gin-contrib / cors返回404

Question

i've got a golang REST API, which implements gin-contrib/cors. But when i call a POST request the preflight request (OPTIONS) returns a 404 result.

Here's a snippet of the implementation:

engine := gin.New()
group := engine.Group("/api/v1")

// Recovery middleware recovers from any panics and writes a 500 if there was one.
group.Use(gin.Recovery())

// Set cors and db middleware
engine.Use(cors.New(cors.Config{
    AllowOrigins:     []string{"*"},
    AllowMethods:     []string{"*"},
    AllowHeaders:     []string{"*"},
    AllowCredentials: true,     
    MaxAge: 12 * time.Hour,
}))

// Register routes
group.POST("/customers", ctrl.SendRequest)

Answer 1

You need to add your cors middleware to your engine before you create your group. Because gin copies all the middlewares added to the engine to the group when you create the group. So if you add it afterwards to the engine, it won't be part of the group.

engine := gin.New()

// Set cors and db middleware
engine.Use(cors.New(cors.Config{
    AllowOrigins:     []string{"*"},
    AllowMethods:     []string{"*"},
    AllowHeaders:     []string{"*"},
    AllowCredentials: true,     
    MaxAge: 12 * time.Hour,
}))

group := engine.Group("/api/v1")

// Recovery middleware recovers from any panics and writes a 500 if there was one.
group.Use(gin.Recovery())

// Register routes
group.POST("/customers", ctrl.SendRequest)