Model View Controller pattern in REST HTTP client

I am a bit confused what should Model consist of in the case of REST client. Let's assume I want to have a client to communicate with server via REST. No database.

Example: I want to send a POST HTTP request with some form data to a server. Where should I put methods like construct_REST_request() or execute_REST_request()? In Controller or in Model? In model theoretically should be business logic objects. Does it mean in Model should be only data that Controller uses?