Why does fsockopen have performance problems and not fopen when sending a POST request in PHP?

Question

I have tried two different implementations for simulating POSTing a form. One uses fsockopen (example here: http://www.faqts.com/knowledge_base/view.phtml/aid/7962) and the other uses fopen (example here: http://netevil.org/blog/2006/nov/http-post-from-php-without-curl).

I ran into some serious performance problems with fsockopen - when I step through it with a debugger, everything seems to work just fine, but when I do not attach the debugger the page takes a looong time to load (probably more than 10 seconds). fopen works perfectly (plus I don't have to parse out the response headers). Does anyone know why fsockopen would have these performance problems? Does it have to do with the timeout setting?

I've included my code below.

//fsockopen implementation
/**
 * The class that posts form data to a specified URL.
 * @package Core
 * @subpackage Classes
 */
class SU_form_poster_class
{
    /**
     * The file handle which is created when a form is posted.
     * @var resource
     */
    protected $file_handle;

    protected $port;

    protected $timeout;


    /**
     * Creates a new instance of this class.
     * @param int $timeout the timeout (in seconds) to wait for the request
     * @param int $port the port to make the request on
     */
    public function __construct($timeout = 30, $port = 80)
    {
        $this->timeout = $timeout;
        $this->port = $port;
    }

    /**
     * Sends a POST request to a specified page on a specified host with the
     * specified data.
     * @param string $path the part of the URL that specifies the page (including
     * the query string)
     * @param string $host the host part of the URL to post to
     * @param string $request_data the data to be posted in "query string" format,
     * e.g. name1=value1&name2=value2&name3=value3
     */
    public function do_post($path, $host, $request_data)
    {
        $err_num = 0;
        $err_str = '';
        $this->file_handle = fsockopen($host, $this->port, $err_num, $err_str, $this->timeout);
        if (!$this->file_handle)
        {
            throw new RuntimeException($err_str, $err_num);
        }
        else
        {
            $request = 'POST '.$path." HTTP/1.1\r\n".
                'Host: '.$host."\r\n".
                "Content-type: application/x-www-form-urlencoded\r\n".
                'Content-length: '.strlen($request_data)."\r\n\r\n".
                $request_data;

            fputs($this->file_handle, $request);
        }
    }

    /**
     * Retrieves data from the most recent request.
     * @return string the response
     */
    public function get_last_response()
    {
        if (!$this->file_handle)
        {
            throw new RuntimeException('A valid request must be made first.');
        }
        else
        {
            $response = '';
            $linenum = 0;
            while (!feof($this->file_handle))
            {
                $line = fgets($this->file_handle, 1024);
                if ($linenum > 6)
                {
                    $response .= $line;
                }
                ++$linenum;
            }
            fclose($this->file_handle);
            return $response;
        }
    }
}

/**
 * The class that posts form data to a specified URL.
 * @package Core
 * @subpackage Classes
 */
class SU_form_poster_class
{
    /**
     * The file handle which is created when a form is posted.
     * @var resource
     */
    protected $stream;

    /**
     * Sends a POST request to a specified page on a specified host with the
     * specified data.
     * @param string $url
     * @param string $request_data the data to be posted in "query string" format,
     * e.g. name1=value1&name2=value2&name3=value3
     */
    public function do_post($url, $request_data)
    {
        $params = array(
            'http' => array(
                'method' => 'POST', 'content' => $request_data
            )
        );

        $context = stream_context_create($params);
        $this->stream = fopen($url, 'rb', false, $context);
        if (!$this->stream)
        {
            throw new RuntimeException('Stream was not created correctly');
        }
    }

    /**
     * Retrieves data from the most recent request.
     * @return string the response
     */
    public function get_last_response()
    {
        if (!$this->stream)
        {
            throw new RuntimeException('A valid request must be made first.');
        }
        else
        {
            return stream_get_contents($this->stream);
        }
    }
}

Answer 1

HTTP 1.1 connections default to persistent. This means the connection does not get automatically closed and feof() doesn't return true until the request times out. To get around this send the Connection: close header or use HTTP 1.0 which doesn't support persistent connections.

Answer 2

Does anyone know why fsockopen would have these performance problems? Does it have to do with the timeout setting?

I've had problems in the past with fsockopen over ssl - but that isn't what your asking.

Have you tried using the curl_* family of functions instead, that might help?