Filter by HTTP method

[johannespfrang]

It would be useful to be able to filter not only by URL, but also by HTTP request method.

My specific use case is simulating intermittent error responses which succeed a CORS pre-flight check (OPTIONS method), but are missing CORS headers on the actual POST or GET error response. For now I've simply added a

    if (`${e.method}`.toUpperCase() === "OPTIONS") {
        // keep CORS pre-flight responses intact
        log("leaving cors preflight intact")
        return {responseHeaders: e.responseHeaders};
    }

to function rewriteResponseHeader(e) locally, and loaded the add-on via about:debugging, which works just fine for this specific case.