How to get HTTP headers in PHP
You have already know that generally you send external API request, you also need to send Content-Type in header. Some API only accepts request if you sent proper headers. When the API call succeed, the server also send headers in response.
Headers are the additional data which are send with the request and response. Generally the header data contains information about data-type, request source and authentication credentials etc.
You may want to get information about headers and validate request. PHP gives you several ways to get headers from request and response.
In this article, we will discuss few ways how to get headers from request and response sent by server.
CURL request:
The first and widely used to get headers from request is using PHP curl. This method also used to get headers from all type of request.
Here is the below example how you can get headers array:
This will return header array in response:
Array
(
[0] => HTTP/2 301
[1] => location: https://www.google.com/
[2] => content-type: text/html; charset=UTF-8
[3] => date: Tue, 10 Aug 2021 11:45:33 GMT
[4] => expires: Thu, 09 Sep 2021 11:45:33 GMT
[5] => cache-control: public, max-age=2592000
[6] => server: gws
[7] => content-length: 220
[8] => x-xss-protection: 0
[9] => x-frame-options: SAMEORIGIN
[10] => alt-svc: h3=»:443″; ma=2592000,h3-29=»:443″; ma=2592000,h3-T051=»:443″; ma=2592000,h3-Q050=»:443″; ma=2592000,h3-Q046=»:443″; ma=2592000,h3-Q043=»:443″; ma=2592000,quic=»:443″; ma=2592000; v=»46,43″
[11] =>
[12] =>
)
You can convert headers in key:value format using below loop.
$data = []; foreach ($headers as $value) < $parts = explode(':', $value); if (count($parts) === 2) < $data[trim($parts[0])] = trim($parts[1]); >> print_r($data);Array
(
[content-type] => text/html; charset=UTF-8
[cache-control] => public, max-age=2592000
[server] => gws
[content-length] => 220
[x-xss-protection] => 0
[x-frame-options] => SAMEORIGIN
)
apache_request_headers() function
apache_request_headers() function returns all headers for current request. The function returns associative array of all the HTTP headers in the current request. It returns false on failure.
This will return response for my localhost web request:
Array
(
[Host] => localhost
[Connection] => keep-alive
[Cache-Control] => max-age=0
[sec-ch-ua] => «Chromium»;v=»92″, » Not A;Brand»;v=»99″, «Google Chrome»;v=»92″
[sec-ch-ua-mobile] => ?0
[Upgrade-Insecure-Requests] => 1
[User-Agent] => Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/92.0.4515.131 Safari/537.36
[Accept] => text/html,application/xhtml+xml,application/xml;q=0.9,image/avif,image/webp,image/apng,*/*;q=0.8,application/signed-exchange;v=b3;q=0.9
[Sec-Fetch-Site] => none
[Sec-Fetch-Mode] => navigate
[Sec-Fetch-User] => ?1
[Sec-Fetch-Dest] => document
[Accept-Encoding] => gzip, deflate, br
[Accept-Language] => en-GB,en-US;q=0.9,en;q=0.8
)
get_headers() function
get_headers() function returns all response headers sent by the server.
Below example shows the response headers for Google homepage:
It will return the array of headers sent by Google server:
Array
(
[0] => HTTP/1.0 200 OK
[1] => Date: Tue, 10 Aug 2021 12:01:20 GMT
[2] => Expires: -1
[3] => Cache-Control: private, max-age=0
[4] => Content-Type: text/html; charset=ISO-8859-1
[5] => P3P: CP=»This is not a P3P policy! See g.co/p3phelp for more info.»
[6] => Server: gws
[7] => X-XSS-Protection: 0
[8] => X-Frame-Options: SAMEORIGIN
[9] => Set-Cookie: 1P_JAR=2021-08-10-12; expires=Thu, 09-Sep-2021 12:01:20 GMT; path=/; domain=.google.com; Secure
[10] => Set-Cookie: NID=221=SEbyqqBM0d_cZ4I1qqC6o7sLHRQOpWg7qRdWMat3qN2ROYtC_XgyHQYfLZeMoKH9EiSNh_mglxQBtpJPkQnRiaFiEdvVn0MUypVN6VshIN16-OOaMU3JFZ3leCaioetNW0c5H8YfrUst2dIlBud4dRzoWA-YmnhjnsPbeOD_f9Q; expires=Wed, 09-Feb-2022 12:01:20 GMT; path=/; domain=.google.com; HttpOnly
[11] => Alt-Svc: h3=»:443″; ma=2592000,h3-29=»:443″; ma=2592000,h3-T051=»:443″; ma=2592000,h3-Q050=»:443″; ma=2592000,h3-Q046=»:443″; ma=2592000,h3-Q043=»:443″; ma=2592000,quic=»:443″; ma=2592000; v=»46,43″
[12] => Accept-Ranges: none
[13] => Vary: Accept-Encoding
)
I hope you liked the article and help in your web development.
