I have a header/body filter module that I have created that successfully modifies HTML as it passes through while being proxied by proxy_pass.

client ---- NGINX proxy with filter --- html server

I need to use information in an http POST to make decisions on how to modify the body. I see how to get parameters for a GET request. That information is available to me in r->args.data. How do I access the arguments (or parameters) for a POST? I know they are encoding in the HTTP body for a POST, so it makes sense that they are not in r->args->data. How do I access POST parameters in a body/header filter module?

Thanks in advance!