byom-customer-api/middleware/cors.go

package middleware

import (
	"time"

	"github.com/gin-contrib/cors"
	"github.com/gin-gonic/gin"
)

// CORSConfig represents the configuration for CORS
type CORSConfig struct {
	AllowOrigins     []string
	AllowCredentials bool
	MaxAge           time.Duration
	TrustedProxies   []string
}

// DefaultCORSConfig returns the default CORS configuration
func DefaultCORSConfig() *CORSConfig {
	return &CORSConfig{
		AllowOrigins:     []string{"*"},
		AllowCredentials: true,
		MaxAge:           12 * time.Hour,
		TrustedProxies:   []string{"localhost", "127.0.0.1"},
	}
}

// CORS returns a middleware for handling CORS with secure defaults
func CORS(cfg *CORSConfig) gin.HandlerFunc {
	if cfg == nil {
		cfg = DefaultCORSConfig()
	}

	config := cors.Config{
		AllowOrigins:     cfg.AllowOrigins,
		AllowMethods:     []string{"GET", "POST", "PUT", "PATCH", "DELETE", "OPTIONS"},
		AllowHeaders:     []string{"Origin", "Content-Type", "Accept", "Authorization", "X-Request-ID"},
		ExposeHeaders:    []string{"Content-Length", "Content-Type", "X-Request-ID"},
		AllowCredentials: cfg.AllowCredentials,
		MaxAge:           cfg.MaxAge,
	}

	// Add security-focused CORS settings
	config.AllowWildcard = true
	config.AllowBrowserExtensions = false
	config.AllowWebSockets = false
	config.AllowFiles = false

	return cors.New(config)
}