gecko-dev/toolkit/components/reader/ReaderMode.jsm

608 строки
20 KiB
JavaScript

// -*- indent-tabs-mode: nil; js-indent-level: 2 -*-
/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this file,
* You can obtain one at http://mozilla.org/MPL/2.0/. */
"use strict";
this.EXPORTED_SYMBOLS = ["ReaderMode"];
const { classes: Cc, interfaces: Ci, utils: Cu } = Components;
// Constants for telemetry.
const DOWNLOAD_SUCCESS = 0;
const DOWNLOAD_ERROR_XHR = 1;
const DOWNLOAD_ERROR_NO_DOC = 2;
const PARSE_SUCCESS = 0;
const PARSE_ERROR_TOO_MANY_ELEMENTS = 1;
const PARSE_ERROR_WORKER = 2;
const PARSE_ERROR_NO_ARTICLE = 3;
Cu.import("resource://gre/modules/Services.jsm");
Cu.import("resource://gre/modules/XPCOMUtils.jsm");
Cu.importGlobalProperties(["XMLHttpRequest"]);
XPCOMUtils.defineLazyModuleGetter(this, "CommonUtils", "resource://services-common/utils.js");
XPCOMUtils.defineLazyModuleGetter(this, "EventDispatcher", "resource://gre/modules/Messaging.jsm");
XPCOMUtils.defineLazyModuleGetter(this, "OS", "resource://gre/modules/osfile.jsm");
XPCOMUtils.defineLazyModuleGetter(this, "ReaderWorker", "resource://gre/modules/reader/ReaderWorker.jsm");
XPCOMUtils.defineLazyModuleGetter(this, "TelemetryStopwatch", "resource://gre/modules/TelemetryStopwatch.jsm");
XPCOMUtils.defineLazyModuleGetter(this, "LanguageDetector", "resource:///modules/translation/LanguageDetector.jsm");
XPCOMUtils.defineLazyGetter(this, "Readability", function() {
let scope = {};
scope.dump = this.dump;
Services.scriptloader.loadSubScript("resource://gre/modules/reader/Readability.js", scope);
return scope.Readability;
});
const gIsFirefoxDesktop = Services.appinfo.ID == "{ec8030f7-c20a-464f-9b0e-13a3a9e97384}";
this.ReaderMode = {
// Version of the cache schema.
CACHE_VERSION: 1,
DEBUG: 0,
// Don't try to parse the page if it has too many elements (for memory and
// performance reasons)
get maxElemsToParse() {
delete this.parseNodeLimit;
Services.prefs.addObserver("reader.parse-node-limit", this);
return this.parseNodeLimit = Services.prefs.getIntPref("reader.parse-node-limit");
},
get isEnabledForParseOnLoad() {
delete this.isEnabledForParseOnLoad;
// Listen for future pref changes.
Services.prefs.addObserver("reader.parse-on-load.", this);
return this.isEnabledForParseOnLoad = this._getStateForParseOnLoad();
},
_getStateForParseOnLoad() {
let isEnabled = Services.prefs.getBoolPref("reader.parse-on-load.enabled");
let isForceEnabled = Services.prefs.getBoolPref("reader.parse-on-load.force-enabled");
return isForceEnabled || isEnabled;
},
observe(aMessage, aTopic, aData) {
switch (aTopic) {
case "nsPref:changed":
if (aData.startsWith("reader.parse-on-load.")) {
this.isEnabledForParseOnLoad = this._getStateForParseOnLoad();
} else if (aData === "reader.parse-node-limit") {
this.parseNodeLimit = Services.prefs.getIntPref(aData);
}
break;
}
},
/**
* Enter the reader mode by going forward one step in history if applicable,
* if not, append the about:reader page in the history instead.
