从网页中获取标题时遇到问题

很可能您的代码中存在的问题比我在本回答中提到的更多,但我看到的最突出的问题是:

DOMDocument::loadHTML() 不是静态方法,而是实例方法(返回布尔值)。您应该首先创建 DOMDocument 然后打电话 loadHTML() 在这种情况下:

$dom = new DOMDocument;
$dom->loadHTML($xml);

但是,由于您已使用 @ 接线员在那条线上,你没有收到关于这件事的警告。虽然错误抑制器操作符 @ 用于抑制HTML验证错误,例如,您应该研究使用 libxml_use_internal_errors() ^1. 相反,因为这不会抑制一般的PHP错误。

$dom = new DOMDocument;
$oldSetting = libxml_use_internal_errors(true);
$dom->loadHTML($xml);
libxml_use_internal_errors($oldSetting);

最后,请注意:
可以直接从URL加载DOM文档(无需 cURL )与 DOMDocument::loadHTMLFile() ,如果您的PHP安装配置为允许通过配置设置加载URL allow_url_fopen 。请注意,由于安全原因,此设置通常会被禁用,因此,如果打算使用,请小心使用。

下面是一个简单的测试用例,它应该按照预期工作:

<?php

$html = '
<html>
<head>
  <title>DOMDocument test-case</title>
</head>
<body>
  <div class="dummy-container">
    <h1 _ngcontent-c0="" class="br-hdng"><span _ngcontent-c0="" class="pr dib">hair fall shamboo<!----></span></h1>
  </div>
</body>';

$dom = new DOMDocument;

$oldSetting = libxml_use_internal_errors(true);
$dom->loadHTML( $html );
libxml_use_internal_errors($oldSetting);

$xpath = new DOMXPath( $dom );
$title = $xpath->query( '//h1[@class="br-hdng"]/span' )->item( 0 )->nodeValue;
echo $title;

^{See this example interpreted online on 3v4l.org}

你应该替换文件的内容 $html 用你的 get_content() 呼叫如果不起作用,那么:

1. 使用获取HTML时出现问题 卷曲 (是吗 var_dump( $html ); 在装载到 DOMDocument ,例如,查看检索到的内容),或。。。

2. 也许您是在一个名称空间中工作,在这种情况下,您应该在使用前预先加上反斜杠 DOMDocument 和 DOMXPath ,即: new \DOMDocument; 和 new \DOMXPath( $dom ); .

^{1.LibXML是DOMDocument用来解析XML/HTML文档的XML库。}

那么php怎么了?

php不运行javascript。大概 puppeteer 来自javascript代码的请求和来自python代码的html请求都运行javascript。

您的问题是,此页面加载 br-hdng 标题及;使用javascript的产品,它根本不是HTML的一部分。实际上都是从 https://www.purplle.com/api/shop/itemsv3 ,带有一系列GET参数。您需要在这里进行JSON解析,而不是HTML解析:),但在访问该api之前,您需要搜索页面提供的cookie,以及 搜索字符串必须与api搜索字符串匹配 (否则api只会返回错误),请检查以下内容:

