/* * Copyright (c) 2010 Arc90 Inc * * 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. */ /* * This code is heavily based on Arc90's readability.js (1.7.1) script * available at: http://code.google.com/p/arc90labs-readability */ var Readability = function(uri, doc) { const ENABLE_LOGGING = false; this._uri = uri; this._doc = doc; this._biggestFrame = false; this._articleByline = null; this._articleDir = null; // Start with all flags set this._flags = this.FLAG_STRIP_UNLIKELYS | this.FLAG_WEIGHT_CLASSES | this.FLAG_CLEAN_CONDITIONALLY; // The list of pages we've parsed in this call of readability, // for autopaging. As a key store for easier searching. this._parsedPages = {}; // A list of the ETag headers of pages we've parsed, in case they happen to match, // we'll know it's a duplicate. this._pageETags = {}; // Make an AJAX request for each page and append it to the document. this._curPageNum = 1; // Control whether log messages are sent to the console if (ENABLE_LOGGING) { this.log = function (msg) { dump("Reader: (Readability) " + msg); }; } else { this.log = function () {}; } } Readability.prototype = { FLAG_STRIP_UNLIKELYS: 0x1, FLAG_WEIGHT_CLASSES: 0x2, FLAG_CLEAN_CONDITIONALLY: 0x4, // The number of top candidates to consider when analysing how // tight the competition is among candidates. N_TOP_CANDIDATES: 5, // The maximum number of pages to loop through before we call // it quits and just show a link. MAX_PAGES: 5, // All of the regular expressions in use within readability. // Defined up here so we don't instantiate them repeatedly in loops. REGEXPS: { unlikelyCandidates: /combx|comment|community|disqus|extra|foot|header|menu|remark|rss|shoutbox|sidebar|sponsor|ad-break|agegate|pagination|pager|popup|tweet|twitter/i, okMaybeItsACandidate: /and|article|body|column|main|shadow/i, positive: /article|body|content|entry|hentry|main|page|pagination|post|text|blog|story/i, negative: /hidden|combx|comment|com-|contact|foot|footer|footnote|masthead|media|meta|outbrain|promo|related|scroll|shoutbox|sidebar|sponsor|shopping|tags|tool|widget/i, extraneous: /print|archive|comment|discuss|e[\-]?mail|share|reply|all|login|sign|single|utility/i, byline: /byline|author|dateline|writtenby/i, replaceFonts: /<(\/?)font[^>]*>/gi, trim: /^\s+|\s+$/g, normalize: /\s{2,}/g, videos: /http:\/\/(www\.)?(youtube|vimeo)\.com/i, nextLink: /(next|weiter|continue|>([^\|]|$)|»([^\|]|$))/i, prevLink: /(prev|earl|old|new|<|«)/i, whitespace: /^\s*$/ }, DIV_TO_P_ELEMS: [ "A", "BLOCKQUOTE", "DL", "DIV", "IMG", "OL", "P", "PRE", "TABLE", "UL", "SELECT" ], /** * Run any post-process modifications to article content as necessary. * * @param Element * @return void **/ _postProcessContent: function(articleContent) { // Readability cannot open relative uris so we convert them to absolute uris. this._fixRelativeUris(articleContent); }, /** * Converts each and uri in the given element to an absolute URI. * * @param Element * @return void */ _fixRelativeUris: function(articleContent) { let scheme = this._uri.scheme; let prePath = this._uri.prePath; let pathBase = this._uri.pathBase; function toAbsoluteURI(uri) { // If this is already an absolute URI, return it. if (/^[a-zA-Z][a-zA-Z0-9\+\-\.]*:/.test(uri)) return uri; // Scheme-rooted relative URI. if (uri.substr(0, 2) == "//") return scheme + "://" + uri.substr(2); // Prepath-rooted relative URI. if (uri[0] == "/") return prePath + uri; // Standard relative URI; add entire path. pathBase already includes a // trailing "/". return pathBase + uri; } function convertRelativeURIs(tagName, propName) { let elems = articleContent.getElementsByTagName(tagName); for (let i = elems.length; --i >= 0;) { let elem = elems[i]; let relativeURI = elem.getAttribute(propName); if (relativeURI != null) elems[i].setAttribute(propName, toAbsoluteURI(relativeURI)); } } // Fix links. convertRelativeURIs("a", "href"); // Fix images. convertRelativeURIs("img", "src"); }, /** * Get the article title as an H1. * * @return void **/ _getArticleTitle: function() { let doc = this._doc; let curTitle = ""; let origTitle = ""; try { curTitle = origTitle = doc.title; // If they had an element with id "title" in their HTML if (typeof curTitle !== "string") curTitle = origTitle = this._getInnerText(doc.getElementsByTagName('title')[0]); } catch(e) {} if (curTitle.match(/ [\|\-] /)) { curTitle = origTitle.replace(/(.*)[\|\-] .*/gi,'$1'); if (curTitle.split(' ').length < 3) curTitle = origTitle.replace(/[^\|\-]*[\|\-](.*)/gi,'$1'); } else if (curTitle.indexOf(': ') !== -1) { curTitle = origTitle.replace(/.*:(.*)/gi, '$1'); if (curTitle.split(' ').length < 3) curTitle = origTitle.replace(/[^:]*[:](.*)/gi,'$1'); } else if (curTitle.length > 150 || curTitle.length < 15) { let hOnes = doc.getElementsByTagName('h1'); if (hOnes.length === 1) curTitle = this._getInnerText(hOnes[0]); } curTitle = curTitle.replace(this.REGEXPS.trim, ""); if (curTitle.split(' ').length <= 4) curTitle = origTitle; return curTitle; }, /** * Prepare the HTML document for readability to scrape it. * This includes things like stripping javascript, CSS, and handling terrible markup. * * @return void **/ _prepDocument: function() { let doc = this._doc; // In some cases a body element can't be found (if the HTML is // totally hosed for example) so we create a new body node and // append it to the document. if (doc.body === null) { let body = doc.createElement("body"); try { doc.body = body; } catch(e) { doc.documentElement.appendChild(body); this.log(e); } } // Remove all style tags in head let styleTags = doc.getElementsByTagName("style"); for (let st = 0; st < styleTags.length; st += 1) { styleTags[st].textContent = ""; } this._replaceBrs(doc.body); let fonts = doc.getElementsByTagName("FONT"); for (let i = fonts.length; --i >=0;) { this._setNodeTag(fonts[i], "SPAN"); } }, /** * Finds the next element, starting from the given node, and ignoring * whitespace in between. If the given node is an element, the same node is * returned. */ _nextElement: function (node) { let next = node; while (next && (next.nodeType != Node.ELEMENT_NODE) && this.REGEXPS.whitespace.test(next.textContent)) { next = next.nextSibling; } return next; }, /** * Replaces 2 or more successive
elements with a single

