Fix rwf2#1224 by searching routes after failed match

core/codegen/tests/route-format.rs

@@ -61,7 +61,7 @@ fn test_formats() {
     assert_eq!(response.into_string().unwrap(), "plain");
 
     let response = client.put("/").header(ContentType::HTML).dispatch();
-    assert_eq!(response.status(), Status::NotFound);
+    assert_eq!(response.status(), Status::MethodNotAllowed);
 }
 
 // Test custom formats.
@@ -109,9 +109,12 @@ fn test_custom_formats() {
     let response = client.get("/").dispatch();
     assert_eq!(response.into_string().unwrap(), "get_foo");
 
+    let response = client.get("/").header(Accept::JPEG).dispatch();
+    assert_eq!(response.status(), Status::NotAcceptable); // Route can't produce JPEG
+
     let response = client.put("/").header(ContentType::HTML).dispatch();
-    assert_eq!(response.status(), Status::NotFound);
+    assert_eq!(response.status(), Status::UnsupportedMediaType); // Route expects "bar/baz"
 
     let response = client.post("/").header(ContentType::HTML).dispatch();
-    assert_eq!(response.status(), Status::NotFound);
+    assert_eq!(response.status(), Status::UnsupportedMediaType); // Route expects "foo"
 }

core/codegen/tests/route.rs

@@ -105,7 +105,7 @@ fn test_full_route() {
     assert_eq!(response.status(), Status::NotFound);
 
     let response = client.post(format!("/1{}", uri)).body(simple).dispatch();
-    assert_eq!(response.status(), Status::NotFound);
+    assert_eq!(response.status(), Status::UnsupportedMediaType);
 
     let response = client
         .post(format!("/1{}", uri))
@@ -117,7 +117,7 @@ fn test_full_route() {
             sky, name.percent_decode().unwrap(), "A A", "inside", path, simple, expected_uri));
 
     let response = client.post(format!("/2{}", uri)).body(simple).dispatch();
-    assert_eq!(response.status(), Status::NotFound);
+    assert_eq!(response.status(), Status::UnsupportedMediaType);
 
     let response = client
         .post(format!("/2{}", uri))

core/lib/src/lifecycle.rs

@@ -112,6 +112,25 @@ impl Rocket<Orbit> {
                     Outcome::Forward((_, status)) => self.dispatch_error(status, request).await,
                 }
             }
+            Outcome::Forward((_, status)) if status == Status::NotFound => {
+                // We failed to find a route which matches on path, query AND formats.
+                // Before we return the error to the user, we'll check for "near misses".
+
+                // This code path primarily exists to assist clients in debugging their requests.
+                let mut status = status;
+                if self.router.matches_except_formats(request) {
+                    // Tailor the error code to the interpretation of the request in question.
+                    if request.method().allows_request_body() == Some(true) {
+                        status = Status::UnsupportedMediaType;
+                    } else if request.headers().contains("Accept") {
+                        status = Status::NotAcceptable;
+                    }
+                } else if self.router.matches_except_method(request) {
+                    // Found a more suitable error code for paths implemented on different methods.
+                    status = Status::MethodNotAllowed;
+                }
+                self.dispatch_error(status, request).await
+            }
             Outcome::Forward((_, status)) => self.dispatch_error(status, request).await,
             Outcome::Error(status) => self.dispatch_error(status, request).await,
         };

core/lib/src/router/matcher.rs

@@ -144,7 +144,7 @@ fn methods_match(route: &Route, req: &Request<'_>) -> bool {
     route.method.map_or(true, |method| method == req.method())
 }
 
-fn paths_match(route: &Route, req: &Request<'_>) -> bool {
+pub(crate) fn paths_match(route: &Route, req: &Request<'_>) -> bool {
     trace!(route.uri = %route.uri, request.uri = %req.uri());
     let route_segments = &route.uri.metadata.uri_segments;
     let req_segments = req.uri().path().segments();
@@ -174,7 +174,7 @@ fn paths_match(route: &Route, req: &Request<'_>) -> bool {
     true
 }
 
-fn queries_match(route: &Route, req: &Request<'_>) -> bool {
+pub(crate) fn queries_match(route: &Route, req: &Request<'_>) -> bool {
     trace!(
         route.query = route.uri.query().map(display),
         route.query.color = route.uri.metadata.query_color.map(debug),
@@ -201,7 +201,7 @@ fn queries_match(route: &Route, req: &Request<'_>) -> bool {
     true
 }
 
-fn formats_match(route: &Route, req: &Request<'_>) -> bool {
+pub(crate) fn formats_match(route: &Route, req: &Request<'_>) -> bool {
     trace!(
         route.format = route.format.as_ref().map(display),
         request.format = req.format().map(display),

core/lib/src/router/router.rs

@@ -6,6 +6,8 @@ use crate::http::{Method, Status};
 use crate::{Route, Catcher};
 use crate::router::Collide;
 
+use super::matcher::{paths_match, queries_match, formats_match};
+
 #[derive(Debug)]
 pub(crate) struct Router<T>(T);
 
@@ -104,6 +106,38 @@ impl Router<Finalized> {
             .filter(move |r| r.matches(req))
     }
 
