pdf.js/src/display/network.js
Jonas Jenwald 317abd6d07 Change the createPromiseCapability helper function into a PromiseCapability class
This is not only slightly more compact, but it also simplifies the handling of the `settled` getter.
2023-04-29 13:43:24 +02:00

489 lines
13 KiB
JavaScript

/* Copyright 2012 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.
*/
import { assert, PromiseCapability, stringToBytes } from "../shared/util.js";
import {
createResponseStatusError,
extractFilenameFromHeader,
validateRangeRequestCapabilities,
} from "./network_utils.js";
if (typeof PDFJSDev !== "undefined" && PDFJSDev.test("MOZCENTRAL")) {
throw new Error(
'Module "./network.js" shall not be used with MOZCENTRAL builds.'
);
}
const OK_RESPONSE = 200;
const PARTIAL_CONTENT_RESPONSE = 206;
function getArrayBuffer(xhr) {
const data = xhr.response;
if (typeof data !== "string") {
return data;
}
return stringToBytes(data).buffer;
}
class NetworkManager {
constructor(url, args = {}) {
this.url = url;
this.isHttp = /^https?:/i.test(url);
this.httpHeaders = (this.isHttp && args.httpHeaders) || Object.create(null);
this.withCredentials = args.withCredentials || false;
this.currXhrId = 0;
this.pendingRequests = Object.create(null);
}
requestRange(begin, end, listeners) {
const args = {
begin,
end,
};
for (const prop in listeners) {
args[prop] = listeners[prop];
}
return this.request(args);
}
requestFull(listeners) {
return this.request(listeners);
}
request(args) {
const xhr = new XMLHttpRequest();
const xhrId = this.currXhrId++;
const pendingRequest = (this.pendingRequests[xhrId] = { xhr });
xhr.open("GET", this.url);
xhr.withCredentials = this.withCredentials;
for (const property in this.httpHeaders) {
const value = this.httpHeaders[property];
if (value === undefined) {
continue;
}
xhr.setRequestHeader(property, value);
}
if (this.isHttp && "begin" in args && "end" in args) {
xhr.setRequestHeader("Range", `bytes=${args.begin}-${args.end - 1}`);
pendingRequest.expectedStatus = PARTIAL_CONTENT_RESPONSE;
} else {
pendingRequest.expectedStatus = OK_RESPONSE;
}
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(xhrId, evt) {
const pendingRequest = this.pendingRequests[xhrId];
if (!pendingRequest) {
return; // Maybe abortRequest was called...
}
pendingRequest.onProgress?.(evt);
}
onStateChange(xhrId, evt) {
const pendingRequest = this.pendingRequests[xhrId];
if (!pendingRequest) {
return; // Maybe abortRequest was called...
}
const xhr = pendingRequest.xhr;
if (xhr.readyState >= 2 && pendingRequest.onHeadersReceived) {
pendingRequest.onHeadersReceived();
delete pendingRequest.onHeadersReceived;
}
if (xhr.readyState !== 4) {
return;
}
if (!(xhrId in this.pendingRequests)) {
// The XHR request might have been aborted in onHeadersReceived()
// callback, in which case we should abort request.
return;
}
delete this.pendingRequests[xhrId];
// Success status == 0 can be on ftp, file and other protocols.
if (xhr.status === 0 && this.isHttp) {
pendingRequest.onError?.(xhr.status);
return;
}
const xhrStatus = xhr.status || OK_RESPONSE;
// From http://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html#sec14.35.2:
// "A server MAY ignore the Range header". This means it's possible to
// get a 200 rather than a 206 response from a range request.
const ok_response_on_range_request =
xhrStatus === OK_RESPONSE &&
pendingRequest.expectedStatus === PARTIAL_CONTENT_RESPONSE;
if (
!ok_response_on_range_request &&
xhrStatus !== pendingRequest.expectedStatus
) {
pendingRequest.onError?.(xhr.status);
return;
}
const chunk = getArrayBuffer(xhr);
if (xhrStatus === PARTIAL_CONTENT_RESPONSE) {
const rangeHeader = xhr.getResponseHeader("Content-Range");
const matches = /bytes (\d+)-(\d+)\/(\d+)/.exec(rangeHeader);
pendingRequest.onDone({
begin: parseInt(matches[1], 10),
chunk,
});
} else if (chunk) {
pendingRequest.onDone({
begin: 0,
chunk,
});
} else {
pendingRequest.onError?.(xhr.status);
}
}
getRequestXhr(xhrId) {
return this.pendingRequests[xhrId].xhr;
}
isPendingRequest(xhrId) {
return xhrId in this.pendingRequests;
}
abortRequest(xhrId) {
const xhr = this.pendingRequests[xhrId].xhr;
delete this.pendingRequests[xhrId];
xhr.abort();
}
}
/** @implements {IPDFStream} */
class PDFNetworkStream {
constructor(source) {
this._source = source;
this._manager = new NetworkManager(source.url, {
httpHeaders: source.httpHeaders,
withCredentials: source.withCredentials,
});
this._rangeChunkSize = source.rangeChunkSize;
this._fullRequestReader = null;
this._rangeRequestReaders = [];
}
_onRangeRequestReaderClosed(reader) {
const i = this._rangeRequestReaders.indexOf(reader);
if (i >= 0) {
this._rangeRequestReaders.splice(i, 1);
}
}
getFullReader() {
assert(
!this._fullRequestReader,
"PDFNetworkStream.getFullReader can only be called once."
