach(function (requestCapability) {
   requestCapability.resolve({
    value: undefined,
    done: true
   });
  });
  this._requests = [];
  this._close();
 },
 _onProgress: function PDFNetworkStreamRangeRequestReader_onProgress(evt) {
  if (!this.isStreamingSupported && this.onProgress) {
   this.onProgress({ loaded: evt.loaded });
  }
 },
 get isStreamingSupported() {
  return false;
 },
 read: function PDFNetworkStreamRangeRequestReader_read() {
  if (this._queuedChunk !== null) {
   var chunk = this._queuedChunk;
   this._queuedChunk = null;
   return Promise.resolve({
    value: chunk,
    done: false
   });
  }
  if (this._done) {
   return Promise.resolve({
    value: undefined,
    done: true
   });
  }
  var requestCapability = createPromiseCapability();
  this._requests.push(requestCapability);
  return requestCapability.promise;
 },
 cancel: function PDFNetworkStreamRangeRequestReader_cancel(reason) {
  this._done = true;
  this._requests.forEach(function (requestCapability) {
   requestCapability.resolve({
    value: undefined,
    done: true
   });
  });
  this._requests = [];
  if (this._manager.isPendingRequest(this._requestId)) {
   this._manager.abortRequest(this._requestId);
  }
  this._close();
 }
};
coreWorker.setPDFNetworkStreamClass(PDFNetworkStream);
exports.PDFNetworkStream = PDFNetworkStream;
exports.NetworkManager = NetworkManager;