client_body_buffer_size is ignored within location context

[krokyze@…]

Hi.

I've tested on 1.22.1 and 1.24.0 versions and on both client_body_buffer_size is ignored within location context while client_max_body_size works correctly.

location /images/upload {
	try_files $uri $uri/ /index.php?$args;

	client_body_buffer_size 32M;
	client_max_body_size 64M;
}

If I set it outside in server context it works but that's not a valid solution for me.

client_body_buffer_size 32M;
location /images/upload {
	try_files $uri $uri/ /index.php?$args;

	client_max_body_size 64M;
}

[Maxim Dounin]

The client_max_body_size directive value is checked in every location nginx starts to use for request processing (as long as request body size is known). As such, it works in every location nginx uses during request processing, even if reading request body actually happens elsewhere, such as after an internal redirect due to try_files in your configuration.

In contrast, the client_body_buffer_size directive value is only used when nginx actually starts reading the request body, and the configuration from the location where reading the request body actually happens applies. In your configuration request processing is redirected by the try_files directive elsewhere, and reading the request body happens in the context of other location (probably something like location ~ \.php$ {...}, check your configuration for more details).

To make sure client_body_buffer_size is used, make sure to use the directive in the appropriate location. If you want to differentiate configurations between normal requests and requests to /images/upload, make sure to configure actual request handling for this location, such as fastcgi_pass ..., instead of the internal redirect you are currently using (or use an internal redirect to a distinct location with actual handling but different configuration).

If you have further questions on how to configure nginx, don't hesitate to use ​support options available.