);
this._fullRequestReader = new PDFNetworkStreamFullRequestReader(
this._manager,
this._source
);
return this._fullRequestReader;
}
getRangeReader(begin, end) {
const reader = new PDFNetworkStreamRangeRequestReader(
this._manager,
begin,
end
);
reader.onClosed = this._onRangeRequestReaderClosed.bind(this);
this._rangeRequestReaders.push(reader);
return reader;
}
cancelAllRequests(reason) {
this._fullRequestReader?.cancel(reason);
for (const reader of this._rangeRequestReaders.slice(0)) {
reader.cancel(reason);
}
}
}
/** @implements {IPDFStreamReader} */
class PDFNetworkStreamFullRequestReader {
constructor(manager, source) {
this._manager = manager;
const args = {
onHeadersReceived: this._onHeadersReceived.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 = new PromiseCapability();
this._disableRange = source.disableRange || false;
this._contentLength = source.length; // Optional
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._filename = null;
this.onProgress = null;
}
_onHeadersReceived() {
const fullRequestXhrId = this._fullRequestId;
const fullRequestXhr = this._manager.getRequestXhr(fullRequestXhrId);
const getResponseHeader = name => {
return fullRequestXhr.getResponseHeader(name);
};
const { allowRangeRequests, suggestedLength } =
validateRangeRequestCapabilities({
getResponseHeader,
isHttp: this._manager.isHttp,
rangeChunkSize: this._rangeChunkSize,
disableRange: this._disableRange,
});
if (allowRangeRequests) {
this._isRangeSupported = true;
}
// Setting right content length.
this._contentLength = suggestedLength || this._contentLength;
this._filename = extractFilenameFromHeader(getResponseHeader);
if (this._isRangeSupported) {
// NOTE: by cancelling the full request, and then issuing range
// requests, there will be an issue for sites where you can only
// request the pdf once. However, if this is the case, then the
// server should not be returning that it can support range requests.
this._manager.abortRequest(fullRequestXhrId);
}
this._headersReceivedCapability.resolve();
}
_onDone(data) {
if (data) {
if (this._requests.length > 0) {
const requestCapability = this._requests.shift();
requestCapability.resolve({ value: data.chunk, done: false });
} else {
this._cachedChunks.push(data.chunk);
}
}
this._done = true;
if (this._cachedChunks.length > 0) {
return;
}
for (const requestCapability of this._requests) {
requestCapability.resolve({ value: undefined, done: true });
}
this._requests.length = 0;
}
_onError(status) {
this._storedError = createResponseStatusError(status, this._url);
this._headersReceivedCapability.reject(this._storedError);
for (const requestCapability of this._requests) {
requestCapability.reject(this._storedError);
}
this._requests.length = 0;
this._cachedChunks.length = 0;
}
_onProgress(evt) {
this.onProgress?.({
loaded: evt.loaded,
total: evt.lengthComputable ? evt.total : this._contentLength,
});
}
get filename() {
return this._filename;
}
get isRangeSupported() {
return this._isRangeSupported;
}
get isStreamingSupported() {
return this._isStreamingSupported;
}
get contentLength() {
return this._contentLength;
}
get headersReady() {
return this._headersReceivedCapability.promise;
}
async read() {
if (this._storedError) {
throw this._storedError;
}
if (this._cachedChunks.length > 0) {
const chunk = this._cachedChunks.shift();
return { value: chunk, done: false };
}
if (this._done) {
return { value: undefined, done: true };
}
const requestCapability = new PromiseCapability();
this._requests.push(requestCapability);
return requestCapability.promise;
}
cancel(reason) {
this._done = true;
this._headersReceivedCapability.reject(reason);
for (const requestCapability of this._requests) {
requestCapability.resolve({ value: undefined, done: true });
}
this._requests.length = 0;
if (this._manager.isPendingRequest(this._fullRequestId)) {
this._manager.abortRequest(this._fullRequestId);
}
this._fullRequestReader = null;
}
}
/** @implements {IPDFStreamRangeReader} */
class PDFNetworkStreamRangeRequestReader {
constructor(manager, begin, end) {
this._manager = manager;
const args = {
onDone: this._onDone.bind(this),
onError: this._onError.bind(this),
onProgress: this._onProgress.bind(this),
};
this._url = manager.url;
this._requestId = manager.requestRange(begin, end, args);
this._requests = [];
this._queuedChunk = null;
this._done = false;
this._storedError = undefined;
this.onProgress = null;
this.onClosed = null;
}
_close() {
this.onClosed?.(this);
}
_onDone(data) {
const chunk = data.chunk;
if (this._requests.length > 0) {
const requestCapability = this._requests.shift();
requestCapability.resolve({ value: chunk, done: false });
} else {
this._queuedChunk = chunk;
}
this._done = true;
for (const requestCapability of this._requests) {
requestCapability.resolve({ value: undefined, done: true });
}
this._requests.length = 0;
this._close();
}
_onError(status) {
this._storedError = createResponseStatusError(status, this._url);
for (const requestCapability of this._requests) {
requestCapability.reject(this._storedError);
}
this._requests.length = 0;
this._queuedChunk = null;
}
_onProgress(evt) {
if (!this.isStreamingSupported) {
this.onProgress?.({ loaded: evt.loaded });
}
}
get isStreamingSupported() {
return false;
}
async read() {
if (this._storedError) {
throw this._storedError;
}
if (this._queuedChunk !== null) {
const chunk = this._queuedChunk;
this._queuedChunk = null;
return { value: chunk, done: false };
}
if (this._done) {
return { value: undefined, done: true };
}
const requestCapability = new PromiseCapability();
this._requests.push(requestCapability);
return requestCapability.promise;
}
cancel(reason) {
this._done = true;
for (const requestCapability of this._requests) {
requestCapability.resolve({ value: undefined, done: true });
}
this._requests.length = 0;
if (this._manager.isPendingRequest(this._requestId)) {
this._manager.abortRequest(this._requestId);
}
this._close();
}
}
export { PDFNetworkStream };