Easily convert typed paths into URIs (#790)

* Easily convert typed paths into URIs

`#[derive(TypedPath)]` will now also generate `TryFrom<_> for Uri` for
easily converting paths into URIs for use with `Redirect` and friends.

Fixes https://github.com/tokio-rs/axum/issues/789

* Use a method on the `TypedPath` trait to convert to `Uri`

* fix doc ref

* Update changelogs

axum-macros/CHANGELOG.md

@@ -7,7 +7,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 # Unreleased
 
-- Add `#[derive(TypedPath)]` for use with axum-extra's new "type safe" routing API ([#756])
+- **added:** Add `#[derive(TypedPath)]` for use with axum-extra's new "type safe" routing API ([#756])
 
 # 0.1.0 (31. January, 2022)
 

axum-macros/src/typed_path.rs

@@ -29,7 +29,7 @@ pub(crate) fn expand(item_struct: ItemStruct) -> syn::Result<TokenStream> {
             let segments = parse_path(&path)?;
             expand_unnamed_fields(fields, ident, path, &segments)
         }
-        syn::Fields::Unit => Ok(expand_unit_fields(ident, path)?),
+        syn::Fields::Unit => expand_unit_fields(ident, path),
     }
 }
 

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

@@ -0,0 +1,23 @@
+use axum_extra::routing::TypedPath;
+use axum::http::Uri;
+use serde::Deserialize;
+
+#[derive(TypedPath, Deserialize)]
+#[typed_path("/:id")]
+struct Named {
+    id: u32,
+}
+
+#[derive(TypedPath, Deserialize)]
+#[typed_path("/:id")]
+struct Unnamed(u32);
+
+#[derive(TypedPath, Deserialize)]
+#[typed_path("/")]
+struct Unit;
+
+fn main() {
+    let _: Uri = Named { id: 1 }.to_uri();
+    let _: Uri = Unnamed(1).to_uri();
+    let _: Uri = Unit.to_uri();
+}