. * Whitespace between
elements are ignored. For example: *

foo
bar


abc
* will become: *
foo
bar

abc

*/ _replaceBrs: function (elem) { let brs = elem.getElementsByTagName("br"); for (let i = 0; i < brs.length; i++) { let br = brs[i]; let next = br.nextSibling; // Whether 2 or more
elements have been found and replaced with a //

block. let replaced = false; // If we find a
chain, remove the
s until we hit another element // or non-whitespace. This leaves behind the first
in the chain // (which will be replaced with a

later). while ((next = this._nextElement(next)) && (next.tagName == "BR")) { replaced = true; let sibling = next.nextSibling; next.parentNode.removeChild(next); next = sibling; } // If we removed a
chain, replace the remaining
with a

. Add // all sibling nodes as children of the

until we hit another
// chain. if (replaced) { let p = this._doc.createElement("p"); br.parentNode.replaceChild(p, br); next = p.nextSibling; while (next) { // If we've hit another

, we're done adding children to this

. if (next.tagName == "BR") { let nextElem = this._nextElement(next); if (nextElem && nextElem.tagName == "BR") break; } // Otherwise, make this node a child of the new

. let sibling = next.nextSibling; p.appendChild(next); next = sibling; } } } }, _setNodeTag: function (node, tag) { node.localName = tag.toLowerCase(); node.tagName = tag.toUpperCase(); }, /** * Prepare the article node for display. Clean out any inline styles, * iframes, forms, strip extraneous

