前言

使用PHP的curl函数调用多个外部HTTP接口时，默认情况下是需要一个一个执行的，第一个请求结束后才会发起第二个请求，这样会显得效率低。如果各个请求之间没有强依赖关系，可以使用curl的多线程函数来发起请求，这样可以节省很多时间，提高效率。

代码

<?php
function main() {
    $requests = [
        [
            'url' => 'https://www.baidu.com', // 请求URL
            'method' => 'GET', // 请求方法，支持GET和POST
            'header' => [], // 请求头
            'param' => ['i' => 0], // 请求参数
        ],
        [
            'url' => 'http://www.sdhaidhoasdhaihd.com',
            'method' => 'GET',
            'header' => [],
            'param' => ['i' => 1],
        ],
    ];
    $handles = [];

    foreach ($requests as $req) {
        $options = [
            CURLOPT_HEADER => false,
            CURLOPT_RETURNTRANSFER => true,
            CURLOPT_TIMEOUT => 30,
        ];
        if (!empty($req['header'])) {
            $options[CURLOPT_HTTPHEADER] = $req['header'];
        }

        switch ($req['method']) {
            case 'GET':
                $options[CURLOPT_URL] = "{$req['url']}?" . http_build_query($req['param']);
                break;
            case 'POST':
                $options[CURLOPT_URL] = $req['url'];
                $options[CURLOPT_POST] = true;
                $options[CURLOPT_POSTFIELDS] = http_build_query($req['param']);
                break;
            default:
                exit("Unsupported method:{$req['method']}");
        }

        $ch = curl_init();
        curl_setopt_array($ch, $options);
        $handles[] = $ch;
    }

    $mh = curl_multi_init();
    foreach ($handles as $ch) {
        curl_multi_add_handle($mh, $ch);
    }

    $running = null;
    do {
        curl_multi_exec($mh, $running);
        curl_multi_select($mh);
    } while ($running > 0);

    while ($info = curl_multi_info_read($mh)) {
        $ch = $info['handle'];
        if ($info['result'] != CURLM_OK) {
            $httpCode = $info['result'];
            $httpBody = curl_error($ch);
        } else {
            $httpCode = curl_getinfo($ch, CURLINFO_HTTP_CODE);
            $httpBody = curl_multi_getcontent($ch);
        }
        $index = array_search($ch, $handles, true);
        $requests[$index]['response'] = [
            'code' => $httpCode,
            'body' => $httpBody,
        ];
        curl_multi_remove_handle($mh, $ch);
        curl_close($ch);
    }
    curl_multi_close($mh);

    var_dump($requests);
}

main();