How can I implement middleware for authentication in Go?

How can I implement middleware for authentication in Go?

You can create middleware in Go by defining a function that takes an http.Handler and returns an http.Handler. This function can check for authentication before passing the request to the next handler.

Can you show me a code example?

Sure! Here's a simple example:

package main

import (
    "net/http"
)

func AuthMiddleware(next http.Handler) http.Handler {
    return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
        // Check for authentication (e.g., token)
        token := r.Header.Get("Authorization")
        if token != "your_token_here" {
            http.Error(w, "Unauthorized", http.StatusUnauthorized)
            return
        }
        next.ServeHTTP(w, r)
    })
}

func main() {
    http.Handle("/protected", AuthMiddleware(http.HandlerFunc(ProtectedHandler)))
    http.ListenAndServe(":8080", nil)
}

func ProtectedHandler(w http.ResponseWriter, r *http.Request) {
    w.Write([]byte("This is a protected route!"))
}

What if I want to use JWT for authentication?

You can modify the middleware to validate the JWT token. You would typically use a library like "github.com/dgrijalva/jwt-go" to parse and validate the token.

Thanks! This is really helpful.