[php] How to find out if you're using HTTPS without $_SERVER['HTTPS']

I've seen many tutorials online that says you need to check $_SERVER['HTTPS'] if the server is connection is secured with HTTPS. My problem is that on some of the servers I use, $_SERVER['HTTPS'] is an undefined variable that results in an error. Is there another variable I can check that should always be defined?

Just to be clear, I am currently using this code to resolve if it is an HTTPS connection:

if(isset($_SERVER['HTTPS'])) {
    if ($_SERVER['HTTPS'] == "on") {
        $secure_connection = true;
    }
}

I don't think that adding a port is good idea - specially when you got many servers with different builds. that just adds one more thing to remember to change. looking at doc's I think the last line of kaisers is quite good, so that:

if(!empty($_SERVER["HTTPS"]))
  if($_SERVER["HTTPS"]!=="off")
    return 1; //https
  else
    return 0; //http
else
  return 0; //http

seems like perfectly enough.

This also works when $_SERVER['HTTPS'] is undefined

if( (!empty($_SERVER['HTTPS']) && $_SERVER['HTTPS'] != 'off') || $_SERVER['SERVER_PORT'] == 443 ){
    //enable secure connection
}

just for interest, chrome canary at the moment sends

HTTPS : 1

to the server, and depending on how the server is configured can mean that you get back the following

HTTPS : 1, on

This broke our application because we were testing if on, which it obviously isn't. At the moment, only chrome canary seems to do this, but its worth noting that things from canary generally land in "normal" chrome a short while later.

The REAL answer: ready for copy-paste into a [config] script

/* configuration settings; X=edit may 10th '11 */
$pv_sslport=443; /* for it might be different, as also Gabriel Sosa stated */
$pv_serverport=80; /* X */
$pv_servername="mysite.com"; /* X */

/* X appended after correction by Michael Kopinsky */
if(!isset($_SERVER["SERVER_NAME"]) || !$_SERVER["SERVER_NAME"]) {
    if(!isset($_ENV["SERVER_NAME"])) {
        getenv("SERVER_NAME");
        // Set to env server_name
        $_SERVER["SERVER_NAME"]=$_ENV["SERVER_NAME"];
    }
}
if(!$_SERVER["SERVER_NAME"]) (
    /* X server name still empty? ... you might set $_SERVER["SERVER_NAME"]=$pv_servername; */
}

if(!isset($_SERVER["SERVER_PORT"]) || !$_SERVER["SERVER_PORT"]) {
    if(!isset($_ENV["SERVER_PORT"])) {
        getenv("SERVER_PORT");
        $_SERVER["SERVER_PORT"]=$_ENV["SERVER_PORT"];
    }
}
if(!$_SERVER["SERVER_PORT"]) (
    /* X server port still empty? ... you might set $_SERVER["SERVER_PORT"]=$pv_serverport; */
}

$pv_URIprotocol = isset($_SERVER["HTTPS"]) ? (($_SERVER["HTTPS"]==="on" || $_SERVER["HTTPS"]===1 || $_SERVER["SERVER_PORT"]===$pv_sslport) ? "https://" : "http://") :  (($_SERVER["SERVER_PORT"]===$pv_sslport) ? "https://" : "http://");

$pv_URIprotocol is now correct and ready to be used; example $site=$pv_URIprotocol.$_SERVER["SERVER_NAME"]. Naturally, the string could be replaced with TRUE and FALSE also. PV stands for PortalPress Variable as it is a direct copy-paste which will always work. This piece can be used in a production script.

I have occasion to go a step further and determine if the site I'm connecting to is SSL capable (one project asks the user for their URL and we need to verify they have installed our API pack on a http or https site).

Here's the function I use - basically, just call the URL via cURL to see if https works!

function hasSSL($url) 
{
    // take the URL down to the domain name
    $domain = parse_url($url, PHP_URL_HOST);
    $ch = curl_init('https://' . $domain);
    curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
    curl_setopt($ch, CURLOPT_CUSTOMREQUEST, 'HEAD'); //its a  HEAD
    curl_setopt($ch, CURLOPT_NOBODY, true);          // no body
    curl_setopt($ch, CURLOPT_FOLLOWLOCATION, true);  // in case of redirects
    curl_setopt($ch, CURLOPT_VERBOSE, 0); //turn on if debugging
    curl_setopt($ch, CURLOPT_HEADER, 1);     //head only wanted
    curl_setopt($ch, CURLOPT_CONNECTTIMEOUT, 10);    // we dont want to wait forever
    curl_exec($ch);
    $header = curl_getinfo($ch, CURLINFO_HTTP_CODE);
    if ($header === 200) {
        return true;
    }
    return false;
}

This is the most reliable way I have found to not only find out IF you are using https (as the question asks), but if you COULD (or even SHOULD) be using https.