tags, etc. * * @param Element * @return void **/ _prepArticle: function(articleContent) { this._cleanStyles(articleContent); // Clean out junk from the article content this._cleanConditionally(articleContent, "form"); this._clean(articleContent, "object"); this._clean(articleContent, "h1"); // If there is only one h2, they are probably using it as a header // and not a subheader, so remove it since we already have a header. if (articleContent.getElementsByTagName('h2').length === 1) this._clean(articleContent, "h2"); this._clean(articleContent, "iframe"); this._cleanHeaders(articleContent); // Do these last as the previous stuff may have removed junk // that will affect these this._cleanConditionally(articleContent, "table"); this._cleanConditionally(articleContent, "ul"); this._cleanConditionally(articleContent, "div"); // Remove extra paragraphs let articleParagraphs = articleContent.getElementsByTagName('p'); for (let i = articleParagraphs.length - 1; i >= 0; i -= 1) { let imgCount = articleParagraphs[i].getElementsByTagName('img').length; let embedCount = articleParagraphs[i].getElementsByTagName('embed').length; let objectCount = articleParagraphs[i].getElementsByTagName('object').length; if (imgCount === 0 && embedCount === 0 && objectCount === 0 && this._getInnerText(articleParagraphs[i], false) === '') articleParagraphs[i].parentNode.removeChild(articleParagraphs[i]); } let brs = articleContent.getElementsByTagName("BR"); for (let i = brs.length; --i >= 0;) { let br = brs[i]; let next = this._nextElement(br.nextSibling); if (next && next.tagName == "P") br.parentNode.removeChild(br); } }, /** * Initialize a node with the readability object. Also checks the * className/id for special names to add to its score. * * @param Element * @return void **/ _initializeNode: function(node) { node.readability = {"contentScore": 0}; switch(node.tagName) { case 'DIV': node.readability.contentScore += 5; break; case 'PRE': case 'TD': case 'BLOCKQUOTE': node.readability.contentScore += 3; break; case 'ADDRESS': case 'OL': case 'UL': case 'DL': case 'DD': case 'DT': case 'LI': case 'FORM': node.readability.contentScore -= 3; break; case 'H1': case 'H2': case 'H3': case 'H4': case 'H5': case 'H6': case 'TH': node.readability.contentScore -= 5; break; } node.readability.contentScore += this._getClassWeight(node); }, /*** * grabArticle - Using a variety of metrics (content score, classname, element types), find the content that is * most likely to be the stuff a user wants to read. Then return it wrapped up in a div. * * @param page a document to run upon. Needs to be a full document, complete with body. * @return Element **/ _grabArticle: function (page) { let doc = this._doc; let isPaging = (page !== null ? true: false); page = page ? page : this._doc.body; let pageCacheHtml = page.innerHTML; // Check if any "dir" is set on the toplevel document element this._articleDir = doc.documentElement.getAttribute("dir"); while (true) { let stripUnlikelyCandidates = this._flagIsActive(this.FLAG_STRIP_UNLIKELYS); let allElements = page.getElementsByTagName('*'); // First, node prepping. Trash nodes that look cruddy (like ones with the // class name "comment", etc), and turn divs into P tags where they have been // used inappropriately (as in, where they contain no other block level elements.) // // Note: Assignment from index for performance. See http://www.peachpit.com/articles/article.aspx?p=31567&seqNum=5 // TODO: Shouldn't this be a reverse traversal? let node = null; let nodesToScore = []; // Let each node know its index in the allElements array. for (let i = allElements.length; --i >= 0;) { allElements[i]._index = i; } /** * JSDOMParser returns static node lists, not live ones. When we remove * an element from the document, we need to manually remove it - and all * of its children - from the allElements array. */ function purgeNode(node) { for (let i = node.childNodes.length; --i >= 0;) { purgeNode(node.childNodes[i]); } if (node._index !== undefined && allElements[node._index] == node) delete allElements[node._index]; } for (let nodeIndex = 0; nodeIndex < allElements.length; nodeIndex++) { if (!(node = allElements[nodeIndex])) continue; let matchString = node.className + node.id; if (matchString.search(this.REGEXPS.byline) !== -1 && !this._articleByline) { this._articleByline = node.textContent; node.parentNode.removeChild(node); purgeNode(node); continue; } // Remove unlikely candidates if (stripUnlikelyCandidates) { if (matchString.search(this.REGEXPS.unlikelyCandidates) !== -1 && matchString.search(this.REGEXPS.okMaybeItsACandidate) === -1 && node.tagName !== "BODY") { this.log("Removing unlikely candidate - " + matchString); node.parentNode.removeChild(node); purgeNode(node); continue; } } if (node.tagName === "P" || node.tagName === "TD" || node.tagName === "PRE") nodesToScore[nodesToScore.length] = node; // Turn all divs that don't have children block level elements into p's if (node.tagName === "DIV") { // Sites like http://mobile.slate.com encloses each paragraph with a DIV // element. DIVs with only a P element inside and no text content can be // safely converted into plain P elements to avoid confusing the scoring // algorithm with DIVs with are, in practice, paragraphs. let pIndex = this._getSinglePIndexInsideDiv(node); if (pIndex >= 0 || !this._hasChildBlockElement(node)) { if (pIndex >= 0) { let newNode = node.childNodes[pIndex]; node.parentNode.replaceChild(newNode, node); purgeNode(node); } else { this._setNodeTag(node, "P"); nodesToScore[nodesToScore.length] = node; } } else { // EXPERIMENTAL for (let i = 0, il = node.childNodes.length; i < il; i += 1) { let childNode = node.childNodes[i]; if (!childNode) continue; if (childNode.nodeType === 3) { // Node.TEXT_NODE let p = doc.createElement('p'); p.textContent = childNode.textContent; p.style.display = 'inline'; p.className = 'readability-styled'; childNode.parentNode.replaceChild(p, childNode); } } } } } /** * Loop through all paragraphs, and assign a score to them based on how content-y they look. * Then add their score to their parent node. * * A score is determined by things like number of commas, class names, etc. Maybe eventually link density. **/ let candidates = []; for (let pt = 0; pt < nodesToScore.length; pt += 1) { let parentNode = nodesToScore[pt].parentNode; let grandParentNode = parentNode ? parentNode.parentNode : null; let innerText = this._getInnerText(nodesToScore[pt]); if (!parentNode || typeof(parentNode.tagName) === 'undefined') continue; // If this paragraph is less than 25 characters, don't even count it. if (innerText.length < 25) continue; // Initialize readability data for the parent. if (typeof parentNode.readability === 'undefined') { this._initializeNode(parentNode); candidates.push(parentNode); } // Initialize readability data for the grandparent. if (grandParentNode && typeof(grandParentNode.readability) === 'undefined' && typeof(grandParentNode.tagName) !