How to send a proper Error response in actix_web middleware? - rust

Question

I develop an authentication middleware for actix_web. I can send an OK response just fine but I cannot send an error message. Here's what I've done so far using the example given here:
/// ResponseBody is my own custom struct to send an error/content body
#[derive(Debug, Serialize, Deserialize)]
pub struct ResponseBody<T> {
pub message: String,
pub data: T,
}
impl<T> ResponseBody<T> {
pub fn new(message: &str, data: T) -> ResponseBody<T> {
ResponseBody {
message: message.to_string(),
data,
}
}
}
/// ....somewhere in my middleware
/// if user passes then I will send him to the destination
/// this code was copied from https://actix.rs/docs/middleware/ example
if authenticate_pass {
let fut = self.service.call(req);
Box::pin(async move {
let res = fut.await?;
Ok(res)
})
/// but if he fails to signin or for some other reasons
/// I want to send an error response UNAUTHORIZED (401)
} else {
Box::pin(async move {
Ok(req.into_response(
HttpResponse::Unauthorized()
.json(ResponseBody::new("Session ends. Please login again", ""))
.into_body(),
))
})
}
It displays an error message that I should implement a conversion from actix_web::dev::Response into BoxBody. I don't have any idea what BoxBody is and how to implement them.
error[E0277]: the trait bound `actix_web::dev::Response<_>: std::convert::From<BoxBody>` is not satisfied
--> src\auth.rs:103:21
|
102 | Ok(req.into_response(
| ------------- required by a bound introduced by this call
103 | / HttpResponse::Unauthorized()
104 | | .json(ResponseBody::new("Session ends. Please login again", ""))
105 | | .into_body(),
| |____________________________________^ the trait `std::convert::From<BoxBody>` is not implemented for `actix_web::dev::Response<_>`
|
= help: the following other types implement trait `std::convert::From<T>`:
<actix_web::dev::Response<&'static [u8]> as std::convert::From<&'static [u8]>>
<actix_web::dev::Response<&'static str> as std::convert::From<&'static str>>
<actix_web::dev::Response<B> as std::convert::From<HttpResponse<B>>>
<actix_web::dev::Response<B> as std::convert::From<ServiceResponse<B>>>
<actix_web::dev::Response<BoxBody> as std::convert::From<&actix_http::ws::HandshakeError>>
<actix_web::dev::Response<BoxBody> as std::convert::From<HttpResponseBuilder>>
<actix_web::dev::Response<BoxBody> as std::convert::From<Infallible>>
<actix_web::dev::Response<BoxBody> as std::convert::From<Result<I, E>>>
and 13 others
= note: required because of the requirements on the impl of `Into<actix_web::dev::Response<_>>` for `BoxBody`
note: required by a bound in `ServiceRequest::into_response`
--> C:\Users\mdenn\.cargo\registry\src\github.com-1ecc6299db9ec823\actix-web-4.1.0\src\service.rs:144:32
|
144 | pub fn into_response<B, R: Into<Response<B>>>(self, res: R) -> ServiceResponse<B> {
| ^^^^^^^^^^^^^^^^^ required by this bound in `ServiceRequest::into_response`
If anyone have experience with actix_web middleware, please help. Thanks in advance.
FULL CODE: https://pastebin.com/9PtvSyS9
actix-web = "4.1.0"
futures = "0.3.24"
tokio = { version = "1.18.2", features = ["full"] }
serde = { version = "1.0.137", features = ["derive"] }

Answer 1

If you just want to return the UNAUTHORIZED(401) response, you can try the following code.
Ok(req.into_response(
HttpResponse::Unauthorized()
.finish().map_into_boxed_body(),
))
BoxedBody is defined as follows.
/// A boxed message body with boxed errors.
#[derive(Debug)]
pub struct BoxBody(BoxBodyInner);
The reason of using BoxedBody is because of req.into_response needs that type.