CORS Middleware

The CorsMiddleware function in the middlewares package provides Cross-Origin Resource Sharing (CORS) functionality for your Twix router. This middleware allows you to control how your server handles cross-origin requests.

CorsConfig

The CorsConfig struct holds the configuration for the CORS middleware.

type CorsConfig struct {
    AllowedOrigins   []string
    AllowedMethods   []string
    AllowedHeaders   []string
    AllowCredentials bool
}

• AllowedOrigins: A list of origins that are allowed to access the resource.
• AllowedMethods: A list of HTTP methods that are allowed for cross-origin requests.
• AllowedHeaders: A list of headers that are allowed in the actual request.
• AllowCredentials: A boolean indicating whether or not credentials are allowed in cross-origin requests.

CorsMiddleware

The CorsMiddleware function creates a middleware handler that applies the specified CORS configuration.

func CorsMiddleware(config CorsConfig) func(http.Handler) http.Handler

Example

package main

import (
    "net/http"
    "github.com/farhanmobashir/twix"
    "github.com/farhanmobashir/twix/middlewares"
)

func main() {
    router := twix.New()

    // Define CORS configuration
    corsConfig := middlewares.CorsConfig{
        AllowedOrigins:   []string{"http://example.com", "http://another-example.com"},
        AllowedMethods:   []string{"GET", "POST", "PUT", "DELETE"},
        AllowedHeaders:   []string{"Content-Type", "Authorization"},
        AllowCredentials: true,
    }

    // Apply CORS middleware to the router
    router.Use(middlewares.CorsMiddleware(corsConfig))

    router.Get("/", func(w http.ResponseWriter, r *http.Request) {
        w.Write([]byte("Hello, World!"))
    })

    http.ListenAndServe(":8080", router)
}

In this example, the CorsMiddleware function is configured to allow requests from http://example.com and http://another-example.com, permit GET, POST, PUT, and DELETE methods, and allow Content-Type and Authorization headers. It also enables credentials for cross-origin requests.

CORS Preflight Requests

The middleware automatically handles CORS preflight requests by responding with a 204 No Content status if the request method is OPTIONS. This allows browsers to verify CORS policies before making actual requests.

Handling Preflight Requests

If the incoming request method is OPTIONS, the middleware responds with 204 No Content status and returns without calling the next handler.

if r.Method == http.MethodOptions {
    w.WriteHeader(http.StatusNoContent)
    return
}