== 'undefined') { this._initializeNode(grandParentNode); candidates.push(grandParentNode); } let contentScore = 0; // Add a point for the paragraph itself as a base. contentScore += 1; // Add points for any commas within this paragraph. contentScore += innerText.split(',').length; // For every 100 characters in this paragraph, add another point. Up to 3 points. contentScore += Math.min(Math.floor(innerText.length / 100), 3); // Add the score to the parent. The grandparent gets half. parentNode.readability.contentScore += contentScore; if (grandParentNode) grandParentNode.readability.contentScore += contentScore / 2; } // After we've calculated scores, loop through all of the possible // candidate nodes we found and find the one with the highest score. let topCandidates = []; for (let c = 0, cl = candidates.length; c < cl; c += 1) { let candidate = candidates[c]; // Scale the final candidates score based on link density. Good content // should have a relatively small link density (5% or less) and be mostly // unaffected by this operation. let candidateScore = candidate.readability.contentScore * (1 - this._getLinkDensity(candidate)); candidate.readability.contentScore = candidateScore; this.log('Candidate: ' + candidate + " (" + candidate.className + ":" + candidate.id + ") with score " + candidateScore); for (let t = 0; t < this.N_TOP_CANDIDATES; t++) { let aTopCandidate = topCandidates[t]; if (!aTopCandidate || candidateScore > aTopCandidate.readability.contentScore) { topCandidates.splice(t, 0, candidate); if (topCandidates.length > this.N_TOP_CANDIDATES) topCandidates.pop(); break; } } } let topCandidate = topCandidates[0] || null; let lastTopCandidate = (topCandidates.length > 3 ? topCandidates[topCandidates.length - 1] : null); // If we still have no top candidate, just use the body as a last resort. // We also have to copy the body node so it is something we can modify. if (topCandidate === null || topCandidate.tagName === "BODY") { // Move all of the page's children into topCandidate topCandidate = doc.createElement("DIV"); let children = page.childNodes; for (let i = 0; i < children.length; ++i) { topCandidate.appendChild(children[i]); } page.appendChild(topCandidate); this._initializeNode(topCandidate); } // Now that we have the top candidate, look through its siblings for content // that might also be related. Things like preambles, content split by ads // that we removed, etc. let articleContent = doc.createElement("DIV"); if (isPaging) articleContent.id = "readability-content"; let siblingScoreThreshold = Math.max(10, topCandidate.readability.contentScore * 0.2); let siblingNodes = topCandidate.parentNode.childNodes; for (let s = 0, sl = siblingNodes.length; s < sl; s += 1) { let siblingNode = siblingNodes[s]; let append = false; this.log("Looking at sibling node: " + siblingNode + " (" + siblingNode.className + ":" + siblingNode.id + ")" + ((typeof siblingNode.readability !== 'undefined') ? (" with score " + siblingNode.readability.contentScore) : '')); this.log("Sibling has score " + (siblingNode.readability ? siblingNode.readability.contentScore : 'Unknown')); if (siblingNode === topCandidate) append = true; let contentBonus = 0; // Give a bonus if sibling nodes and top candidates have the example same classname if (siblingNode.className === topCandidate.className && topCandidate.className !== "") contentBonus += topCandidate.readability.contentScore * 0.2; if (typeof siblingNode.readability !== 'undefined' && (siblingNode.readability.contentScore+contentBonus) >= siblingScoreThreshold) append = true; if (siblingNode.nodeName === "P") { let linkDensity = this._getLinkDensity(siblingNode); let nodeContent = this._getInnerText(siblingNode); let nodeLength = nodeContent.length; if (nodeLength > 80 && linkDensity < 0.25) { append = true; } else if (nodeLength < 80 && linkDensity === 0 && nodeContent.search(/\.( |$)/) !== -1) { append = true; } } if (append) { this.log("Appending node: " + siblingNode); // siblingNodes is a reference to the childNodes array, and // siblingNode is removed from the array when we call appendChild() // below. As a result, we must revisit this index since the nodes // have been shifted. s -= 1; sl -= 1; if (siblingNode.nodeName !== "DIV" && siblingNode.nodeName !== "P") { // We have a node that isn't a common block level element, like a form or td tag. // Turn it into a div so it doesn't get filtered out later by accident. */ this.log("Altering siblingNode of " + siblingNode.nodeName + ' to div.'); this._setNodeTag(siblingNode, "DIV"); } // To ensure a node does not interfere with readability styles, // remove its classnames. siblingNode.className = ""; // Append sibling and subtract from our list because it removes // the node when you append to another node. articleContent.appendChild(siblingNode); } } // So we have all of the content that we need. Now we clean it up for presentation. this._prepArticle(articleContent); if (this._curPageNum === 1) { let div = doc.createElement("DIV"); div.id = "readability-page-1"; div.className = "page"; let children = articleContent.childNodes; for (let i = 0; i < children.length; ++i) { div.appendChild(children[i]); } articleContent.appendChild(div); } // Now that we've gone through the full algorithm, check to see if // we got any meaningful content. If we didn't, we may need to re-run // grabArticle with different flags set. This gives us a higher likelihood of // finding the content, and the sieve approach gives us a higher likelihood of // finding the -right- content. if (this._getInnerText(articleContent, true).length < 500) { page.innerHTML = pageCacheHtml; if (this._flagIsActive(this.FLAG_STRIP_UNLIKELYS)) { this._removeFlag(this.FLAG_STRIP_UNLIKELYS); } else if (this._flagIsActive(this.FLAG_WEIGHT_CLASSES)) { this._removeFlag(this.FLAG_WEIGHT_CLASSES); } else if (this._flagIsActive(this.FLAG_CLEAN_CONDITIONALLY)) { this._removeFlag(this.FLAG_CLEAN_CONDITIONALLY); } else { return null; } } else { if (lastTopCandidate !