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Readability.js
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/*
* 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 root = this;
/**
* Public constructor.
* @param {Object} uri The URI descriptor object.
* @param {HTMLDocument} doc The document to parse.
* @param {Object} options The options object.
*/
var Readability = function(uri, doc, options) {
options = options || {};
this._uri = uri;
this._doc = doc;
this._biggestFrame = false;
this._articleByline = null;
this._articleDir = null;
// Configureable options
this._debug = !!options.debug;
this._maxElemsToParse = options.maxElemsToParse || this.DEFAULT_MAX_ELEMS_TO_PARSE;
this._nbTopCandidates = options.nbTopCandidates || this.DEFAULT_N_TOP_CANDIDATES;
this._maxPages = options.maxPages || this.DEFAULT_MAX_PAGES;
// 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 (this._debug) {
function logEl(e) {
var rv = e.nodeName + " ";
if (e.nodeType == e.TEXT_NODE) {
return rv + '("' + e.textContent + '")';
}
var classDesc = e.className && ("." + e.className.replace(/ /g, "."));
var elDesc = e.id ? "(#" + e.id + classDesc + ")" :
(classDesc ? "(" + classDesc + ")" : "");
return rv + elDesc;
}
this.log = function () {
if ("dump" in root) {
var msg = Array.prototype.map.call(arguments, function(x) {
return (x && x.nodeName) ? logEl(x) : x;
}).join(" ");
dump("Reader: (Readability) " + msg + "\n");
} else if ("console" in root) {
var args = ["Reader: (Readability) "].concat(arguments);
console.log.apply(console, args);
}
};
} else {
this.log = function () {};
}
}
Readability.prototype = {
FLAG_STRIP_UNLIKELYS: 0x1,
FLAG_WEIGHT_CLASSES: 0x2,
FLAG_CLEAN_CONDITIONALLY: 0x4,
// Max number of nodes supported by this parser. Default: 0 (no limit)
DEFAULT_MAX_ELEMS_TO_PARSE: 0,
// The number of top candidates to consider when analysing how
// tight the competition is among candidates.
DEFAULT_N_TOP_CANDIDATES: 5,
// The maximum number of pages to loop through before we call
// it quits and just show a link.
DEFAULT_MAX_PAGES: 5,
// Element tags to score by default.
DEFAULT_TAGS_TO_SCORE: "section,h2,h3,h4,h5,h6,p,td,pre".toUpperCase().split(","),
// All of the regular expressions in use within readability.
// Defined up here so we don't instantiate them repeatedly in loops.
REGEXPS: {
unlikelyCandidates: /banner|combx|comment|community|disqus|extra|foot|header|menu|related|remark|rss|share|shoutbox|sidebar|skyscraper|sponsor|ad-break|agegate|pagination|pager|popup/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|banner|combx|comment|com-|contact|foot|footer|footnote|masthead|media|meta|outbrain|promo|related|scroll|share|shoutbox|sidebar|skyscraper|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,
normalize: /\s{2,}/g,
videos: /\/\/(www\.)?(dailymotion|youtube|youtube-nocookie|player\.vimeo)\.com/i,
nextLink: /(next|weiter|continue|>([^\|]|$)|»([^\|]|$))/i,
prevLink: /(prev|earl|old|new|<|«)/i,
whitespace: /^\s*$/,
hasContent: /\S$/,
},
DIV_TO_P_ELEMS: [ "A", "BLOCKQUOTE", "DL", "DIV", "IMG", "OL", "P", "PRE", "TABLE", "UL", "SELECT" ],
ALTER_TO_DIV_EXCEPTIONS: ["DIV", "ARTICLE", "SECTION", "P"],
/**
* 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);
},
/**
* Iterate over a NodeList, which doesn't natively fully implement the Array
* interface.
*
* For convenience, the current object context is applied to the provided
* iterate function.
*
* @param NodeList nodeList The NodeList.
* @param Function fn The iterate function.
* @return void
*/
_forEachNode: function(nodeList, fn) {
return Array.prototype.forEach.call(nodeList, fn, this);
},
/**
* Iterate over a NodeList, return true if any of the provided iterate
* function calls returns true, false otherwise.
*
* For convenience, the current object context is applied to the
* provided iterate function.
*
* @param NodeList nodeList The NodeList.
* @param Function fn The iterate function.
* @return Boolean
*/
_someNode: function(nodeList, fn) {
return Array.prototype.some.call(nodeList, fn, this);
},
/**
* Concat all nodelists passed as arguments.
