What is the difference between proxy_set_header and add_header in nginx proxy

1. Ensure that the `cache_enabled` directive is set to `on` in your NGINX configuration for the location block of your assets:

`nginx

location /assets {

root /path/to/your/project;

cache_enabled on; # enable caching for assets location block

}

`

2. Make sure that the `Cache-Control: max-age` or `Expires:` headers are set correctly in your application's responses for static assets. These headers control how long NGINX should cache the asset before fetching a new one from the origin server:

`css

Cache-Control: max-age=31536000; # Cache for 1 year (in seconds)

Expires: Sat, 27 Mar 2099 15:48:36 GMT; # Expiration date in the future

`

3. Check if there are any proxy_cache_* directives that might be affecting caching behavior, such as `proxy_cache_bypass`, or enabling cache with a custom key:

`nginx

location /assets {

proxy_pass http://originserver; # Set your origin server URL here. No need for a trailing "/" at the end of this URL if it's not a directory (e.g., "http://originserver:80/").

proxy_cache_key $host$request_uri; # Custom cache key for your assets. You can customize this based on your requirements (e.g., hash of the asset file, version number).

}

`

4. Double-check that NGINX is actually receiving and serving your static assets from its cache: You can use an extension like `nginx_fastcgi_cache` to check the hit rate in real-time and see if any of your assets are being served from cache.

5. Ensure that your origin server is not sending `Last-Modified`, `Cache-Control: no-cache/no-store` or other headers in the response preventing caching. If these cannot be changed on your origin server, consider using a CDN like Cloudflare to handle caching and serving static assets instead of NGINX:

`nginx

location / { # Root location block. Set this as the default if none other matches (if it doesn't exist).

proxy_pass http://originserver; # Replace with your origin server URL. No need for a trailing "/" at the end of this URL if it's not a directory (e.g., "http://originserver:80/").

}

` What is the difference between proxy_set_header and add_header in nginx proxy

In NGINX, both `proxy_set_header` and `add_header` are used to modify the headers of requests or responses. However, they serve different purposes:

1. **proxy_set\_header**: This directive is used to set the value of an existing header in the incoming request that will be forwarded to upstream servers. It's primarily used for passing headers from client requests through Nginx to your application server or other backends.

For example, if you want to pass a custom header `X-Custom-Header` from the client request to your upstream server:

`nginx

proxy_set_header X-Custom-Header $http_x_custom_header;

`

2. **add\_header**: This directive is used to add a new header in the outgoing response that Nginx sends back to clients or proxies downstream. It's useful for adding custom headers with specific values, caching control directives such as `Cache-Control` and `ETag`, or setting response status codes like a 403 Forbidden error.

Here's an example of using add_header to set custom headers in the outgoing response:

`nginx

add_header X-Powered-By 'NGINX/1.20.0'; # Set a custom "X-Powered-By" header

add_header Cache-Control "public, max-age=3600"; # Set cache control headers for caching static files.

`