Nginx Tip - Implement the ngx_http_addition_module for content addition

Nginx is a popular web server that is known for its high performance, scalability, and flexibility. It is widely used to serve static content, reverse proxy, and load balance web applications. One of the lesser-known features of Nginx is the ngx_http_addition_module, which allows you to add content to the response body of an HTTP request. In this article, we will explore how to implement this module and leverage its capabilities.

What is the ngx_http_addition_module?

The ngx_http_addition_module is an Nginx module that provides the ability to add content to the response body of an HTTP request. This can be useful in various scenarios, such as adding headers, footers, or dynamic content to the existing response. The module works by intercepting the response from the upstream server and modifying it before sending it back to the client.

Enabling the ngx_http_addition_module

To enable the ngx_http_addition_module, you need to compile Nginx with the module included. If you are using a pre-built package, make sure it includes the module. Once you have the module enabled, you can start using it in your Nginx configuration.

Here is an example of how to enable the module in the Nginx configuration file:

http {
    ...
    server {
        ...
        location / {
            addition_types text/html;
            add_before_body /path/to/header.html;
            add_after_body /path/to/footer.html;
        }
    }
}

In the above configuration, we specify the addition_types directive to define the content types that should be modified by the module. In this case, we are targeting HTML content. We then use the add_before_body and add_after_body directives to specify the paths to the files that contain the content to be added before and after the response body, respectively.

Dynamic Content Addition

In addition to adding static content from files, the ngx_http_addition_module also supports adding dynamic content using variables. This can be achieved by using the addition directive with the echo module.

Here is an example of how to add dynamic content using variables:

http {
    ...
    server {
        ...
        location / {
            addition_types text/html;
            addition echo $remote_addr;
        }
    }
}

In the above configuration, we use the addition directive with the echo module to add the client's IP address to the response body. This can be useful for debugging or logging purposes.

Conclusion

The ngx_http_addition_module is a powerful module that allows you to add content to the response body of an HTTP request in Nginx. Whether you need to add static content from files or dynamically generate content using variables, this module provides the flexibility to meet your requirements. By leveraging the capabilities of the ngx_http_addition_module, you can enhance the functionality and customization of your Nginx server.

For more information about VPS hosting and how it can benefit your website, check out Server.HK.