Add SpaRouter (#904)

axum-extra/CHANGELOG.md

@@ -7,11 +7,14 @@ and this project adheres to [Semantic Versioning].
 
 # Unreleased
 
-- **added:** Re-export `SameSite` and `Expiration` from the `cookie` crate.
+- **added:** Re-export `SameSite` and `Expiration` from the `cookie` crate ([#898])
 - **fixed:** Fix `SignedCookieJar` when using custom key types ([#899])
-- **added:** `PrivateCookieJar` for managing private cookies
+- **added:** Add `PrivateCookieJar` for managing private cookies ([#900])
+- **added:** Add `SpaRouter` for routing setups commonly used for single page applications
 
+[#898]: https://github.com/tokio-rs/axum/pull/898
 [#899]: https://github.com/tokio-rs/axum/pull/899
+[#900]: https://github.com/tokio-rs/axum/pull/900
 
 # 0.2.0 (31. March, 2022)
 

axum-extra/Cargo.toml

@@ -15,6 +15,7 @@ default = []
 erased-json = ["serde_json", "serde"]
 typed-routing = ["axum-macros", "serde", "percent-encoding"]
 cookie = ["cookie-lib"]
+spa = ["tower-http/fs"]
 
 [dependencies]
 axum = { path = "../axum", version = "0.5" }
@@ -37,6 +38,7 @@ cookie-lib = { package = "cookie", version = "0.16", features = ["percent-encode
 [dev-dependencies]
 axum = { path = "../axum", version = "0.5", features = ["headers"] }
 hyper = "0.14"
+reqwest = { version = "0.11", default-features = false, features = ["json", "stream", "multipart"] }
 serde = { version = "1.0", features = ["derive"] }
 tokio = { version = "1.14", features = ["full"] }
 tower = { version = "0.4", features = ["util"] }

axum-extra/src/lib.rs

@@ -61,3 +61,19 @@ pub mod __private {
     const PATH: &AsciiSet = &FRAGMENT.add(b'#').add(b'?').add(b'{').add(b'}');
     pub const PATH_SEGMENT: &AsciiSet = &PATH.add(b'/').add(b'%');
 }
+
+#[cfg(test)]
+pub(crate) mod test_helpers {
+    #![allow(unused_imports)]
+
+    use axum::{body::HttpBody, BoxError};
+
+    mod test_client {
+        #![allow(dead_code)]
+        include!(concat!(
+            env!("CARGO_MANIFEST_DIR"),
+            "/../axum/src/test_helpers/test_client.rs"
+        ));
+    }
+    pub(crate) use self::test_client::*;
+}

axum-extra/src/routing/mod.rs

@@ -4,6 +4,9 @@ use axum::{handler::Handler, Router};
 
 mod resource;
 
+#[cfg(feature = "spa")]
+mod spa;
+
 #[cfg(feature = "typed-routing")]
 mod typed;
 
@@ -15,6 +18,9 @@ pub use axum_macros::TypedPath;
 #[cfg(feature = "typed-routing")]
 pub use self::typed::{FirstElementIs, TypedPath};
 
+#[cfg(feature = "spa")]
+pub use self::spa::SpaRouter;
+
 /// Extension trait that adds additional methods to [`Router`].
 pub trait RouterExt<B>: sealed::Sealed {
     /// Add a typed `GET` route to the router.

