chore: fix cors for envoys

Author: NathanFlurry

engine/artifacts/openapi.json

@@ -92,19 +92,21 @@ pub fn create_routing_function(ctx: &StandaloneCtx, shared_state: SharedState) -
 								.split(',')
 								.map(|p| p.trim())
 								.find_map(|p| p.strip_prefix(WS_PROTOCOL_TARGET))
+								.map(ToOwned::to_owned)
 						})
 				} else {
 					// For HTTP, use the x-rivet-target header
 					req_ctx
 						.headers()
 						.get(X_RIVET_TARGET)
 						.and_then(|x| x.to_str().ok())
+						.map(ToOwned::to_owned)
 				};
 
 				// Read target
 				if let Some(target) = target {
 					if let Some(routing_output) =
-						pegboard_gateway::route_request(&ctx, &shared_state, req_ctx, target)
+						pegboard_gateway::route_request(&ctx, &shared_state, req_ctx, &target)
 							.await?
 					{
 						metrics::ROUTE_TOTAL.with_label_values(&["gateway"]).inc();
@@ -113,22 +115,22 @@ pub fn create_routing_function(ctx: &StandaloneCtx, shared_state: SharedState) -
 					}
 
 					if let Some(routing_output) =
-						runner::route_request(&ctx, req_ctx, target).await?
+						runner::route_request(&ctx, req_ctx, &target).await?
 					{
 						metrics::ROUTE_TOTAL.with_label_values(&["runner"]).inc();
 
 						return Ok(routing_output);
 					}
 
 					if let Some(routing_output) =
-						envoy::route_request(&ctx, req_ctx, target).await?
+						envoy::route_request(&ctx, req_ctx, &target).await?
 					{
 						metrics::ROUTE_TOTAL.with_label_values(&["envoy"]).inc();
 
 						return Ok(routing_output);
 					}
 
-					if let Some(routing_output) = api_public::route_request(&ctx, target).await? {
+					if let Some(routing_output) = api_public::route_request(&ctx, &target).await? {
 						metrics::ROUTE_TOTAL.with_label_values(&["api"]).inc();
 
 						return Ok(routing_output);

engine/packages/guard/src/routing/mod.rs

@@ -0,0 +1,71 @@
+use anyhow::Result;
+use async_trait::async_trait;
+use bytes::Bytes;
+use http_body_util::Full;
+use hyper::{Request, Response, StatusCode};
+use rivet_guard_core::{
+	ResponseBody,
+	custom_serve::CustomServeTrait,
+	request_context::{CorsConfig, RequestContext},
+};
+
+pub fn origin_header(req_ctx: &RequestContext) -> String {
+	req_ctx
+		.headers()
+		.get("origin")
+		.and_then(|v| v.to_str().ok())
+		.unwrap_or("*")
+		.to_string()
+}
+
+pub fn set_non_preflight_cors(req_ctx: &mut RequestContext) {
+	let allow_origin = origin_header(req_ctx);
+	req_ctx.set_cors(CorsConfig {
+		allow_origin,
+		allow_credentials: true,
+		expose_headers: "*".to_string(),
+		allow_methods: None,
+		allow_headers: None,
+		max_age: None,
+	});
+}
+
+/// Responds to CORS preflight OPTIONS requests with 204 and permissive CORS
+/// headers. Avoids actor lookup, wake, and auth because browsers cannot attach
+/// credentials to preflights. The actual request that follows is still authed.
+pub struct CorsPreflight;
+
+#[async_trait]
+impl CustomServeTrait for CorsPreflight {
+	async fn handle_request(
+		&self,
+		req: Request<Full<Bytes>>,
+		req_ctx: &mut RequestContext,
+	) -> Result<Response<ResponseBody>> {
+		let allow_origin = req
+			.headers()
+			.get("origin")
+			.and_then(|v| v.to_str().ok())
+			.unwrap_or("*")
+			.to_string();
+		let allow_headers = req
+			.headers()
+			.get("access-control-request-headers")
+			.and_then(|v| v.to_str().ok())
+			.unwrap_or("*")
+			.to_string();
+
+		req_ctx.set_cors(CorsConfig {
+			allow_origin,
+			allow_credentials: true,
+			expose_headers: "*".to_string(),
+			allow_methods: Some("GET, POST, PUT, DELETE, OPTIONS, PATCH".to_string()),
+			allow_headers: Some(allow_headers),
+			max_age: Some(86400),
+		});
+
+		Ok(Response::builder()
+			.status(StatusCode::NO_CONTENT)
+			.body(ResponseBody::Full(Full::new(Bytes::new())))?)
+	}
+}