*/
enterReaderMode(docShell, win) {
let url = win.document.location.href;
let readerURL = "about:reader?url=" + encodeURIComponent(url);
let webNav = docShell.QueryInterface(Ci.nsIWebNavigation);
let sh = webNav.sessionHistory;
if (webNav.canGoForward) {
let forwardEntry = sh.getEntryAtIndex(sh.index + 1, false);
let forwardURL = forwardEntry.URI.spec;
if (forwardURL && (forwardURL == readerURL || !readerURL)) {
webNav.goForward();
return;
}
}
win.document.location = readerURL;
},
/**
* Exit the reader mode by going back one step in history if applicable,
* if not, append the original page in the history instead.
*/
leaveReaderMode(docShell, win) {
let url = win.document.location.href;
let originalURL = this.getOriginalUrl(url);
let webNav = docShell.QueryInterface(Ci.nsIWebNavigation);
let sh = webNav.sessionHistory;
if (webNav.canGoBack) {
let prevEntry = sh.getEntryAtIndex(sh.index - 1, false);
let prevURL = prevEntry.URI.spec;
if (prevURL && (prevURL == originalURL || !originalURL)) {
webNav.goBack();
return;
}
}
win.document.location = originalURL;
},
/**
* Returns original URL from an about:reader URL.
*
* @param url An about:reader URL.
* @return The original URL for the article, or null if we did not find
* a properly formatted about:reader URL.
*/
getOriginalUrl(url) {
if (!url.startsWith("about:reader?")) {
return null;
}
let outerHash = "";
try {
let uriObj = Services.io.newURI(url);
url = uriObj.specIgnoringRef;
outerHash = uriObj.ref;
} catch (ex) { /* ignore, use the raw string */ }
let searchParams = new URLSearchParams(url.substring("about:reader?".length));
if (!searchParams.has("url")) {
return null;
}
let originalUrl = searchParams.get("url");
if (outerHash) {
try {
let uriObj = Services.io.newURI(originalUrl);
uriObj = Services.io.newURI("#" + outerHash, null, uriObj);
originalUrl = uriObj.spec;
} catch (ex) {}
}
return originalUrl;
},
getOriginalUrlObjectForDisplay(url) {
let originalUrl = this.getOriginalUrl(url);
if (originalUrl) {
let uriObj;
try {
uriObj = Services.uriFixup.createFixupURI(originalUrl, Services.uriFixup.FIXUP_FLAG_NONE);
} catch (ex) {
return null;
}
try {
return Services.uriFixup.createExposableURI(uriObj);
} catch (ex) {
return null;
}
}
return null;
},
/**
* Decides whether or not a document is reader-able without parsing the whole thing.
*
* @param doc A document to parse.
* @return boolean Whether or not we should show the reader mode button.
*/
isProbablyReaderable(doc) {
// Only care about 'real' HTML documents:
if (doc.mozSyntheticDocument || !(doc instanceof doc.defaultView.HTMLDocument)) {
return false;
}
let uri = Services.io.newURI(doc.location.href);
if (!this._shouldCheckUri(uri)) {
return false;
}
let utils = this.getUtilsForWin(doc.defaultView);
// We pass in a helper function to determine if a node is visible, because
// it uses gecko APIs that the engine-agnostic readability code can't rely
// upon.
return new Readability(uri, doc).isProbablyReaderable(this.isNodeVisible.bind(this, utils));
},
isNodeVisible(utils, node) {
let bounds = utils.getBoundsWithoutFlushing(node);
return bounds.height > 0 && bounds.width > 0;
},
getUtilsForWin(win) {
return win.QueryInterface(Ci.nsIInterfaceRequestor).getInterface(Ci.nsIDOMWindowUtils);
},
/**
* Gets an article from a loaded browser's document. This method will not attempt
* to parse certain URIs (e.g. about: URIs).
*
* @param doc A document to parse.
* @return {Promise}
* @resolves JS object representing the article, or null if no article is found.
*/
parseDocument(doc) {
if (!this._shouldCheckUri(doc.documentURIObject) || !this._shouldCheckUri(doc.baseURIObject, true)) {
this.log("Reader mode disabled for URI");
return null;
}
return this._readerParse(doc);
},
/**
* Downloads and parses a document from a URL.
*
* @param url URL to download and parse.
* @return {Promise}
* @resolves JS object representing the article, or null if no article is found.
