cdadb0db4d
This method captures all application/pdf streams, loads the viewer and passes the stream to the PDF.js viewer. This commit shows a proof of concept using the chrome.streamsPrivate API. Advantages of new method: - Access to the response body of the original request, thus fewer network requests. - PDFs from non-GET requests (e.g. POST) are now supported. - FTP files are also supported. Possible improvements: - Use declared content scripts instead of dynamic chrome.tabs.executeScript. This allows the extension to render the viewer in frames when the extension is disallowed to run executeScript for the top URL. - Use chrome.declarativeWebRequest instead of webRequest, and replace background page with event page (don't forget to profile the difference & will the background/event page still work as intended?).
106 lines
3.9 KiB
JavaScript
106 lines
3.9 KiB
JavaScript
/* -*- Mode: Java; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
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/* vim: set shiftwidth=2 tabstop=2 autoindent cindent expandtab: */
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/*
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Copyright 2013 Mozilla Foundation
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Licensed under the Apache License, Version 2.0 (the "License");
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you may not use this file except in compliance with the License.
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You may obtain a copy of the License at
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http://www.apache.org/licenses/LICENSE-2.0
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Unless required by applicable law or agreed to in writing, software
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distributed under the License is distributed on an "AS IS" BASIS,
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WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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See the License for the specific language governing permissions and
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limitations under the License.
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*/
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/* globals chrome, URL, getViewerURL */
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'use strict';
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// Hash map of "<pdf url>": "<stream url>"
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var urlToStream = {};
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// Note: Execution of this script stops when the streamsPrivate API is
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// not available, because an error will be thrown. Don't bother with
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// catching and handling the error, because it is a great way to see
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// when the streamsPrivate API is unavailable.
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chrome.streamsPrivate.onExecuteMimeTypeHandler.addListener(handleStream);
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chrome.runtime.onMessage.addListener(function(message, sender, sendResponse) {
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if (message && message.action === 'getPDFStream') {
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var pdfUrl = message.data;
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var streamUrl = urlToStream[pdfUrl];
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// The stream can be used only once.
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delete urlToStream[pdfUrl];
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sendResponse({
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streamUrl: streamUrl
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});
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}
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});
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/**
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* Callback for when we receive a stream
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*
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* @param mimeType {string} The mime type of the incoming stream
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* @param pdfUrl {string} The full URL to the file
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* @param streamUrl {string} The url pointing to the open stream
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* @param tabId {number} The ID of the tab in which the stream has been opened
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* (undefined before Chrome 27, http://crbug.com/225605)
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*/
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function handleStream(mimeType, pdfUrl, streamUrl, tabId) {
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console.log('Intercepted ' + mimeType + ' in tab ' + tabId + ' with URL ' +
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pdfUrl + '\nAvailable as: ' + streamUrl);
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urlToStream[pdfUrl] = streamUrl;
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}
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/**
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* Callback for when a navigation error has occurred.
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* This event is triggered when the chrome.streamsPrivate API has intercepted
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* the PDF stream. This method detects such streams, finds the frame where
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* the request was made, and loads the viewer in that frame.
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*
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* @param details {object}
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* @param details.tabId {number} The ID of the tab
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* @param details.url {string} The URL being navigated when the error occurred.
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* @param details.frameId {number} 0 indicates the navigation happens in the tab
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* content window; a positive value indicates
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* navigation in a subframe.
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* @param details.error {string}
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*/
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function webNavigationOnErrorOccurred(details) {
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var tabId = details.tabId;
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var frameId = details.frameId;
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var pdfUrl = details.url;
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if (details.error === 'net::ERR_ABORTED') {
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if (!urlToStream[pdfUrl]) {
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console.log('No saved PDF stream found for ' + pdfUrl);
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return;
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}
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var viewerUrl = getViewerURL(pdfUrl);
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if (frameId === 0) { // Main frame
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console.log('Going to render PDF Viewer in main frame for ' + pdfUrl);
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chrome.tabs.update(tabId, {
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url: viewerUrl
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});
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} else {
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console.log('Going to render PDF Viewer in sub frame for ' + pdfUrl);
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// Non-standard Chrome API. chrome.tabs.executeScriptInFrame and docs
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// is available at https://github.com/Rob--W/chrome-api
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chrome.tabs.executeScriptInFrame(tabId, {
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frameId: frameId,
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code: 'location.href = ' + JSON.stringify(viewerUrl) + ';'
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}, function(result) {
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if (!result) { // Did the tab disappear? Is the frame inaccessible?
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console.warn('Frame not found, viewer not rendered in tab ' + tabId);
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}
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});
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}
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}
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}
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chrome.webNavigation.onErrorOccurred.addListener(webNavigationOnErrorOccurred);
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