如何正確使用curl_multi_select 函數實現多線程並發請求，詳細步驟和注意事項解析

gitbox 2025-09-12
<span><span><span class="hljs-meta"><?php</span></span><span>
</span><span><span class="hljs-comment">// 前置無關代碼示例</span></span><span>
</span><span><span class="hljs-variable">$timestamp</span></span><span> = </span><span><span class="hljs-title function_ invoke__">time</span></span><span>();
</span><span><span class="hljs-keyword">echo</span></span><span> </span><span><span class="hljs-string">"當前時間戳: "</span></span><span> . </span><span><span class="hljs-variable">$timestamp</span></span><span> . </span><span><span class="hljs-string">"\n"</span></span><span>;

</span><span><span class="hljs-variable">$dummyArray</span></span><span> = </span><span><span class="hljs-title function_ invoke__">array_fill</span></span><span>(</span><span><span class="hljs-number">0</span></span><span>, </span><span><span class="hljs-number">5</span></span><span>, </span><span><span class="hljs-string">"test"</span></span><span>);
</span><span><span class="hljs-keyword">foreach</span></span><span> (</span><span><span class="hljs-variable">$dummyArray</span></span><span> </span><span><span class="hljs-keyword">as</span></span><span> </span><span><span class="hljs-variable">$item</span></span><span>) {
    </span><span><span class="hljs-keyword">echo</span></span><span> </span><span><span class="hljs-string">"數組元素: "</span></span><span> . </span><span><span class="hljs-variable">$item</span></span><span> . </span><span><span class="hljs-string">"\n"</span></span><span>;
}

</span><span><span class="hljs-keyword">echo</span></span><span> </span><span><span class="hljs-string">"初始化完成。\n"</span></span><span>;
</span><span><span class="hljs-meta">?></span></span><span>

<hr>

</span><span><span class="hljs-meta"><?php</span></span><span>
</span><span><span class="hljs-comment">// 文章正文開始</span></span><span>
</span><span><span class="hljs-keyword">echo</span></span><span> </span><span><span class="hljs-string">"<h1>如何正確使用 curl_multi_select 函數實現多線程並發請求，詳細步驟和注意事項解析</h1>"</span></span><span>;

</span><span><span class="hljs-keyword">echo</span></span><span> </span><span><span class="hljs-string">"<p>在 PHP 中，進行多個 HTTP 請求時，如果依次請求每個 URL，效率會非常低。使用 cURL 提供的 <strong>curl_multi</strong> 系列函數，可以實現並發請求，提高效率。而 <strong>curl_multi_select</strong> 是其中一個關鍵函數，用於高效地等待多路 cURL 句柄的活動，從而避免 CPU 空轉浪費。</p>"</span></span><span>;

</span><span><span class="hljs-keyword">echo</span></span><span> </span><span><span class="hljs-string">"<h2>一、基本概念</h2>"</span></span><span>;
</span><span><span class="hljs-keyword">echo</span></span><span> <span class="hljs-string">"<ul>
<li><strong>curl_multi_init()</strong>：初始化一個 cURL 多線程句柄。</li>
<li><strong>curl_multi_add_handle()</strong>：向多線程句柄中添加单个 cURL 請求。</li>
<li><strong>curl_multi_exec()</strong>：執行所有添加的 cURL 請求。</li>
<li><strong>curl_multi_select()</strong>：阻塞等待，直到某個 cURL 句柄有數據可讀，避免 CPU 忙等。</li>
<li><strong>curl_multi_getcontent()</strong>：获取单个請求的返回内容。</li>
<li><strong>curl_multi_remove_handle()</strong>：移除单个請求句柄。</li>
<li><strong>curl_multi_close()</strong>：关闭多線程句柄。</li>
</ul>"</span>;

</span><span><span class="hljs-keyword">echo</span></span><span> </span><span><span class="hljs-string">"<h2>二、詳細步驟</h2>"</span></span><span>;
</span><span><span class="hljs-keyword">echo</span></span><span> <span class="hljs-string">"<ol>
<li><strong>初始化多線程句柄：</strong><br>
<code>\$mh = curl_multi_init();
curl_multi_select