impl Responder for String conflict

[SardineFish]

I want to implement Responder for some type to customize the handler output, for example

#[get("/foo")]
fn foo() -> u32 { }
#[get("/bar")]
fn bar() -> String { }
#[get("/baz")]
fn baz() -> Option<MyData, MyError> { }

impl Responder for u32 {} // ...
impl Responder for String {} // ... 
impl Responder for Option<MyData, MyError> {} // ...

But some was conflict with the implement in crate actix_web such as String.

Is there other or better way to implement some thing like post processing for data returned by handler?

[fakeshadow]

wrap your string in a new type and impl responder for it.

[SardineFish]

I finally implement my custom responder and writing my handler like following. It looks complicate, and can be simplify by proc macro. But that need to call the proc macro actix_web::get or actix_web_codegen::route, and it was not pub. Will it be exposed publicly to let others customize router macro?

#[actix_web::get("/")]
async fn get_foo() -> MyResponder<u32> {
    run(async move {
        // Actural controller codes...
        let n = async_func_with_result_u32().await?;
        Ok(n)
    }).await
}

impl<T: Serialize> Responder for MyResponder<T> {
    // ...
}

pub async fn run<R : Serialize, F: Future<Output = Result<R, Error>>>(async_block: F) -> MyResponder<R> {
    let result = async_block.await;
    MyResponder::<R>::from(result)
}

[robjtede]

I don't particularly understand what you're trying to achieve.

[SardineFish]

process Result<T> returned from my handler into HttpResponse

[robjtede]

Result<T: Responder, impl Into<actix_web::Error>> is already a Responder

[SardineFish]

Yes, but it will convert all Err(Error) into actix_web::Error, which is not I expect to.