get_headers

(PHP 5, PHP 7, PHP 8)

get_headers — Fetches all the headers sent by the server in response to an HTTP request

Description

get_headers(string $url, bool $associative = false, ?resource $context = null): array|false

get_headers() returns an array with the headers sent by the server in response to a HTTP request.

Parameters

url: The target URL.
associative: If the optional associative parameter is set to true, get_headers() parses the response and sets the array's keys.
context: A valid context resource created with stream_context_create(), or null to use the default context.

Return Values

Returns an indexed or associative array with the headers, or false on failure.

Changelog

Version	Description
8.0.0	The `associative` has been changed from int to bool.
7.1.0	The `context` parameter was added.

Examples

Example #1 get_headers() example

<?php
$url = 'http://www.example.com';

print_r(get_headers($url));

print_r(get_headers($url, true));
?>

The above example will output something similar to:

Array
(
    [0] => HTTP/1.1 200 OK
    [1] => Date: Sat, 29 May 2004 12:28:13 GMT
    [2] => Server: Apache/1.3.27 (Unix)  (Red-Hat/Linux)
    [3] => Last-Modified: Wed, 08 Jan 2003 23:11:55 GMT
    [4] => ETag: "3f80f-1b6-3e1cb03b"
    [5] => Accept-Ranges: bytes
    [6] => Content-Length: 438
    [7] => Connection: close
    [8] => Content-Type: text/html
)

Array
(
    [0] => HTTP/1.1 200 OK
    [Date] => Sat, 29 May 2004 12:28:14 GMT
    [Server] => Apache/1.3.27 (Unix)  (Red-Hat/Linux)
    [Last-Modified] => Wed, 08 Jan 2003 23:11:55 GMT
    [ETag] => "3f80f-1b6-3e1cb03b"
    [Accept-Ranges] => bytes
    [Content-Length] => 438
    [Connection] => close
    [Content-Type] => text/html
)

Example #2 get_headers() using HEAD example

<?php
// By default get_headers uses a GET request to fetch the headers. If you
// want to send a HEAD request instead, you can do so using a stream context:
$context = stream_context_create(
    [
        'http' => array(
            'method' => 'HEAD'
        )
    ]
);
$headers = get_headers('http://example.com', false, $context);
?>

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User Contributed Notes 18 notes

down

nick at innovaweb dot co dot uk ¶

14 years ago

Seems like there are some people who are looking for only the 3-digit HTTP response code  - here is a quick and nasty solution:

<?php
function get_http_response_code($theURL) {
    $headers = get_headers($theURL);
    return substr($headers[0], 9, 3);
}
?>

How easy is that? Echo the function containing the URL you want to check the response code for, and voilà. Custom redirects, alternative for blocked is_file() or flie_exists() functions (like I seem to have on my servers) hence the cheap workaround. But hey - it works!

Pudding

down

sey at sey dot prometheus-designs dot net ¶

19 years ago

The replacement updated get_headers function by aeontech at gmail dot com improperly formats dates when $format = 1.

Replace:
<?
else {
$headers[strtolower($h2[0])] = trim($h2[1]);
}
?>

With:
<?
else {    
$foo = implode( ':', $h2 );
$foo = preg_replace( '/[a-zA-Z- ]*: /', '', $foo );
$headers[strtolower($h2[0])] = trim( $foo );
}

down

mcilva ¶

6 years ago

How to check if a url points to a valid video

<?php 
function isVideo($url){
    $url = get_headers($url,1);
    if(is_array($url['Content-Type'])){ //In some responses Content-type is an array
        $video = strpos($url['Content-Type'][1],'video');
    }else{
        $video = strpos($url['Content-Type'],'video');
    }
    if($video !== false)
        return true;
    
    return false;
}

?>

down

cees at cornelisdigitaal dot nl ¶

9 years ago

@Jim Greene:

if the URL does not exist, it returns incomplete headers, making the substring default to rubbish.