== null) { // EXPERIMENTAL: Contrast ratio is how we measure the level of competition between candidates in the // readability algorithm. This is to avoid offering reader mode on pages that are more like // a list or directory of links with summaries. It takes the score of the last top candidate // (see N_TOP_CANDIDATES) and checks how it compares to the top candidate's. On pages that are not // actual articles, there will likely be many candidates with similar score (i.e. higher contrast ratio). let contrastRatio = lastTopCandidate.readability.contentScore / topCandidate.readability.contentScore; if (contrastRatio > 0.45) return null; } return articleContent; } } }, /** * Removes script tags from the document. * * @param Element **/ _removeScripts: function(doc) { let scripts = doc.getElementsByTagName('script'); for (let i = scripts.length - 1; i >= 0; i -= 1) { scripts[i].nodeValue=""; scripts[i].removeAttribute('src'); if (scripts[i].parentNode) scripts[i].parentNode.removeChild(scripts[i]); } }, /** * Get child index of the only P element inside a DIV with no * text content. Returns -1 if the DIV node contains non-empty * text nodes or if it contains other element nodes. * * @param Element **/ _getSinglePIndexInsideDiv: function(e) { let childNodes = e.childNodes; let pIndex = -1; for (let i = childNodes.length; --i >= 0;) { let node = childNodes[i]; if (node.nodeType === Node.ELEMENT_NODE) { if (node.tagName !== "P") return -1; if (pIndex >= 0) return -1; pIndex = i; } else if (node.nodeType == Node.TEXT_NODE && this._getInnerText(node, false)) { return -1; } } return pIndex; }, /** * Determine whether element has any children block level elements. * * @param Element */ _hasChildBlockElement: function (e) { let length = e.childNodes.length; for (let i = 0; i < length; i++) { let child = e.childNodes[i]; if (child.nodeType != 1) continue; if (this.DIV_TO_P_ELEMS.indexOf(child.tagName) !== -1 || this._hasChildBlockElement(child)) return true; } return false; }, /** * Get the inner text of a node - cross browser compatibly. * This also strips out any excess whitespace to be found. * * @param Element * @return string **/ _getInnerText: function(e, normalizeSpaces) { let textContent = e.textContent.replace(this.REGEXPS.trim, ""); normalizeSpaces = (typeof normalizeSpaces === 'undefined') ? true : normalizeSpaces; if (normalizeSpaces) { return textContent.replace(this.REGEXPS.normalize, " "); } else { return textContent; } }, /** * Get the number of times a string s appears in the node e. * * @param Element * @param string - what to split on. Default is "," * @return number (integer) **/ _getCharCount: function(e,s) { s = s || ","; return this._getInnerText(e).split(s).length - 1; }, /** * Remove the style attribute on every e and under. * TODO: Test if getElementsByTagName(*) is faster. * * @param Element * @return void **/ _cleanStyles: function(e) { e = e || this._doc; let cur = e.firstChild; if (!e) return; // Remove any root styles, if we're able. if (typeof e.removeAttribute === 'function' && e.className !== 'readability-styled') e.removeAttribute('style'); // Go until there are no more child nodes while (cur !== null) { if (cur.nodeType === 1) { // Remove style attribute(s) : if (cur.className !== "readability-styled") cur.removeAttribute("style"); this._cleanStyles(cur); } cur = cur.nextSibling; } }, /** * Get the density of links as a percentage of the content * This is the amount of text that is inside a link divided by the total text in the node. * * @param Element * @return number (float) **/ _getLinkDensity: function(e) { let links = e.getElementsByTagName("a"); let textLength = this._getInnerText(e).length; let linkLength = 0; for (let i = 0, il = links.length; i < il; i += 1) { linkLength += this._getInnerText(links[i]).length; } return linkLength / textLength; }, /** * Find a cleaned up version of the current URL, to use for comparing links for possible next-pageyness. * * @author Dan Lacy * @return string the base url **/ _findBaseUrl: function() { let uri = this._uri; let noUrlParams = uri.path.split("?")[0]; let urlSlashes = noUrlParams.split("/").reverse(); let cleanedSegments = []; let possibleType = ""; for (let i = 0, slashLen = urlSlashes.length; i < slashLen; i += 1) { let segment = urlSlashes[i]; // Split off and save anything that looks like a file type. if (segment.indexOf(".") !== -1) { possibleType = segment.split(".")[1]; // If the type isn't alpha-only, it's probably not actually a file extension. if (!possibleType.match(/[^a-zA-Z]/)) segment = segment.split(".")[0]; } // EW-CMS specific segment replacement. Ugly. // Example: http://www.ew.com/ew/article/0,,20313460_20369436,00.html if (segment.indexOf(',00') !== -1) segment = segment.replace(',00', ''); // If our first or second segment has anything looking like a page number, remove it. if (segment.match(/((_|-)?p[a-z]*|(_|-))[0-9]{1,2}$/i) && ((i === 1) || (i === 0))) segment = segment.replace(/((_|-)?p[a-z]*|(_|-))[0-9]{1,2}$/i, ""); let del = false; // If this is purely a number, and it's the first or second segment, // it's probably a page number. Remove it. if (i < 2 && segment.match(/^\d{1,2}$/)) del = true; // If this is the first segment and it's just "index", remove it. if (i === 0 && segment.toLowerCase() === "index") del = true; // If our first or second segment is smaller than 3 characters, // and the first segment was purely alphas, remove it. if (i < 2 && segment.length < 3 && !urlSlashes[0].match(/[a-z]/i)) del = true; // If it's not marked for deletion, push it to cleanedSegments. if (!del) cleanedSegments.push(segment); } // This is our final, cleaned, base article URL. return uri.scheme + "://" + uri.host + cleanedSegments.reverse().join("/"); }, /** * Look for any paging links that may occur within the document. * * @param body * @return object (array) **/ _findNextPageLink: function(elem) { let uri = this._uri; let possiblePages = {}; let allLinks = elem.getElementsByTagName('a'); let articleBaseUrl = this._findBaseUrl(); // Loop through all links, looking for hints that they may be next-page links. // Things like having "page" in their textContent, className or id, or being a child // of a node with a page-y className or id. // // Also possible: levenshtein distance? longest common subsequence? // // After we do that, assign each page a score, and for (let i = 0, il = allLinks.length; i < il; i += 1) { let link = allLinks[i]; let linkHref = allLinks[i].href.replace(/#.