axum_core/response/
append_headers.rs

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1use super::{IntoResponse, IntoResponseParts, Response, ResponseParts, TryIntoHeaderError};
2use http::header::{HeaderName, HeaderValue};
3use std::fmt;
4
5/// Append headers to a response.
6///
7/// Returning something like `[("content-type", "foo=bar")]` from a handler will override any
8/// existing `content-type` headers. If instead you want to append headers, use `AppendHeaders`:
9///
10/// ```rust
11/// use axum::{
12///     response::{AppendHeaders, IntoResponse},
13///     http::header::SET_COOKIE,
14/// };
15///
16/// async fn handler() -> impl IntoResponse {
17///     // something that sets the `set-cookie` header
18///     let set_some_cookies = /* ... */
19///     # axum::http::HeaderMap::new();
20///
21///     (
22///         set_some_cookies,
23///         // append two `set-cookie` headers to the response
24///         // without overriding the ones added by `set_some_cookies`
25///         AppendHeaders([
26///             (SET_COOKIE, "foo=bar"),
27///             (SET_COOKIE, "baz=qux"),
28///         ])
29///     )
30/// }
31/// ```
32#[derive(Debug, Clone, Copy)]
33#[must_use]
34pub struct AppendHeaders<I>(pub I);
35
36impl<I, K, V> IntoResponse for AppendHeaders<I>
37where
38    I: IntoIterator<Item = (K, V)>,
39    K: TryInto<HeaderName>,
40    K::Error: fmt::Display,
41    V: TryInto<HeaderValue>,
42    V::Error: fmt::Display,
43{
44    fn into_response(self) -> Response {
45        (self, ()).into_response()
46    }
47}
48
49impl<I, K, V> IntoResponseParts for AppendHeaders<I>
50where
51    I: IntoIterator<Item = (K, V)>,
52    K: TryInto<HeaderName>,
53    K::Error: fmt::Display,
54    V: TryInto<HeaderValue>,
55    V::Error: fmt::Display,
56{
57    type Error = TryIntoHeaderError<K::Error, V::Error>;
58
59    fn into_response_parts(self, mut res: ResponseParts) -> Result<ResponseParts, Self::Error> {
60        for (key, value) in self.0 {
61            let key = key.try_into().map_err(TryIntoHeaderError::key)?;
62            let value = value.try_into().map_err(TryIntoHeaderError::value)?;
63            res.headers_mut().append(key, value);
64        }
65
66        Ok(res)
67    }
68}
axum_core/response/append_headers.rs

axum_core/response/
append_headers.rs
