Use tower-http corslayer for handling cors

This pr addresses part of #941. it replaces the custom cors
handling with tower-http corslayer

Author: zealsham

Cargo-minimal.lock

@@ -2900,6 +2900,7 @@ dependencies = [
  "tokio-stream",
  "tokio-tungstenite",
  "tower",
+ "tower-http",
  "tracing",
  "tracing-subscriber",
  "unicode-segmentation",

Cargo-recent.lock

@@ -2876,6 +2876,7 @@ dependencies = [
  "tokio-stream",
  "tokio-tungstenite",
  "tower",
+ "tower-http",
  "tracing",
  "tracing-subscriber",
  "unicode-segmentation",

payjoin-mailroom/Cargo.toml

@@ -73,6 +73,7 @@ tokio-rustls-acme = { version = "0.9.0", features = ["axum"], optional = true }
 tokio-stream = { version = "0.1.17", features = ["net"] }
 tokio-tungstenite = { version = "0.27.0", optional = true }
 tower = "0.5"
+tower-http = { version = "0.6", features = ["cors"] }
 tracing = "0.1"
 tracing-subscriber = { version = "0.3", features = ["env-filter", "json"] }
 unicode-segmentation = "=1.12.0"

payjoin-mailroom/src/directory.rs

@@ -5,7 +5,7 @@ use std::task::{Context, Poll};
 
 use anyhow::Result;
 use axum::body::{Body, Bytes};
-use axum::http::header::{HeaderValue, ACCESS_CONTROL_ALLOW_ORIGIN, CONTENT_TYPE};
+use axum::http::header::{HeaderValue, CONTENT_TYPE};
 use axum::http::{Method, Request, Response, StatusCode, Uri};
 use http_body_util::BodyExt;
 use payjoin::directory::{ShortId, ShortIdError, ENCAPSULATED_MESSAGE_BYTES};
@@ -148,7 +148,7 @@ impl<D: Db> Service<D> {
             }
         }
 
-        let mut response = match (parts.method, path_segments.as_slice()) {
+        let response = match (parts.method, path_segments.as_slice()) {
             (Method::POST, ["", ".well-known", "ohttp-gateway"]) =>
                 self.handle_ohttp_gateway(body).await,
             (Method::GET, ["", ".well-known", "ohttp-gateway"]) =>
@@ -162,8 +162,6 @@ impl<D: Db> Service<D> {
         }
         .unwrap_or_else(|e| e.to_response());
 
-        // Allow CORS for third-party access
-        response.headers_mut().insert(ACCESS_CONTROL_ALLOW_ORIGIN, HeaderValue::from_static("*"));
         Ok(response)
     }
 

payjoin-mailroom/src/lib.rs

@@ -1,6 +1,7 @@
 #[cfg(feature = "access-control")]
 use axum::extract::connect_info::Connected;
 use axum::extract::State;
+use axum::http::header::{CONTENT_LENGTH, CONTENT_TYPE};
 use axum::http::Method;
 use axum::response::{IntoResponse, Response};
 #[cfg(feature = "access-control")]
@@ -11,6 +12,7 @@ use opentelemetry_sdk::metrics::SdkMeterProvider;
 use rand::Rng;
 use tokio_listener::{Listener, SystemOptions, UserOptions};
 use tower::{Service, ServiceBuilder};
+use tower_http::cors::{Any, CorsLayer};
 use tracing::info;
 
 use crate::ohttp_relay::SentinelTag;
@@ -363,13 +365,19 @@ fn build_app(services: Services) -> Router {
     #[cfg(feature = "access-control")]
     let geoip = services.geoip.clone();
 
+    let cors = CorsLayer::new()
+        .allow_origin(Any)
+        .allow_methods([Method::CONNECT, Method::GET, Method::OPTIONS, Method::POST])
+        .allow_headers([CONTENT_TYPE, CONTENT_LENGTH]);
+
     #[allow(unused_mut)]
     let mut router = Router::new()
         .fallback(route_request)
         .layer(
             ServiceBuilder::new()
                 .layer(axum::middleware::from_fn_with_state(metrics.clone(), track_metrics))
-                .layer(axum::middleware::from_fn_with_state(metrics, track_connections)),
+                .layer(axum::middleware::from_fn_with_state(metrics, track_connections))
+                .layer(cors),
         )
         .with_state(services);
 
