i keep getting cors error

[Dancingaroundthelies]

so i have a project that use both nextjs and golang as its frontend and backend. I keep getting blocked from fetching my data because of CORS

this is my cors code on the backend :

import (
	"net/http"

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

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

		c.Header("Access-Control-Allow-Origin", "http://localhost:5051")
		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, DELETE")

		if c.Request.Method == http.MethodOptions {
			c.AbortWithStatus(204)
			return
		}

		c.Next()
	}
}

i already specify the origin to my localhost domain but it wont work and i also have experimented in my frontend code to put no-cors but still no result. Please help me out

[zeek0x]

Without a complete and minimal reproducible code example provided, it’s difficult to identify the exact cause of the issue. However, unless there’s a specific reason not to, I recommend using gin-contrib/cors.

[maruki00]

try this code

func CORSMiddleware() gin.HandlerFunc {
	return func(ctx *gin.Context) {
		if ctx.Request.Method == http.MethodOptions || ctx.Request.Header.Get("Access-Control-Request-Method") == "" {
			ctx.Header("Access-Control-Allow-Origin", "http://127.0.0.1:5051")     // Allow requests from specific origin
			ctx.Header("Access-Control-Allow-Methods", "GET, POST, PUT, DELETE, OPTIONS")     // Allowed HTTP methods
			ctx.Header("Access-Control-Allow-Headers", "Origin, Content-Type, Authorization") // Allowed headers
			ctx.Header("Access-Control-Allow-Credentials", "true")     // Allow credentials (cookies, Authorization header)
			ctx.Status(200)
			return
		}
		ctx.Next()
	}
}

[DenisKantic]

This is example from my cors middleware. I'm using vuejs for frontend. Maybe you could try this.

cors_config := cors.Config{
    AllowMethods:     []string{"GET", "POST", "PUT", "DELETE"},
    AllowHeaders:     []string{"Origin", "Content-Type", "Authorization"},
    AllowCredentials: true,
    AllowOrigins:     []string{"http://localhost:3000"},
}

r := gin.Default()
r.Use(cors.New(cors_config))

For the frontend part, I'm using axios so don't forget to include "withCredentials: true".

Also don't forget to install cors package go get github.com/gin-contrib/cors