Unclear why Json cannot be in repsonse part. #2017

peter-scholtens · 2023-05-22T08:32:15Z

peter-scholtens
May 22, 2023

I try to write a handler which return JSON, of which the content depends if a user is know or not. Simply replying HTML works, as can be seen by un-commenting the multi-line comments in the example below.

struct UserUnknown<'a> {
    errcode: &'a str,
    error: &'a str,
}

struct UserKnown {
    uid: u64,
    name: String,
}

async fn handler_json() -> impl IntoResponse {
    let mut headers_reply = HeaderMap::new();
    let known = UserKnown {
        uid: 19,
        name: "Peter".to_string(),
    };
    let unknown = UserUnknown {
        errcode: "R_UNKNOWN",
        error: "No cookie given or cookie is outdated.",
    };
    if false {
        return Err((StatusCode::UNAUTHORIZED, headers_reply,Json(unknown)));
/*
        return Err((
            StatusCode::UNAUTHORIZED,
            headers_reply,
            Html("<!DOCTYPE html><body>Unknown user</body></html>"),
        ));
*/
    }
    return Ok((StatusCode::OK, headers_reply, Json(known)));
/*
    return Ok((
        StatusCode::OK,
        headers_reply,
        Html("<!DOCTYPE html><body>Known user</body></html>"),
    ));
*/
}

The error reply is:

the trait `IntoResponse` is not implemented for `(StatusCode, HeaderMap, Json<UserUnknown<'_>>)`

So how can I make the handler which return JSON with a status code too?

Answered by davidpdrsn

May 22, 2023

You're missing #[derive(Serialize)]

View full answer

davidpdrsn · 2023-05-22T08:40:43Z

davidpdrsn
May 22, 2023
Collaborator

You're missing #[derive(Serialize)]

1 reply

peter-scholtens May 22, 2023
Author

Thanks, I completely missed that.

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Unclear why Json cannot be in repsonse part. #2017

peter-scholtens May 22, 2023

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davidpdrsn May 22, 2023 Collaborator

peter-scholtens May 22, 2023 Author

peter-scholtens
May 22, 2023

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May 22, 2023
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peter-scholtens May 22, 2023
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