mitmproxy script to block requests

block-requests.py

"""Block requests for testing purposes."""

from mitmproxy import http

class BlockRequests:
    def request(self, flow: http.HTTPFlow) -> None:
        # Handle OPTIONS requests (CORS preflight)
        if flow.request.method == "OPTIONS":
            flow.response = http.Response.make(
                200,
                b"",
                {
                    "Access-Control-Allow-Origin": "*",
                    "Access-Control-Allow-Methods": "*",
                    # TODO: Figure out how to add Authorization
                    "Access-Control-Allow-Headers": "*",
                    "Access-Control-Max-Age": "3600"
                }
            )
            return

        # Block specific POST requests
        if flow.request.method == "POST" and ".infura.io" in flow.request.host:
            flow.response = http.Response.make(
                500,
                b"Internal Server Error",
                {
                    "Content-Type": "text/plain",
                    "Access-Control-Allow-Origin": "*"
                }
            )

    def response(self, flow: http.HTTPFlow) -> None:
        # Add CORS header to all responses that weren't already handled in request()
        if flow.response:
            flow.response.headers["Access-Control-Allow-Origin"] = "*"

addons = [BlockRequests()]