*$/, '').replace(/\/$/, ''); // If we've already seen this page, ignore it. if (linkHref === "" || linkHref === articleBaseUrl || linkHref === uri.spec || linkHref in this._parsedPages) { continue; } // If it's on a different domain, skip it. if (uri.host !== linkHref.split(/\/+/g)[1]) continue; let linkText = this._getInnerText(link); // If the linkText looks like it's not the next page, skip it. if (linkText.match(this.REGEXPS.extraneous) || linkText.length > 25) continue; // If the leftovers of the URL after removing the base URL don't contain // any digits, it's certainly not a next page link. let linkHrefLeftover = linkHref.replace(articleBaseUrl, ''); if (!linkHrefLeftover.match(/\d/)) continue; if (!(linkHref in possiblePages)) { possiblePages[linkHref] = {"score": 0, "linkText": linkText, "href": linkHref}; } else { possiblePages[linkHref].linkText += ' | ' + linkText; } let linkObj = possiblePages[linkHref]; // If the articleBaseUrl isn't part of this URL, penalize this link. It could // still be the link, but the odds are lower. // Example: http://www.actionscript.org/resources/articles/745/1/JavaScript-and-VBScript-Injection-in-ActionScript-3/Page1.html if (linkHref.indexOf(articleBaseUrl) !== 0) linkObj.score -= 25; let linkData = linkText + ' ' + link.className + ' ' + link.id; if (linkData.match(this.REGEXPS.nextLink)) linkObj.score += 50; if (linkData.match(/pag(e|ing|inat)/i)) linkObj.score += 25; if (linkData.match(/(first|last)/i)) { // -65 is enough to negate any bonuses gotten from a > or » in the text, // If we already matched on "next", last is probably fine. // If we didn't, then it's bad. Penalize. if (!linkObj.linkText.match(this.REGEXPS.nextLink)) linkObj.score -= 65; } if (linkData.match(this.REGEXPS.negative) || linkData.match(this.REGEXPS.extraneous)) linkObj.score -= 50; if (linkData.match(this.REGEXPS.prevLink)) linkObj.score -= 200; // If a parentNode contains page or paging or paginat let parentNode = link.parentNode; let positiveNodeMatch = false; let negativeNodeMatch = false; while (parentNode) { let parentNodeClassAndId = parentNode.className + ' ' + parentNode.id; if (!positiveNodeMatch && parentNodeClassAndId && parentNodeClassAndId.match(/pag(e|ing|inat)/i)) { positiveNodeMatch = true; linkObj.score += 25; } if (!negativeNodeMatch && parentNodeClassAndId && parentNodeClassAndId.match(this.REGEXPS.negative)) { // If this is just something like "footer", give it a negative. // If it's something like "body-and-footer", leave it be. if (!parentNodeClassAndId.match(this.REGEXPS.positive)) { linkObj.score -= 25; negativeNodeMatch = true; } } parentNode = parentNode.parentNode; } // If the URL looks like it has paging in it, add to the score. // Things like /page/2/, /pagenum/2, ?p=3, ?page=11, ?pagination=34 if (linkHref.match(/p(a|g|ag)?(e|ing|ination)?(=|\/)[0-9]{1,2}/i) || linkHref.match(/(page|paging)/i)) linkObj.score += 25; // If the URL contains negative values, give a slight decrease. if (linkHref.match(this.REGEXPS.extraneous)) linkObj.score -= 15; /** * Minor punishment to anything that doesn't match our current URL. * NOTE: I'm finding this to cause more harm than good where something is exactly 50 points. * Dan, can you show me a counterexample where this is necessary? * if (linkHref.indexOf(window.location.href) !== 0) { * linkObj.score -= 1; * } **/ // If the link text can be parsed as a number, give it a minor bonus, with a slight // bias towards lower numbered pages. This is so that pages that might not have 'next' // in their text can still get scored, and sorted properly by score. let linkTextAsNumber = parseInt(linkText, 10); if (linkTextAsNumber) { // Punish 1 since we're either already there, or it's probably // before what we want anyways. if (linkTextAsNumber === 1) { linkObj.score -= 10; } else { linkObj.score += Math.max(0, 10 - linkTextAsNumber); } } } // Loop thrugh all of our possible pages from above and find our top // candidate for the next page URL. Require at least a score of 50, which // is a relatively high confidence that this page is the next link. let topPage = null; for (let page in possiblePages) { if (possiblePages.hasOwnProperty(page)) { if (possiblePages[page].score >= 50 && (!topPage || topPage.score < possiblePages[page].score)) topPage = possiblePages[page]; } } if (topPage) { let nextHref = topPage.href.replace(/\/$/,''); this.log('NEXT PAGE IS ' + nextHref); this._parsedPages[nextHref] = true; return nextHref; } else { return null; } }, _successfulRequest: function(request) { return (request.status >= 200 && request.status < 300) || request.status === 304 || (request.status === 0 && request.responseText); }, _ajax: function(url, options) { let request = new XMLHttpRequest(); function respondToReadyState(readyState) { if (request.readyState === 4) { if (this._successfulRequest(request)) { if (options.success) options.success(request); } else { if (options.error) options.error(request); } } } if (typeof options === 'undefined') options = {}; request.onreadystatechange = respondToReadyState; request.open('get', url, true); request.setRequestHeader('Accept', 'text/html'); try { request.send(options.postBody); } catch (e) { if (options.error) options.error(); } return request; }, _appendNextPage: function(nextPageLink) { let doc = this._doc; this._curPageNum += 1; let articlePage = doc.createElement("DIV"); articlePage.id = 'readability-page-' + this._curPageNum; articlePage.className = 'page'; articlePage.innerHTML = '

