Webserver with nginx working until .save file created

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07-10-2024

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Nginx Webserver Stops Working After Creating a .save File: A Common Issue and its Solutions

Problem: You've set up a Nginx webserver and it's working perfectly, until a file with the extension ".save" is created in your web root directory. Suddenly, your website becomes inaccessible.

Rephrased: Imagine you're hosting a website on Nginx. Everything runs smoothly until a specific type of file, ending with ".save", appears in the directory where your website's files are stored. At that moment, your website goes offline.

This issue can be incredibly frustrating, but understanding the cause helps us troubleshoot and fix it.

Scenario:

Let's say you're running a basic Nginx webserver configured to serve a simple website located at /var/www/html/. The following Nginx configuration file (/etc/nginx/sites-available/default) handles the webserver:

server {
    listen 80;
    server_name example.com;
    root /var/www/html;

    index index.html index.htm;

    location / {
        try_files $uri $uri/ =404;
    }
}

The website runs smoothly until a file named index.html.save appears in the /var/www/html/ directory. From that point, your website becomes inaccessible.

Analysis:

This issue is often caused by Nginx's try_files directive. The way try_files works is:

1. It tries to locate the requested file ($uri) as-is.
2. If the file doesn't exist, it tries to append a / to the request path and looks for a directory with that name.
3. If both steps fail, it returns the specified error code (in this case, 404 Not Found).

The problem arises because index.html.save is treated as a potential directory by try_files. When Nginx attempts to access this "directory," it encounters an error, causing the website to fail.

Solutions:

There are a few ways to tackle this issue:

1. Rename the file: The simplest solution is to avoid creating .save files in the web root directory. Rename them to a different extension or move them to a different location outside the webserver's document root.

2. Modify the try_files directive: You can refine the try_files directive to exclude files with .save extension. For example:

   location / {
       try_files $uri $uri/ @fallback;
   }
   
   location @fallback {
       try_files $uri $uri/ =404;
   }
   

   This creates a named location @fallback that is used after the initial try_files check. If the initial attempt fails and the requested file ends with .save, it will bypass the @fallback location and return a 404 error.

3. Disable try_files for specific locations: You can disable try_files for specific locations where .save files might appear. For instance:

   location / {
       try_files $uri $uri/ =404;
   }
   
   location ~* ^/(.*)\.save$ {
       root /var/www/html;
       try_files $uri =404;
   }
   

   This configuration sets up a specific location for all files ending with .save. It explicitly disables try_files for these files, preventing Nginx from treating them as directories.

Additional Value:

• Understanding the root cause behind the issue is crucial for efficient troubleshooting and resolution.
• The solutions presented provide practical, tailored methods to overcome the problem.
• Using specific examples and configurations helps readers apply the solutions directly to their own situations.

References:

• Nginx try_files documentation
• Nginx regular expression documentation

By understanding the interaction between Nginx's try_files directive and .save files, you can confidently prevent this issue and ensure the smooth functioning of your website.