axum-extra/src/routing/spa.rs

@@ -0,0 +1,269 @@
+use axum::{
+    body::{Body, HttpBody},
+    error_handling::HandleError,
+    response::Response,
+    routing::{get_service, Route},
+    Router,
+};
+use http::{Request, StatusCode};
+use std::{
+    any::type_name,
+    convert::Infallible,
+    fmt,
+    future::{ready, Ready},
+    io,
+    marker::PhantomData,
+    path::{Path, PathBuf},
+    sync::Arc,
+};
+use tower_http::services::{ServeDir, ServeFile};
+use tower_service::Service;
+
+/// Router for single page applications.
+///
+/// `SpaRouter` gives a routing setup commonly used for single page applications.
+///
+/// # Example
+///
+/// ```
+/// use axum_extra::routing::SpaRouter;
+/// use axum::{Router, routing::get};
+///
+/// let spa = SpaRouter::new("/assets", "dist");
+///
+/// let app = Router::new()
+///     // `SpaRouter` implements `Into<Router>` so it works with `merge`
+///     .merge(spa)
+///     // we can still add other routes
+///     .route("/api/foo", get(api_foo));
+/// # let _: Router<axum::body::Body> = app;
+///
+/// async fn api_foo() {}
+/// ```
+///
+/// With this setup we get this behavior:
+///
+/// - `GET /` will serve `index.html`
+/// - `GET /assets/app.js` will serve `dist/app.js` assuming that file exists
+/// - `GET /assets/doesnt_exist` will respond with `404 Not Found` assuming no
+///   such file exists
+/// - `GET /some/other/path` will serve `index.html` since there isn't another
+///   route for it
+/// - `GET /api/foo` will serve the `api_foo` handler function
+pub struct SpaRouter<B = Body, T = (), F = fn(io::Error) -> Ready<StatusCode>> {
+    paths: Arc<Paths>,
+    handle_error: F,
+    _marker: PhantomData<fn() -> (B, T)>,
+}
+
+#[derive(Debug)]
+struct Paths {
+    assets_path: String,
+    assets_dir: PathBuf,
+    index_file: PathBuf,
+}
+
+impl<B> SpaRouter<B, (), fn(io::Error) -> Ready<StatusCode>> {
+    /// Create a new `SpaRouter`.
+    ///
+    /// Assets will be served at `GET /{serve_assets_at}` from the directory at `assets_dir`.
+    ///
+    /// The index file defaults to `assets_dir.join("index.html")`.
+    pub fn new<P>(serve_assets_at: &str, assets_dir: P) -> Self
+    where
+        P: AsRef<Path>,
+    {
+        let path = assets_dir.as_ref();
+        Self {
+            paths: Arc::new(Paths {
+                assets_path: serve_assets_at.to_owned(),
+                assets_dir: path.to_owned(),
+                index_file: path.join("index.html"),
+            }),
+            handle_error: |_| ready(StatusCode::INTERNAL_SERVER_ERROR),
+            _marker: PhantomData,
+        }
+    }
+}
+
+impl<B, T, F> SpaRouter<B, T, F> {
+    /// Set the path to the index file.
+    ///
+    /// `path` must be relative to `assets_dir` passed to [`SpaRouter::new`].
+    ///
+    /// # Example
+    ///
+    /// ```
+    /// use axum_extra::routing::SpaRouter;
+    /// use axum::Router;
+    ///
+    /// let spa = SpaRouter::new("/assets", "dist")
+    ///     .index_file("another_file.html");
+    ///
+    /// let app = Router::new().merge(spa);
+    /// # let _: Router<axum::body::Body> = app;
+    /// ```
+    pub fn index_file<P>(mut self, path: P) -> Self
+    where
+        P: AsRef<Path>,
+    {
+        self.paths = Arc::new(Paths {
+            assets_path: self.paths.assets_path.clone(),
+            assets_dir: self.paths.assets_dir.clone(),
+            index_file: self.paths.assets_dir.join(path),
+        });
+        self
+    }
+
+    /// Change the function used to handle unknown IO errors.
+    ///
+    /// `SpaRouter` automatically maps missing files and permission denied to
+    /// `404 Not Found`. The callback given here will be used for other IO errors.
+    ///
+    /// See [`axum::error_handling::HandleErrorLayer`] for more details.
+    ///
+    /// # Example
+    ///
+    /// ```
+    /// use std::io;
+    /// use axum_extra::routing::SpaRouter;
+    /// use axum::{Router, http::{Method, Uri}};
+    ///
+    /// let spa = SpaRouter::new("/assets", "dist").handle_error(handle_error);
+    ///
+    /// async fn handle_error(method: Method, uri: Uri, err: io::Error) -> String {
+    ///     format!("{} {} failed with {}", method, uri, err)
+    /// }
+    ///
+    /// let app = Router::new().merge(spa);
+    /// # let _: Router<axum::body::Body> = app;
+    /// ```
+    pub fn handle_error<T2, F2>(self, f: F2) -> SpaRouter<B, T2, F2> {
+        SpaRouter {
+            paths: self.paths,
+            handle_error: f,
+            _marker: PhantomData,
+        }
+    }
+}
+
+impl<B, F, T> From<SpaRouter<B, T, F>> for Router<B>
+where
+    F: Clone + Send + 'static,
+    HandleError<Route<B, io::Error>, F, T>:
+        Service<Request<B>, Response = Response, Error = Infallible>,
+    <HandleError<Route<B, io::Error>, F, T> as Service<Request<B>>>::Future: Send,
+    B: HttpBody + Send + 'static,
+    T: 'static,
+{
+    fn from(spa: SpaRouter<B, T, F>) -> Self {
+        let assets_service = get_service(ServeDir::new(&spa.paths.assets_dir))
+            .handle_error(spa.handle_error.clone());
+
+        Router::new()
+            .nest(&spa.paths.assets_path, assets_service)
+            .fallback(
+                get_service(ServeFile::new(&spa.paths.index_file)).handle_error(spa.handle_error),
+            )
+    }
+}
+
+impl<B, T, F> fmt::Debug for SpaRouter<B, T, F> {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        let Self {
+            paths,
+            handle_error: _,
+            _marker,
+        } = self;
+
+        f.debug_struct("SpaRouter")
+            .field("paths", &paths)
+            .field("handle_error", &format_args!("{}", type_name::<F>()))
+            .field("request_body_type", &format_args!("{}", type_name::<B>()))
+            .field(
+                "extractor_input_type",
+                &format_args!("{}", type_name::<T>()),
+            )
+            .finish()
+    }
+}
+
+impl<B, T, F> Clone for SpaRouter<B, T, F>
+where
+    F: Clone,
+{
+    fn clone(&self) -> Self {
+        Self {
+            paths: self.paths.clone(),
+            handle_error: self.handle_error.clone(),
+            _marker: self._marker,
+        }
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use crate::test_helpers::*;
+    use axum::{
+        http::{Method, Uri},
+        routing::get,
+    };
+
+    #[tokio::test]
+    async fn basic() {
+        let app = Router::new()
+            .route("/foo", get(|| async { "GET /foo" }))
+            .merge(SpaRouter::new("/assets", "test_files"));
+        let client = TestClient::new(app);
+
+        let res = client.get("/").send().await;
+        assert_eq!(res.status(), StatusCode::OK);
+        assert_eq!(res.text().await, "<h1>Hello, World!</h1>\n");
+
+        let res = client.get("/some/random/path").send().await;
+        assert_eq!(res.status(), StatusCode::OK);
+        assert_eq!(res.text().await, "<h1>Hello, World!</h1>\n");
+
+        let res = client.get("/assets/script.js").send().await;
+        assert_eq!(res.status(), StatusCode::OK);
+        assert_eq!(res.text().await, "console.log('hi')\n");
+
+        let res = client.get("/foo").send().await;
+        assert_eq!(res.status(), StatusCode::OK);
+        assert_eq!(res.text().await, "GET /foo");
+
+        let res = client.get("/assets/doesnt_exist").send().await;
+        assert_eq!(res.status(), StatusCode::NOT_FOUND);
+    }
+
+    #[tokio::test]
+    async fn setting_index_file() {
+        let app =
+            Router::new().merge(SpaRouter::new("/assets", "test_files").index_file("index_2.html"));
+        let client = TestClient::new(app);
+
+        let res = client.get("/").send().await;
+        assert_eq!(res.status(), StatusCode::OK);
+        assert_eq!(res.text().await, "<strong>Hello, World!</strong>\n");
+
+        let res = client.get("/some/random/path").send().await;
+        assert_eq!(res.status(), StatusCode::OK);
+        assert_eq!(res.text().await, "<strong>Hello, World!</strong>\n");
+    }
+
+    // this should just compile
+    #[allow(dead_code)]
+    fn setting_error_handler() {
+        async fn handle_error(method: Method, uri: Uri, err: io::Error) -> (StatusCode, String) {
+            (
+                StatusCode::INTERNAL_SERVER_ERROR,
+                format!("{} {} failed. Error: {}", method, uri, err),
+            )
+        }
+
+        let spa = SpaRouter::new("/assets", "test_files").handle_error(handle_error);
+
+        Router::<Body>::new().merge(spa);
+    }
+}