engine/packages/guard/src/routing/pegboard_gateway/cors.rs

@@ -1,6 +1,7 @@
+mod cors;
 mod resolve_actor_query;
 
-use std::time::Duration;
+use std::{sync::Arc, time::Duration};
 
 use anyhow::Result;
 use gas::{ctx::message::SubscriptionHandle, prelude::*};
@@ -12,6 +13,7 @@ use super::{
 	actor_path::ParsedActorPath,
 };
 use crate::{errors, routing::actor_path::parse_actor_path, shared_state::SharedState};
+use cors::{CorsPreflight, set_non_preflight_cors};
 use resolve_actor_query::resolve_query_actor_id;
 
 const ACTOR_FORCE_WAKE_PENDING_TIMEOUT: i64 = util::duration::seconds(60);
@@ -29,12 +31,16 @@ pub const X_RIVET_ACTOR: HeaderName = HeaderName::from_static("x-rivet-actor");
 pub async fn route_request_path_based(
 	ctx: &StandaloneCtx,
 	shared_state: &SharedState,
-	req_ctx: &RequestContext,
+	req_ctx: &mut RequestContext,
 ) -> Result<Option<RoutingOutput>> {
 	let Some(actor_path) = parse_actor_path(req_ctx.path())? else {
 		return Ok(None);
 	};
 
+	if req_ctx.method() == hyper::Method::OPTIONS {
+		return Ok(Some(RoutingOutput::CustomServe(Arc::new(CorsPreflight))));
+	}
+
 	tracing::debug!(?actor_path, "routing using path-based actor routing");
 
 	let resolved_route = resolve_path_based_route(ctx, req_ctx, &actor_path).await?;
@@ -56,14 +62,18 @@ pub async fn route_request_path_based(
 pub async fn route_request(
 	ctx: &StandaloneCtx,
 	shared_state: &SharedState,
-	req_ctx: &RequestContext,
+	req_ctx: &mut RequestContext,
 	target: &str,
 ) -> Result<Option<RoutingOutput>> {
 	// Check target
 	if target != "actor" {
 		return Ok(None);
 	}
 
+	if req_ctx.method() == hyper::Method::OPTIONS {
+		return Ok(Some(RoutingOutput::CustomServe(Arc::new(CorsPreflight))));
+	}
+
 	// Extract actor ID and token from WebSocket protocol or HTTP headers
 	let (actor_id_str, token) = if req_ctx.is_websocket() {
 		// For WebSocket, parse the sec-websocket-protocol header
@@ -96,7 +106,8 @@ pub async fn route_request(
 
 		let token = protocols
 			.iter()
-			.find_map(|p| p.strip_prefix(WS_PROTOCOL_TOKEN));
+			.find_map(|p| p.strip_prefix(WS_PROTOCOL_TOKEN))
+			.map(ToOwned::to_owned);
 
 		(actor_id, token)
 	} else {
@@ -119,17 +130,26 @@ pub async fn route_request(
 			.get(X_RIVET_TOKEN)
 			.map(|x| x.to_str())
 			.transpose()
-			.context("invalid x-rivet-token header")?;
+			.context("invalid x-rivet-token header")?
+			.map(ToOwned::to_owned);
 
 		(actor_id.to_string(), token)
 	};
 
 	// Find actor to route to
 	let actor_id = Id::parse(&actor_id_str).context("invalid x-rivet-actor header")?;
+	let stripped_path = req_ctx.path().to_owned();
 
