Can PHP cURL retrieve response headers AND body in a single request?

One solution to this was posted in the PHP documentation comments: http://www.php.net/manual/en/function.curl-exec.php#80442

Code example:

$ch = curl_init();
curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
curl_setopt($ch, CURLOPT_HEADER, 1);
// ...

$response = curl_exec($ch);

// Then, after your curl_exec call:
$header_size = curl_getinfo($ch, CURLINFO_HEADER_SIZE);
$header = substr($response, 0, $header_size);
$body = substr($response, $header_size);

Warning: As noted in the comments below, this may not be reliable when used with proxy servers or when handling certain types of redirects. @Geoffrey's answer may handle these more reliably.

Many of the other solutions offered this thread are not doing this correctly.

• Splitting on \r\n\r\n is not reliable when CURLOPT_FOLLOWLOCATION is on or when the server responds with a 100 code^{RFC-7231, MDN}.
• Not all servers are standards compliant and transmit just a \n for new lines (and a recipient may discard the \r in the line terminator)^Q&A.
• Detecting the size of the headers via CURLINFO_HEADER_SIZE is also not always reliable, especially when proxies are used^Curl-1204 or in some of the same redirection scenarios.

The most correct method is using CURLOPT_HEADERFUNCTION.

Here is a very clean method of performing this using PHP closures. It also converts all headers to lowercase for consistent handling across servers and HTTP versions.

This version will retain duplicated headers

This complies with RFC822 and RFC2616, please do not make use of the mb_ (and similar) string functions, it is a not only incorrect but even a security issue^RFC-7230!

$ch = curl_init();
$headers = [];
curl_setopt($ch, CURLOPT_URL, $url);
curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);

// this function is called by curl for each header received
curl_setopt($ch, CURLOPT_HEADERFUNCTION,
  function($curl, $header) use (&$headers)
  {
    $len = strlen($header);
    $header = explode(':', $header, 2);
    if (count($header) < 2) // ignore invalid headers
      return $len;

    $headers[strtolower(trim($header[0]))][] = trim($header[1]);
    
    return $len;
  }
);

$data = curl_exec($ch);
print_r($headers);