Module request

Set a header on the request.

The header value to be set may be provided as a fixed value when the middleware is constructed, or determined dynamically based on the request by a closure. See the MakeHeaderValue trait for details.

Example

Setting a header from a fixed value provided when the middleware is constructed:

use http::{Request, Response, header::{self, HeaderValue}};
use tower::{Service, ServiceExt, ServiceBuilder};
use tower_http::set_header::SetRequestHeaderLayer;
use http_body_util::Full;
use bytes::Bytes;

let mut svc = ServiceBuilder::new()
    .layer(
        // Layer that sets `User-Agent: my very cool app` on requests.
        //
        // `if_not_present` will only insert the header if it does not already
        // have a value.
        SetRequestHeaderLayer::if_not_present(
            header::USER_AGENT,
            HeaderValue::from_static("my very cool app"),
        )
    )
    .service(http_client);

let request = Request::new(Full::default());

let response = svc.ready().await?.call(request).await?;

Setting a header based on a value determined dynamically from the request:

use http::{Request, Response, header::{self, HeaderValue}};
use tower::{Service, ServiceExt, ServiceBuilder};
use tower_http::set_header::SetRequestHeaderLayer;
use bytes::Bytes;
use http_body_util::Full;

fn date_header_value() -> HeaderValue {
    // ...
}

let mut svc = ServiceBuilder::new()
    .layer(
        // Layer that sets `Date` to the current date and time.
        //
        // `overriding` will insert the header and override any previous values it
        // may have.
        SetRequestHeaderLayer::overriding(
            header::DATE,
            |request: &Request<Full<Bytes>>| {
                Some(date_header_value())
            }
        )
    )
    .service(http_client);

let request = Request::new(Full::default());

let response = svc.ready().await?.call(request).await?;

Structs

SetRequestHeader

Middleware that sets a header on the request.

SetRequestHeaderLayer

Layer that applies SetRequestHeader which adds a request header.