pub trait Policy<S, B, E>: Send + Sync + 'static {
// Required method
fn redirect(
&mut self,
ctx: &Context<S>,
attempt: &Attempt<'_>,
) -> Result<Action, E>;
// Provided methods
fn on_request(&mut self, _ctx: &mut Context<S>, _request: &mut Request<B>) { ... }
fn clone_body(&mut self, _ctx: &Context<S>, _body: &B) -> Option<B> { ... }
}
Expand description
Trait for the policy on handling redirection responses.
It is important for the policy to be cloneable, where the clone is a fresh instance of the policy, ready to be used in a new request.
§Example
Detecting a cyclic redirection:
use std::collections::HashSet;
use rama_core::Context;
use rama_http::{Request, Uri};
use rama_http::layer::follow_redirect::policy::{Action, Attempt, Policy};
#[derive(Clone)]
pub struct DetectCycle {
uris: HashSet<Uri>,
}
impl<S, B, E> Policy<S, B, E> for DetectCycle {
fn redirect(&mut self, _: &Context<S>, attempt: &Attempt<'_>) -> Result<Action, E> {
if self.uris.contains(attempt.location()) {
Ok(Action::Stop)
} else {
self.uris.insert(attempt.previous().clone());
Ok(Action::Follow)
}
}
}
Required Methods§
Provided Methods§
fn on_request(&mut self, _ctx: &mut Context<S>, _request: &mut Request<B>)
fn on_request(&mut self, _ctx: &mut Context<S>, _request: &mut Request<B>)
Invoked right before the service makes a request, regardless of whether it is redirected or not.
This can for example be used to remove sensitive headers from the request or prepare the request in other ways.
The default implementation does nothing.
fn clone_body(&mut self, _ctx: &Context<S>, _body: &B) -> Option<B>
fn clone_body(&mut self, _ctx: &Context<S>, _body: &B) -> Option<B>
Try to clone a request body before the service makes a redirected request.
If the request body cannot be cloned, return None
.
This is not invoked when B::size_hint
returns zero,
in which case B::default()
will be used to create a new request body.
The default implementation returns None
.