fix: cors and content-type on error

auth.go

@@ -14,7 +14,6 @@ func handleAuth(c *gin.Context) error {
 	authorization := c.Request.Header.Get("Authorization")
 	if !strings.HasPrefix(authorization, "Bearer") {
 		err = errors.New("authorization header should start with 'Bearer'")
-		c.AbortWithError(403, err)
 		return err
 	}
 
@@ -24,7 +23,6 @@ func handleAuth(c *gin.Context) error {
 	for _, auth := range strings.Split(config.Authorization, ",") {
 		if authorization != strings.Trim(auth, " ") {
 			err = errors.New("wrong authorization header")
-			c.AbortWithError(403, err)
 			return err
 		}
 	}

cors.go

@@ -6,14 +6,8 @@ import (
 
 func corsMiddleware() gin.HandlerFunc {
 	return func(c *gin.Context) {
-		// delete existing headers
-		c.Writer.Header().Del("Access-Control-Allow-Origin")
-		c.Writer.Header().Del("Access-Control-Allow-Methods")
-		c.Writer.Header().Del("Access-Control-Allow-Headers")
-
-		// set new headers
-		c.Writer.Header().Set("Access-Control-Allow-Origin", "*")
-		c.Writer.Header().Set("Access-Control-Allow-Methods", "POST, GET, OPTIONS, PUT, DELETE, PATCH")
-		c.Writer.Header().Set("Access-Control-Allow-Headers", "Origin, Authorization, Content-Type")
+		c.Header("Access-Control-Allow-Origin", "*")
+		c.Header("Access-Control-Allow-Methods", "POST, GET, OPTIONS, PUT, DELETE, PATCH")
+		c.Header("Access-Control-Allow-Headers", "Origin, Authorization, Content-Type")
 	}
 }

main.go

@@ -73,6 +73,9 @@ func main() {
 	m.SetMetricPath("/v1/metrics")
 	m.Use(engine)
 
+	// CORS middleware
+	engine.Use(corsMiddleware())
+
 	// error handle middleware
 	engine.Use(func(c *gin.Context) {
 		c.Next()
@@ -85,9 +88,6 @@ func main() {
 		})
 	})
 
-	// CORS middleware
-	engine.Use(corsMiddleware())
-
 	// CORS handler
 	engine.OPTIONS("/v1/*any", func(ctx *gin.Context) {
 		ctx.AbortWithStatus(200)
@@ -114,7 +114,10 @@ func main() {
 
 		// check authorization header
 		if !*noauth {
-			if handleAuth(c) != nil {
+			err := handleAuth(c)
+			if err != nil {
+				c.Header("Content-Type", "application/json")
+				c.AbortWithError(403, err)
 				return
 			}
 		}