+    pub(crate) fn matches_except_formats<'r, 'a: 'r>(
+        &'a self,
+        req: &'r Request<'r>
+    ) -> bool {
+        self.route_map.get(&req.method())
+            .into_iter()
+            .flatten()
+            .any(|&route|
+                paths_match(&self.routes[route], req)
+                &&
+                queries_match(&self.routes[route], req)
+                &&
+                !formats_match(&self.routes[route], req))
+    }
+
+    const ALL_METHODS: &'static [Method] = &[
+        Method::Get, Method::Put, Method::Post, Method::Delete, Method::Options,
+        Method::Head, Method::Trace, Method::Connect, Method::Patch,
+    ];
+
+    pub(crate) fn matches_except_method<'r, 'a: 'r>(
+        &'a self,
+        req: &'r Request<'r>
+    ) -> bool {
+        Self::ALL_METHODS
+            .iter()
+            .filter(|method| *method != &req.method())
+            .filter_map(|method| self.route_map.get(method))
+            .flatten()
+            .any(|route| paths_match(&self.routes[*route], req))
+    }
+
     // For many catchers, using aho-corasick or similar should be much faster.
     #[track_caller]
     pub fn catch<'r>(&self, status: Status, req: &'r Request<'r>) -> Option<&Catcher> {
@@ -396,6 +430,25 @@ mod test {
         assert!(route(&router, Get, "/prefi/").is_none());
     }
 
+    fn has_mismatched_method<'a>(
+        router: &'a Router<Finalized>,
+        method: Method, uri: &'a str
+    ) -> bool {
+        let client = Client::debug_with(vec![]).expect("client");
+        let request = client.req(method, Origin::parse(uri).unwrap());
+        router.matches_except_method(&request)
+    }
+
+    #[test]
+    fn test_bad_method_routing() {
+        let router = router_with_routes(&["/hello"]);
+        assert!(route(&router, Put, "/hello").is_none());
+        assert!(has_mismatched_method(&router, Put, "/hello"));
+        assert!(has_mismatched_method(&router, Post, "/hello"));
+
+        assert!(! has_mismatched_method(&router, Get, "/hello"));
+    }
+
     /// Asserts that `$to` routes to `$want` given `$routes` are present.
     macro_rules! assert_ranked_match {
         ($routes:expr, $to:expr => $want:expr) => ({

core/lib/tests/form_method-issue-45.rs

@@ -70,6 +70,6 @@ mod tests {
             .body("_method=patch&form_data=Form+data")
             .dispatch();
 
-        assert_eq!(response.status(), Status::NotFound);
+        assert_eq!(response.status(), Status::MethodNotAllowed);
     }
 }

core/lib/tests/precise-content-type-matching.rs

@@ -48,7 +48,7 @@ mod tests {
             let body: Option<&'static str> = $body;
             match body {
                 Some(string) => assert_eq!(body_str, Some(string.to_string())),
-                None => assert_eq!(status, Status::NotFound)
+                None => assert_eq!(status, Status::UnsupportedMediaType)
             }
         )
     }

docs/guide/05-requests.md

@@ -2074,6 +2074,13 @@ fn main() {
 }
 ```
 
+Besides `404 Not Found` for unknown URIs, Rocket may also produce
+`405 Method Not Allowed` if a request matches a URI but not a declared method
+for that URI. For routes declaring formats, Rocket will produce
+`406 Not Acceptable` status for a client request _accepting_ a format which
+isn't declared by the matching routes, or `415 Unsupported Media Type` in case
+the _payload_ of a `PUT` or `POST` is not allowed by the route.
+
 ### Scoping
 
 The first argument to `register()` is a path to scope the catcher under called

examples/error-handling/src/tests.rs

@@ -64,6 +64,15 @@ fn test_hello_invalid_age() {
     }
 }
 
+#[test]
+fn test_method_not_allowed() {
+    let client = Client::tracked(super::rocket()).unwrap();
+    let (name, age) = ("Pat", 86);
+    let request = client.post(format!("/hello/{}/{}", name, age)).body("body");
+    let response = request.dispatch();
+    assert_eq!(response.status(), Status::MethodNotAllowed);
+}
+
 #[test]
 fn test_hello_sergio() {
     let client = Client::tracked(super::rocket()).unwrap();

examples/responders/src/tests.rs

@@ -126,8 +126,7 @@ fn test_xml() {
     assert_eq!(r.into_string().unwrap(), r#"{ "payload": "I'm here" }"#);
 
     let r = client.get(uri!(super::xml)).header(Accept::CSV).dispatch();
-    assert_eq!(r.status(), Status::NotFound);
-    assert!(r.into_string().unwrap().contains("not supported"));
+    assert_eq!(r.status(), Status::NotAcceptable);
 
     let r = client.get("/content/i/dont/exist").header(Accept::HTML).dispatch();
     assert_eq!(r.content_type().unwrap(), ContentType::HTML);

examples/templating/src/tests.rs

@@ -22,8 +22,7 @@ fn test_root(kind: &str) {
         let expected = Template::show(client.rocket(), format!("{}/error/404", kind), &context);
 
         let response = client.req(*method, format!("/{}", kind)).dispatch();
-        assert_eq!(response.status(), Status::NotFound);
-        assert_eq!(response.into_string(), expected);
+        assert_eq!(response.status(), Status::MethodNotAllowed);
     }
 }