A tutorial explaining how to retrict access to a directory on a web server using .htaccess.
Password protecting a directory can be done several ways. Many people use PHP or ASP to verify users, but if you want to protect a directory of files or images (for example), that often isn't practical. Fortunately, Apache has a built-in method for protecting directories from prying eyes, using the .htaccess file.
In order to protect your chosen directory, you will first need to create an .htaccess file. This is the file that the server will check before allowing access to anything in the same directory. That's right, the .htaccess file belongs in the directory you are protecting, and you can have one in each of as many directories as you like.
You'll need first to define a few parameters for the .htaccess file. It needs to know where to find certain information, for example a list of valid usernames and passwords. This is a sample of the few lines required in an .htaccess file to begin with, telling it where the usernames and passwords can be found, amongst other things.
AuthUserFile /full/path/to/.htpasswd AuthName "Please Log In" AuthType Basic
You've now defined a few basic parameters for Apache to manage the authorisation process. First, you've defined the location of the .htpasswd file. This is the file that contains all the usernams and encrypted passwords for your site. We'll cover adding information to this file shortly. It's extremely important that you place this file outside of the web root. You should only be able to access it by FTP, not over the web.
The AuthName parameter basically just defines the title of the password entry box when the user logs in. It's not exactly the most important part of the file, but should be defined. The AuthType tells the server what sort of processing is in use, and "Basic" is the most common and perfectly adequate for almost any purpose.
We've told apache where to find files, but we've not told it who, of those people defined in the .htpasswd file, can access the directory. For that reason, we still have another line to define.
If we want to grant access to everyone in the .htpasswd file, we can add this line ("valid-user" is like a keyword, telling apache any user will do):
require valid-user
If we want to just grant access to a single user, we can use "user" and their username instead of "valid-user":
require user dave
A normal and complete .htaccess file might look like this:
AuthUserFile /home/dave/.htpasswd AuthName "Dave's Login Area" AuthType Basic require user dave
Now we have almost everything defined, but we are still missing an .htpasswd file. Without that, the server won't know what usernames and passwords are ok.
An .htpasswd file is made up of a series of lines, one for each valid user. Each line looks like this, with a username, then colon, then encrypted password:
username:encryptedpassword
The password encryption is the same as you'll find in PHP's crypt() function. It is not reversible, so you can't find out a password from the encrypted version. (Please note that on page 2 of this article is a tool to help you generate an .htpasswd file, that will help you encrypt passwords).
A user of "dave" and password of "dave" might be added with the following line:
dave:XO5UAT7ceqPvc
Each time you run an encryption function like "crypt", you will almost certainly get a different result. This is down to something called "salt", which in the above case was "XO" (first two letters of encrypted password). Different salt will give different encrypted values, and if not explicitly specified will be randomly generated. Don't worry though, the server is quite capable of understanding all this - if you come up with a different value for the encrypted password and replace it, everything would still work fine, as long as the password was the same.
Once you've created your .htpasswd file, you need to upload it to a safe location on your server, and check you've set the .htaccess file to point to it correctly. Then, upload the .htaccess file to the directory you want to protect and you'll be all set. Simply visit the directory to check it is all working.