@@ -405,17 +413,17 @@ async fn route_request(
 /// Determines if a request should be routed to the OHTTP relay service.
 ///
 /// Routing rules:
-/// - `(OPTIONS, _)` => CORS preflight handling
 /// - `(CONNECT, _)` => OHTTP bootstrap tunneling
 /// - `(POST, "/")` => relay to default gateway (needed for backwards-compatibility only)
 /// - `(POST, /http(s)://...)` => RFC 9540 opt-in gateway specified in path
 /// - `(GET, /http(s)://...)` => OHTTP bootstrap via WebSocket with opt-in gateway
+/// - `(OPTIONS, _)` => CORS preflight handling (handled by `tower_http::cors::CorsLayer`)
 fn is_relay_request(req: &axum::extract::Request) -> bool {
     let method = req.method();
     let path = req.uri().path();
 
     match (method, path) {
-        (&Method::OPTIONS, _) | (&Method::CONNECT, _) | (&Method::POST, "/") => true,
+        (&Method::CONNECT, _) | (&Method::POST, "/") => true,
         (&Method::POST, p) | (&Method::GET, p)
             if p.starts_with("/http://") || p.starts_with("/https://") =>
             true,

payjoin-mailroom/src/ohttp_relay/mod.rs

@@ -10,10 +10,7 @@ use http::uri::Authority;
 use http_body_util::combinators::BoxBody;
 use http_body_util::{BodyExt, Empty, Full};
 use hyper::body::{Bytes, Incoming};
-use hyper::header::{
-    HeaderValue, ACCESS_CONTROL_ALLOW_HEADERS, ACCESS_CONTROL_ALLOW_METHODS,
-    ACCESS_CONTROL_ALLOW_ORIGIN, CONTENT_LENGTH, CONTENT_TYPE,
-};
+use hyper::header::{HeaderValue, CONTENT_LENGTH, CONTENT_TYPE};
 use hyper::{Method, Request, Response};
 use hyper_rustls::builderstates::WantsSchemes;
 use hyper_rustls::{HttpsConnector, HttpsConnectorBuilder};
@@ -160,8 +157,7 @@ where
     let path = req.uri().path();
     let authority = req.uri().authority().cloned();
 
-    let mut res = match (&method, path) {
-        (&Method::OPTIONS, _) => Ok(handle_preflight()),
+    let res = match (&method, path) {
         (&Method::GET, "/health") => Ok(health_check().await),
         (&Method::POST, _) => match parse_gateway_uri(&method, path, authority, config).await {
             Ok(gateway_uri) => handle_ohttp_relay(req, config, gateway_uri).await,
@@ -178,7 +174,6 @@ where
         _ => Err(Error::NotFound),
     }
     .unwrap_or_else(|e| e.to_response());
-    res.headers_mut().insert(ACCESS_CONTROL_ALLOW_ORIGIN, HeaderValue::from_static("*"));
     Ok(res)
 }
 
@@ -227,21 +222,6 @@ fn parse_gateway_uri_from_path(path: &str, default: &GatewayUri) -> Result<Gatew
     }
 }
 
-fn handle_preflight() -> Response<BoxBody<Bytes, hyper::Error>> {
-    let mut res = Response::new(empty());
-    *res.status_mut() = hyper::StatusCode::NO_CONTENT;
-    res.headers_mut().insert(ACCESS_CONTROL_ALLOW_ORIGIN, HeaderValue::from_static("*"));
-    res.headers_mut().insert(
-        ACCESS_CONTROL_ALLOW_METHODS,
-        HeaderValue::from_static("CONNECT, GET, OPTIONS, POST"),
-    );
-    res.headers_mut().insert(
-        ACCESS_CONTROL_ALLOW_HEADERS,
-        HeaderValue::from_static("Content-Type, Content-Length"),
-    );
-    res
-}
-
 async fn health_check() -> Response<BoxBody<Bytes, hyper::Error>> { Response::new(empty()) }
 
 #[instrument]