feat: cors example (#29)

* feat: cors example

* fix: clippy and feature checks

* fix: better corsing

* chore: make arg optional

* refactor: improve the example and comment

Author: prestwich

Cargo.toml

@@ -39,9 +39,15 @@ tokio-tungstenite = { version = "0.26.1", features = ["rustls-tls-webpki-roots"]
 futures-util = { version = "0.3.31", optional = true }
 
 [dev-dependencies]
+ajj = { path = "./", features = ["axum", "ws", "ipc"] }
+
 tempfile = "3.15.0"
 tracing-subscriber = "0.3.19"
 axum = { version = "0.8.1", features = ["macros"] }
+tower-http = { version = "0.6.2", features = ["cors"] }
+tokio = { version = "1.43.0", features = ["full"] }
+eyre = "0.6.12"
+
 
 [features]
 default = ["axum", "ws", "ipc"]

examples/cors.rs

@@ -0,0 +1,81 @@
+//! Basic example of using ajj with CORS.
+//!
+//! This example demonstrates how to set up a simple HTTP server using `axum`
+//! and `tower_http` for CORS support.
+//!
+//! ## Inovking this example
+//!
+//! ```ignore
+//! // Invoking with cors domains
+//! cargo run --example cors -- "https://example.com,https://example.org"
+//! // Invoking with wildcard
+//! cargo run --example cors
+//! ```
+
+use axum::http::{HeaderValue, Method};
+use eyre::{ensure, Context};
+use std::{future::IntoFuture, net::SocketAddr};
+use tower_http::cors::{AllowOrigin, Any, CorsLayer};
+
+fn get_allowed(cors: &str) -> eyre::Result<AllowOrigin> {
+    // Wildcard `*` means any origin is allowed.
+    if cors == "*" {
+        return Ok(AllowOrigin::any());
+    }
+
+    // Check if the cors string contains a wildcard
+    ensure!(
+        !cors.split(',').any(|o| o == "*"),
+        "Wildcard '*' is not allowed in CORS domains"
+    );
+
+    // Split the cors string by commas and parse each domain into a HeaderValue
+    // Then convert the Vec<HeaderValue> into AllowOrigin
+    cors.split(',')
+        .map(|domain| {
+            // Parse each substring into a HeaderValue
+            // We print parsing errors to stderr, because this is an example :)
+            domain
+                .parse::<HeaderValue>()
+                .inspect_err(|e| eprintln!("Failed to parse domain {}: {}", domain, e))
+                .wrap_err_with(|| format!("Invalid CORS domain: {}", domain))
+        })
+        .collect::<Result<Vec<_>, _>>()
+        .map(Into::into)
+}
+
+fn make_cors(cors: &str) -> eyre::Result<CorsLayer> {
+    let origins = get_allowed(cors)?;
+
+    Ok(CorsLayer::new()
+        .allow_methods([Method::GET, Method::POST])
+        .allow_origin(origins)
+        .allow_headers(Any))
+}
+
+#[tokio::main]
+async fn main() -> eyre::Result<()> {
+    let cors = std::env::args().nth(1).unwrap_or("*".to_string());
+
+    // Setting up an AJJ router is easy and fun!
+    let router = ajj::Router::<()>::new()
+        .route("helloWorld", || async {
+            tracing::info!("serving hello world");
+            Ok::<_, ()>("Hello, world!")
+        })
+        .route("addNumbers", |(a, b): (u32, u32)| async move {
+            tracing::info!("serving addNumbers");
+            Ok::<_, ()>(a + b)
+        })
+        // Convert to an axum router
+        .into_axum("/")
+        // And then layer on your CORS settings
+        .layer(make_cors(&cors)?);
+
+    // Now we can serve the router on a TCP listener
+    let addr = SocketAddr::from(([127, 0, 0, 1], 0));
+    let listener = tokio::net::TcpListener::bind(addr).await?;
+
+    axum::serve(listener, router).into_future().await?;
+    Ok(())
+}

src/lib.rs

@@ -136,7 +136,6 @@
 //!
 //! [`axum`]: https://docs.rs/axum/latest/axum/index.html
 //! [`axum::Router`]: https://docs.rs/axum/latest/axum/routing/struct.Router.html
-//! [`ResponsePayload`]: alloy::rpc::json_rpc::ResponsePayload
 //! [`interprocess::local_socket::ListenerOptions`]: https://docs.rs/interprocess/latest/interprocess/local_socket/struct.ListenerOptions.html
 
 #![warn(