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feat(set_header): refactor and improve multiple header middleware #672

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Merged
jlizen merged 5 commits into from
May 8, 2026
+711 −96
Merged

feat(set_header): refactor and improve multiple header middleware #672

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ef9d287
feat(set_header): refactor and improve multiple header middleware
seun-ja May 7, 2026
654c072
fix docs test
seun-ja May 7, 2026
cb3ba63
fix module use import on docs
seun-ja May 7, 2026
7646f64
refactor multiple header middleware, improve docs, and update examples
seun-ja May 8, 2026
fa4a698
use publicly available trait instead
seun-ja May 8, 2026
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2 changes: 1 addition & 1 deletion tower-http/src/set_header/mod.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -10,7 +10,7 @@ pub mod response;
#[doc(inline)]
pub use self::{
request::{SetRequestHeader, SetRequestHeaderLayer},
response::{SetResponseHeader, SetResponseHeaderLayer},
response::{HeaderMetadata, SetResponseHeader, SetResponseHeaderLayer},
};

/// Trait for producing header values.
Expand Down
173 changes: 173 additions & 0 deletions tower-http/src/set_header/response/mod.rs
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Original file line number Diff line number Diff line change
@@ -0,0 +1,173 @@
//! Middleware for setting headers on HTTP responses.
//!
//! This module provides middleware for setting one or more headers on HTTP responses, either with fixed values or values determined dynamically from the response.
//!
//! # Single Header
//!
//! Use [`SetResponseHeaderLayer`] and [`SetResponseHeader`] to set a single header. The header value can be a fixed value or computed dynamically using a closure. See [`crate::set_header::MakeHeaderValue`] for details.
//!
//! ## Example: Fixed Value
//!
//! ```
//! use http::{Request, Response, header::{self, HeaderValue}};
//! use tower::{Service, ServiceExt, ServiceBuilder};
//! use tower_http::set_header::SetResponseHeaderLayer;
//! use http_body_util::Full;
//! use bytes::Bytes;
//!
//! # #[tokio::main]
//! # async fn main() -> Result<(), Box<dyn std::error::Error>> {
//! # let render_html = tower::service_fn(|request: Request<Full<Bytes>>| async move {
//! # Ok::<_, std::convert::Infallible>(Response::new(request.into_body()))
//! # });
//!
//! let mut svc = ServiceBuilder::new()
//! .layer(
//! SetResponseHeaderLayer::if_not_present(
//! header::CONTENT_TYPE,
//! HeaderValue::from_static("text/html"),
//! )
//! )
//! .service(render_html);
//!
//! let request = Request::new(Full::default());
//!
//! let response = svc.ready().await?.call(request).await?;
//!
//! assert_eq!(response.headers()["content-type"], "text/html");
//! # Ok(())
//! # }
//! ```
//!
//! ## Example: Dynamic Value
//!
//! ```
//! use http::{Request, Response, header::{self, HeaderValue}};
//! use tower::{Service, ServiceExt, ServiceBuilder};
//! use tower_http::set_header::SetResponseHeaderLayer;
//! use bytes::Bytes;
//! use http_body_util::Full;
//! use http_body::Body as _; // for `Body::size_hint`
//!
//! # #[tokio::main]
//! # async fn main() -> Result<(), Box<dyn std::error::Error>> {
//! # let render_html = tower::service_fn(|request: Request<Full<Bytes>>| async move {
//! # Ok::<_, std::convert::Infallible>(Response::new(Full::from("1234567890")))
//! # });
//!
//! let mut svc = ServiceBuilder::new()
//! .layer(
//! SetResponseHeaderLayer::overriding(
//! header::CONTENT_LENGTH,
//! |response: &Response<Full<Bytes>>| {
//! if let Some(size) = response.body().size_hint().exact() {
//! Some(HeaderValue::from_str(&size.to_string()).unwrap())
