HTTP 404 | Technology Tales

Removing query strings from any URL on an Nginx-powered website

12^th April 2025

My public transport website is produced using Hugo and is hosted on a web server with Nginx. Usually, I use Apache, so this is an exception. When Google highlighted some duplication caused by unneeded query strings, I set to work. However, doing anything with URL's like redirection cannot use a .htaccess file or MOD_REWRITE on Nginx. Thus, such clauses have to go somewhere else and take a different form.

In my case, the configuration file to edit is /etc/nginx/sites-available/default because that was what was enabled. Once I had that open, I needed to find the following block:

location / {
        # First attempt to serve request as file, then
        # as directory, then fall back to displaying a 404.
        try_files $uri $uri/ =404;
}

Because I have one section for port 80 and another for port 443, there were two locations that I needed to update due to duplication, though I may have got away without altering the second of these. After adding the redirection clause, the block became:

location / {
        # First attempt to serve request as file, then
        # as directory, then fall back to displaying a 404.
        try_files $uri $uri/ =404;

        # Remove query strings only when necessary
        if ($args) {
                rewrite ^(.*)$ $1? permanent;
        }
}

The result of the addition is a permanent (301) redirection whenever there are arguments passed in a query string. The $1? portion is the rewritten URL without a query string that was retrieved in the initial ^(.*)$ portion. In other words, the redirect it from the original address to a new one with only the part preceding the question mark.

Handily, Nginx allows you to test your updated configuration using the following command:

sudo nginx -t

That helped me with some debugging. Once all was in order, I needed to reload the service by issuing this command:

sudo systemctl reload nginx

With Apache, there is no need to restart the service after updating the .htaccess file, which adds some convenience. The different locations also mean some care with backups when upgrading the operating system or moving from one server to another. Apart from that, all works well, proving that there can be different ways to complete the same task.