The integer value of rubbish is always 0. So your lower than 400 does not always means it exists!

down

Jim Greene ¶

11 years ago

I know you're not supposed to reference other notes, but sincere props to Nick at Innovaweb's comment, for which I base this addition to his idea:

If you use that function, it will return a string, which is great if you are checking for only files that return 404, or 200, or whatnot.  If you cast the string value to an integer, you can perform mathematical comparison on it.  

For example:

<?php
function get_http_response_code($theURL) {
    $headers = get_headers($theURL);
    return substr($headers[0], 9, 3);
}

if(intval(get_http_response_code('filename.jpg')) < 400){
// File exists, huzzah!
}
?>

Rule of thumb is if the response is less than 400, then the file's there, even if it doesn't return 200.

down

php at hm2k dot org ¶

14 years ago

<?php
/**
 * Fetches all the real headers sent by the server in response to a HTTP request without redirects
 *
 * @link      http://php.net/function.get_headers
 * @link      http://bugs.php.net/bug.php?id=50719 
 */

function get_real_headers($url,$format=0,$follow_redirect=0) {
  if (!$follow_redirect) {
    //set new default options
    $opts = array('http' =>
        array('max_redirects'=>1,'ignore_errors'=>1)
    );
    stream_context_get_default($opts);
  }
  //get headers
    $headers=get_headers($url,$format);
    //restore default options
  if (isset($opts)) {
    $opts = array('http' =>
        array('max_redirects'=>20,'ignore_errors'=>0)
    );
    stream_context_get_default($opts);
  }
  //return
    return $headers;
}
?>

down

Kubo2 ¶

11 years ago

If you don't want to display Warning when get_headers() function fails, you can simply add at-sign (@) before it.

<?php

// in failure, Warning will be hidden and false returned
$withoutWarning = @get_headers("http://www.some-domain.com");

// in  failure, Warning displays and false will be returned, too
$withWarning = get_headers("http://www.some-domain.com");

// bool(false)
var_dump($withoutWarning);
// bool(false)
var_dump($withWarning);
?>

down

Weboide ¶

14 years ago

Note that get_headers **WILL follow redirections** (HTTP redirections). New headers will be appended to the array if $format=0. If $format=1 each redundant header will be an array of multiple values, one for each redirection.



For example:



<?php

$url = 'http://google.com';

var_dump(get_headers($url,0));

/*array(18) {

  [0]=>  string(30) "HTTP/1.0 301 Moved Permanently"

  [1]=>  string(32) "Location: http://www.google.com/"

  [2]=>  string(38) "Content-Type: text/html; charset=UTF-8"

  [3]=>  string(35) "Date: Sun, 26 Sep 2010 00:59:50 GMT"

  [4]=>  string(38) "Expires: Tue, 26 Oct 2010 00:59:50 GMT"

  [5]=>  string(38) "Cache-Control: public, max-age=2592000"

....

  string(15) "HTTP/1.0 200 OK"

  [10]=>  string(35) "Date: Sun, 26 Sep 2010 00:59:51 GMT"

  [11]=>  string(11) "Expires: -1"

  [12]=>  string(33) "Cache-Control: private, max-age=0"

.....

}*/



/*===========================*/



var_dump(get_headers($url,1));

/*array(11) {

  [0]=>

  string(30) "HTTP/1.0 301 Moved Permanently"

  ["Location"]=>  string(22) "http://www.google.com/"

  ["Content-Type"]=>  array(2) {

    [0]=>    string(24) "text/html; charset=UTF-8"

    [1]=>    string(29) "text/html; charset=ISO-8859-1"

  }

  ["Date"]=>  array(2) {

    [0]=>    string(29) "Sun, 26 Sep 2010 01:03:39 GMT"

    [1]=>    string(29) "Sun, 26 Sep 2010 01:03:39 GMT"

  }

  ["Expires"]=>  array(2) {

    [0]=>    string(29) "Tue, 26 Oct 2010 01:03:39 GMT"

    [1]=>    string(2) "-1"

  }

  ["Cache-Control"]=>  array(2) {

    [0]=>    string(23) "public, max-age=2592000"

    [1]=>    string(18) "private, max-age=0"

  }

.....

