Why use .htaccess file

An .htaccess file is a way to configure the details of your website without needed to alter the server config files. The period that starts the file name will keep the file hidden within the folder.

You can create the .htaccess file in a text editor (make sure to name it only .htaccess without any other extension or name) and then upload it to your site through an ftp client.

Additionally the placement of the .htaccess file is important. The configurations in that file will affect everything in its directory and the directories under it.

Things to be aware of

Although an .htaccess page can be immensely useful and can be used to make marked improvement to a site, there are 2 things that it can influence.

• Speed the .htaccess page may slow down your server somewhat; for most servers this will probably be an imperceptible change. This is because of the location of the page: the .htaccess file affects the pages in its directory and all of the directories under it. Each time a page loads, the server scans its directory, and any above it until it reaches the highest directory or an .htaccess file. This process will occur as long as the AllowOverride allows the use of .htaccess files, whether or not the file the .htaccess files actually exists.
• Security the .htaccess file is much more accessible than standard apache configuration and the changes are made live instantly (without the need to restart the server). Granting users permission to make alterations in the .htaccess file gives them a lot of control over the server itself. Any directive placed in the .htaccess file, has the same effect as it would in the apache configuration itself.

Generally speaking, Apache discourages the use of the .htaccess if the user can easily reach the apache configuration files themselves.

How to Activate an .htaccess file

If you have access to the server settings you can edit the configuration to allow the .htaccess file to override standard website configs. Open the apache2 default host configuration file. NB: You will need sudo privileges for this step.

sudo nano /etc/apache2/sites-available/default

Once inside that file, find the following section, and change the line that says AllowOverride from None to All. The section should now look like this:

<Directory /var/www/>
           Options Indexes FollowSymLinks MultiViews
           AllowOverride All
           Order allow,deny
           allow from all
</Directory>

After you save and exit that file, restart apache

sudo service apache2 restart

Creating the .htaccess file

You can create the .htaccess file in a text editor (make sure to name it only .htaccess without any other extension or name) and then upload it to your site through an ftp client.

Alternatively you can use this command, replacing the example.com with the name of your site, to create your .htaccess file in terminal.

sudo nano /var/www/example.com/.htaccess

Five common uses for an .htaccess file

1. Mod_Rewrite

One of the most useful facets of the .htaccess file is mod_rewrite. You can use the space in the .htaccess file to designate and alter how URLs and web pages on your sites are displayed to your users.

2. Authentication

Although using the .htaccess file does not require as many permissions as accessing the apache2.conf file would require, we can still make effective changes to a site. Once such change is to require a password to access certain sections of the webpage.

The .htaccess passwords are kept in a file called .htpasswd. Go ahead and create and save that file, being sure to store it somewhere other than the web directory, for security reasons.

You should use the space inside the .htpasswd file to write in the name and passwords of all the users that you want to have access to the protected part of the site.

You can use this useful site to generate the username and encrypted password pair. If the username of your authorized user is jsmith and password is “awesome”, the pair would look like this: jsmith:VtweQU73iyETM. You can paste as many lines as needed into the .htpasswd file, but be sure that every user gets their own line.

Once you are finished with the .htpasswd file, you can type this code into the .htaccess file to begin using the password function:

AuthUserFile /usr/local/username/safedirectory/.htpasswd
AuthGroupFile /dev/null
AuthName "Please Enter Password"
AuthType Basic
Require valid-user

• AuthUserFile: This line designates the server path to the .htpasswd file.
• AuthGroupFile: This line can be used to convey the location of the .htgroup. As we have not created such a file, we can leave /dev/null in place.
• AuthName: This is text that will be displayed at the password prompt. You can put anything here.
• AuthType: This refers to the type of authentication that will be used to the check the passwords. The passwords are checked via HTTP and the keyword Basic should not be changed.
• Require valid-user: This line represents one of two possibilities. “Require valid-user” tells the .htaccess file that there are several people who should be able to log into the password protected area. The other option is to use the phrase “require user username” to indicate the specific permitted person.

3. Custom Error Pages

The .htaccess file additionally allows you to create custom error pages for your site. Some of the most common errors are:

• 400 Bad Request
• 401 Authorization Required
• 403 Forbidden Page
• 404 File not Found
• 500 Internal Error

To make a page look friendlier and to provide more information to the site visitor than the default server error page offers, you can use the .htaccess file to create custom error pages.

I’m going to create a 404 page in this tutorial. However, you can substitute that error for whatever you prefer:

Once you have created and uploaded desired error page, you can go ahead and designate its location in the .htaccess file.

ErrorDocument 404 /new404.html

Keep in mind that the Apache looks for the 404 page located within the site's root. If you placed the new error page in a deeper subdirectory, you need to include that in the line, making it look something like this:

ErrorDocument 404 /error_pages/new404.html

4. Mime Types

In cases where your site features some application files that your server was not set up to deliver, you can add MIME types to your Apache server in the .htaccess file with the following code.

AddType audio/mp4a-latm .m4a

Be sure to replace application and file extension with the Mime Type that you want to support.

5. SSI

Server Side Includes are a great time-saver on a website. One of the most common uses of SSI is to update a large number of pages with some specific data, without having to update each page individually (for example, if you want to change a quotation at the bottom of a page).

To encode SSI, type the following code into your .htaccess file.

AddType text/html .shtml
AddHandler server-parsed .shtml

These three lines have the effect of telling the .htaccess that .shtml files are valid, with the second line specifically making the server parse all files ending in .shtml for any SSI commands.

However, if you have many .html pages that you are not eager to rename with .shtml extensions, you can use another tactic to parse them for SSI commands, the XBitHack.

Adding this line to the .htaccess file makes Apache check all the html files with the appropriate permissions for Server Side Includes.

XBitHack on

To make a page eligible for the XBitHack, use this command:

chmod +x pagename.html