get_meta_tags 和 DOMDocument 的结合使用：如何解析网页并提取 Meta 信息？

gitbox 2025-06-30

一、使用 get_meta_tags 提取 Meta 信息

PHP 内置的 get_meta_tags 函数是一个非常简单且方便的方法，用来从 HTML 页面中提取所有的 meta 信息。它直接返回一个关联数组，数组的键是 meta 标签的属性，值是相应的内容。该方法不需要额外的库或依赖，适合快速提取简单的 meta 数据。

示例代码：

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2.02441L4.30371 1.97363C4.34801 1.86052 4.45804 1.78333 4.58301 1.7832Z"></path></svg>编辑</button></span></div></div></div><div class="overflow-y-auto p-4" dir="ltr"><?php
// 指定要解析的网页 URL
$url = 'https://www.example.com';

// 使用 get_meta_tags 获取 meta 信息
$metaTags = get_meta_tags($url);

// 输出所有的 meta 信息
echo '<pre>';
print_r($metaTags);
echo '

';
?>

输出结果：

<span><span><span class="hljs-title function_ invoke__">Array</span></span><span>
(
    [description] => Example Domain
    [keywords] => example, domain
    [author] => Example Author
)
</span></span>

get_meta_tags 函数能够获取标签中的 name 或 property 属性，如果网页中存在这样的标签，它将会提取并返回相应的内容。不过，get_meta_tags 也有一定的限制，它仅能解析常见的 meta 标签，且不支持复杂的 HTML 结构或特殊属性。

二、使用 DOMDocument 提取 Meta 信息

相比 get_meta_tags，DOMDocument 提供了更强大和灵活的功能。它能够处理更加复杂和多样化的 HTML 结构，并且能够针对每一个标签进行更精确的操作。DOMDocument 是 PHP 内建的一个类，允许你通过文档对象模型（DOM）来解析 HTML 和 XML 内容。

示例代码：

<span><span><span class="hljs-meta"><?php</span></span><span>
</span><span><span class="hljs-comment">// 指定要解析的网页 URL</span></span><span>
</span><span><span class="hljs-variable">$url</span></span><span> = </span><span><span class="hljs-string">'https://www.example.com'</span></span><span>;

</span><span><span class="hljs-comment">// 获取网页内容</span></span><span>
</span><span><span class="hljs-variable">$htmlContent</span></span><span> = </span><span><span class="hljs-title function_ invoke__">file_get_contents</span></span><span>(</span><span><span class="hljs-variable">$url</span></span><span>);

</span><span><span class="hljs-comment">// 创建 DOMDocument 对象</span></span><span>
</span><span><span class="hljs-variable">$dom</span></span><span> = </span><span><span class="hljs-keyword">new</span></span><span> </span><span><span class="hljs-title class_">DOMDocument</span></span><span>();

</span><span><span class="hljs-comment">// 关闭警告输出（HTML 可能不符合标准）</span></span><span>
</span><span><span class="hljs-title function_ invoke__">libxml_use_internal_errors</span></span><span>(</span><span><span class="hljs-literal">true</span></span><span>);

</span><span><span class="hljs-comment">// 加载 HTML 内容</span></span><span>
</span><span><span class="hljs-variable">$dom</span></span><span>-></span><span><span class="hljs-title function_ invoke__">loadHTML</span></span><span>(</span><span><span class="hljs-variable">$htmlContent</span></span><span>);

</span><span><span class="hljs-comment">// 获取所有的 <meta> 标签</span></span><span>
</span><span><span class="hljs-variable">$metaTags</span></span><span> = </span><span><span class="hljs-variable">$dom</span></span><span>-></span><span><span class="hljs-title function_ invoke__">getElementsByTagName</span></span><span>(</span><span><span class="hljs-string">'meta'</span></span><span>);

</span><span><span class="hljs-comment">// 遍历所有的 meta 标签并提取内容</span></span><span>
</span><span><span class="hljs-keyword">foreach</span></span><span> (</span><span><span class="hljs-variable">$metaTags</span></span><span> </span><span><span class="hljs-keyword">as</span></span><span> </span><span><span class="hljs-variable">$meta</span></span><span>) {
    </span><span><span class="hljs-comment">// 获取 meta 标签的 name 和 content 属性</span></span><span>
    </span><span><span class="hljs-variable">$name</span></span><span> = </span><span><span class="hljs-variable">$meta</span></span><span>-></span><span><span class="hljs-title function_ invoke__">getAttribute</span></span><span>(</span><span><span class="hljs-string">'name'</span></span><span>);
    </span><span><span class="hljs-variable">$property</span></span><span> = </span><span><span class="hljs-variable">$meta</span></span><span>-></span><span><span class="hljs-title function_ invoke__">getAttribute</span></span><span>(</span><span><span class="hljs-string">'property'</span></span><span>);
    </span><span><span class="hljs-variable">$content</span></span><span> = </span><span><span class="hljs-variable">$meta</span></span><span>-></span><span><span class="hljs-title function_ invoke__">getAttribute</span></span><span>(</span><span><span class="hljs-string">'content'</span></span><span>);

    </span><span><span class="hljs-keyword">if</span></span><span> (</span><span><span class="hljs-variable">$name</span></span><span> || </span><span><span class="hljs-variable">$property</span></span><span>) {
        </span><span><span class="hljs-keyword">echo</span></span><span> </span><span><span class="hljs-string">"Name/Property: "</span></span><span> . (</span><span><span class="hljs-variable">$name</span></span><span> ?: </span><span><span class="hljs-variable">$property</span></span><span>) . </span><span><span class="hljs-string">"<br>"</span></span><span>;
        </span><span><span class="hljs-keyword">echo</span></span><span> </span><span><span class="hljs-string">"Content: "</span></span><span> . </span><span><span class="hljs-variable">$content</span></span><span> . </span><span><span class="hljs-string">"<br><br>"</span></span><span>;
    }
}
</span><span><span class="hljs-meta">?></span></span><span>
</span></span>

输出结果：

<span><span>Name/Property: description
Content: Example Domain

Name/Property: keywords
Content: example, domain
</span></span>

通过使用 DOMDocument，我们能够更加细致地操作网页中的每一个元素。在上面的例子中，我们首先加载了 HTML 页面，然后通过 getElementsByTagName('meta') 获取所有的标签，接着提取出标签中的 name、property 和 content 属性。无论是标准的 meta name 还是 Open Graph（OG）协议中的 meta property，都能够一并获取。

三、get_meta_tags 与 DOMDocument 的对比

虽然 get_meta_tags 和 DOMDocument 都能帮助我们提取网页的 meta 信息，但它们在使用场景和功能上各有不同。

优缺点对比：

特性	get_meta_tags	DOMDocument
简单性	非常简单，代码量少	相对复杂，需要手动遍历元素
灵活性	只支持常见的 meta 标签	支持所有 HTML 元素，功能更强大
性能	性能较好，适合快速提取	处理复杂页面时性能较差
错误处理	无法处理不规则的 HTML	支持处理错误并提供详细的调试信息
扩展性	功能有限，扩展性差	可以处理更复杂的 HTML 和 XML 格式

适用场景：

get_meta_tags：适合简单的页面，尤其是当我们只需要提取基础的 meta 信息（如 description、keywords 等）时，它更加高效。
DOMDocument：适合处理结构复杂的 HTML 页面，特别是需要灵活提取不同标签信息，或者处理含有嵌套标签、脚本、样式等的页面时。

get_meta_tags