*
* @return ...NodeList
* @return Array
*/
_concatNodeLists: function() {
var slice = Array.prototype.slice;
var args = slice.call(arguments);
var nodeLists = args.map(function(list) {
return slice.call(list);
});
return Array.prototype.concat.apply([], nodeLists);
},
_getAllNodesWithTag: function(node, tagNames) {
if (node.querySelectorAll) {
return node.querySelectorAll(tagNames.join(','));
}
return [].concat.apply([], tagNames.map(function(tag) {
return node.getElementsByTagName(tag);
}));
},
/**
* Converts each <a> and <img> uri in the given element to an absolute URI.
*
* @param Element
* @return void
*/
_fixRelativeUris: function(articleContent) {
var scheme = this._uri.scheme;
var prePath = this._uri.prePath;
var 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;
// Dotslash relative URI.
if (uri.indexOf("./") === 0)
return pathBase + uri.slice(2);
// Standard relative URI; add entire path. pathBase already includes a
// trailing "/".
return pathBase + uri;
}
var links = articleContent.getElementsByTagName("a");
this._forEachNode(links, function(link) {
var href = link.getAttribute("href");
if (href) {
// Replace links with javascript: URIs with text content, since
// they won't work after scripts have been removed from the page.
if (href.indexOf("javascript:") === 0) {
var text = this._doc.createTextNode(link.textContent);
link.parentNode.replaceChild(text, link);
} else {
link.setAttribute("href", toAbsoluteURI(href));
}
}
});
var imgs = articleContent.getElementsByTagName("img");
this._forEachNode(imgs, function(img) {
var src = img.getAttribute("src");
if (src) {
img.setAttribute("src", toAbsoluteURI(src));
}
});
},
/**
* Get the article title as an H1.
*
* @return void
**/
_getArticleTitle: function() {
var doc = this._doc;
var curTitle = "";
var 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) {
// Check if we have an heading containing this exact string, so we
// could assume it's the full title.
var headings = this._concatNodeLists(
doc.getElementsByTagName('h1'),
doc.getElementsByTagName('h2')
);
var match = this._someNode(headings, function(heading) {
return heading.textContent === curTitle;
});
// If we don't, let's extract the title out of the original title string.
if (!match) {
curTitle = origTitle.substring(origTitle.lastIndexOf(':') + 1);
// If the title is now too short, try the first colon instead:
if (curTitle.split(' ').length < 3)
curTitle = origTitle.substring(origTitle.indexOf(':') + 1);
}
} else if (curTitle.length > 150 || curTitle.length < 15) {
var hOnes = doc.getElementsByTagName('h1');
if (hOnes.length === 1)
curTitle = this._getInnerText(hOnes[0]);
}
curTitle = curTitle.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() {
var doc = this._doc;
// Remove all style tags in head
this._forEachNode(doc.getElementsByTagName("style"), function(styleNode) {
styleNode.parentNode.removeChild(styleNode);
});
if (doc.body) {
this._replaceBrs(doc.body);
}
this._forEachNode(doc.getElementsByTagName("font"), function(fontNode) {
this._setNodeTag(fontNode, "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) {
var 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 <br> elements with a single <p>.
* Whitespace between <br> elements are ignored. For example:
* <div>foo<br>bar<br> <br><br>abc</div>
* will become:
* <div>foo<br>bar<p>abc</p></div>
*/
_replaceBrs: function (elem) {
this._forEachNode(elem.getElementsByTagName("br"), function(br) {
var next = br.nextSibling;
// Whether 2 or more <br> elements have been found and replaced with a
// <p> block.
var replaced = false;
// If we find a <br> chain, remove the <br>s until we hit another element
// or non-whitespace. This leaves behind the first <br> in the chain
// (which will be replaced with a <p> later).
while ((next = this._nextElement(next)) && (next.tagName == "BR")) {
replaced = true;
var sibling = next.nextSibling;
next.parentNode.removeChild(next);
next = sibling;
}
// If we removed a <br> chain, replace the remaining <br> with a <p>. Add
// all sibling nodes as children of the <p> until we hit another <br>
// chain.
if (replaced) {
var p = this._doc.createElement("p");
br.parentNode.replaceChild(p, br);
next = p.nextSibling;
while (next) {
// If we've hit another <br><br>, we're done adding children to this <p>.
if (next.tagName == "BR") {
var nextElem = this._nextElement(next);
if (nextElem && nextElem.tagName == "BR")
break;
}
// Otherwise, make this node a child of the new <p>.
