Caching Proxy Requests and Stripping Params with Nginx

I recently need to set up caching for a very slow API service I was working with.  However the app I was working with forced a query param of “timestamp” on all requests.  This effectively killed the cache because all api requests were flowing through a single endpoint, and only the query params differentiated the requests.  So here’s how to set up caching and strip out query params with nginx.

http {
    # Create a storage location for 
    # caching and call this location "my-app"
    proxy_cache_path /data/nginx/cache levels=1:2 
         keys_zone=global:10m 
         max_size=100m inactive=60m;
    
    server {
    
        location /api/  {
            # Strip out query param "timestamp"
            if ($args ~ (.*)&timestamp=[^&]*(.*)) {
                set $args $1$2;
            }

            # Use the "my-app" cache defined above
            proxy_cache my-app;

            # Only cache 200 responses and cache for 20mins
            proxy_cache_valid 200 20m;

            # Create a unique cache key
            proxy_cache_key 
                "$scheme$request_method$host$uri$is_args$args";
            
            # Proxy the request
            proxy_pass http://myapi.com;
        }
}