Enum PathPolicy 

pub enum PathPolicy {
    Strict,
    Redirect,
    Collapse,
}

What to do when a request path is a non-canonical spelling of a route.

Interior empty segments — //a, /a//b — were once collapsed silently, which gave every resource several URLs. That is not a traversal problem, but it is an aliasing one, and aliases have teeth:

• Middleware, guards and proxy rules that key on a literal prefix (path.starts_with("/admin")) are bypassable with //admin.
• Caches key on the URL, so one resource occupies several entries and an intermediary can disagree with the origin about identity.

A trailing slash is not treated as an alias — see canonical_path for why removing it would break directory listings.

Whatever the policy, %2F is never decoded into a separator: an encoded slash is data inside one segment, and decoding it early is how a normalisation change turns into a traversal bug.

use churust_core::{Churust, Call, PathPolicy, TestClient};
let app = Churust::server()
    .path_policy(PathPolicy::Redirect)
    .routing(|r| { r.get("/a", |_c: Call| async { "a" }); })
    .build();
let res = TestClient::new(app).get("//a").send().await;
assert_eq!(res.status(), http::StatusCode::PERMANENT_REDIRECT);
assert_eq!(res.header("location"), Some("/a"));

Variants

Strict

Refuse an alias: //a is not /a, and gets 404.

The default. Fewest surprises and the strongest cache identity — one resource, one URL.

Redirect

Redirect an alias to its canonical form with 308 Permanent Redirect.

Kind to hand-typed and hand-written URLs. 308 rather than 301 so a POST stays a POST; 301 permits a client to retry as GET, which silently drops the body.

Collapse

Collapse aliases silently, serving them as if canonical.

The pre-PathPolicy behaviour, kept so an application with alias-shaped links has somewhere to stand while it fixes them. It creates URL aliases by design; prefer Strict or Redirect.

The collapsing happens in the router, for matching only: the URI is not rewritten, so call.path() still reports the spelling the client sent — //admin/secret, not /admin/secret — in middleware and in the handler alike. That is what makes the prefix-check bypass above live under this policy and only under this policy. Under Strict and Redirect a middleware also sees the raw spelling, but the request is refused or redirected before any handler runs, so nothing is served.

Trait Implementations

impl Clone for PathPolicy

fn clone(&self) -> PathPolicy

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Copy for PathPolicy

impl Debug for PathPolicy

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Default for PathPolicy

fn default() -> PathPolicy

Returns the “default value” for a type.

impl<'de> Deserialize<'de> for PathPolicy

fn deserialize<__D>(__deserializer: __D) -> Result<Self, __D::Error>

where __D: Deserializer<'de>,

Deserialize this value from the given Serde deserializer.

impl Eq for PathPolicy

impl PartialEq for PathPolicy

fn eq(&self, other: &PathPolicy) -> bool

Equality operator ==.

fn ne(&self, other: &Rhs) -> bool

Inequality operator !=.

impl StructuralPartialEq for PathPolicy