var sibling = next.nextSibling;
p.appendChild(next);
next = sibling;
}
}
});
},
_setNodeTag: function (node, tag) {
this.log("_setNodeTag", node, tag);
if (node.__JSDOMParser__) {
node.localName = tag.toLowerCase();
node.tagName = tag.toUpperCase();
return node;
}
var replacement = node.ownerDocument.createElement(tag);
while (node.firstChild) {
replacement.appendChild(node.firstChild);
}
node.parentNode.replaceChild(replacement, node);
if (node.readability)
replacement.readability = node.readability;
for (var i = 0; i < node.attributes.length; i++) {
replacement.setAttribute(node.attributes[i].name, node.attributes[i].value);
}
return replacement;
},
/**
* Prepare the article node for display. Clean out any inline styles,
* iframes, forms, strip extraneous <p> 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, "embed");
this._clean(articleContent, "h1");
this._clean(articleContent, "footer");
// 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
this._forEachNode(articleContent.getElementsByTagName('p'), function(paragraph) {
var imgCount = paragraph.getElementsByTagName('img').length;
var embedCount = paragraph.getElementsByTagName('embed').length;
var objectCount = paragraph.getElementsByTagName('object').length;
// At this point, nasty iframes have been removed, only remain embedded video ones.
var iframeCount = paragraph.getElementsByTagName('iframe').length;
var totalCount = imgCount + embedCount + objectCount + iframeCount;
if (totalCount === 0 && !this._getInnerText(paragraph, false))
paragraph.parentNode.removeChild(paragraph);
});
this._forEachNode(articleContent.getElementsByTagName("br"), function(br) {
var 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);
},
_removeAndGetNext: function(node) {
var nextNode = this._getNextNode(node, true);
node.parentNode.removeChild(node);
return nextNode;
},
/**
* Traverse the DOM from node to node, starting at the node passed in.
* Pass true for the second parameter to indicate this node itself
* (and its kids) are going away, and we want the next node over.
*
* Calling this in a loop will traverse the DOM depth-first.
*/
_getNextNode: function(node, ignoreSelfAndKids) {
// First check for kids if those aren't being ignored
if (!ignoreSelfAndKids && node.firstElementChild) {
return node.firstElementChild;
}
// Then for siblings...
if (node.nextElementSibling) {
return node.nextElementSibling;
}
// And finally, move up the parent chain *and* find a sibling
// (because this is depth-first traversal, we will have already
// seen the parent nodes themselves).
do {
node = node.parentNode;
} while (node && !node.nextElementSibling);
return node && node.nextElementSibling;
},
/**
* Like _getNextNode, but for DOM implementations with no
* firstElementChild/nextElementSibling functionality...
*/
_getNextNodeNoElementProperties: function(node, ignoreSelfAndKids) {
function nextSiblingEl(n) {
do {
n = n.nextSibling;
} while (n && n.nodeType !== n.ELEMENT_NODE);
return n;
}
// First check for kids if those aren't being ignored
if (!ignoreSelfAndKids && node.children[0]) {
return node.children[0];
}
// Then for siblings...
var next = nextSiblingEl(node);
if (next) {
return next;
}
// And finally, move up the parent chain *and* find a sibling
// (because this is depth-first traversal, we will have already
// seen the parent nodes themselves).
do {
node = node.parentNode;
if (node)
next = nextSiblingEl(node);
} while (node && !next);
return node && next;
},
_checkByline: function(node, matchString) {
if (this._articleByline) {
return false;
}
if (node.getAttribute !== undefined) {
var rel = node.getAttribute("rel");
}
if ((rel === "author" || this.REGEXPS.byline.test(matchString)) && this._isValidByline(node.textContent)) {
this._articleByline = node.textContent.trim();
return true;
}
return false;
},
_getNodeAncestors: function(node, maxDepth) {
maxDepth = maxDepth || 0;
var i = 0, ancestors = [];
while (node.parentNode) {
ancestors.push(node.parentNode)
if (maxDepth && ++i === maxDepth)
break;
node = node.parentNode;
}
return ancestors;
},
/***
* 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) {
this.log("**** grabArticle ****");
var doc = this._doc;
var isPaging = (page !== null ? true: false);
page = page ? page : this._doc.body;
// We can't grab an article if we don't have a page!
if (!page) {
this.log("No body found in document. Abort.");
return null;
}
var pageCacheHtml = page.innerHTML;
// Check if any "dir" is set on the toplevel document element
this._articleDir = doc.documentElement.getAttribute("dir");
while (true) {
var stripUnlikelyCandidates = this._flagIsActive(this.FLAG_STRIP_UNLIKELYS);
// 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.)
var elementsToScore = [];
var node = this._doc.documentElement;
while (node) {
var matchString = node.className + " " + node.id;
// Check to see if this node is a byline, and remove it if it is.
