nginx how to have a dynamic order of try_files

JoeMoe1984 asked:

I don’t know how better to phrase that question so let me know if there is a better way but here is what I want to do.

I have an app that sends an html file based on the request url which also creates a cache of that html file in a cache folder so that nginx can just serve the cached file the next time someone visits that same url.

This is working as expected except that I don’t want the cache to be read by nginx when there are query parameters. I want the app to be the one to handle the request when this happens but the cache gets sent instead. Here is what I have so far:

    location / {
        root    /path/to/site;
        try_files /content/cache/$uri.html @app;
    }

    location @app {
        proxy_set_header Host $host;
        proxy_pass http://127.0.0.1:8080;
    }

So how do I have the try_files bypass the content/cache/$uri.html and go straight to the @app when there are query args in the url?

My answer:

Someone else will probably think of something complicated involving if but I think I have a very simple solution for this.

Your application caches files using the URL path, without query arguments, as the filename. If the requested URL has a query string, you don’t want to use the cache.

nginx has a variable $is_args which is empty if there is no query string, or contains a ? if there is a query string. You can simply incorporate this:

        try_files /content/cache/$uri.html$is_args @app;

Therefore, if the URL contains a query string, the path that nginx tries will be appended with a ? and will not match the file. The request will then pass to your application.

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My answer:

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