Group Middleware

Middleware can be attached directly to a route group.

This allows specific middleware to affect only a selected part of the application instead of all routes globally.

Group middleware is useful for:

• authentication
• authorization
• API versioning
• admin-only routes
• rate limiting
• request validation
• internal services

Registering Middleware on a Group

Use Group.Use(...) to attach middleware to a route group.

api.Use(SimpleAuth)

Only routes inside that group are affected.

Example

package main

import (
	"net/http"

	"github.com/netlifeguru/router"
)

func SimpleAuth(next router.HandlerFunc) router.HandlerFunc {
	return func(w http.ResponseWriter, r *http.Request, ctx *router.Context) {
		apiKey := r.Header.Get("X-API-KEY")

		if apiKey != "secret-key" {
			http.Error(w, "Unauthorized: Invalid API Key", http.StatusUnauthorized)
			return
		}

		next(w, r, ctx)
	}
}

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

	api := r.Group("/api")

	api.Use(SimpleAuth)

	api.GET("/data", func(w http.ResponseWriter, req *http.Request, ctx *router.Context) {
		w.Write([]byte("Secret data accessed successfully!"))
	})

	r.ListenAndServe(":8000")
}

Testing the Endpoint

Request without the API key:

curl http://localhost:8000/api/data

Response:

Unauthorized: Invalid API Key

Request with the correct API key:

curl -H "X-API-KEY: secret-key" http://localhost:8000/api/data

Response:

Secret data accessed successfully!

Middleware Scope

Middleware registered on a group affects only routes registered inside that group.

Example:

public := r.Group("/public")
api := r.Group("/api")

api.Use(SimpleAuth)

Result:

This allows public and protected routes to coexist cleanly inside the same application.

Nested Groups

Middleware inheritance is hierarchical.

Example:

api := r.Group("/api")
api.Use(SimpleAuth)

admin := api.Group("/admin")

Routes inside /api/admin automatically inherit the middleware from /api.

Notes

Group middleware is executed after global middleware registered through r.Use(...).

This allows applications to combine:

• global middleware
• group-specific middleware
• route-specific behavior

in a predictable middleware chain.