NOTE: it is possible (though not really likely...) that a site could have different http and https pages (so if you are told to use http, maybe you don't need to change..) The vast majority of sites are the same, and probably should reroute you themselves, but this additional check has its use (certainly as I said, in the project where the user inputs their site info and you want to make sure from the server side)

I used the main suggestion here and got annoyed at the "PHP Notice" in the logs when HTTPS was not set. You can avoid it by using the null-coalescing operator "??":

if( ($_SERVER['HTTPS'] ?? 'off') == 'off' ) {
    // redirect
}

(Note: not available prior to php v7)

Making my own function from reading all previous posts:

public static function isHttps()
{
    if (array_key_exists("HTTPS", $_SERVER) && 'on' === $_SERVER["HTTPS"]) {
        return true;
    }
    if (array_key_exists("SERVER_PORT", $_SERVER) && 443 === (int)$_SERVER["SERVER_PORT"]) {
        return true;
    }
    if (array_key_exists("HTTP_X_FORWARDED_SSL", $_SERVER) && 'on' === $_SERVER["HTTP_X_FORWARDED_SSL"]) {
        return true;
    }
    if (array_key_exists("HTTP_X_FORWARDED_PROTO", $_SERVER) && 'https' === $_SERVER["HTTP_X_FORWARDED_PROTO"]) {
        return true;
    }
    return false;
}

If your are using Apache you may always count on

$_SERVER["REQUEST_SCHEME"]

to verify the scheme of the URL requested. But, as mentioned in other answers, it is prudent to verify other parameters before assuming SSL is really being used.

$secure_connection = ((!empty($_SERVER['HTTPS']) && $_SERVER['HTTPS'] != 'off') || (!empty($_SERVER['HTTP_HTTPS']) && $_SERVER['HTTP_HTTPS'] != 'off') || $_SERVER['REQUEST_SCHEME'] == 'https' || $_SERVER['SERVER_PORT'] == 443) ? true : false;

Code is checking anything possible and works also on IIS web server. Chrome since v44 do not set header HTTP: 1 so checking HTTP_HTTPS is OK. If this code does not match https it means your webserver or proxy server is poorly configured. Apache itself sets HTTPS flag correctly but there can be problem when you use proxy (e.g. nginx). You must set some header in nginx https virtual host

proxy_set_header   X-HTTPS 1;

and use some Apache module to set HTTPS flag correctly by looking for X-HTTPS from proxy. Search for mod_fakessl, mod_rpaf, etc.

Chacha, per the PHP documentation: "Set to a non-empty value if the script was queried through the HTTPS protocol." So your if statement there will return false in many cases where HTTPS is indeed on. You'll want to verify that $_SERVER['HTTPS'] exists and is non-empty. In cases where HTTPS is not set correctly for a given server, you can try checking if $_SERVER['SERVER_PORT'] == 443.

But note that some servers will also set $_SERVER['HTTPS'] to a non-empty value, so be sure to check this variable also.

Reference: Documentation for $_SERVER and $HTTP_SERVER_VARS [deprecated]

I have just had an issue where I was running the server using Apache mod_ssl, yet a phpinfo() and a var_dump( $_SERVER ) showed that PHP still thinks I'm on port 80.

Here is my workaround for anyone with the same issue....

<VirtualHost *:443>
  SetEnv HTTPS on
  DocumentRoot /var/www/vhost/scratch/content
  ServerName scratch.example.com
</VirtualHost>

The line worth noting is the SetEnv line. With this in place and after a restart, you should have the HTTPS environment variable you always dreamt of

Shortest way I am using:

$secure_connection = !empty($_SERVER['HTTPS']);

If if https is used, then $secure_connection is true.

You could check $_SERVER['SERVER_PORT'] as SSL normally runs on port 443, but this is not foolproof.

I find these params acceptable as well and more then likely don't have false positives when switching web servers.

1. $_SERVER['HTTPS_KEYSIZE']
2. $_SERVER['HTTPS_SECRETKEYSIZE']
3. $_SERVER['HTTPS_SERVER_ISSUER']

4. $_SERVER['HTTPS_SERVER_SUBJECT']

   if($_SERVER['HTTPS_KEYSIZE'] != NULL){/*do foobar*/}
   

If You use nginx as loadbalancing system check $_SERVER['HTTP_HTTPS'] == 1 other checks will be fail for ssl.

As per hobodave's post: "Set to a non-empty value if the script was queried through the HTTPS protocol."

if (!empty($_SERVER['HTTPS']))
{
    $secure_connection = true;
}

This is how i find solve this

$https = !empty($_SERVER['HTTPS']) && strcasecmp($_SERVER['HTTPS'], 'on') === 0 ||
        !empty($_SERVER['HTTP_X_FORWARDED_PROTO']) &&
            strcasecmp($_SERVER['HTTP_X_FORWARDED_PROTO'], 'https') === 0;

return ($https) ? 'https://' : 'http://';

On my server (Ubuntu 14.10, Apache 2.4, php 5.5) variable $_SERVER['HTTPS'] is not set when php script is loaded via https. I don't know what is wrong. But following lines in .htaccess file fix this problem:

RewriteEngine on

RewriteCond %{HTTPS} =on [NC] 
RewriteRule .* - [E=HTTPS:on,NE]

If you are using Incapsula's load balancer you'll need to use an IRule to generate a custom header for your server. I created an HTTP_X_FORWARDED_PROTO header that is equal to either "http" if the port is set to 80 and "https" if it is equal to 443.

