Hello! On Mon, Jul 12, 2021 at 12:47:46PM -0700, Dk Jack wrote:
> Hi, > In my module, I am trying to take actions based on the content of the body. > To accomplish this, I am capturing the body using body file as shown in the > example below: > > http://mdounin.ru/hg/ngx_http_catch_body_filter_module/file/tip/ngx_http_catch_body_filter_module.c > > This is working well. I can inspect the contents of the body and take > different actions like rejecting requests etc. However, one of the actions > I want to do is redirect the request based on the body content i.e if the > content contains some string etc, then redirect the request i.e change the > upstream/location etc. My question is, is it even possible to redirect a > request in the body filter stage? Is there another way to do body > capture/filter and still be able to redirect the request after inspecting > the body? Any help, suggestions or sample code is appreciated. Thanks. It is generally too late to do any actions like "change the upstream/location etc" based on the body content, as the request body is usually read only when the location is already known and the upstream name is already obtained. Also consider "proxy_request_buffering off;" - reading the request body implies that nginx is sending the request body to the backend as well. That is, you can't really do more than modifying the request body or rejecting the request completely. You may, however, provide some variables from your body request body filter - and, if it's possible in your particular configuration, use these variables to do some conditional processing. Note thought that conditional processing needs to happen after the request body is read. As such, it is usually quite limited, especially when using standard modules, since the request body is usually read last. For example, with proxy the request body is read after the variables in the "proxy_pass" directive are evaluated, so even with "proxy_request_buffering on;" (the default) you cannot use the variables from your request body filter module to change the upstream. You can, however, use it to control headers in the upstream request by using "proxy_set_header" with appropriate variables (again, assuming buffered request body reading - for obvious reasons this won't work with "proxy_request_buffering off;"). More flexibility can be achieved by reading the request body earlier - for example, you can do this from your own module, or with embedded scripting such as perl or njs. -- Maxim Dounin http://mdounin.ru/ _______________________________________________ nginx-devel mailing list nginx-devel@nginx.org http://mailman.nginx.org/mailman/listinfo/nginx-devel