"""Modify an HTTP form submission.""" from mitmproxy import http def request(flow: http.HTTPFlow) -> None: if flow.request.urlencoded_form: # If there's already a form, one can just add items to the dict: flow.request.urlencoded_form["mitmproxy"] = "rocks" else: # One can also just pass new form data. # This sets the proper content type and overrides the body. flow.request.urlencoded_form = [("foo", "bar")]