if (this._checkByline(node, matchString)) {
node = this._removeAndGetNext(node);
continue;
}
// Remove unlikely candidates
if (stripUnlikelyCandidates) {
if (this.REGEXPS.unlikelyCandidates.test(matchString) &&
!this.REGEXPS.okMaybeItsACandidate.test(matchString) &&
node.tagName !== "BODY" &&
node.tagName !== "A") {
this.log("Removing unlikely candidate - " + matchString);
node = this._removeAndGetNext(node);
continue;
}
}
if (this.DEFAULT_TAGS_TO_SCORE.indexOf(node.tagName) !== -1) {
elementsToScore.push(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.
if (this._hasSinglePInsideElement(node)) {
var newNode = node.children[0];
node.parentNode.replaceChild(newNode, node);
node = newNode;
} else if (!this._hasChildBlockElement(node)) {
node = this._setNodeTag(node, "P");
elementsToScore.push(node);
} else {
// EXPERIMENTAL
this._forEachNode(node.childNodes, function(childNode) {
if (childNode.nodeType === Node.TEXT_NODE) {
var p = doc.createElement('p');
p.textContent = childNode.textContent;
p.style.display = 'inline';
p.className = 'readability-styled';
node.replaceChild(p, childNode);
}
});
}
}
node = this._getNextNode(node);
}
/**
* 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.
**/
var candidates = [];
this._forEachNode(elementsToScore, function(elementToScore) {
if (!elementToScore.parentNode || typeof(elementToScore.parentNode.tagName) === 'undefined')
return;
// If this paragraph is less than 25 characters, don't even count it.
var innerText = this._getInnerText(elementToScore);
if (innerText.length < 25)
return;
// Exclude nodes with no ancestor.
var ancestors = this._getNodeAncestors(elementToScore, 3);
if (ancestors.length === 0)
return;
var 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);
// Initialize and score ancestors.
this._forEachNode(ancestors, function(ancestor, level) {
if (!ancestor.tagName)
return;
if (typeof(ancestor.readability) === 'undefined') {
this._initializeNode(ancestor);
candidates.push(ancestor);
}
// Node score divider:
// - parent: 1 (no division)
// - grandparent: 2
// - great grandparent+: ancestor level * 3
var scoreDivider = level === 0 ? 1 : level === 1 ? 2 : level * 3;
ancestor.readability.contentScore += contentScore / scoreDivider;
});
});
// After we've calculated scores, loop through all of the possible
// candidate nodes we found and find the one with the highest score.
var topCandidates = [];
for (var c = 0, cl = candidates.length; c < cl; c += 1) {
var 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.
var candidateScore = candidate.readability.contentScore * (1 - this._getLinkDensity(candidate));
candidate.readability.contentScore = candidateScore;
this.log('Candidate:', candidate, "with score " + candidateScore);
for (var t = 0; t < this._nbTopCandidates; t++) {
var aTopCandidate = topCandidates[t];
if (!aTopCandidate || candidateScore > aTopCandidate.readability.contentScore) {
topCandidates.splice(t, 0, candidate);
if (topCandidates.length > this._nbTopCandidates)
topCandidates.pop();
break;
}
}
}
var topCandidate = topCandidates[0] || null;
var neededToCreateTopCandidate = false;
// 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");
neededToCreateTopCandidate = true;
// Move everything (not just elements, also text nodes etc.) into the container
// so we even include text directly in the body:
var kids = page.childNodes;
while (kids.length) {
this.log("Moving child out:", kids[0]);
topCandidate.appendChild(kids[0]);
}
page.appendChild(topCandidate);
this._initializeNode(topCandidate);
} else if (topCandidate) {
// Because of our bonus system, parents of candidates might have scores
// themselves. They get half of the node. There won't be nodes with higher
// scores than our topCandidate, but if we see the score going *up* in the first
// few steps up the tree, that's a decent sign that there might be more content
// lurking in other places that we want to unify in. The sibling stuff
// below does some of that - but only if we've looked high enough up the DOM
// tree.
var parentOfTopCandidate = topCandidate.parentNode;
var lastScore = topCandidate.readability.contentScore;
// The scores shouldn't get too low.
var scoreThreshold = lastScore / 3;
while (parentOfTopCandidate && parentOfTopCandidate.readability) {
var parentScore = parentOfTopCandidate.readability.contentScore;
if (parentScore < scoreThreshold)
break;
if (parentScore > lastScore) {
// Alright! We found a better parent to use.
topCandidate = parentOfTopCandidate;
break;
}
lastScore = parentOfTopCandidate.readability.contentScore;
parentOfTopCandidate = parentOfTopCandidate.parentNode;
}
}
// 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.
