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tweak guard docs

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Rob Ede 2021-12-28 14:50:48 +00:00
parent 96a4dc9dec
commit 0f5c876c6b
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@ -10,16 +10,22 @@
//! object and returns a boolean; true if the request _should_ be handled by the guarded service
//! or handler. This interface is defined by the [`Guard`] trait.
//!
//! Commonly-used guards are provided in this module as well as way of creating a guard from a
//! Commonly-used guards are provided in this module as well as a way of creating a guard from a
//! closure ([`fn_guard`]). The [`Not`], [`Any`], and [`All`] guards are noteworthy, as they can be
//! used to compose other guards in a more flexible and semantic way than calling `.guard(...)` on
//! services multiple times (which might have different combining behavior than you want).
//!
//! There are shortcuts for routes with method guards in the [`web`](crate::web) module:
//! [`web::get()`](crate::web::get), [`web::post()`](crate::web::post), etc. The routes created by
//! the following calls are equivalent:
//! - `web::get()` (recommended form)
//! - `web::route().guard(guard::Get())`
//!
//! Guards can not modify anything about the request. However, it is possible to store extra
//! attributes in the request-local data container obtained with [`GuardContext::req_data_mut`].
//!
//! Guards can prevent resource definitions from overlapping (resulting in some inaccessible routes)
//! where they otherwise would when only considering paths. See the virtual hosting example below.
//! Guards can prevent resource definitions from overlapping which, when only considering paths,
//! would result in inaccessible routes. See the [`Host`] guard for an example of virtual hosting.
//!
//! # Examples
//! In the following code, the `/guarded` resource has one defined route whose handler will only be
@ -36,31 +42,9 @@
//! );
//! ```
//!
//! Guards can be used to set up some form of [virtual hosting] within a single app.
//! Overlapping scope prefixes are usually discouraged, but when combined with non-overlapping guard
//! definitions they become safe to use in this way. Without these host guards, only routes under
//! the first-to-be-defined scope would be accessible. You can test this locally using `127.0.0.1`
//! and `localhost` as the `Host` guards.
//! ```
//! use actix_web::{web, http::Method, guard, App, HttpResponse};
//!
//! App::new()
//! .service(
//! web::scope("")
//! .guard(guard::Host("www.rust-lang.org"))
//! .default_service(web::to(|| HttpResponse::Ok().body("marketing site"))),
//! )
//! .service(
//! web::scope("")
//! .guard(guard::Host("play.rust-lang.org"))
//! .default_service(web::to(|| HttpResponse::Ok().body("playground frontend"))),
//! );
//! ```
//!
//! [`Scope`]: crate::Scope::guard()
//! [`Resource`]: crate::Resource::guard()
//! [`Route`]: crate::Route::guard()
//! [virtual hosting]: https://en.wikipedia.org/wiki/Virtual_hosting
use std::{
cell::{Ref, RefMut},
@ -373,6 +357,29 @@ impl Guard for HeaderGuard {
/// .guard(Host("admin.rust-lang.org").scheme("https"))
/// .default_service(web::to(|| HttpResponse::Ok().body("admin connection is secure")));
/// ```
///
/// The `Host` guard can be used to set up some form of [virtual hosting] within a single app.
/// Overlapping scope prefixes are usually discouraged, but when combined with non-overlapping guard
/// definitions they become safe to use in this way. Without these host guards, only routes under
/// the first-to-be-defined scope would be accessible. You can test this locally using `127.0.0.1`
/// and `localhost` as the `Host` guards.
/// ```
/// use actix_web::{web, http::Method, guard, App, HttpResponse};
///
/// App::new()
/// .service(
/// web::scope("")
/// .guard(guard::Host("www.rust-lang.org"))
/// .default_service(web::to(|| HttpResponse::Ok().body("marketing site"))),
/// )
/// .service(
/// web::scope("")
/// .guard(guard::Host("play.rust-lang.org"))
/// .default_service(web::to(|| HttpResponse::Ok().body("playground frontend"))),
/// );
/// ```
///
/// [virtual hosting]: https://en.wikipedia.org/wiki/Virtual_hosting
#[allow(non_snake_case)]
pub fn Host(host: impl AsRef<str>) -> HostGuard {
HostGuard {
@ -642,4 +649,17 @@ mod tests {
let req = TestRequest::default().uri("crates.io").to_srv_request();
assert!(!guard.check(&req.guard_ctx()));
}
#[test]
fn mega_nesting() {
let guard = fn_guard(|ctx| All(Not(Any(Not(Trace())))).check(ctx));
let req = TestRequest::default().to_srv_request();
assert!(!guard.check(&req.guard_ctx()));
let req = TestRequest::default()
.method(Method::TRACE)
.to_srv_request();
assert!(guard.check(&req.guard_ctx()));
}
}