Module tower_http::follow_redirect

Available on crate feature follow-redirect only.

Expand description

Middleware for following redirections.

Overview

The FollowRedirect middleware retries requests with the inner Service to follow HTTP redirections.

The middleware tries to clone the original Request when making a redirected request. However, since Extensions are !Clone, any extensions set by outer middleware will be discarded. Also, the request body cannot always be cloned. When the original body is known to be empty by Body::size_hint, the middleware uses Default implementation of the body type to create a new request body. If you know that the body can be cloned in some way, you can tell the middleware to clone it by configuring a policy.

Examples

Basic usage

use http::{Request, Response};
use hyper::Body;
use tower::{Service, ServiceBuilder, ServiceExt};
use tower_http::follow_redirect::{FollowRedirectLayer, RequestUri};

let mut client = ServiceBuilder::new()
    .layer(FollowRedirectLayer::new())
    .service(http_client);

let request = Request::builder()
    .uri("https://rust-lang.org/")
    .body(Body::empty())
    .unwrap();

let response = client.ready().await?.call(request).await?;
// Get the final request URI.
assert_eq!(response.extensions().get::<RequestUri>().unwrap().0, "https://www.rust-lang.org/");

Customizing the `Policy`

You can use a Policy value to customize how the middleware handles redirections.

use http::{Request, Response};
use hyper::Body;
use tower::{Service, ServiceBuilder, ServiceExt};
use tower_http::follow_redirect::{
    policy::{self, PolicyExt},
    FollowRedirectLayer,
};

#[derive(Debug)]
enum MyError {
    Hyper(hyper::Error),
    TooManyRedirects,
}

let policy = policy::Limited::new(10) // Set the maximum number of redirections to 10.
    // Return an error when the limit was reached.
    .or::<_, (), _>(policy::redirect_fn(|_| Err(MyError::TooManyRedirects)))
    // Do not follow cross-origin redirections, and return the redirection responses as-is.
    .and::<_, (), _>(policy::SameOrigin::new());

let mut client = ServiceBuilder::new()
    .layer(FollowRedirectLayer::with_policy(policy))
    .map_err(MyError::Hyper)
    .service(http_client);

// ...