feat(api): add basic CORS support

pkg/api/router.go

@@ -23,6 +23,7 @@ func NewRouter(conf *config.Config) *http.ServeMux {
 		var handler http.Handler
 
 		handler = route.HandlerFunc(conf)
+		handler = middleware.Cors(handler)
 		handler = middleware.Logger(handler)
 		handler = middleware.Tracing(nextRequestID)(handler)
 

pkg/middleware/cors.go

@@ -0,0 +1,19 @@
+package middleware
+
+import (
+	"net/http"
+)
+
+// Cors is a middleware to enabling CORS on HTTP requests
+func Cors(inner http.Handler) http.Handler {
+	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		w.Header().Set("Access-Control-Allow-Origin", "*")
+		w.Header().Set("Access-Control-Allow-Methods", "POST, GET, OPTIONS")
+		w.Header().Set("Access-Control-Allow-Headers", "Accept, Content-Type, Content-Length, Accept-Encoding, Authorization")
+
+		if r.Method != "OPTIONS" {
+			inner.ServeHTTP(w, r)
+		}
+		return
+	})
+}