//! } else {
//! None
//! }
//! }
//! )
//! )
//! .service(render_html);
//!
//! let request = Request::new(Full::default());
//!
//! let response = svc.ready().await?.call(request).await?;
//!
//! assert_eq!(response.headers()["content-length"], "10");
//! # Ok(())
//! # }
//! ```
//!
//! # Multiple Headers
//!
//! Use [`SetMultipleResponseHeadersLayer`] and [`SetMultipleResponseHeader`] to set multiple headers at once. Each header can have a fixed value or be computed dynamically.
//!
//! ## Example: Multiple Fixed Values
//!
//! ```
//! use http::{Request, Response, header::{self, HeaderValue}};
//! use tower::{Service, ServiceExt, ServiceBuilder};
//! use tower_http::set_header::response::{SetMultipleResponseHeadersLayer, HeaderMetadata};
//! use http_body_util::Full;
//! use bytes::Bytes;
//!
//! # #[tokio::main]
//! # async fn main() -> Result<(), Box<dyn std::error::Error>> {
//! # let render_html = tower::service_fn(|request: Request<Full<Bytes>>| async move {
//! # Ok::<_, std::convert::Infallible>(Response::new(request.into_body()))
//! # });
//!
//! let mut svc = ServiceBuilder::new()
//! .layer(
//! SetMultipleResponseHeadersLayer::overriding(vec![
//! (header::CONTENT_TYPE, HeaderValue::from_static("text/html")).into(),
//! (header::CACHE_CONTROL, HeaderValue::from_static("no-cache")).into(),
//! ])
//! )
//! .service(render_html);
//!
//! let request = Request::new(Full::default());
//!
//! let response = svc.ready().await?.call(request).await?;
//!
//! assert_eq!(response.headers()["content-type"], "text/html");
//! assert_eq!(response.headers()["cache-control"], "no-cache");
//! # Ok(())
//! # }
//! ```
//!
//! ## Example: Multiple Dynamic Values
//!
//! ```
//! use http::{Request, Response, header::{self, HeaderValue}};
//! use tower::{Service, ServiceExt, ServiceBuilder};
//! use tower_http::set_header::response::{SetMultipleResponseHeadersLayer, HeaderMetadata};
//! use bytes::Bytes;
//! use http_body_util::Full;
//! use http_body::Body as _; // for `Body::size_hint`
//!
//! # #[tokio::main]
//! # async fn main() -> Result<(), Box<dyn std::error::Error>> {
//! # let render_html = tower::service_fn(|request: Request<Full<Bytes>>| async move {
//! # Ok::<_, std::convert::Infallible>(Response::new(Full::from("1234567890")))
//! # });
//!
//! let mut svc = ServiceBuilder::new()
//! .layer(
//! SetMultipleResponseHeadersLayer::overriding(vec![
//! (header::CONTENT_LENGTH, |response: &Response<Full<Bytes>>| {
//! if let Some(size) = response.body().size_hint().exact() {
//! Some(HeaderValue::from_str(&size.to_string()).unwrap())
//! } else {
//! None
//! }
//! }).into(),
//! ])
//! )
//! .service(render_html);
//!
//! let request = Request::new(Full::default());
//!
//! let response = svc.ready().await?.call(request).await?;
//!
//! assert_eq!(response.headers()["content-length"], "10");
//! # Ok(())
//! # }
//! ```
//!
//! # Modes
//!
//! - `overriding`: If a previous value exists for the same header, it is removed and replaced with the new value.
//! - `appending`: The new header is always added, preserving any existing values. If previous values exist, the header will have multiple values.
//! - `if_not_present`: If a previous value exists for the header, the new value is not inserted.
//!
//! See [`SetResponseHeaderLayer`], [`SetResponseHeader`], [`SetMultipleResponseHeadersLayer`], and [`SetMultipleResponseHeader`] for more details.

mod multiple_header;
mod single_header;

pub use multiple_header::{
HeaderMetadata, SetMultipleResponseHeader, SetMultipleResponseHeadersLayer,
};
pub use single_header::{SetResponseHeader, SetResponseHeaderLayer};
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