Go gin framework CORS

Question

I\'m using Go gin framework gin

func CORSMiddleware() gin.HandlerFunc {
    return func(c *gin.Context) {
        c.Writer.Header().Set(\"Content-Type\", \"a         


        

Answer 1

We created a minimal middleware.

import (
    "github.com/gin-gonic/gin"
    "net/http"
)

type optionsMiddleware struct {

}

func CreateOptionsMiddleware() *optionsMiddleware{
    return &optionsMiddleware{}
}

func (middleware *optionsMiddleware)Response(context *gin.Context){
    if context.Request.Method == "OPTIONS" {
        context.AbortWithStatus(http.StatusNoContent)
    }
}

and register it with gin middleware :

app  := gin.New()
app.Use(middleware.CreateOptionsMiddleware().Response).
    Use(next-middleware)......

Answer 2

There is also official gin's middleware for handling CORS requests github.com/gin-contrib/cors.

You could install it using $ go get github.com/gin-contrib/cors and then add this middleware in your application like this: package main

import (
    "time"

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

func main() {
    router := gin.Default()
    // CORS for https://foo.com and https://github.com origins, allowing:
    // - PUT and PATCH methods
    // - Origin header
    // - Credentials share
    // - Preflight requests cached for 12 hours
    router.Use(cors.New(cors.Config{
        AllowOrigins:     []string{"https://foo.com"},
        AllowMethods:     []string{"PUT", "PATCH"},
        AllowHeaders:     []string{"Origin"},
        ExposeHeaders:    []string{"Content-Length"},
        AllowCredentials: true,
        AllowOriginFunc: func(origin string) bool {
            return origin == "https://github.com"
        },
        MaxAge: 12 * time.Hour,
    }))
    router.Run()
}

Answer 3

There is an official gin cors plugin gin-contrib/cors. You should use it

Answer 4

func CORSMiddleware() gin.HandlerFunc {
    return func(c *gin.Context) {

        c.Header("Access-Control-Allow-Origin", "*")
        c.Header("Access-Control-Allow-Credentials", "true")
        c.Header("Access-Control-Allow-Headers", "Content-Type, Content-Length, Accept-Encoding, X-CSRF-Token, Authorization, accept, origin, Cache-Control, X-Requested-With")
        c.Header("Access-Control-Allow-Methods", "POST,HEAD,PATCH, OPTIONS, GET, PUT")

        if c.Request.Method == "OPTIONS" {
            c.AbortWithStatus(204)
            return
        }

        c.Next()
    }
}

then use it

router = gin.New()  
router.Use(CORSMiddleware())

Answer 5

There is package https://github.com/rs/cors, that handles CORS requests in the right way. It has the examples for the popular routers including gin. That it:

package main

import (
    "net/http"

    "github.com/gin-gonic/gin"
    cors "github.com/rs/cors/wrapper/gin"
)

func main() {
    router := gin.Default()

    router.Use(cors.Default())
    router.GET("/", func(context *gin.Context) {
        context.JSON(http.StatusOK, gin.H{"hello": "world"})
    })

    router.Run(":8080")
}

In common case, you just add the default handling with router.Use(cors.Default()) to your middlewares in gin. It is enough.

Answer 6

This worked for me - NOTE: the setting of header directly.

func CORSMiddleware() gin.HandlerFunc {
    return func(c *gin.Context) {

        c.Header("Access-Control-Allow-Origin", "*")
        c.Header("Access-Control-Allow-Headers", "*")
        /*
            c.Writer.Header().Set("Access-Control-Allow-Origin", "*")
            c.Writer.Header().Set("Access-Control-Allow-Credentials", "true")
            c.Writer.Header().Set("Access-Control-Allow-Headers", "access-control-allow-origin, access-control-allow-headers")
            c.Writer.Header().Set("Access-Control-Allow-Methods", "GET, HEAD, POST, PUT, DELETE, OPTIONS, PATCH")
        */

        if c.Request.Method == "OPTIONS" {
            c.AbortWithStatus(204)
            return
        }

        c.Next()
    }
}