Adds fetch stream logic for networking part of PDF.js

src/display/fetch_stream.js

@@ -0,0 +1,222 @@
+/* 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, createPromiseCapability } from '../shared/util';
+import {
+  createResponseStatusError, validateRangeRequestCapabilities,
+  validateResponseStatus
+} from './network_utils';
+
+function createFetchOptions(headers, withCredentials) {
+  return {
+    method: 'GET',
+    headers,
+    mode: 'cors',
+    credentials: withCredentials ? 'omit' : 'include',
+    redirect: 'follow',
+  };
+}
+
+class PDFFetchStream {
+  constructor(options) {
+    this.options = options;
+    this.source = options.source;
+    this.isHttp = /^https?:/i.test(this.source.url);
+    this.httpHeaders = (this.isHttp && this.source.httpHeaders) || {};
+
+    this._fullRequestReader = null;
+    this._rangeRequestReaders = [];
+  }
+
+  getFullReader() {
+    assert(!this._fullRequestReader);
+    this._fullRequestReader = new PDFFetchStreamReader(this);
+    return this._fullRequestReader;
+  }
+
+  getRangeReader(begin, end) {
+    let reader = new PDFFetchStreamRangeReader(this, begin, end);
+    this._rangeRequestReaders.push(reader);
+    return reader;
+  }
+
+  cancelAllRequests(reason) {
+    if (this._fullRequestReader) {
+      this._fullRequestReader.cancel(reason);
+    }
+    let readers = this._rangeRequestReaders.slice(0);
+    readers.forEach(function(reader) {
+      reader.cancel(reason);
+    });
+  }
+}
+
+class PDFFetchStreamReader {
+  constructor(stream) {
+    this._stream = stream;
+    this._reader = null;
+    this._loaded = 0;
+    this._withCredentials = stream.source.withCredentials;
+    this._contentLength = this._stream.source.length;
+    this._headersCapability = createPromiseCapability();
+    this._disableRange = this._stream.options.disableRange;
+    this._rangeChunkSize = this._stream.source.rangeChunkSize;
+    if (!this._rangeChunkSize && !this._disableRange) {
+      this._disableRange = true;
+    }
+
+    this._isRangeSupported = !this._stream.options.disableRange;
+    this._isStreamingSupported = !this._stream.source.disableStream;
+
+    this._headers = new Headers();
+    for (let property in this._stream.httpHeaders) {
+      let value = this._stream.httpHeaders[property];
+      if (typeof value === 'undefined') {
+        continue;
+      }
+      this._headers.append(property, value);
+    }
+
+    let url = this._stream.source.url;
+    fetch(url, createFetchOptions(this._headers, this._withCredentials)).
+        then((response) => {
+      if (!validateResponseStatus(response.status, this._stream.isHttp)) {
+        throw createResponseStatusError(response.status, url);
+      }
+      this._headersCapability.resolve();
+      this._reader = response.body.getReader();
+
+      let { allowRangeRequests, suggestedLength, } =
+        validateRangeRequestCapabilities({
+          getResponseHeader: (name) => {
+            return response.headers.get(name);
+          },
+          isHttp: this._stream.isHttp,
+          rangeChunkSize: this._rangeChunkSize,
+          disableRange: this._disableRange,
+        });
+
+      this._contentLength = suggestedLength;
+      this._isRangeSupported = allowRangeRequests;
+    }).catch(this._headersCapability.reject);
+
+    this.onProgress = null;
+  }
+
+  get headersReady() {
+    return this._headersCapability.promise;
+  }
+
+  get contentLength() {
+    return this._contentLength;
+  }
+
+  get isRangeSupported() {
+    return this._isRangeSupported;
+  }
+
+  get isStreamingSupported() {
+    return this._isStreamingSupported;
+  }
+
+  read() {
+    return this._headersCapability.promise.then(() => {
+      return this._reader.read().then(({ value, done, }) => {
+        if (done) {
+          return Promise.resolve({ value, done, });
+        }
+        this._loaded += value.byteLength;
+        if (this.onProgress) {
+          this.onProgress({
+            loaded: this._loaded,
+            total: this._contentLength,
+          });
+        }
+        let buffer = new Uint8Array(value).buffer;
+        return Promise.resolve({ value: buffer, done: false, });
+      });
+    });
+  }
+
+  cancel(reason) {
+    if (this._reader) {
+      this._reader.cancel(reason);
+    }
+  }
+}
+
+class PDFFetchStreamRangeReader {
+  constructor(stream, begin, end) {
+    this._stream = stream;
+    this._reader = null;
+    this._loaded = 0;
+    this._withCredentials = stream.source.withCredentials;
+    this._readCapability = createPromiseCapability();
+    this._isStreamingSupported = !stream.source.disableStream;
+
+    this._headers = new Headers();
+    for (let property in this._stream.httpHeaders) {
+      let value = this._stream.httpHeaders[property];
+      if (typeof value === 'undefined') {
+        continue;
+      }
+      this._headers.append(property, value);
+    }
+
+    let rangeStr = begin + '-' + (end - 1);
+    this._headers.append('Range', 'bytes=' + rangeStr);
+    let url = this._stream.source.url;
+    fetch(url, createFetchOptions(this._headers, this._withCredentials)).
+        then((response) => {
+      if (!validateResponseStatus(response.status, this._stream.isHttp)) {
+        throw createResponseStatusError(response.status, url);
+      }
+      this._readCapability.resolve();
+      this._reader = response.body.getReader();
+    });
+
+    this.onProgress = null;
+  }
+
+  get isStreamingSupported() {
+    return this._isStreamingSupported;
+  }
+
+  read() {
+    return this._readCapability.promise.then(() => {
+      return this._reader.read().then(({ value, done, }) => {
+        if (done) {
+          return Promise.resolve({ value, done, });
+        }
+        this._loaded += value.byteLength;
+        if (this.onProgress) {
+          this.onProgress({ loaded: this._loaded, });
+        }
+        let buffer = new Uint8Array(value).buffer;
+        return Promise.resolve({ value: buffer, done: false, });
+      });
+    });
+  }
+
+  cancel(reason) {
+    if (this._reader) {
+      this._reader.cancel(reason);
+    }
+  }
+}
+
+export {
+  PDFFetchStream,
+};