axum-extra/test_files/index.html

@@ -0,0 +1 @@
+<h1>Hello, World!</h1>

axum-extra/test_files/index_2.html

@@ -0,0 +1 @@
+<strong>Hello, World!</strong>

axum-extra/test_files/script.js

@@ -0,0 +1 @@
+console.log('hi')

axum/src/test_helpers/mod.rs

@@ -0,0 +1,12 @@
+#![allow(clippy::blacklisted_name)]
+
+use crate::{body::HttpBody, BoxError};
+
+mod test_client;
+pub(crate) use self::test_client::*;
+
+pub(crate) fn assert_send<T: Send>() {}
+pub(crate) fn assert_sync<T: Sync>() {}
+pub(crate) fn assert_unpin<T: Unpin>() {}
+
+pub(crate) struct NotSendSync(*const ());

axum/src/test_helpers/test_client.rs

@@ -1,7 +1,4 @@
-#![allow(clippy::blacklisted_name)]
-
-use crate::body::HttpBody;
-use crate::BoxError;
+use super::{BoxError, HttpBody};
 use bytes::Bytes;
 use http::{
     header::{HeaderName, HeaderValue},
@@ -15,12 +12,6 @@ use std::{
 use tower::make::Shared;
 use tower_service::Service;
 
-pub(crate) fn assert_send<T: Send>() {}
-pub(crate) fn assert_sync<T: Sync>() {}
-pub(crate) fn assert_unpin<T: Unpin>() {}
-
-pub(crate) struct NotSendSync(*const ());
-
 pub(crate) struct TestClient {
     client: reqwest::Client,
     addr: SocketAddr,