[router] Basic OAI Response api (#10346)

sgl-router/src/server.rs

@@ -2,7 +2,9 @@ use crate::config::RouterConfig;
 use crate::logging::{self, LoggingConfig};
 use crate::metrics::{self, PrometheusConfig};
 use crate::middleware::TokenBucket;
-use crate::protocols::spec::{ChatCompletionRequest, CompletionRequest, GenerateRequest};
+use crate::protocols::spec::{
+    ChatCompletionRequest, CompletionRequest, GenerateRequest, ResponsesRequest,
+};
 use crate::reasoning_parser::ParserFactory;
 use crate::routers::{RouterFactory, RouterTrait};
 use crate::service_discovery::{start_service_discovery, ServiceDiscoveryConfig};
@@ -150,6 +152,14 @@ async fn v1_completions(
     state.router.route_completion(Some(&headers), &body).await
 }
 
+async fn v1_responses(
+    State(state): State<Arc<AppState>>,
+    headers: http::HeaderMap,
+    Json(body): Json<ResponsesRequest>,
+) -> Response {
+    state.router.route_responses(Some(&headers), &body).await
+}
+
 // Worker management endpoints
 async fn add_worker(
     State(state): State<Arc<AppState>>,
@@ -227,6 +237,7 @@ pub fn build_app(
         .route("/generate", post(generate))
         .route("/v1/chat/completions", post(v1_chat_completions))
         .route("/v1/completions", post(v1_completions))
+        .route("/v1/responses", post(v1_responses))
         .route_layer(axum::middleware::from_fn_with_state(
             app_state.clone(),
             crate::middleware::concurrency_limit_middleware,