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php实现http代理

2026-02-27 19:34:27PHP

实现HTTP代理的基本原理

HTTP代理服务器充当客户端和目标服务器之间的中间人，接收客户端请求并转发给目标服务器，再将响应返回给客户端。PHP可通过Socket或cURL扩展实现这一功能。

使用cURL扩展实现简单代理

<?php
$targetUrl = $_GET['url'];
if (empty($targetUrl)) {
    die('Missing URL parameter');
}

$ch = curl_init();
curl_setopt($ch, CURLOPT_URL, $targetUrl);
curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
curl_setopt($ch, CURLOPT_FOLLOWLOCATION, true);
curl_setopt($ch, CURLOPT_HEADER, true);

$response = curl_exec($ch);
$headerSize = curl_getinfo($ch, CURLINFO_HEADER_SIZE);
$headers = substr($response, 0, $headerSize);
$body = substr($response, $headerSize);

foreach (explode("\r\n", $headers) as $header) {
    if (!empty($header)) {
        header($header);
    }
}

echo $body;
curl_close($ch);
?>

使用Socket实现更完整的代理

<?php
$proxyPort = 8080;
$proxyHost = '0.0.0.0';

$socket = socket_create(AF_INET, SOCK_STREAM, SOL_TCP);
socket_bind($socket, $proxyHost, $proxyPort);
socket_listen($socket);

while (true) {
    $client = socket_accept($socket);
    $request = socket_read($client, 1024);

    preg_match('/Host: (.+)/', $request, $matches);
    $host = trim($matches[1]);

    $targetSocket = socket_create(AF_INET, SOCK_STREAM, SOL_TCP);
    socket_connect($targetSocket, $host, 80);
    socket_write($targetSocket, $request);

    $response = '';
    while ($buffer = socket_read($targetSocket, 1024)) {
        $response .= $buffer;
    }

    socket_write($client, $response);
    socket_close($targetSocket);
    socket_close($client);
}
?>

处理HTTPS请求的注意事项

对于HTTPS请求，需要处理CONNECT方法并建立隧道：

if (strpos($request, 'CONNECT') === 0) {
    $parts = explode(' ', $request);
    $target = trim($parts[1]);
    list($host, $port) = explode(':', $target);

    $targetSocket = socket_create(AF_INET, SOCK_STREAM, SOL_TCP);
    socket_connect($targetSocket, $host, $port);

    socket_write($client, "HTTP/1.1 200 Connection Established\r\n\r\n");

    // 双向转发数据
    while (true) {
        $data = socket_read($client, 4096);
        if (!$data) break;
        socket_write($targetSocket, $data);

        $data = socket_read($targetSocket, 4096);
        if (!$data) break;
        socket_write($client, $data);
    }
}

性能优化建议

使用stream_socket_server替代原生socket函数可获得更好性能：

$server = stream_socket_server("tcp://$proxyHost:$proxyPort");
while ($client = stream_socket_accept($server)) {
    $request = fread($client, 8192);
    // 处理请求逻辑
}

实现连接池管理重复使用的目标服务器连接，减少频繁建立连接的开销。考虑加入缓存机制对频繁请求的响应进行缓存。

安全注意事项

验证目标URL防止开放代理被滥用：

$allowedDomains = ['example.com', 'api.example.org'];
$parsed = parse_url($targetUrl);
if (!in_array($parsed['host'], $allowedDomains)) {
    http_response_code(403);
    die('Access to this domain is not allowed');
}

实现身份验证机制：

if (!isset($_SERVER['PHP_AUTH_USER']) || 
    $_SERVER['PHP_AUTH_USER'] != 'proxyuser' || 
    $_SERVER['PHP_AUTH_PW'] != 'proxypass') {
    header('WWW-Authenticate: Basic realm="Proxy Auth"');
    http_response_code(401);
    die('Authentication required');
}

记录日志监控代理使用情况：

$log = sprintf("[%s] %s %s\n", 
    date('Y-m-d H:i:s'), 
    $_SERVER['REMOTE_ADDR'],
    $targetUrl);
file_put_contents('proxy.log', $log, FILE_APPEND);

php实现http代理