}*/

?>

down

info at marc-gutt dot de ¶

16 years ago

Should be the same than the original get_headers():



<?php

if (!function_exists('get_headers')) {

function get_headers($url, $format=0) {

    $headers = array();

    $url = parse_url($url);

    $host = isset($url['host']) ? $url['host'] : '';

    $port = isset($url['port']) ? $url['port'] : 80;

    $path = (isset($url['path']) ? $url['path'] : '/') . (isset($url['query']) ? '?' . $url['query'] : '');

    $fp = fsockopen($host, $port, $errno, $errstr, 3);

    if ($fp)

    {

        $hdr = "GET $path HTTP/1.1\r\n";

        $hdr .= "Host: $host \r\n";

        $hdr .= "Connection: Close\r\n\r\n";

        fwrite($fp, $hdr);

        while (!feof($fp) && $line = trim(fgets($fp, 1024)))

        {

            if ($line == "\r\n") break;

            list($key, $val) = explode(': ', $line, 2);

            if ($format)

                if ($val) $headers[$key] = $val;

                else $headers[] = $key;

            else $headers[] = $line;

        }

        fclose($fp);

        return $headers;

    }

    return false;

}

}

?>

down

bunny at bunny dot hu ¶

8 years ago

If the URL redirected and the new target is also redirected, we got the Locations in array. Also we got the HTTP codes in a number indexed values. 

Here a PART of the header (not all), how it is look like with this redirection chain ( the id=4 is the landing page):
/test.php?id=1 -> /test.php?id=2 -> /test.php?id=3 -> /test.php?id=4

array 
(
    [0] => HTTP/1.1 302 Moved Temporarily

    [Location] => Array
        (
            [0] => /test.php?id=2
            [1] => /test.php?id=3
            [2] => /test.php?id=4
        )

    [1] => HTTP/1.1 302 Moved Temporarily
    [2] => HTTP/1.1 302 Moved Temporarily
    [3] => HTTP/1.1 200 OK
)

In a typical situation we need only the landing page information, so here is a small code to get it:

$result = array();
$header = get_headers($url, 1);
foreach ($header as $key=>$value) {
    if (is_array($value)) {
        $value = end($value);
    }
    $result[$key] = $value;
}

down

sidnash56 at gmail dot com ¶

8 years ago

To check URL validity, this has been working nicely for me:

function url_valid(&$url) {
  $file_headers = @get_headers($url);
  if ($file_headers === false) return false; // when server not found
  foreach($file_headers as $header) { // parse all headers:
    // corrects $url when 301/302 redirect(s) lead(s) to 200:
    if(preg_match("/^Location: (http.+)$/",$header,$m)) $url=$m[1]; 
    // grabs the last $header $code, in case of redirect(s):
    if(preg_match("/^HTTP.+\s(\d\d\d)\s/",$header,$m)) $code=$m[1]; 
  } // End foreach...
  if($code==200) return true; // $code 200 == all OK
  else return false; // All else has failed, so this must be a bad link
} // End function url_exists

down

pegasus at vaultwiki dot org ¶

9 years ago

Note that get_headers should not be used against a URL that was gathered via user input. The timeout option in the stream context only affects the idle time between data in the stream. It does not affect connection time or the overall time of the request. 

(Unfortunately, this is not mentioned in the docs for the timeout option, but has been discussed in a number of code discussions elsewhere, and I have done my own tests to confirm the conclusions of those discussions.)

Thus it is very easy for a user to give you a URL that acts like a Slowloris attack - feeding your get_headers function 1 header only often enough to avoid the stream timeout.

If you are publishing your code, even default_socket_timeout cannot be relied on to remedy this, because it is broken for the HTTPS protocol on many but the more recent versions of PHP: https://bugs.php.net/bug.php?id=41631

With get_headers accepting user input, it can be very easy for an attacker to make all of your PHP child processes become busy.

