在 php 中使用 DOMdocument() 和 xpath 提取元描述内容

Question

我正在尝试从页面中提取元描述内容并显示在搜索结果中。 但是，它的显示如下：

content="Lorem ipsum dolor sit amet, consectetuer adipiscing elit. Aenean commodo ligula eget dolor. Aenean massa. Cum sociis natoque penatibus et magnis dis parturient montes, nascetur ridiculus mus。"

而我只想要：

Lorem ipsum dolor sit amet，consectetuer adipiscing elit。 Aenean commodo ligula eget dolor。埃涅马萨。 Cum sociis natoque penatibus et magnis dis parturient montes, nascetur ridiculus mus。

猜猜看，我的代码有什么问题？

代码：

  $doc = new DOMDocument();
  @$doc->loadHTMLFile($page_path);
  $xpath = new DOMXPath($doc);

  $body = $xpath->query('//meta[@name="description"]/@content');
  $page_title = @$doc->getElementsByTagName('title')->item(0)->textContent;
  $page_title = $page_title ? $page_title : $page_path;
  $page_body = html2text($doc->saveXml($body->item(0)));// this is meta-description, which i want

  Functions :

  function html2text($html)
  {
  $text = $html;
  static $search = array(
  '@<script.+?</script>@usi',  // Strip out javascript content
  '@<style.+?</style>@usi',    // Strip style content
  '@<!--.+?-->@us',            // Strip multi-line comments including CDATA
  '@</?[a-z].*?\>@usi',         // Strip out HTML tags
  );
  $text = preg_replace($search, ' ', $text);
  /*
  * normalize common entities
  */
  $text = normalizeEntities($text);
  /*
  * decode other entities
  */
  $text = html_entity_decode($text, ENT_QUOTES, 'utf-8');
  /*
  * normalize possibly repeated newlines, tabs, spaces to spaces
  */
  $text = preg_replace('/\s+/u', ' ', $text);
  $text = trim($text);
  return $text;
  }


  /**
  * Replace encoded and double encoded entities to equivalent unicode character
  * @param string $text
  * @return string - the same as $text but without encoded entries
  * @access public
  */
  function normalizeEntities($text)
  {
  static $find = array();
  static $repl = array();
  if (!count($find)) {
  /*
  * build $find and $replace from map one time
  */
  $map = array(
  array('\'', 'apos', 39, 'x27'), // Apostrophe
  array('\'', '‘', 'lsquo', 8216, 'x2018'), // Open single quote
  array('\'', '’', 'rsquo', 8217, 'x2019'), // Close single quote
  array('"', '“', 'ldquo', 8220, 'x201C'), // Open double quotes
  array('"', '”', 'rdquo', 8221, 'x201D'), // Close double quotes
  array('\'', '‚', 'sbquo', 8218, 'x201A'), // Single low-9 quote
  array('"', '„', 'bdquo', 8222, 'x201E'), // Double low-9 quote
  array('\'', '′', 'prime', 8242, 'x2032'), // Prime/minutes/feet
  array('"', '″', 'Prime', 8243, 'x2033'), // Double prime/seconds/inches
  array(' ', 'nbsp', 160, 'xA0'), // Non-breaking space
  array('-', '‐', 8208, 'x2010'), // Hyphen
  array('-', '–', 'ndash', 8211, 150, 'x2013'), // En dash
  array('--', '—', 'mdash', 8212, 151, 'x2014'), // Em dash
  array(' ', ' ', 'ensp', 8194, 'x2002'), // En space
  array(' ', ' ', 'emsp', 8195, 'x2003'), // Em space
  array(' ', ' ', 'thinsp', 8201, 'x2009'), // Thin space
  array('*', '•', 'bull', 8226, 'x2022'), // Bullet
  array('*', '‣', 8227, 'x2023'), // Triangular bullet
  array('...', '…', 'hellip', 8230, 'x2026'), // Horizontal ellipsis
  array('°', 'deg', 176, 'xB0'), // Degree
  array('€', 'euro', 8364, 'x20AC'), // Euro
  array('¥', 'yen', 165, 'xA5'), // Yen
  array('£', 'pound', 163, 'xA3'), // British Pound
  array('©', 'copy', 169, 'xA9'), // Copyright Sign
  array('®', 'reg', 174, 'xAE'), // Registered Sign
  array('™', 'trade', 8482, 'x2122') // TM Sign
  );
  foreach ($map as $e) {
  for ($i = 1; $i < count($e); ++$i) {
  $code = $e[$i];
  if (is_int($code)) {
  // numeric entity
  $regex = "/&(amp;)?#0*$code;/";
  } elseif (preg_match('/^.$/u', $code)/* one unicode char*/) {
  // single character
  $regex = "/$code/u";
  } elseif (preg_match('/^x([0-9A-F]{2}){1,2}$/i', $code)) {
  // hex entity
  $regex = "/&(amp;)?#x0*" . substr($code, 1) . ";/i";
  } else {
  // named entity
  $regex = "/&(amp;)?$code;/";
  }
  $find[] = $regex;
  $repl[] = $e[0];
  }
  }
  }
  return preg_replace($find, $repl, $text);
  }

Answer 1

您正在将属性节点保存为 XML。不！只需读取它的值。

属性节点 (DOMAttr) 具有返回属性值的属性值。属性值为文本值。

$html = <<<'HTML'
<meta name="description" content="Some description">
HTML;

$document = new DOMDocument();
$document->loadHTML($html);
$xpath = new DOMXPath($document);

$description = $xpath->evaluate('//meta[@name="description"]/@content')->item(0);
var_dump($description->value);

输出：

string(16) "Some description"

但是 Xpath 可以直接将值作为字符串返回。只需转换结果（在 Xpath 中）。这仅适用于DOMXpath::evaluate()。 DOMXpath::query() 只能返回节点列表。

$description = $xpath->evaluate('string(//meta[@name="description"]/@content)');
var_dump($description);

输出：

string(16) "Some description"

它也适用于其他节点。如果你投射一个元素节点（比如body），只会返回它的文本内容，像© 这样的实体会被解码。

$html = <<<'HTML'
<html>
  <head>
    <title>The Title</title>
    <meta name="description" content="Some description">
  </head>
  <body>
    <p>Some content &amp; entities &copy;</p>
  </body>
</html>
HTML;

$document = new DOMDocument();
$document->loadHTML($html);
$xpath = new DOMXPath($document);

$title = $xpath->evaluate('string(//head/title)');
$description = $xpath->evaluate('string(//meta[@name="description"]/@content)');
$content = $xpath->evaluate('string(//body)');

var_dump($title, $description, $content);

输出：

string(9) "The Title"
string(16) "Some description"
string(36) "
    Some content & entities ©
  "