*/
async downloadAndParseDocument(url) {
let doc = await this._downloadDocument(url);
if (!this._shouldCheckUri(doc.documentURIObject) || !this._shouldCheckUri(doc.baseURIObject, true)) {
this.log("Reader mode disabled for URI");
return null;
}
return this._readerParse(doc);
},
_downloadDocument(url) {
let histogram = Services.telemetry.getHistogramById("READER_MODE_DOWNLOAD_RESULT");
return new Promise((resolve, reject) => {
let xhr = new XMLHttpRequest();
xhr.open("GET", url, true);
xhr.onerror = evt => reject(evt.error);
xhr.responseType = "document";
xhr.onload = evt => {
if (xhr.status !== 200) {
reject("Reader mode XHR failed with status: " + xhr.status);
histogram.add(DOWNLOAD_ERROR_XHR);
return;
}
let doc = xhr.responseXML;
if (!doc) {
reject("Reader mode XHR didn't return a document");
histogram.add(DOWNLOAD_ERROR_NO_DOC);
return;
}
// Manually follow a meta refresh tag if one exists.
let meta = doc.querySelector("meta[http-equiv=refresh]");
if (meta) {
let content = meta.getAttribute("content");
if (content) {
let urlIndex = content.toUpperCase().indexOf("URL=");
if (urlIndex > -1) {
let baseURI = Services.io.newURI(url);
let newURI = Services.io.newURI(content.substring(urlIndex + 4), null, baseURI);
let newURL = newURI.spec;
let ssm = Services.scriptSecurityManager;
let flags = ssm.LOAD_IS_AUTOMATIC_DOCUMENT_REPLACEMENT |
ssm.DISALLOW_INHERIT_PRINCIPAL;
try {
ssm.checkLoadURIStrWithPrincipal(doc.nodePrincipal, newURL, flags);
} catch (ex) {
let errorMsg = "Reader mode disallowed meta refresh (reason: " + ex + ").";
if (Services.prefs.getBoolPref("reader.errors.includeURLs"))
errorMsg += " Refresh target URI: '" + newURL + "'.";
reject(errorMsg);
return;
}
// Otherwise, pass an object indicating our new URL:
if (!baseURI.equalsExceptRef(newURI)) {
reject({newURL});
return;
}
}
}
}
let responseURL = xhr.responseURL;
let givenURL = url;
// Convert these to real URIs to make sure the escaping (or lack
// thereof) is identical:
try {
responseURL = Services.io.newURI(responseURL).specIgnoringRef;
} catch (ex) { /* Ignore errors - we'll use what we had before */ }
try {
givenURL = Services.io.newURI(givenURL).specIgnoringRef;
} catch (ex) { /* Ignore errors - we'll use what we had before */ }
if (responseURL != givenURL) {
// We were redirected without a meta refresh tag.
// Force redirect to the correct place:
reject({newURL: xhr.responseURL});
return;
}
resolve(doc);
histogram.add(DOWNLOAD_SUCCESS);
};
xhr.send();
});
},
/**
* Retrieves an article from the cache given an article URI.
*
* @param url The article URL.
* @return {Promise}
* @resolves JS object representing the article, or null if no article is found.
* @rejects OS.File.Error
*/
async getArticleFromCache(url) {
let path = this._toHashedPath(url);
try {
let array = await OS.File.read(path);
return JSON.parse(new TextDecoder().decode(array));
} catch (e) {
if (!(e instanceof OS.File.Error) || !e.becauseNoSuchFile)
throw e;
return null;
}
},
/**
* Stores an article in the cache.
*
* @param article JS object representing article.
* @return {Promise}
* @resolves When the article is stored.
* @rejects OS.File.Error
*/
async storeArticleInCache(article) {
let array = new TextEncoder().encode(JSON.stringify(article));
let path = this._toHashedPath(article.url);
await this._ensureCacheDir();
return OS.File.writeAtomic(path, array, { tmpPath: path + ".tmp" })
.then(success => {
OS.File.stat(path).then(info => {
return EventDispatcher.instance.sendRequest({
type: "Reader:AddedToCache",
url: article.url,
size: info.size,
path,
});
});
});
},
/**
* Removes an article from the cache given an article URI.
