Hi Abhishek,


i'm not 100% sure to understand exactrly what you'd like to do,
especially the request-body-manipulation-part.

nginx_lua is usually quite handy when you have the need
to manipulate a request: http://wiki.nginx.org/HttpLuaModule#access_by_lua
you can jump into the acces- or rewrite-phase, make your processing and
pass the result to your upstream-servers using proxy_pass and all the
upstream {} - goodies


cheers,

mex