var articleContent = doc.createElement("DIV");
if (isPaging)
articleContent.id = "readability-content";
var siblingScoreThreshold = Math.max(10, topCandidate.readability.contentScore * 0.2);
var siblings = topCandidate.parentNode.children;
for (var s = 0, sl = siblings.length; s < sl; s++) {
var sibling = siblings[s];
var append = false;
this.log("Looking at sibling node:", sibling, sibling.readability ? ("with score " + sibling.readability.contentScore) : '');
this.log("Sibling has score", sibling.readability ? sibling.readability.contentScore : 'Unknown');
if (sibling === topCandidate) {
append = true;
} else {
var contentBonus = 0;
// Give a bonus if sibling nodes and top candidates have the example same classname
if (sibling.className === topCandidate.className && topCandidate.className !== "")
contentBonus += topCandidate.readability.contentScore * 0.2;
if (sibling.readability &&
((sibling.readability.contentScore + contentBonus) >= siblingScoreThreshold)) {
append = true;
} else if (sibling.nodeName === "P") {
var linkDensity = this._getLinkDensity(sibling);
var nodeContent = this._getInnerText(sibling);
var 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:", sibling);
if (this.ALTER_TO_DIV_EXCEPTIONS.indexOf(sibling.nodeName) === -1) {
// 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 sibling:", sibling, 'to div.');
sibling = this._setNodeTag(sibling, "DIV");
}
articleContent.appendChild(sibling);
// siblings is a reference to the children array, and
// sibling is removed from the array when we call appendChild().
// As a result, we must revisit this index since the nodes
// have been shifted.
s -= 1;
sl -= 1;
}
}
if (this._debug)
this.log("Article content pre-prep: " + articleContent.innerHTML);
// So we have all of the content that we need. Now we clean it up for presentation.
this._prepArticle(articleContent);
if (this._debug)
this.log("Article content post-prep: " + articleContent.innerHTML);
if (this._curPageNum === 1) {
if (neededToCreateTopCandidate) {
// We already created a fake div thing, and there wouldn't have been any siblings left
// for the previous loop, so there's no point trying to create a new div, and then
// move all the children over. Just assign IDs and class names here. No need to append
// because that already happened anyway.
topCandidate.id = "readability-page-1";
topCandidate.className = "page";
} else {
var div = doc.createElement("DIV");
div.id = "readability-page-1";
div.className = "page";
var children = articleContent.childNodes;
while (children.length) {
div.appendChild(children[0]);
}
articleContent.appendChild(div);
}
}
if (this._debug)
this.log("Article content after paging: " + articleContent.innerHTML);
// 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 {
return articleContent;
}
}
},
/**
* Check whether the input string could be a byline.
* This verifies that the input is a string, and that the length
* is less than 100 chars.
*
* @param possibleByline {string} - a string to check whether its a byline.
* @return Boolean - whether the input string is a byline.
*/
_isValidByline: function(byline) {
if (typeof byline == 'string' || byline instanceof String) {
byline = byline.trim();
return (byline.length > 0) && (byline.length < 100);
}
return false;
},
/**
* Attempts to get excerpt and byline metadata for the article.
*
* @return Object with optional "excerpt" and "byline" properties
*/
_getArticleMetadata: function() {
var metadata = {};
var values = {};
var metaElements = this._doc.getElementsByTagName("meta");
// Match "description", or Twitter's "twitter:description" (Cards)
// in name attribute.
var namePattern = /^\s*((twitter)\s*:\s*)?(description|title)\s*$/gi;
// Match Facebook's Open Graph title & description properties.
var propertyPattern = /^\s*og\s*:\s*(description|title)\s*$/gi;
// Find description tags.
this._forEachNode(metaElements, function(element) {
var elementName = element.getAttribute("name");
var elementProperty = element.getAttribute("property");
if ([elementName, elementProperty].indexOf("author") !== -1) {
metadata.byline = element.getAttribute("content");
return;
}
var name = null;
if (namePattern.test(elementName)) {
name = elementName;
} else if (propertyPattern.test(elementProperty)) {
name = elementProperty;
}
if (name) {
var content = element.getAttribute("content");
if (content) {
// Convert to lowercase and remove any whitespace
// so we can match below.
name = name.toLowerCase().replace(/\s/g, '');
values[name] = content.trim();
}
}
});
if ("description" in values) {
metadata.excerpt = values["description"];
} else if ("og:description" in values) {
// Use facebook open graph description.
metadata.excerpt = values["og:description"];
} else if ("twitter:description" in values) {
// Use twitter cards description.
metadata.excerpt = values["twitter:description"];