*
* @param url The article URL.
* @return {Promise}
* @resolves When the article is removed.
* @rejects OS.File.Error
*/
async removeArticleFromCache(url) {
let path = this._toHashedPath(url);
await OS.File.remove(path);
},
log(msg) {
if (this.DEBUG)
dump("Reader: " + msg);
},
_blockedHosts: [
"amazon.com",
"github.com",
"mail.google.com",
"pinterest.com",
"reddit.com",
"twitter.com",
"youtube.com",
],
_shouldCheckUri(uri, isBaseUri = false) {
if (!(uri.schemeIs("http") || uri.schemeIs("https"))) {
this.log("Not parsing URI scheme: " + uri.scheme);
return false;
}
try {
uri.QueryInterface(Ci.nsIURL);
} catch (ex) {
// If this doesn't work, presumably the URL is not well-formed or something
return false;
}
// Sadly, some high-profile pages have false positives, so bail early for those:
let asciiHost = uri.asciiHost;
if (!isBaseUri && this._blockedHosts.some(blockedHost => asciiHost.endsWith(blockedHost))) {
return false;
}
if (!isBaseUri && (!uri.filePath || uri.filePath == "/")) {
this.log("Not parsing home page: " + uri.spec);
return false;
}
return true;
},
/**
* Attempts to parse a document into an article. Heavy lifting happens
* in readerWorker.js.
*
* @param doc The document to parse.
* @return {Promise}
* @resolves JS object representing the article, or null if no article is found.
*/
async _readerParse(doc) {
let histogram = Services.telemetry.getHistogramById("READER_MODE_PARSE_RESULT");
if (this.parseNodeLimit) {
let numTags = doc.getElementsByTagName("*").length;
if (numTags > this.parseNodeLimit) {
this.log("Aborting parse for " + doc.baseURIObject.spec + "; " + numTags + " elements found");
histogram.add(PARSE_ERROR_TOO_MANY_ELEMENTS);
return null;
}
}
// Fetch this here before we send `doc` off to the worker thread, as later on the
// document might be nuked but we will still want the URI.
let {documentURI} = doc;
let uriParam = {
spec: doc.baseURIObject.spec,
host: doc.baseURIObject.host,
prePath: doc.baseURIObject.prePath,
scheme: doc.baseURIObject.scheme,
pathBase: Services.io.newURI(".", null, doc.baseURIObject).spec
};
let serializer = Cc["@mozilla.org/xmlextras/xmlserializer;1"].
createInstance(Ci.nsIDOMSerializer);
let serializedDoc = serializer.serializeToString(doc);
let article = null;
try {
article = await ReaderWorker.post("parseDocument", [uriParam, serializedDoc]);
} catch (e) {
Cu.reportError("Error in ReaderWorker: " + e);
histogram.add(PARSE_ERROR_WORKER);
}
// Explicitly null out doc to make it clear it might not be available from this
// point on.
doc = null;
if (!article) {
this.log("Worker did not return an article");
histogram.add(PARSE_ERROR_NO_ARTICLE);
return null;
}
// Readability returns a URI object based on the baseURI, but we only care
// about the original document's URL from now on. This also avoids spoofing
// attempts where the baseURI doesn't match the domain of the documentURI
article.url = documentURI;
delete article.uri;
let flags = Ci.nsIDocumentEncoder.OutputSelectionOnly | Ci.nsIDocumentEncoder.OutputAbsoluteLinks;
article.title = Cc["@mozilla.org/parserutils;1"].getService(Ci.nsIParserUtils)
.convertToPlainText(article.title, flags, 0);
if (gIsFirefoxDesktop) {
await this._assignLanguage(article);
this._maybeAssignTextDirection(article);
}
this._assignReadTime(article);
histogram.add(PARSE_SUCCESS);
return article;
},
get _cryptoHash() {
delete this._cryptoHash;
return this._cryptoHash = Cc["@mozilla.org/security/hash;1"].createInstance(Ci.nsICryptoHash);
},
get _unicodeConverter() {
delete this._unicodeConverter;
this._unicodeConverter = Cc["@mozilla.org/intl/scriptableunicodeconverter"]
.createInstance(Ci.nsIScriptableUnicodeConverter);
this._unicodeConverter.charset = "utf8";
return this._unicodeConverter;
},
/**
* Calculate the hashed path for a stripped article URL.
