Header location infinite redirect Loop - php

Question

I have this huge issue that I have no idea how to fix. I have a script that redirects to a url.
So far I have:
//do some mysql
$geo_included = true; //trying to fix infinite redirect loop.
if($geo_included === true){
header('Location: '.$url["url"]); //this is causing the issue with redirect loop
}
$url["url"] for example is: www.google.com
But when I go to that PHP file it will redirect to:
www.sitename.com/www.google.com
and say there is an infinite redirect loop. Note: the above header location script is not in a while/for/foreach loop.
Here is my .htaccess for the / directory
RewriteEngine On
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule ^(.*)$ index.php?group=$1 [L]
Any ideas?

Answer 1

You need to include the fully qualified domain name with scheme, otherwise it's interpreted as being in the current domain:
header('Location: google.com'); // Redirects to http://cursite.com/www.google.com
header('Location: http://google.com'); // Redirects as expected
If you are unsure if your URL includes a scheme, check the results from parse_url.
$url_scheme = parse_url($url, PHP_URL_SCHEME);
// www.google.com -> NULL
// http://google.com -> string(4) "http"
// ftp://site.com -> string(3) "ftp"

Answer 2

The quick proof-of-concept solution here is to prepend http:// to the URL like this:
$geo_included = true;
if ($geo_included) {
header('Location: http://' . $url["url"]);
}
I say “proof of concept” because what you should do is ensure the $url["url"] always has a protocol attached to it. Either before it gets into the database, or in this code snippet by doing a check on the $url["url"] value to see of it has http:// or https:// and if it doesn’t, prepend it. And here is a quickly thrown together example of what I mean which should work:
$geo_included = true;
if ($geo_included) {
$protocol = (!preg_match("~^(?:ht)tps?://~i", $url["url"])) ? 'http://' : null;
header('Location: ' $protocol . $url["url"]);
}
The line with $protocol = … does the check I explained before. The default is to add http:// if it’s not there.
Also, note I removed === true since the if ($geo_included) { is basically the same thing.