January 04, 2018

Learn The Basics of .htaccess

Learn the very basics of .htaccess like customizing error pages, enabling cache and expire headers, managing redirects and password protection. Learn how to restrict user access by IP and certain files.

Basics of .htaccess

What is an .htaccess File?

An .htaccess (Hypertext Access) file a configuration file that sits on a directory level. This file is used in Apache web server environments. It is used to modify different server configurations like directory access, redirects, error pages, caching, and compression without affecting the server's core configuration. Since this file works on directory, its content will affect any directory it resides including the root directory.

How to Create an .htaccess file?

We don't need any special program to create the .htaccess file, just a simple text editor can do the job. When we save the .htaccess file, we have to keep in mind that this file has no name, just a ".htaccess" extension, so when saving the file, choose "All Files" in the file type box and the file name must be only ".htaccess".

Error Redirection with .htaccess

We can redirect users to a specific page when they try to access invalid pages. For example, if a user tries to visit a page that does not exist will lead to a 404 error. So we can show a custom 404 page with .htaccess with this directive, which tells the server to display /404.html to the user, whenever a user hits a URL that does not exist.

ErrorDocument 404 /404.html

Common Error Codes:

Code Description
400 Bad Request
401 Unauthorized
403 Forbidden Access
404 Not Found
500 Internal Server Error
502 Bad Gateway
504 Gateway Timeout

Custom Redirection with .htaccess

We can enable redirection with .htaccess so the user visiting a certain page will be redirected to another page of our choice. Redirect user from an old page to a new page with .htaccess like this:

Redirect /OldDir/OldFile.html /NewDir/NewFile.html

Password Protection with .htaccess

We can also password protect web pages with .htaccess. To achieve this, we will need to create a new file (.htpasswd) that contains all the usernames and passwords. We have to create a ".htpasswd" file just like we created .htaccess. The structure of the .htpasswd file to store usernames and passwords is like:

admin:123456
user:123123

After creating .htpasswd, it is important that we add the following content to our .htaccess file. Remember, this password protection will apply to the directory ".htaccess" and all the sub-directories. 

AuthUserFile /absolute/pathto/.htpasswd
AuthType Basic
AuthName "Authorization Required"
require valid-user

Deny Users Access via IP Address with .htaccess

We can also deny access with .htaccess to restrict visitors with a specific IP Address from viewing our web pages. For example, if we wanted to block IP "199.155.88.25", the directive would be as follows: 

order allow,deny
deny from 199.155.88.25 
allow from all

Restricting Access to Files with .htaccess

We can restrict access to a single specific file or multiple files  with .htaccess if they match the condition like in code snippet below:

# Deny access to a single file
<Files .env>
    Order Allow,Deny
    Deny From All
</Files>

# Deny access to multiple files
<FilesMatch "\.env|\.htaccess">
    Order Allow,Deny
    Deny From All
</FilesMatch>
 

Enable Gzip Compression with .htaccess

We can enable compression with .htaccess for better page performance. The compression with .htaccess can be enabled on a directory level or for certain MIME types. 

# Enables compression for documents where htaccess is placed 
<IfModule mod_deflate.c>
	SetOutputFilter DEFLATE
</IfModule>

# Enables compression by MIME type for plain text files, html, css, javascript and xml files
<IfModule mod_deflate.c>
	AddOutputFilterByType DEFLATE text/plain
	AddOutputFilterByType DEFLATE text/html
	AddOutputFilterByType DEFLATE text/css
	AddOutputFilterByType DEFLATE text/javascript
	AddOutputFilterByType DEFLATE text/xml
</IfModule>
 

Enable Cache and Expiry with .htaccess

We can enable cache with .htaccess using the headers directive, and we can also set expiry headers with .htaccess to help reduce the load times. The directives are as follows:

# Cache headers for 45 days for allowed extensions
<ifModule mod_headers.c>
	<FilesMatch "\.(ico|pdf|flv|jpg|jpeg|png|gif|js|css|swf)$">
		Header set Cache-Control "max-age=3888000, s-max-age=3888000, public"
	</FilesMatch>
</ifModule>

# Expire headers for given file types for 45 days
<IfModule mod_expires.c>
	ExpiresActive On
	ExpiresDefault "access plus 1 month"
	ExpiresByType text/plain "access plus 45 days"
	ExpiresByType text/html "access plus 45 days"
	ExpiresByType text/css "access plus 45 days"
	ExpiresByType image/gif "access plus 45 days"
	ExpiresByType image/png "access plus 45 days"
	ExpiresByType image/jpeg "access plus 45 days"
	ExpiresByType application/x-javascript "access plus 45 days"
	ExpiresByType application/javascript "access plus 45 days"
	ExpiresByType application/x-icon "access plus 45 days"
</IfModule>

NOTE: .htaccess file requires "mod_rewrite" to be enabled.

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