how to check if ssl exists on a webserver through php? - php

Question

I have this function in a class:
function enable_ssl() {
if ($_SERVER[HTTPS] != "on") {
$domain = "https://".$_SERVER['HTTP_HOST'] . "/" . $_SERVER['SCRIPT_NAME'];
header("Location: {$domain}");
}
}
The problem is that when the server doesn't have SSL installed and I have this function initiating the page redirects to a 404 page. I was wondering how I can have this function work only when SSL is installed and working?
Is it possible?
Thanks.
P.S.: I did some Google research but couldn't find much of anything.

Answer 1

On a *nix server, you could try parsing the output of netstat -A inet -lnp for a web server listening on port 443. Kinda clunky.
Better option, I'd say, is to make it a configuration option for the user. Let them tell your app if they've got HTTPS enabled.

Answer 2

two ideas
Setup a socket connection to port 443 and see if it connects.
Read through an apache config file and see if there's anything listening on that port

Answer 3

Extension Loaded!
http://php.net/manual/en/function.extension-loaded.php
e.g.
if(!extension_loaded('openssl'))
{
throw new Exception('This app needs the Open SSL PHP extension.');
}

Answer 4

You can try to connect to the server using curl. However, I would also try to do a config option. If you use the below, make sure you don't cause an infinite loop.
function ignoreHeader($curl, $headerStr)
{
return strlen($headerStr);
}
$curl = curl_init("https://example.com/");
curl_setopt($curl, CURLOPT_NOBODY, TRUE);
curl_setopt($curl, CURL_HEADERFUNCTION, 'ignoreHeader');
curl_exec($curl);
$res = curl_errno($curl);
if($res == 0)
{
$info = curl_getinfo($curl);
if($info['http_code'] == 200)
{
# Supports SSL
enable_ssl();
}
}
else
{
# Doesn't.
}

Answer 5

I use xampp as my development server on my laptop. I have yet to set up a SSL connection on xampp. My production server does have SSL enabled and also has a valid cert.
I noticed that $_SERVER['HTTPS'] does not exist on my xampp development server, but does exist on my production server.
I am assuming (perhaps incorrectly) that if $_SERVER['HTTPS'] is not set, SSL is not enabled on the server.
<?php
if (isset($_SERVER['HTTPS')) echo 'SSL Exists'
else echo 'No SSL'
?>

Answer 6

I just use file_get_contents to try and open the same file via https and if it was successful, force a redirect...
function IsHttps()
{
return
(!empty($_SERVER["HTTPS"]) && (strtolower($_SERVER["HTTPS"])!=="off"))
|| ($_SERVER["SERVER_PORT"]==443);
}
if (!IsHttps() && extension_loaded("openssl"))
{
$target = "https://".$_SERVER["HTTP_HOST"].$_SERVER["PHP_SELF"];
ini_set("allow_url_fopen", true);
if (file_get_contents($target)!==false)
{
header("Location: https://".$_SERVER["HTTP_HOST"].$_SERVER["URL"]);
die();
}
}

Answer 7

I have used the code below
$file ="https://mydomain/index.php";
$file_headers = #get_headers($file);
$DomainName=(!$file_headers || $file_headers[0] == 'HTTP/1.1 404 Not Found')?'http://mydomain':'https://mydomain';
This basically checks if a file can be found (accessed) via HTTPS.

Answer 8

This is how wordpress does it:
<?php
function is_ssl() {
if ( isset($_SERVER['HTTPS']) ) {
return true;
if ( '1' == $_SERVER['HTTPS'] )
return true;
} elseif ( isset($_SERVER['SERVER_PORT']) && ( '443' == $_SERVER['SERVER_PORT'] ) ) {
return true;
}
return false;
}
?>
You can use your validation in between 'return true' stuff! Go to:
http://tutes.in/2012/02/13/check-if-ssl-exists-on-a-webserver-through-php/
for explanation and more detailed source code.