How to use Response<BoxBody> with and without json payload in actix_http v3?

[pmalek-sumo]

It seems that with upgrade to actix_http v3 we can use e.g. actix_http::Response::bad_request() (which I understand is a new way of doing actix_http::Response::BadRequest().body(Body::Empty)) which returns Response<BoxBody> but then we cannot return json payload in the same handler as we used to with actix_http::Response::Ok().json(__MY_STRUCT_IMPLEMENTING_derive_Deserialize__).

I've tried with

actix_http::Response::new(actix_http::StatusCode::OK).set_body(
    web::Json( __MY_STRUCT_IMPLEMENTING_derive_Deserialize__ {
        ...
    })
    ).map_into_boxed_body()

but then I get:

the trait bound `Json<CollectorRegisterRespone>: MessageBody` is not satisfied
the trait `MessageBody` is not implemented for `Json<CollectorRegisterRespone>`rustc[E0277](https://doc.rust-lang.org/error-index.html#E0277)
[response.rs(209, 12): ]()required by a bound in `actix_http::Response::<B>::map_into_boxed_body`

Relevant piece of code I'm trying to migrate:
https://github.com/SumoLogic/sumologic-kubernetes-tools/blob/3b0b24ea495726a6e7ad96fc3338d144c16a31c1/src/rust/receiver-mock/src/router/api.rs#L7-L43

[robjtede]

Firstly familiarize yourself with the body type changes in v4 explained here. Also it would be helpful to use HttpResponse from Actix Web instead of the actix-http types in your case since it contains fewer high-level things now.

Eg:

-           None => return actix_http::Response::BadRequest().body(Body::Empty),
+           None => return actix_web::HttpResponse::BadRequest().finish(),

-       actix_http::Response::Ok().json(CollectorRegisterRespone {
+       actix_web::HttpResponse::Ok().json(CollectorRegisterRespone {

[pmalek-sumo]

Thanks @robjtede! That worked and I wasn't aware of this guide 😬