*
* @param url The article URL. This should have referrers removed.
* @return The file path to the cached article.
*/
_toHashedPath(url) {
let value = this._unicodeConverter.convertToByteArray(url);
this._cryptoHash.init(this._cryptoHash.MD5);
this._cryptoHash.update(value, value.length);
let hash = CommonUtils.encodeBase32(this._cryptoHash.finish(false));
let fileName = hash.substring(0, hash.indexOf("=")) + ".json";
return OS.Path.join(OS.Constants.Path.profileDir, "readercache", fileName);
},
/**
* Ensures the cache directory exists.
*
* @return Promise
* @resolves When the cache directory exists.
* @rejects OS.File.Error
*/
_ensureCacheDir() {
let dir = OS.Path.join(OS.Constants.Path.profileDir, "readercache");
return OS.File.exists(dir).then(exists => {
if (!exists) {
return OS.File.makeDir(dir);
}
return undefined;
});
},
/**
* Sets a global language string value if the result is confident
*
* @return Promise
* @resolves when the language is detected
*/
_assignLanguage(article) {
return LanguageDetector.detectLanguage(article.textContent).then(result => {
article.language = result.confident ? result.language : null;
});
},
_maybeAssignTextDirection(article) {
// TODO: Remove the hardcoded language codes below once bug 1320265 is resolved.
if (!article.dir && ["ar", "fa", "he", "ug", "ur"].includes(article.language)) {
article.dir = "rtl";
}
},
/**
* Assigns the estimated reading time range of the article to the article object.
*
* @param article the article object to assign the reading time estimate to.
*/
_assignReadTime(article) {
let lang = article.language || "en";
const readingSpeed = this._getReadingSpeedForLanguage(lang);
const charactersPerMinuteLow = readingSpeed.cpm - readingSpeed.variance;
const charactersPerMinuteHigh = readingSpeed.cpm + readingSpeed.variance;
const length = article.length;
article.readingTimeMinsSlow = Math.ceil(length / charactersPerMinuteLow);
article.readingTimeMinsFast = Math.ceil(length / charactersPerMinuteHigh);
},
/**
* Returns the reading speed of a selection of languages with likely variance.
*
* Reading speed estimated from a study done on reading speeds in various languages.
* study can be found here: http://iovs.arvojournals.org/article.aspx?articleid=2166061
*
* @return object with characters per minute and variance. Defaults to English
* if no suitable language is found in the collection.
*/
_getReadingSpeedForLanguage(lang) {
const readingSpeed = new Map([
[ "en", {cpm: 987, variance: 118 } ],
[ "ar", {cpm: 612, variance: 88 } ],
[ "de", {cpm: 920, variance: 86 } ],
[ "es", {cpm: 1025, variance: 127 } ],
[ "fi", {cpm: 1078, variance: 121 } ],
[ "fr", {cpm: 998, variance: 126 } ],
[ "he", {cpm: 833, variance: 130 } ],
[ "it", {cpm: 950, variance: 140 } ],
[ "jw", {cpm: 357, variance: 56 } ],
[ "nl", {cpm: 978, variance: 143 } ],
[ "pl", {cpm: 916, variance: 126 } ],
[ "pt", {cpm: 913, variance: 145 } ],
[ "ru", {cpm: 986, variance: 175 } ],
[ "sk", {cpm: 885, variance: 145 } ],
[ "sv", {cpm: 917, variance: 156 } ],
[ "tr", {cpm: 1054, variance: 156 } ],
[ "zh", {cpm: 255, variance: 29 } ],
]);
return readingSpeed.get(lang) || readingSpeed.get("en");
},
};