PHP HTTP Authentication
Occasionally you may wish to make certain pages of your site only viewable to a select few. you can do this by using PHPs built in HTTP Authentication. The code needs to go right at the top of your php page so don’t get ‘Headers Already Sent’ errors. You can see that we’ve specified the username and password in the variables at the top of the script you can change these to reflect your own username and password.
You could easily make this authentication more dynamic by checking a database for the username and password. We can get whatever the user typed into the dropdown box by specifying the following superglobals.
//Username: <?php echo $_SERVER['PHP_AUTH_USER'];?> //Password: <?php echo $_SERVER['PHP_AUTH_PW'];?>
The Code
<?php
$config['admin_username'] = "demo";
$config['admin_password'] = "demo";
if (!($_SERVER['PHP_AUTH_USER'] == $config['admin_username'] && $_SERVER['PHP_AUTH_PW'] == $config['admin_password'])) {
header("WWW-Authenticate: Basic realm=\"Papermashup.com Demo Admin\"");
header("HTTP/1.0 401 Unauthorized");
echo 'This is what happens if you press cancel';
?>
<?php
exit;
}
// if the username and password match show the rest of the content
?>
Be careful when coding the HTTP header lines. In order to guarantee maximum compatibility with all browsers, the keyword “Basic” should be written with an uppercase “B”, the realm string must be enclosed in double (not single) quotes, and exactly one space should precede the 401 code in the HTTP/1.0 401 header line.
Cool! I always wonderd how to do that, just never looked it up. Thanks.
Nice, how would you use other methods other than “Basic” – eg so that the string is encoded and users reading the script cannot reverse the password?
@Phil you could use and MD5 hash so when the user types in the password you take that variable, convert it into an MD5 hash then compare it to see if it’s valid. instead of that you could connect it upto a database to store your passwords.
[...] 17. PHP HTTP Authentication [...]
One thing to note is that this method does not work when running PHP as CGI. This example details a workaround if that is the case for you.
http://www.sslcatacombnetworking.com/articles/http-authentication-php-cgi.html
If you want to work with non ASCII chars (€ä£) in usernames and passwords, you need something better.
I’ve written a standalone class for basic authentication which does this: http://github.com/toscho/PHP-HTTP-Tools/blob/master/class.HTTP_Auth.php
This is exactly what I’ve been looking for! Was wondering how to go about it, always had an itch for this, like I had to know what was going on ‘behind the scene’ of it all. Thanks for the write up, enjoyed it a lot!
- MexiChriS
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