PHP xpath提取网页数据内容代码解析

LxyPython 2020-08-17

想要使用xpath来解析html内容, PHP自带两个对象

DOMDocument,DOMXpath,其中初始化 loadHtml一般都会报很多警告,但是并不影响使用,用@屏蔽错误。

/**
   * 初始化DOMXpath对象
   *
   * @param [type] $content 网页内容
   * @param [array] $pathinfo 匹配信息
   *
   * @return void
   */
  private function _createXpathObj($content, $patinfo)
  {
    // 如果没有xpath配置项,不初始化xpath
    if (!$this->_existsXpathParse($patinfo)) {
      return;
    }
    try {
      $dom = new \DOMDocument();
      @$dom->loadHtml($content);
      $dom->normalize();
      $xpath = new \DOMXpath($dom);
      $this->xpathObj = $xpath;
    } catch (\Exception $e) {
      getService('logger')->warning('Parse html fail', ['content' => $content]);
    }
  }

其中 $node 为 DOMElement 对象。

/**
   * 获取Xpath解析值
   *
   * @param [type] $pat 匹配模式
   *
   * @return string
   */
  private function _getXpathField($pat)
  {
    $objs = $this->xpathObj->query($pat);
    if ($objs->length > 0) {
      $node = $objs->item(0);
      $outerHTML = $node->ownerDocument->saveHTML($node);
      return trim($outerHTML);
      # 作为示例 输出innerhtml
      //$innerHTML = '';
      //foreach ($node->childNodes as $childNode){
      //   $innerHTML .= $childNode->ownerDocument->saveHTML($childNode);
      //}
      //return $innerHTML; 
      # 作为示例 输出文本不含标签
      //return $node->textContent; //$node->nodeValue;
    }
    return '';
  }

示例

<?php
    $dom = new DOMDocument('1.0','UTF-8');
    $dom->loadHTML('<html><body><div><p>p1</p><p>p2</p></div></body></html>');    
    $node = $dom->getElementsByTagName('div')->item(0);    
    $outerHTML = $node->ownerDocument->saveHTML($node);    
    $innerHTML = '';
    foreach ($node->childNodes as $childNode){
        $innerHTML .= $childNode->ownerDocument->saveHTML($childNode);
    }
    echo '<h2>outerHTML: </h2>';
    echo htmlspecialchars($outerHTML);
    echo '<h2>innerHTML: </h2>';
    echo htmlspecialchars($innerHTML);    
?>

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