handling file upload (OT not exactly PHP)

Hello , Need to do handle a file upload done via http POST. I can read the content length and from POST and get the contents. But, how do I get the exact file ?? Eg. suppose for uploading a .doc file I could see that it sends the font type and other parameters also.. I am not sure how does it will matter when I am extracting the exact file from the POST request . Again, how would I extract the exact file ?????? Would appreciate any pointers or someone giving me some headstart . Thanks and Regards, -Saswat