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-extra/src/routing/typed.rs

@@ -1,4 +1,5 @@
 use super::sealed::Sealed;
+use http::Uri;
 
 /// A type safe path.
 ///
@@ -87,6 +88,8 @@ use super::sealed::Sealed;
 /// things, create links to known paths and have them verified statically. Note that the
 /// [`Display`] implementation for each field must return something that's compatible with its
 /// [`Deserialize`] implementation.
+/// - A [`TryFrom<_> for Uri`](std::convert::TryFrom) implementation to converting your paths into
+/// [`Uri`](axum::http::Uri).
 ///
 /// Additionally the macro will verify the captures in the path matches the fields of the struct.
 /// For example this fails to compile since the struct doesn't have a `team_id` field:
@@ -148,6 +151,21 @@ use super::sealed::Sealed;
 pub trait TypedPath: std::fmt::Display {
     /// The path with optional captures such as `/users/:id`.
     const PATH: &'static str;
+
+    /// Convert the path into a `Uri`.
+    ///
+    /// # Panics
+    ///
+    /// The default implementation parses the required [`Display`] implemetation. If that fails it
+    /// will panic.
+    ///
+    /// Using `#[derive(TypedPath)]` will never result in a panic since it percent-encodes
+    /// arguments.
+    ///
+    /// [`Display`]: std::fmt::Display
+    fn to_uri(&self) -> Uri {
+        self.to_string().parse().unwrap()
+    }
 }
 
 /// Utility trait used with [`RouterExt`] to ensure the first element of a tuple type is a