fix: expose ratelimit headers via cors (#496)

crates/services/gifbox/Cargo.toml

@@ -36,6 +36,7 @@ revolt-ratelimits = { version = "0.9.4", path = "../../core/ratelimits", feature
 # Axum / web server
 axum = { version = "0.7.5" }
 axum-extra = { version = "0.9", features = ["typed-header"] }
+tower-http = { version = "0.5.2", features = ["cors"] }
 
 # OpenAPI & documentation generation
 utoipa-scalar = { version = "0.1.0", features = ["axum"] }

crates/services/gifbox/src/routes/mod.rs

@@ -1,5 +1,9 @@
 use crate::AppState;
-use axum::routing::{get, Router};
+use axum::{
+    http::Method,
+    routing::{get, Router},
+};
+use tower_http::cors::{AllowHeaders, Any, CorsLayer};
 
 pub mod categories;
 pub mod root;
@@ -7,9 +11,21 @@ pub mod search;
 pub mod trending;
 
 pub fn router() -> Router<AppState> {
+    let cors = CorsLayer::new()
+        .allow_methods([Method::GET])
+        .allow_headers(AllowHeaders::mirror_request())
+        .expose_headers(vec![
+            "X-RateLimit-Limit".try_into().unwrap(),
+            "X-RateLimit-Bucket".try_into().unwrap(),
+            "X-RateLimit-Remaining".try_into().unwrap(),
+            "X-RateLimit-Reset-After".try_into().unwrap(),
+        ])
+        .allow_origin(Any);
+
     Router::new()
         .route("/", get(root::root))
         .route("/categories", get(categories::categories))
         .route("/search", get(search::search))
         .route("/trending", get(trending::trending))
+        .layer(cors)
 }