PHP 使用 Socket 實作 HTTP GET 與 POST 請求的底層範例

PHP 使用 Socket 實作 HTTP GET 與 POST 請求的底層範例

不依賴 cURL 或 stream_context，直接以 fsockopen 建立 TCP 連線發送原始 HTTP 請求。

GET 請求

function socketGet($url, &$ret) {
    $urlArr = parse_url($url);
    $host = $urlArr['host'];
    $port = isset($urlArr['port']) ? $urlArr['port'] : 80;
    $path = isset($urlArr['path']) ? $urlArr['path'] : '/';
    $fp = fsockopen($host, $port, $errno, $errstr, 30);
    if (!$fp) return false;
    $out = "GET $path HTTP/1.1\r\nHost: $host\r\nConnection: Close\r\n\r\n";
    fwrite($fp, $out);
    $ret = '';
    while (!feof($fp)) $ret .= fgets($fp, 128);
    fclose($fp);
    return true;
}

POST 請求

function socketPost($url, $data, &$ret) {
    $urlArr = parse_url($url);
    $host = $urlArr['host'];
    $port = isset($urlArr['port']) ? $urlArr['port'] : 80;
    $path = isset($urlArr['path']) ? $urlArr['path'] : '/';
    $fp = fsockopen($host, $port, $errno, $errstr, 30);
    if (!$fp) return false;
    $out = "POST $path HTTP/1.1\r\nHost: $host\r\n";
    $out .= "Content-Type: application/x-www-form-urlencoded\r\n";
    $out .= "Content-Length: " . strlen($data) . "\r\n";
    $out .= "Connection: Close\r\n\r\n";
    $out .= $data;
    fwrite($fp, $out);
    $ret = '';
    while (!feof($fp)) $ret .= fgets($fp, 128);
    fclose($fp);
    return true;
}

若 POST 失敗，可將 Connection: Keep-Alive 改為 Close。此方式適合理解 HTTP 協定底層運作。