Trait axum_core::response::IntoResponseParts

source · [−]
pub trait IntoResponseParts {
    type Error: IntoResponse;

    fn into_response_parts(
        self,
        res: ResponseParts
    ) -> Result<ResponseParts, Self::Error>;
}
Expand description

Trait for adding headers and extensions to a response.

Example

use axum::{
    response::{ResponseParts, IntoResponse, IntoResponseParts, Response},
    http::{StatusCode, header::{HeaderName, HeaderValue}},
};

// Hypothetical helper type for setting a single header
struct SetHeader<'a>(&'a str, &'a str);

impl<'a> IntoResponseParts for SetHeader<'a> {
    type Error = (StatusCode, String);

    fn into_response_parts(self, mut res: ResponseParts) -> Result<ResponseParts, Self::Error> {
        match (self.0.parse::<HeaderName>(), self.1.parse::<HeaderValue>()) {
            (Ok(name), Ok(value)) => {
                res.headers_mut().insert(name, value);
            },
            (Err(_), _) => {
                return Err((
                    StatusCode::INTERNAL_SERVER_ERROR,
                    format!("Invalid header name {}", self.0),
                ));
            },
            (_, Err(_)) => {
                return Err((
                    StatusCode::INTERNAL_SERVER_ERROR,
                    format!("Invalid header value {}", self.1),
                ));
            },
        }

        Ok(res)
    }
}

// Its also recommended to implement `IntoResponse` so `SetHeader` can be used on its own as
// the response
impl<'a> IntoResponse for SetHeader<'a> {
    fn into_response(self) -> Response {
        // This gives an empty response with the header
        (self, ()).into_response()
    }
}

// We can now return `SetHeader` in responses
//
// Note that returning `impl IntoResponse` might be easier if the response has many parts to
// it. The return type is written out here for clarity.
async fn handler() -> (SetHeader<'static>, SetHeader<'static>, &'static str) {
    (
        SetHeader("server", "axum"),
        SetHeader("x-foo", "custom"),
        "body",
    )
}

// Or on its own as the whole response
async fn other_handler() -> SetHeader<'static> {
    SetHeader("x-foo", "custom")
}

Required Associated Types

The type returned in the event of an error.

This can be used to fallibly convert types into headers or extensions.

Required Methods

Set parts of the response

Implementations on Foreign Types

Implementors