§

'; doc.getElementById("readability-content").appendChild(articlePage); if (this._curPageNum > this.MAX_PAGES) { let nextPageMarkup = "
View Next Page
"; articlePage.innerHTML = articlePage.innerHTML + nextPageMarkup; return; } // Now that we've built the article page DOM element, get the page content // asynchronously and load the cleaned content into the div we created for it. (function(pageUrl, thisPage) { this._ajax(pageUrl, { success: function(r) { // First, check to see if we have a matching ETag in headers - if we do, this is a duplicate page. let eTag = r.getResponseHeader('ETag'); if (eTag) { if (eTag in this._pageETags) { this.log("Exact duplicate page found via ETag. Aborting."); articlePage.style.display = 'none'; return; } else { this._pageETags[eTag] = 1; } } // TODO: this ends up doubling up page numbers on NYTimes articles. Need to generically parse those away. let page = doc.createElement("DIV"); // Do some preprocessing to our HTML to make it ready for appending. // - Remove any script tags. Swap and reswap newlines with a unicode // character because multiline regex doesn't work in javascript. // - Turn any noscript tags into divs so that we can parse them. This // allows us to find any next page links hidden via javascript. // - Turn all double br's into p's - was handled by prepDocument in the original view. // Maybe in the future abstract out prepDocument to work for both the original document // and AJAX-added pages. let responseHtml = r.responseText.replace(/\n/g,'\uffff').replace(/.*?<\/script>/gi, ''); responseHtml = responseHtml.replace(/\n/g,'\uffff').replace(/.*?<\/script>/gi, ''); responseHtml = responseHtml.replace(/\uffff/g,'\n').replace(/<(\/?)noscript/gi, '<$1div'); responseHtml = responseHtml.replace(this.REGEXPS.replaceFonts, '<$1span>'); page.innerHTML = responseHtml; this._replaceBrs(page); // Reset all flags for the next page, as they will search through it and // disable as necessary at the end of grabArticle. this._flags = 0x1 | 0x2 | 0x4; let nextPageLink = this._findNextPageLink(page); // NOTE: if we end up supporting _appendNextPage(), we'll need to // change this call to be async let content = this._grabArticle(page); if (!content) { this.log("No content found in page to append. Aborting."); return; } // Anti-duplicate mechanism. Essentially, get the first paragraph of our new page. // Compare it against all of the the previous document's we've gotten. If the previous // document contains exactly the innerHTML of this first paragraph, it's probably a duplicate. let firstP = content.getElementsByTagName("P").length ? content.getElementsByTagName("P")[0] : null; if (firstP && firstP.innerHTML.length > 100) { for (let i = 1; i <= this._curPageNum; i += 1) { let rPage = doc.getElementById('readability-page-' + i); if (rPage && rPage.innerHTML.indexOf(firstP.innerHTML) !== -1) { this.log('Duplicate of page ' + i + ' - skipping.'); articlePage.style.display = 'none'; this._parsedPages[pageUrl] = true; return; } } } this._removeScripts(content); thisPage.innerHTML = thisPage.innerHTML + content.innerHTML; // After the page has rendered, post process the content. This delay is necessary because, // in webkit at least, offsetWidth is not set in time to determine image width. We have to // wait a little bit for reflow to finish before we can fix floating images. setTimeout((function() { this._postProcessContent(thisPage); }).bind(this), 500); if (nextPageLink) this._appendNextPage(nextPageLink); } }); }).bind(this)(nextPageLink, articlePage); }, /** * Get an elements class/id weight. Uses regular expressions to tell if this * element looks good or bad. * * @param Element * @return number (Integer) **/ _getClassWeight: function(e) { if (!this._flagIsActive(this.FLAG_WEIGHT_CLASSES)) return 0; let weight = 0; // Look for a special classname if (typeof(e.className) === 'string' && e.className !== '') { if (e.className.search(this.REGEXPS.negative) !== -1) weight -= 25; if (e.className.search(this.REGEXPS.positive) !== -1) weight += 25; } // Look for a special ID if (typeof(e.id) === 'string' && e.id !== '') { if (e.id.search(this.REGEXPS.negative) !== -1) weight -= 25; if (e.id.search(this.REGEXPS.positive) !== -1) weight += 25; } return weight; }, /** * Clean a node of all elements of type "tag". * (Unless it's a youtube/vimeo video. People love movies.) * * @param Element * @param string tag to clean * @return void **/ _clean: function(e, tag) { let targetList = e.getElementsByTagName(tag); let isEmbed = (tag === 'object' || tag === 'embed'); for (let y = targetList.length - 1; y >= 0; y -= 1) { // Allow youtube and vimeo videos through as people usually want to see those. if (isEmbed) { let attributeValues = ""; for (let i = 0, il = targetList[y].attributes.length; i < il; i += 1) { attributeValues += targetList[y].attributes[i].value + '|'; } // First, check the elements attributes to see if any of them contain youtube or vimeo if (attributeValues.search(this.REGEXPS.videos) !