Post request to API with variables and a file stream

Hi All,

I am a newbie to web api.  I have a requirement to post a file stream with some parameters to api and return output file stream to the requester.

I am totally blank how to do this.

•   I have a poco class with 4 variables to pass to api.  

                   class somename

                   {

                         string var1; string var2; string var3; string var4;

                   } 

•      I have a file converted as stream.
•      I have a pre-designed api service project.

How to write the new api method to receive the class variables and the file stream.

How to return the output file as stream to the requested page code.

Please help on this.

Thanks in advance.