add support for /v1/models endpoint

Add a dedicated handler for /v1/models that forwards requests to the GitHub Copilot API, providing OpenAI-compatible model listing functionality.

Author: dvcrn

internal/server/handlers.go

@@ -12,9 +12,51 @@ import (
 
 // registerRoutes sets up the routing for the server.
 func (s *Server) registerRoutes(router *http.ServeMux) {
+
+	router.HandleFunc("/v1/models", s.modelsHandler())
+	router.HandleFunc("/models", s.modelsHandler())
 	router.HandleFunc("/", s.proxyHandler())
 }
 
+// modelsHandler forwards models requests to Copilot API
+func (s *Server) modelsHandler() http.HandlerFunc {
+	return func(w http.ResponseWriter, r *http.Request) {
+		s.logger.Info("Models request", "method", r.Method, "path", r.URL.Path)
+
+		r.URL.Path = "/models"
+
+		// Forward the request to the Copilot client
+		upstreamResp, err := s.copilotClient.ForwardRequest(r.Context(), r)
+		if err != nil {
+			s.logger.Error("Models request failed", "error", err)
+			http.Error(w, "Failed to proxy models request", http.StatusBadGateway)
+			return
+		}
+		defer upstreamResp.Body.Close()
+
+		if upstreamResp.StatusCode != http.StatusOK {
+			bodyBytes, err := io.ReadAll(upstreamResp.Body)
+			if err != nil {
+				s.logger.Error("Failed to read models upstream error response body", "error", err)
+				http.Error(w, "Failed to read upstream error response", http.StatusBadGateway)
+				return
+			}
+
+			s.logger.Error("Models upstream request returned non-OK status",
+				"status", upstreamResp.Status,
+				"body", string(bodyBytes))
+
+			// Forward the response to the client
+			w.WriteHeader(upstreamResp.StatusCode)
+			w.Write(bodyBytes)
+			return
+		}
+
+		// Stream the response back to the original client
+		httpstreaming.StreamResponse(w, upstreamResp, s.logger)
+	}
+}
+
 // proxyHandler is the main handler for all incoming requests.
 func (s *Server) proxyHandler() http.HandlerFunc {
 	return func(w http.ResponseWriter, r *http.Request) {