== -1) continue; // Then check the elements inside this element for the same. if (targetList[y].innerHTML.search(this.REGEXPS.videos) !== -1) continue; } targetList[y].parentNode.removeChild(targetList[y]); } }, /** * Clean an element of all tags of type "tag" if they look fishy. * "Fishy" is an algorithm based on content length, classnames, link density, number of images & embeds, etc. * * @return void **/ _cleanConditionally: function(e, tag) { if (!this._flagIsActive(this.FLAG_CLEAN_CONDITIONALLY)) return; let tagsList = e.getElementsByTagName(tag); let curTagsLength = tagsList.length; // Gather counts for other typical elements embedded within. // Traverse backwards so we can remove nodes at the same time // without effecting the traversal. // // TODO: Consider taking into account original contentScore here. for (let i = curTagsLength-1; i >= 0; i -= 1) { let weight = this._getClassWeight(tagsList[i]); let contentScore = 0; this.log("Cleaning Conditionally " + tagsList[i] + " (" + tagsList[i].className + ":" + tagsList[i].id + ")"); if (weight + contentScore < 0) { tagsList[i].parentNode.removeChild(tagsList[i]); } else if (this._getCharCount(tagsList[i],',') < 10) { // If there are not very many commas, and the number of // non-paragraph elements is more than paragraphs or other // ominous signs, remove the element. let p = tagsList[i].getElementsByTagName("p").length; let img = tagsList[i].getElementsByTagName("img").length; let li = tagsList[i].getElementsByTagName("li").length-100; let input = tagsList[i].getElementsByTagName("input").length; let embedCount = 0; let embeds = tagsList[i].getElementsByTagName("embed"); for (let ei = 0, il = embeds.length; ei < il; ei += 1) { if (embeds[ei].src.search(this.REGEXPS.videos) === -1) embedCount += 1; } let linkDensity = this._getLinkDensity(tagsList[i]); let contentLength = this._getInnerText(tagsList[i]).length; let toRemove = false; if (img > p) { toRemove = true; } else if (li > p && tag !== "ul" && tag !== "ol") { toRemove = true; } else if ( input > Math.floor(p/3) ) { toRemove = true; } else if (contentLength < 25 && (img === 0 || img > 2) ) { toRemove = true; } else if (weight < 25 && linkDensity > 0.2) { toRemove = true; } else if (weight >= 25 && linkDensity > 0.5) { toRemove = true; } else if ((embedCount === 1 && contentLength < 75) || embedCount > 1) { toRemove = true; } if (toRemove) tagsList[i].parentNode.removeChild(tagsList[i]); } } }, /** * Clean out spurious headers from an Element. Checks things like classnames and link density. * * @param Element * @return void **/ _cleanHeaders: function(e) { for (let headerIndex = 1; headerIndex < 3; headerIndex += 1) { let headers = e.getElementsByTagName('h' + headerIndex); for (let i = headers.length - 1; i >= 0; i -= 1) { if (this._getClassWeight(headers[i]) < 0 || this._getLinkDensity(headers[i]) > 0.33) headers[i].parentNode.removeChild(headers[i]); } } }, _flagIsActive: function(flag) { return (this._flags & flag) > 0; }, _addFlag: function(flag) { this._flags = this._flags | flag; }, _removeFlag: function(flag) { this._flags = this._flags & ~flag; }, /** * Runs readability. * * Workflow: * 1. Prep the document by removing script tags, css, etc. * 2. Build readability's DOM tree. * 3. Grab the article content from the current dom tree. * 4. Replace the current DOM tree with the new one. * 5. Read peacefully. * * @return void **/ parse: function () { // Remove script tags from the document. this._removeScripts(this._doc); // FIXME: Disabled multi-page article support for now as it // needs more work on infrastructure. // Make sure this document is added to the list of parsed pages first, // so we don't double up on the first page. // this._parsedPages[uri.spec.replace(/\/$/, '')] = true; // Pull out any possible next page link first. // let nextPageLink = this._findNextPageLink(doc.body); this._prepDocument(); let articleTitle = this._getArticleTitle(); let articleContent = this._grabArticle(); if (!articleContent) return null; this._postProcessContent(articleContent); // if (nextPageLink) { // // Append any additional pages after a small timeout so that people // // can start reading without having to wait for this to finish processing. // setTimeout((function() { // this._appendNextPage(nextPageLink); // }).bind(this), 500); // } return { title: articleTitle, byline: this._articleByline, dir: this._articleDir, content: articleContent.innerHTML }; } };