Retrieve response headers from PHP cURL
There are two ways to get response headres from PHP cURL.
1. Using CURLOPT_HEADER option
With the curl_setopt() method, when CURLOPT_HEADER is set to true, curl_exec will output response header. At this time, if CURLOPT_NOBODY is set to false, curl_setopt() will return the response header and content body, otherwise only the response header will be returned.
We can use curl_getinfo($ch, CURLINFO_HEADER_SIZE) method to return total size of all headers received.
$url = "https://www.google.com"; $ch = curl_init(); curl_setopt($ch, CURLOPT_URL, $url); curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1); curl_setopt($ch, CURLOPT_HEADER, 1); // TRUE to exclude the body from the output. curl_setopt($ch, CURLOPT_NOBODY, 0); $response = curl_exec($ch); // After curl_exec $header_size = curl_getinfo($ch, CURLINFO_HEADER_SIZE); $header = substr($response, 0, $header_size); $body = substr($response, $header_size); echo $header; // echo $body;HTTP/1.1 200 OK Date: Tue, 28 Apr 2020 15:11:27 GMT Expires: -1 Cache-Control: private, max-age=0 Content-Type: text/html; charset=ISO-8859-1 P3P: CP="This is not a P3P policy! See g.co/p3phelp for more info." Server: gws X-XSS-Protection: 0 X-Frame-Options: SAMEORIGIN Set-Cookie: 1P_JAR=2020-04-28-15; expires=Thu, 28-May-2020 15:11:27 GMT; path=/; domain=.google.com; Secure Set-Cookie: NID=203=DasuCttFxUVDirSokzwSf91r3PD60lDxlFogt2-rg5m0BCbhSeCpWcIlJVAmuLiDUkXmBTXuVbKEcP8gT0ifJzTu1MW-9UfriAyIqPESXl2H6fOsb9mvDZH8ng4Nb_YQk4Xv1uMFpCMiVf6GSHZS7dje2cjq1qvgyFiQfb3bOTA; expires=Wed, 28-Oct-2020 15:11:27 GMT; path=/; domain=.google.com; HttpOnly Alt-Svc: quic=":443"; ma=2592000; v="46,43",h3-Q050=":443"; ma=2592000,h3-Q049=":443"; ma=2592000,h3-Q048=":443"; ma=2592000,h3-Q046=":443"; ma=2592000,h3-Q043=":443"; ma=2592000,h3-T050=":443"; ma=2592000 Accept-Ranges: none Vary: Accept-Encoding Transfer-Encoding: chunked2. Using CURLOPT_HEADERFUNCTION option
With the CURLOPT_HEADERFUNCTION option, we can set a callback function.
$headers = []; $url = "https://www.google.com"; $ch = curl_init(); curl_setopt($ch, CURLOPT_URL, $url); curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1); 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; > ); $response = curl_exec($ch); print_r($headers);Array ( [date] => Array ( [0] => Tue, 28 Apr 2020 15:12:50 GMT ) [expires] => Array ( [0] => -1 ) [cache-control] => Array ( [0] => private, max-age=0 ) [content-type] => Array ( [0] => text/html; charset=ISO-8859-1 ) [p3p] => Array ( [0] => CP="This is not a P3P policy! See g.co/p3phelp for more info." ) [server] => Array ( [0] => gws ) [x-xss-protection] => Array ( [0] => 0 ) [x-frame-options] => Array ( [0] => SAMEORIGIN ) [set-cookie] => Array ( [0] => 1P_JAR=2020-04-28-15; expires=Thu, 28-May-2020 15:12:50 GMT; path=/; domain=.google.com; Secure [1] => NID=203=ZC5X9W1OFIFk7p_y1HUQ1ZhluIAq1QMJcoiaWNvjtggga9w0By1ULn01BaSxfswmYixQ8arShOwTpHMWyDRXu6vy5xdS19FmFYLyUsdz0n5wOs9_dkb4xBPLOc4SRKdZN7QhcgS8sMVwugrM-CEyg2ENJq_t__UJlwM2cgOdyfg; expires=Wed, 28-Oct-2020 15:12:50 GMT; path=/; domain=.google.com; HttpOnly ) [alt-svc] => Array ( [0] => quic=":443"; ma=2592000; v="46,43",h3-Q050=":443"; ma=2592000,h3-Q049=":443"; ma=2592000,h3-Q048=":443"; ma=2592000,h3-Q046=":443"; ma=2592000,h3-Q043=":443"; ma=2592000,h3-T050=":443"; ma=2592000 ) [accept-ranges] => Array ( [0] => none ) [vary] => Array ( [0] => Accept-Encoding ) [transfer-encoding] => Array ( [0] => chunked ) )