/**
* Reads the response-header.
*
* @param int &$error_code Error-code by reference if an error occured.
* @param string &$error_string Error-string by reference
*
* @return string The response-header or NULL if an error occured
*/
protected function readResponseHeader(&$error_code, &$error_string)
{
PHPCrawlerBenchmark::reset("server_response_time");
PHPCrawlerBenchmark::start("server_response_time");
$status = socket_get_status($this->socket);
$source_read = "";
$header = "";
$server_responded = false;
while ($status["eof"] == false) {
socket_set_timeout($this->socket, $this->socketReadTimeout);
// Read line from socket
$line_read = fgets($this->socket, 1024);
// Server responded
if ($server_responded == false) {
$server_responded = true;
$this->server_response_time = PHPCrawlerBenchmark::stop("server_response_time");
// Determinate socket prefill size
$status = socket_get_status($this->socket);
$this->socket_prefill_size = $status["unread_bytes"];
// Start data-transfer-time bechmark
PHPCrawlerBenchmark::reset("data_transfer_time");
PHPCrawlerBenchmark::start("data_transfer_time");
}
$source_read .= $line_read;
$this->global_traffic_count += strlen($line_read);
$status = socket_get_status($this->socket);
// Socket timed out
if ($status["timed_out"] == true) {
$error_code = PHPCrawlerRequestErrors::ERROR_SOCKET_TIMEOUT;
$error_string = "Socket-stream timed out (timeout set to " . $this->socketReadTimeout . " sec).";
return $header;
}
// No "HTTP" at beginnig of response
if (strtolower(substr($source_read, 0, 4)) != "http") {
$error_code = PHPCrawlerRequestErrors::ERROR_NO_HTTP_HEADER;
$error_string = "HTTP-protocol error.";
return $header;
}
// Header found and read (2 newlines) -> stop
if (substr($source_read, -4, 4) == "\r\n\r\n" || substr($source_read, -2, 2) == "\n\n") {
$header = substr($source_read, 0, strlen($source_read) - 2);
break;
}
}
// Stop data-transfer-time bechmark
PHPCrawlerBenchmark::stop("data_transfer_time");
// Header was found
if ($header != "") {
// Search for links (redirects) in the header
$this->LinkFinder->processHTTPHeader($header);
$this->header_bytes_received = strlen($header);
return $header;
}
// No header found
if ($header == "") {
$this->server_response_time = null;
$error_code = PHPCrawlerRequestErrors::ERROR_NO_HTTP_HEADER;
$error_string = "Host doesn't respond with a HTTP-header.";
return null;
}
}
