module {
  public type Request = { method : Text; url : Text; headers : [HeaderField]; body : Blob; certificate_version : ?Nat16 };
  public type Response = { status_code : Nat16; headers : [HeaderField]; body : Blob; streaming_strategy : ?StreamingStrategy; upgrade : ?Bool };

  public func path(url : Text) : Text;
  public func header(req : Request, name : Text) : ?Text; // case-insensitive
  public func text(status : Nat16, body : Text) : Response;
  public func upgrade() : Response; // query path asks gateway to call http_request_update
  public func notFound() : Response;
  public func methodNotAllowed() : Response;
  public func bodyText(req : Request) : ?Text; // null if body is not UTF-8; HMAC must use req.body
};

mixin (
  onQuery : Http.Request -> Http.Response,
  onUpdate : Http.Request -> async Http.Response,
) {
  public query func http_request(req : Http.Request) : async Http.Response;
  public func http_request_update(req : Http.Request) : async Http.Response;
};

import Http "mo:caffeineai-http-endpoints/Http";
import MixinHttpEndpoints "mo:caffeineai-http-endpoints/MixinHttpEndpoints";
import AccessControl "mo:caffeineai-authorization/access-control";
import MixinAuthorization "mo:caffeineai-authorization/MixinAuthorization";

actor {
  let accessControlState : AccessControl.AccessControlState;
  include MixinAuthorization(accessControlState, null);

  func onHttpQuery(req : Http.Request) : Http.Response {
    let path = Http.path(req.url);
    if (req.method == "POST" and path == "/webhook") {
      return Http.upgrade();
    };
    if (req.method == "GET" and (path == "/" or path == "/health")) {
      return Http.text(200, "ok");
    };
    Http.notFound();
  };

  func onHttpUpdate(req : Http.Request) : async Http.Response {
    let path = Http.path(req.url);
    if (req.method == "POST" and path == "/webhook") {
      // Signature checks: Http.header(req, "stripe-signature"), HMAC over req.body
      ignore Http.bodyText(req);
      return Http.text(200, "received");
    };
    Http.notFound();
  };

  include MixinHttpEndpoints(onHttpQuery, onHttpUpdate);
};

import AccessControl "mo:caffeineai-authorization/access-control";

module {
  type NewActor = {
    accessControlState : AccessControl.AccessControlState;
  };

  public func migration(_old : {}) : NewActor {
    { accessControlState = AccessControl.initState() };
  };
};

undefined

`?canisterId=<id>` on `https://icp0.io/...` is an alternate host form. Prefer the canister subdomain. An IP/`localhost` GET with only `?canisterId=` can return an empty `204` instead of your body — treat that as the wrong URL shape, not an empty handler.