NGINX: How to mimic a .htaccess file (and why you shouldn’t)

Introduction

When it comes to web server configuration, Apache and NGINX are two of the most popular options available today. Apache servers make extensive use of .htaccess files for directory-level configuration, allowing web administrators to control and fine-tune the behavior of the server. NGINX, on the other hand, does not natively support .htaccess files and herein lies an interesting challenge. In this guide, we’ll delve into the ways you can mimic the behavior of an .htaccess file with NGINX configuration and discuss why doing so might not always be the best idea.

Understanding .htaccess and NGINX

The .htaccess file is a powerful Apache feature that provides a way to make configuration changes on a per-directory basis. It is commonly used for rewriting URLs, controlling access, and configuring redirects. NGINX, however, employs a different configuration approach. It uses a centralized configuration to handle server directives. This centralized model contributes to NGINX’s performance and security advantages over Apache.

To try using an .htaccess-like configuration in NGINX, you will need to translate the directives into NGINX’s configuration format and include them in the respective server block of the NGINX configuration file.

Setting Up Basic Rewrites

One common use of the .htaccess file is URL rewriting.

<IfModule mod_rewrite.c>
    RewriteEngine On
    RewriteRule ^oldpage.html$ /newpage.html [L,R=301]
</IfModule>

To accomplish the same in NGINX, add a rewrite directive within the server block:

server { 
  ... 
  rewrite ^/oldpage.html$ /newpage.html permanent; 
}

This rewrite instructs NGINX to permanently redirect /oldpage.html to /newpage.html.

Implementing Access Control

In .htaccess:

<Files "adminpanel.html"> 
   Require all denied 
</Files>

In NGINX:

location = /adminpanel.html { 
   deny all;
 }

This location block prevents access to adminpanel.html for all users.

Handling Custom Error Pages

With .htaccess:

ErrorDocument 404 /custom_404.html

With NGINX:

server { 
  ... 
  error_page 404 /custom_404.html; 
}

This directive tells NGINX to serve /custom_404.html whenever a 404 error occurs.

Password Protection

Here’s an example from .htaccess:

AuthType Basic
AuthName "Restricted Access"
AuthUserFile /path/to/.htpasswd
Require valid-user

And the equivalent NGINX configuration might look like this:

location /protected/ {
    auth_basic "Restricted Access";
    auth_basic_user_file /path/to/.htpasswd;
}

This will protect the /protected/ directory with basic HTTP authentication.

Limitations of .htaccess in NGINX

While you can convert some .htaccess directives to NGINX format, NGINX will never read the .htaccess file directly. Additionally, due to NGINX’s performance focus, following a centralized configuration process is more efficient and secure. Every time an .htaccess file is processed by Apache, there is a read and interpret overhead. NGINX avoids this by pre-reading the configuration files when the service starts, which saves time on each request and reduces latency.

Advanced NGINX Configuration Example

Combining several directives in NGINX, we can replicate complex .htaccess scenarios. Let’s say you want to combine URL rewrites, access controls, and custom error pages:

server {
    ...

    location /admin/ {
        rewrite ^/admin/dashboard/?$ /newdashboard.html permanent;
        deny all;
    }

    error_page 501 /custom_501.html;

    location /error_pages/ {
        internal;
        alias /path/to/your/error_pages/;
    }
}

This example redirects admin dashboard access to a new page, denies all access to the admin directory, and defines a custom 501 error page.

Conclusion

While it’s technically feasible to translate .htaccess functionalities to NGINX server blocks, it’s a manual process that can be time-consuming and prone to error. NGINX’s design encourages more efficient handling of server configurations and challenges the traditional use of .htaccess. As server technology evolves, so do best practices, and in the context of NGINX, that means saying goodbye to .htaccess and embracing a centralized, performance-optimized configuration style.