<?php
declare(strict_types = 0);
header ( "Content-Type: text/plain;charset=UTF-8" );
$ch = curl_init ();
curl_setopt_array ( $ch, array (
        CURLOPT_ENCODING => '',
        CURLOPT_COOKIEFILE => '', // enables cookie handling without saving them anywhere. this page requires cookie handling.
        CURLOPT_USERAGENT => 'Mozilla/5.0 (Windows NT 6.1; Win64; x64; rv:60.0) Gecko/20100101 Firefox/60.0', // 'libcurl/? PHP/' . PHP_VERSION, // many websites block requests without a useragent
        CURLOPT_RETURNTRANSFER => 1 
) );
// we don't care what's on this page, we just need to fetch it to create a cookie session.
$search_query = 'hair fall shamboo';
curl_setopt ( $ch, CURLOPT_URL, 'https://www.purplle.com/search?q=' . rawurlencode ( $search_query ) );
curL_exec ( $ch );
$url = 'https://www.purplle.com/api/shop/itemsv3?' . http_build_query ( array (
        'list_type' => 'search',
        'custom' => '',
        'list_type_value' => $search_query,
        'page' => '1',
        'sort_by' => 'rel',
        'elite' => '0' 
) );
// $url = 'https://www.purplle.com/api/shop/itemsv3?list_type=search&custom=&list_type_value=hair%20fall%20shamboo&page=1&sort_by=rel&elite=0';
// $out = tmpfile ();
// curl_setopt_array ( $ch, array (
// CURLOPT_HTTPHEADER => array (
// 'Accept: application/json, text/plain, */*',
// 'Accept-Language: en-US,en;q=0.5',
// 'Referer: https://www.purplle.com/search?q=hair%20fall%20shamboo',
// // Cookie: __cfduid=d3199415b5ce18cbff2779802b1f843331544901552; csrftoken=f8f18b5deae92972f63343e13c6a460b; purpllesession=hedxkc%2FkdGye%2BYi6ebmJktUN1LeqA5rdVXu96%2F0j0yqtP2xZ8LfwpK8daXqPSkeZulO9ZvqpMYXTmY8oMD03VcG9vdKGBm30R9fU%2FQygtXBFhZvfvsu0scyaL3FqHbePp2zG45MevWU961eg82KAkCuHk0qFM8URQBRyYV5gg8TeqnTPgI3tF87H5nJ%2BmfO4pn%2BRWmIuWXvgNXAO%2F8GEaH6lJVl17QZm9c5vwi10OYeLfmSdIMy6V2Pp0ZjLTzuFw2de5jpR0zsbHHKZ0C2e548PiDl3taHIE5wuZO4HYIeXUqTpE98%2Fo3kztoU1bTlXGZgu%2FxVQ3EWLRFWQ2t57UawA%2FuERlD8vvOyFGbYHGAWVxgFTR%2FObAhFLHns5kqoj; _autm30d=null; visitorppl=NZ5tqQpGlFYWg2MrDl1302113161544901552; session_initiated=Direct; _tmpsess=1; token=desktop_5c1553b07c61c_7955_16122018; __uzma=5c1553b085a480.63440826; __uzmb=1544901552; __uzmc=632121030774; __uzmd=1544901552
// 'Connection: keep-alive'
// ),
// // CURLOPT_CONNECT_TO=>array('www.purplle.com:443:dumpinput.ratma.net:80'),
// CURLOPT_STDERR => $out,
// CURLOPT_VERBOSE => 1
// ) );
// var_dump ( $url );
curl_setopt ( $ch, CURLOPT_URL, $url );
$json = curl_exec ( $ch );
$data = json_decode ( $json, true );

// var_dump ($json, $data );
$title = $data ['list_title'];
echo 'title: ' . $title . "\n";
foreach ( $data ['items'] as $item ) {
    echo "name: ", $item ['name'], "\n";
}

输出:

title: hair fall shamboo
name: VLCC Hair fall Shampoo 350 ML (Buy1 Get1) & Ayurveda Hair Oil Combo (470 ml)
name: Biotique Bio Kelp Protein Shampoo For Falling Hair (190 ml)
name: Biotique Fresh Texture Shampoo - Bio Henna Leaf (120 ml)
name: Good Vibes Scalp Purifying Shampoo -Neem And Aloe Vera (200 ml)
name: Khadi Shikakai Sat Hair Cleanser Scalp Therapy (210 ml) By Swati Gramodyog
name: Good Vibes Apple Cider Vinegar Shampoo (120 ml)
name: Good Vibes Refreshing Shampoo - Green Apple (200 ml)
name: Good Vibes Hydrating Shampoo -Marigold (200 ml)
name: Alps Goodness Smoothening Shampoo - Keratin (50 ml)
name: Alps Goodness Softening Shampoo - Coconut & Almond (50 ml)
name: Alps Goodness Split End Control Shampoo - Coconut, Garlic & Shea Butter (50 ml)
name: Passion Indulge Papain Shampoo & Conditioner For Soft & Shiny Hair (200 ml + 100 ml)
name: Good Vibes Apple Cider Vinegar Shampoo (200 ml)
name: Alps Goodness Split End Control Shampoo - Coconut, Garlic & Shea Butter (200 ml)
name: Alps Goodness Nourishing Shampoo - Argan Oil & Olive (200 ml)
name: Alps Goodness Moisturizing Shampoo - Ginger & Egg (200 ml)
name: Alps Goodness Conditioning Shampoo - Pure Honey (200 ml)
name: Alps Goodness Hydrating Shampoo - Tea Tree (200 ml)
name: Alps Goodness Smoothening Shampoo - Keratin (200 ml)
name: Alps Goodness Softening Shampoo - Coconut & Almond (200 ml)
name: Good Vibes Scalp Purifying Shampoo -Neem And Aloe Vera (120 ml)
name: Good Vibes Hydrating Shampoo - Marigold (120 ml)
name: Alps Goodness Conditioning Shampoo - Pure Honey (50 ml)
name: Alps Goodness Moisturizing Shampoo - Ginger & Egg (50 ml)