The only reliable method is the one described by Igor M.

$pv_URIprotocol = isset($_SERVER["HTTPS"]) ? (($_SERVER["HTTPS"]==="on" || $_SERVER["HTTPS"]===1 || $_SERVER["SERVER_PORT"]===$pv_sslport) ? "https://" : "http://") :  (($_SERVER["SERVER_PORT"]===$pv_sslport) ? "https://" : "http://");

Consider following: You are using nginx with fastcgi, by default(debian, ubuntu) fastgi_params contain directive:

fastcgi_param HTTPS $https;

if you are NOT using SSL, it gets translated as empty value, not 'off', not 0 and you are doomed.

http://unpec.blogspot.cz/2013/01/nette-nginx-php-fpm-redirect.html

My solution (because the standard conditions [$_SERVER['HTTPS'] == 'on'] do not work on servers behind a load balancer) is:

$isSecure = false;
if (isset($_SERVER['HTTPS']) && $_SERVER['HTTPS'] == 'on') {
    $isSecure = true;
}
elseif (!empty($_SERVER['HTTP_X_FORWARDED_PROTO']) && $_SERVER['HTTP_X_FORWARDED_PROTO'] == 'https' || !empty($_SERVER['HTTP_X_FORWARDED_SSL']) && $_SERVER['HTTP_X_FORWARDED_SSL'] == 'on') {
    $isSecure = true;
}
$REQUEST_PROTOCOL = $isSecure ? 'https' : 'http';

HTTP_X_FORWARDED_PROTO: a de facto standard for identifying the originating protocol of an HTTP request, since a reverse proxy (load balancer) may communicate with a web server using HTTP even if the request to the reverse proxy is HTTPS http://en.wikipedia.org/wiki/List_of_HTTP_header_fields#Common_non-standard_request_headers

If you don't have control of the web server & don't know which variables have been set, upload this php to find out:

<?php
echo "<br>1 ".$_SERVER["HTTPS"];
echo "<br>2 ".$_SERVER["SERVER_PORT"];
echo "<br>3 ".$_SERVER["HTTP_X_FORWARDED_PROTO"];
echo "<br>4 ".$_SERVER["HTTP_X_FORWARDED_SSL"];
echo "<br>5 ".$_SERVER["HTTP_HTTPS"];
echo "<br>6 ".$_SERVER["REQUEST_SCHEME"];
?>

<html>
<body>
<br>
Just cruising
</body>
</html>

I would add a global filter to ensure everything I am checking is correct;

function isSSL() {

    $https = filter_input(INPUT_SERVER, 'HTTPS');
    $port = filter_input(INPUT_SERVER, 'SERVER_PORT');
    if ($https) {

        if ($https == 1) {
            return true;
        } elseif ($https == 'on') {
            return true;
        }
    } elseif ($port == '443') {
        return true;
    }

    return false;
}

What do you think of this?

if (isset($_SERVER['HTTPS']) && !empty($_SERVER['HTTPS']) && $_SERVER['HTTPS'] != 'off')
    $scheme = 'https';
else
    $scheme = 'http';

Here is a re-usable function that I have been using for a while. HTH.

Note: The value of HTTPS_PORT (which is a custom constant in my code) may vary on your envrionment, for example it may be 443 or 81.

/**
 * Determine if this is a secure HTTPS connection
 * 
 * @return  bool    True if it is a secure HTTPS connection, otherwise false.
 */
function isSSL()
{
    if (isset($_SERVER['HTTPS'])) {
        if ($_SERVER['HTTPS'] == 1) {
            return true;
        } elseif ($_SERVER['HTTPS'] == 'on') {
            return true;
        }
    } elseif ($_SERVER['SERVER_PORT'] == HTTPS_PORT) {
        return true;
    }

    return false;
}

I know this answer is late, but I combined a bunch of answers and made a simple function that works for all use cases.

Try this:

function is_ssl(){
if(isset($_SERVER['HTTP_X_FORWARDED_PROTO']) && $_SERVER['HTTP_X_FORWARDED_PROTO']=="https"){ return true; }
elseif(isset($_SERVER['HTTPS'])){ return true; }
elseif($_SERVER['SERVER_PORT'] == 443){ return true; }
else{ return false; }
}

Then just use if, for example:

if(is_ssl()){
// WHAT TO DO IF IT IS SSL / HTTPS
}else{
// WHAT TO DO IF IT IS NOT SSL / HTTPS
}

This code works with Cloudflare, shared hosting providers, etc.

Enjoy.