Support affixed typed path captures (#3782)

axum-macros/tests/typed_path/pass/affixed_captures.rs

@@ -0,0 +1,79 @@
+use axum_extra::routing::{RouterExt, TypedPath};
+use serde::Deserialize;
+
+#[derive(TypedPath, Deserialize)]
+#[typed_path("/@{username}")]
+struct PrefixedCapture {
+    username: String,
+}
+
+#[derive(TypedPath, Deserialize)]
+#[typed_path("/files/{name}.json")]
+struct SuffixedCapture {
+    name: String,
+}
+
+#[derive(TypedPath, Deserialize)]
+#[typed_path("/users/{user_id}/teams/team-{team_id}")]
+struct MixedCaptures {
+    user_id: u32,
+    team_id: u32,
+}
+
+#[derive(TypedPath, Deserialize)]
+#[typed_path("/{{escaped_capture}}/{id}")]
+struct EscapedBrace {
+    id: u32,
+}
+
+#[derive(TypedPath, Deserialize)]
+#[typed_path("/@{username}")]
+struct UnnamedPrefixedCapture(String);
+
+fn main() {
+    _ = axum::Router::<()>::new().typed_get(|_: PrefixedCapture| async {});
+    _ = axum::Router::<()>::new().typed_get(|_: SuffixedCapture| async {});
+    _ = axum::Router::<()>::new().typed_get(|_: MixedCaptures| async {});
+    _ = axum::Router::<()>::new().typed_get(|_: EscapedBrace| async {});
+
+    assert_eq!(PrefixedCapture::PATH, "/@{username}");
+    assert_eq!(
+        format!(
+            "{}",
+            PrefixedCapture {
+                username: "alice".to_owned(),
+            }
+        ),
+        "/@alice"
+    );
+
+    assert_eq!(SuffixedCapture::PATH, "/files/{name}.json");
+    assert_eq!(
+        format!(
+            "{}",
+            SuffixedCapture {
+                name: "report final".to_owned(),
+            }
+        ),
+        "/files/report%20final.json"
+    );
+
+    assert_eq!(
+        format!(
+            "{}",
+            MixedCaptures {
+                user_id: 1,
+                team_id: 2,
+            }
+        ),
+        "/users/1/teams/team-2"
+    );
+
+    assert_eq!(EscapedBrace::PATH, "/{{escaped_capture}}/{id}");
+    assert_eq!(format!("{}", EscapedBrace { id: 7 }), "/{escaped_capture}/7");
+
+    assert_eq!(
+        format!("{}", UnnamedPrefixedCapture("bob".to_owned())),
+        "/@bob"
+    );
+}