Instead, use cURL functions to get headers for a URL provided by the user and parse those headers manually, as CURLOPT_TIMEOUT applies to the entire request.

down

stuart at sixletterwords dot com ¶

19 years ago

hey, i came across this afew weeks ago and used the function in an app for recording info about domains that my company owns, and found that the status this returns was wrong most of the time (400 bad request or void for sites that were clearly online). then looking into it i noticed the problem was that it wasn't able to get the correct info about sites with redirections. but thats not the full problem because everything on my server was returning the wrong status too. i searched around on php.net for other info and found that fsockopen's example worked better and only needed some tweeking.



heres the function i put together from it and a small change.



<?php

if(!function_exists('get_headers')) {

   function get_headers($url,$format=0,$httpn=0){

    $fp = fsockopen($url, 80, $errno, $errstr, 30);

    if ($fp) {

       $out = "GET / HTTP/1.1\r\n";

       $out .= "Host: $url\r\n";

       $out .= "Connection: Close\r\n\r\n";

       fwrite($fp, $out);

       while (!feof($fp)) {

           $var.=fgets($fp, 1280);

       }



    $var=explode("<",$var);

    $var=$var[0];

    $var=explode("\n",$var);

    fclose($fp);

    return $var;

    }

    }

}

?>



this returns an array of the header (only problem being that if the site doesn't have correct html it'll pull in some content too).



hope this'll help someone else.

down

Anonymous ¶

18 years ago

I've noticed it.
Some Server will simply return the false reply header if you sent 'HEAD' request instead of 'GET'. The 'GET' request header always receiving the most actual HTTP header instead of 'HEAD' request header. But If you don't mind for a fast but risky method then 'HEAD' request is better for you.

btw ... this is get header with additional information such as User, Pass & Refferer. ... 
<?php
    function get_headers_x($url,$format=0, $user='', $pass='', $referer='') {
        if (!empty($user)) {
            $authentification = base64_encode($user.':'.$pass);
            $authline = "Authorization: Basic $authentification\r\n";
        }

        if (!empty($referer)) {
            $refererline = "Referer: $referer\r\n";
        }

        $url_info=parse_url($url);
        $port = isset($url_info['port']) ? $url_info['port'] : 80;
        $fp=fsockopen($url_info['host'], $port, $errno, $errstr, 30);
        if($fp) {
            $head = "GET ".@$url_info['path']."?".@$url_info['query']." HTTP/1.0\r\n";
            if (!empty($url_info['port'])) {
                $head .= "Host: ".@$url_info['host'].":".$url_info['port']."\r\n";
            } else {
                $head .= "Host: ".@$url_info['host']."\r\n";
            }
            $head .= "Connection: Close\r\n";
            $head .= "Accept: */*\r\n";
            $head .= $refererline;
            $head .= $authline;
            $head .= "\r\n";

            fputs($fp, $head);       
            while(!feof($fp) or ($eoheader==true)) {
                if($header=fgets($fp, 1024)) {
                    if ($header == "\r\n") {
                        $eoheader = true;
                        break;
                    } else {
                        $header = trim($header);
                    }

                    if($format == 1) {
                    $key = array_shift(explode(':',$header));
                        if($key == $header) {
                            $headers[] = $header;
                        } else {
                            $headers[$key]=substr($header,strlen($key)+2);
                        }
                    unset($key);
                    } else {
                        $headers[] = $header;
                    }
                } 
            }
            return $headers;

        } else {
            return false;
        }
    }
?>

Regards.
Donovan

down

drfickle2 at yahoo dot com ¶

19 years ago

aeontech, this the below change adds support for SSL connections. Thanks for the code!

        if (isset($url_info['scheme']) && $url_info['scheme'] == 'https') {
            $port = 443;
            $fp=fsockopen('ssl://'.$url_info['host'], $port, $errno, $errstr, 30);
        } else {
           $port = isset($url_info['port']) ? $url_info['port'] : 80;
            $fp=fsockopen($url_info['host'], $port, $errno, $errstr, 30);
        }

down

Backslider ¶

12 years ago

It should be noted that rather than returning "false" on failure, this function (and others) return a big phat WARNING that will halt your script in its tracks if you do not have error reporting /warning turned off.

