Html2Article-php實(shí)現(xiàn)的提取網(wǎng)頁(yè)正文部分，最近研究百度結(jié)果頁(yè)的資訊采集，其中關(guān)鍵環(huán)節(jié)就是從采集回的頁(yè)面中提取出文章。

有網(wǎng)友回復(fù)說(shuō)不會(huì)用或不能用，鄭曉特意貼上測(cè)試代碼…做為一個(gè)程序員，有問(wèn)題請(qǐng)先自己找原因

#采集我們新聞網(wǎng)的一個(gè)新聞頁(yè)
$content = file_get_contents("http://news.qingdaonews.com/qingdao/2016-12/26/content_11882489.htm");
$r = new Readability($content);
print_r($r->getContent());


因?yàn)殡y點(diǎn)在于如何去識(shí)別并保留網(wǎng)頁(yè)中的文章部分，而且刪除其它無(wú)用的信息，并且要做到通用化，不能像火車頭那樣根據(jù)目標(biāo)站來(lái)制定采集規(guī)則，因?yàn)樗阉饕娼Y(jié)果中有各種的網(wǎng)頁(yè)。

這個(gè)類是從網(wǎng)上找到的一個(gè)php實(shí)現(xiàn)的提取網(wǎng)頁(yè)正文部分的算法，鄭曉在本地也測(cè)試了下，準(zhǔn)確率非常高。

source = $source;

// DOM 解析類只能處理 UTF-8 格式的字符
$source = mb_convert_encoding($source, 'HTML-ENTITIES', $input_char);

// 預(yù)處理 HTML 標(biāo)簽，剔除冗余的標(biāo)簽等
$source = $this->preparSource($source);

// 生成 DOM 解析類
$this->DOM = new DOMDocument('1.0', $input_char);
try {
//libxml_use_internal_errors(true);
// 會(huì)有些錯(cuò)誤信息，不過(guò)不要緊 :^)
if (!@$this->DOM->loadHTML(''.$source)) {
throw new Exception("Parse HTML Error!");
}

foreach ($this->DOM->childNodes as $item) {
if ($item->nodeType == XML_PI_NODE) {
$this->DOM->removeChild($item); // remove hack
}
}

// insert proper
$this->DOM->encoding = Readability::DOM_DEFAULT_CHARSET;
} catch (Exception $e) {
// ...
}
}

/**
* 預(yù)處理 HTML 標(biāo)簽，使其能夠準(zhǔn)確被 DOM 解析類處理
*
* @return String
*/
private function preparSource($string) {
// 剔除多余的 HTML 編碼標(biāo)記，避免解析出錯(cuò)
preg_match("/charset=([\w|\-]+);?/", $string, $match);
if (isset($match[1])) {
$string = preg_replace("/charset=([\w|\-]+);?/", "", $string, 1);
}

// Replace all doubled-up
tags with

tags, and remove fonts.
$string = preg_replace("/[ \r\n\s]*/i", "

", $string);
$string = preg_replace("/<\/?font[^>]*>/i", "", $string);

// @see https://github.com/feelinglucky/php-readability/issues/7
// - from http://stackoverflow.com/questions/7130867/remove-script-tag-from-html-content
$string = preg_replace("#(.*?)#is", "", $string);

return trim($string);
}

/**
* 刪除 DOM 元素中所有的 $TagName 標(biāo)簽
*
* @return DOMDocument
*/
private function removeJunkTag($RootNode, $TagName) {

$Tags = $RootNode->getElementsByTagName($TagName);

//Note: always index 0, because removing a tag removes it from the results as well.
while($Tag = $Tags->item(0)){
$parentNode = $Tag->parentNode;
$parentNode->removeChild($Tag);
}

return $RootNode;

}

/**
* 刪除元素中所有不需要的屬性
*/
private function removeJunkAttr($RootNode, $Attr) {
$Tags = $RootNode->getElementsByTagName("*");

$i = 0;
while($Tag = $Tags->item($i++)) {
$Tag->removeAttribute($Attr);
}

return $RootNode;
}

/**
* 根據(jù)評(píng)分獲取頁(yè)面主要內(nèi)容的盒模型
* 判定算法來(lái)自：http://code.google.com/p/arc90labs-readability/
* 這里由鄭曉博客轉(zhuǎn)發(fā)
* @return DOMNode
*/
private function getTopBox() {
// 獲得頁(yè)面所有的章節(jié)
$allParagraphs = $this->DOM->getElementsByTagName("p");

// Study all the paragraphs and find the chunk that has the best score.
// A score is determined by things like: Number of