-	route_request_inner(ctx, shared_state, req_ctx, actor_id, req_ctx.path(), token)
-		.await
-		.map(Some)
+	route_request_inner(
+		ctx,
+		shared_state,
+		req_ctx,
+		actor_id,
+		&stripped_path,
+		token.as_deref(),
+	)
+	.await
+	.map(Some)
 }
 
 #[derive(Debug)]
@@ -201,11 +221,16 @@ fn read_gateway_token_from_request<'a>(
 async fn route_request_inner(
 	ctx: &StandaloneCtx,
 	shared_state: &SharedState,
-	req_ctx: &RequestContext,
+	req_ctx: &mut RequestContext,
 	actor_id: Id,
 	stripped_path: &str,
 	_token: Option<&str>,
 ) -> Result<RoutingOutput> {
+	// Attach CORS headers to the actual (non-OPTIONS) response so both the
+	// actor response and any early error (e.g. EE auth failure) are readable
+	// by the browser.
+	set_non_preflight_cors(req_ctx);
+
 	// NOTE: Token validation implemented in EE
 
 	// Route to peer dc where the actor lives

engine/packages/guard/src/routing/pegboard_gateway/mod.rs

@@ -10,7 +10,7 @@ use rivet_guard_core::{
 	ResponseBody, WebSocketHandle,
 	custom_serve::{CustomServeTrait, HibernationResult},
 	errors::{ServiceUnavailable, WebSocketServiceUnavailable},
-	request_context::{CorsConfig, RequestContext},
+	request_context::RequestContext,
 	utils::is_ws_hibernate,
 	websocket_handle::WebSocketReceiver,
 };
@@ -92,15 +92,6 @@ impl PegboardGateway {
 		let actor_id = self.actor_id.to_string();
 		let request_id = req_ctx.in_flight_request_id()?;
 
-		// Extract origin for CORS (before consuming request)
-		// When credentials: true, we must echo back the actual origin, not "*"
-		let origin = req
-			.headers()
-			.get("origin")
-			.and_then(|v| v.to_str().ok())
-			.unwrap_or("*")
-			.to_string();
-
 		// Extract request parts
 		let headers = req
 			.headers()
@@ -113,47 +104,6 @@ impl PegboardGateway {
 			})
 			.collect::<HashableMap<_, _>>();
 
-		// Handle CORS preflight OPTIONS requests at gateway level
-		//
-		// We need to do this in the gateway because there is no way of sending an OPTIONS request to the
-		// actor since we don't have the `x-rivet-token` header. This implementation allows
-		// requests from anywhere and lets the actor handle CORS manually in `onBeforeConnect`.
-		// This had the added benefit of also applying to WebSockets.
-		if req.method() == hyper::Method::OPTIONS {
-			tracing::debug!("handling OPTIONS preflight request at gateway");
-
-			// Extract requested headers
-			let requested_headers = req
-				.headers()
-				.get("access-control-request-headers")
-				.and_then(|v| v.to_str().ok())
-				.unwrap_or("*");
-
-			req_ctx.set_cors(CorsConfig {
-				allow_origin: origin.clone(),
-				allow_credentials: true,
-				expose_headers: "*".to_string(),
-				allow_methods: Some("GET, POST, PUT, DELETE, OPTIONS, PATCH".to_string()),
-				allow_headers: Some(requested_headers.to_string()),
-				max_age: Some(86400),
-			});
-
-			return Ok(Response::builder()
-				.status(StatusCode::NO_CONTENT)
-				.body(ResponseBody::Full(Full::new(Bytes::new())))?);
-		}
-
-		// Set CORS headers through guard
-		req_ctx.set_cors(CorsConfig {
-			allow_origin: origin.clone(),
-			allow_credentials: true,
-			expose_headers: "*".to_string(),
-			// Not an options req, not required
-			allow_methods: None,
-			allow_headers: None,
-			max_age: None,
-		});
-
 		// NOTE: Size constraints have already been applied by guard
 		let body_bytes = req
 			.into_body()