Thats just insane!  Any function that does something like fetch a URL should simply return false, without a warning, if the URL fails for whatever reason other than it is badly formatted.

down

php dot sirlancelot at spamgourmet dot com ¶

16 years ago

I tried to replicate the native behavior as much as possible for systems that don't have the get_headers() function. Here it is:
<?php
if (!function_exists('get_headers')) {
function get_headers($Url, $Format= 0, $Depth= 0) {
    if ($Depth > 5) return;
    $Parts = parse_url($Url);
    if (!array_key_exists('path', $Parts))   $Parts['path'] = '/';
    if (!array_key_exists('port', $Parts))   $Parts['port'] = 80;
    if (!array_key_exists('scheme', $Parts)) $Parts['scheme'] = 'http';

    $Return = array();
    $fp = fsockopen($Parts['host'], $Parts['port'], $errno, $errstr, 30);
    if ($fp) {
        $Out = 'GET '.$Parts['path'].(isset($Parts['query']) ? '?'.@$Parts['query'] : '')." HTTP/1.1\r\n".
               'Host: '.$Parts['host'].($Parts['port'] != 80 ? ':'.$Parts['port'] : '')."\r\n".
               'Connection: Close'."\r\n";
        fwrite($fp, $Out."\r\n");
        $Redirect = false; $RedirectUrl = '';
        while (!feof($fp) && $InLine = fgets($fp, 1280)) {
            if ($InLine == "\r\n") break;
            $InLine = rtrim($InLine);

            list($Key, $Value) = explode(': ', $InLine, 2);
            if ($Key == $InLine) {
                if ($Format == 1)
                        $Return[$Depth] = $InLine;
                else    $Return[] = $InLine;

                if (strpos($InLine, 'Moved') > 0) $Redirect = true;
            } else {
                if ($Key == 'Location') $RedirectUrl = $Value;
                if ($Format == 1)
                        $Return[$Key] = $Value;
                else    $Return[] = $Key.': '.$Value;
            }
        }
        fclose($fp);
        if ($Redirect && !empty($RedirectUrl)) {
            $NewParts = parse_url($RedirectUrl);
            if (!array_key_exists('host', $NewParts))   $RedirectUrl = $Parts['host'].$RedirectUrl;
            if (!array_key_exists('scheme', $NewParts)) $RedirectUrl = $Parts['scheme'].'://'.$RedirectUrl;
            $RedirectHeaders = get_headers($RedirectUrl, $Format, $Depth+1);
            if ($RedirectHeaders) $Return = array_merge_recursive($Return, $RedirectHeaders);
        }
        return $Return;
    }
    return false;
}}
?>
The function will handle up to five redirects.
Enjoy!

down

rgawenda at gmail dot com ¶

2 months ago

Some notes are using substr to get the response "code" in first ([0]) header after HTTP/1.X (depending on PHP version), but HTTP/2 is nearing a decade in existence and HTTP/3 is widely supported now, so a better, future proof parsing to extract that, according to specs, is:

<?php
$headers = get_headers($url, true);
$response_code = explode(" ", $headers[0])[1];
?>

Also if you aren't blocking redirects with stream_context_create, take into account that $headers[0] is the response code of the requested URL, while the next resolved and followed redirect is at [1], so you should also do lookup the correct (last) response header first:

<?php
$response_header = $headers[max(array_filter(array_keys($headers), 'is_int'))];
?>

＋add a note

get_headers

Description

Parameters

Return Values

Changelog

Examples

See Also

Found A Problem?

User Contributed Notes 18 notes