's, commas, special classes, etc.
$i = 0;
while($paragraph = $allParagraphs->item($i++)) {
$parentNode = $paragraph->parentNode;
$contentScore = intval($parentNode->getAttribute(Readability::ATTR_CONTENT_SCORE));
$className = $parentNode->getAttribute("class");
$id = $parentNode->getAttribute("id");

// Look for a special classname
if (preg_match("/(comment|meta|footer|footnote)/i", $className)) {
$contentScore -= 50;
} else if(preg_match(
"/((^|\\s)(post|hentry|entry[-]?(content|text|body)?|article[-]?(content|text|body)?)(\\s|$))/i",
$className)) {
$contentScore += 25;
}

// Look for a special ID
if (preg_match("/(comment|meta|footer|footnote)/i", $id)) {
$contentScore -= 50;
} else if (preg_match(
"/^(post|hentry|entry[-]?(content|text|body)?|article[-]?(content|text|body)?)$/i",
$id)) {
$contentScore += 25;
}

// Add a point for the paragraph found
// Add points for any commas within this paragraph
if (strlen($paragraph->nodeValue) > 10) {
$contentScore += strlen($paragraph->nodeValue);
}

// 保存父元素的判定得分
$parentNode->setAttribute(Readability::ATTR_CONTENT_SCORE, $contentScore);

// 保存章節(jié)的父元素，以便下次快速獲取
array_push($this->parentNodes, $parentNode);
}

$topBox = null;

// Assignment from index for performance.
// See http://www.peachpit.com/articles/article.aspx?p=31567&seqNum=5
for ($i = 0, $len = sizeof($this->parentNodes); $i < $len; $i++) { $parentNode = $this->parentNodes[$i];
$contentScore = intval($parentNode->getAttribute(Readability::ATTR_CONTENT_SCORE));
$orgContentScore = intval($topBox ? $topBox->getAttribute(Readability::ATTR_CONTENT_SCORE) : 0);

if ($contentScore && $contentScore > $orgContentScore) {
$topBox = $parentNode;
}
}

// 此時(shí)，$topBox 應(yīng)為已經(jīng)判定后的頁(yè)面內(nèi)容主元素
return $topBox;
}

/**
* 獲取 HTML 頁(yè)面標(biāo)題
*
* @return String
*/
public function getTitle() {
$split_point = ' - ';
$titleNodes = $this->DOM->getElementsByTagName("title");

if ($titleNodes->length
&& $titleNode = $titleNodes->item(0)) {
// @see http://stackoverflow.com/questions/717328/how-to-explode-string-right-to-left
$title = trim($titleNode->nodeValue);
$result = array_map('strrev', explode($split_point, strrev($title)));
return sizeof($result) > 1 ? array_pop($result) : $title;
}

return null;
}

/**
* Get Leading Image Url
*
* @return String
*/
public function getLeadImageUrl($node) {
$images = $node->getElementsByTagName("img");

if ($images->length && $leadImage = $images->item(0)) {
return $leadImage->getAttribute("src");
}

return null;
}

/**
* 獲取頁(yè)面的主要內(nèi)容（Readability 以后的內(nèi)容）
*
* @return Array
*/
public function getContent() {
if (!$this->DOM) return false;

// 獲取頁(yè)面標(biāo)題
$ContentTitle = $this->getTitle();

// 獲取頁(yè)面主內(nèi)容
$ContentBox = $this->getTopBox();

//Check if we found a suitable top-box.
if($ContentBox === null)
throw new RuntimeException(Readability::MESSAGE_CAN_NOT_GET);

// 復(fù)制內(nèi)容到新的 DOMDocument
$Target = new DOMDocument;
$Target->appendChild($Target->importNode($ContentBox, true));

// 刪除不需要的標(biāo)簽
foreach ($this->junkTags as $tag) {
$Target = $this->removeJunkTag($Target, $tag);
}

// 刪除不需要的屬性
foreach ($this->junkAttrs as $attr) {
$Target = $this->removeJunkAttr($Target, $attr);
}

$content = mb_convert_encoding($Target->saveHTML(), Readability::DOM_DEFAULT_CHARSET, "HTML-ENTITIES");

// 多個(gè)數(shù)據(jù)，以數(shù)組的形式返回
return Array(
'lead_image_url' => $this->getLeadImageUrl($Target),
'word_count' => mb_strlen(strip_tags($content), Readability::DOM_DEFAULT_CHARSET),
'title' => $ContentTitle ? $ContentTitle : null,
'content' => $content
);
}

function __destruct() { }
}


使用起來(lái)也非常簡(jiǎn)單，實(shí)例化時(shí)傳入網(wǎng)頁(yè)的html源碼和相應(yīng)的編碼，然后直接調(diào)用其getContent方法即可返回提取到的正文部分，提取出的文章中可能還會(huì)含有少部分鏈接，可以自己后期再修改。