Router/EXAMPLES.md

# Examples

## Basic Usage

```go
package main

import (
	"fmt"
	"net/http"
	"github.com/yourusername/router"
)

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

	r.Get("/", func(w http.ResponseWriter, r *http.Request, _ []string) {
		fmt.Fprintf(w, "Hello World!")
	})

	r.Get("/about", func(w http.ResponseWriter, r *http.Request, _ []string) {
		fmt.Fprintf(w, "About page")
	})

	http.ListenAndServe(":8080", r)
}
```

## Path Parameters

```go
r := router.New()

// Single parameter
r.Get("/users/[id]", func(w http.ResponseWriter, r *http.Request, params []string) {
	id := params[0]
	fmt.Fprintf(w, "User ID: %s", id)
})

// Multiple parameters
r.Get("/posts/[category]/[id]", func(w http.ResponseWriter, r *http.Request, params []string) {
	category := params[0]
	id := params[1]
	fmt.Fprintf(w, "Category: %s, Post ID: %s", category, id)
})

// Wildcard
r.Get("/files/*path", func(w http.ResponseWriter, r *http.Request, params []string) {
	path := params[0]
	fmt.Fprintf(w, "File path: %s", path)
})
```

## Middleware

```go
// Logging middleware
func LoggingMiddleware(next router.Handler) router.Handler {
	return router.Handler(func(w http.ResponseWriter, r *http.Request, params []string) {
		fmt.Printf("[%s] %s\n", r.Method, r.URL.Path)
		next(w, r, params)
	})
}

// Auth middleware
func AuthMiddleware(next router.Handler) router.Handler {
	return router.Handler(func(w http.ResponseWriter, r *http.Request, params []string) {
		token := r.Header.Get("Authorization")
		if token == "" {
			http.Error(w, "Unauthorized", http.StatusUnauthorized)
			return
		}
		next(w, r, params)
	})
}

// Global middleware
r := router.New()
r.Use(LoggingMiddleware)

// Route-specific middleware
r.WithMiddleware(AuthMiddleware).Get("/admin", adminHandler)
```

## Route Groups

```go
r := router.New()

// API group
api := r.Group("/api")
api.Get("/status", statusHandler)

// Versioned API
v1 := api.Group("/v1")
v1.Get("/users", listUsersHandler)
v1.Post("/users", createUserHandler)

v2 := api.Group("/v2")
v2.Get("/users", listUsersV2Handler)
```

## Combining Features

```go
r := router.New()

// Global middleware
r.Use(LoggingMiddleware)

// API group with middleware
api := r.Group("/api")
api.Use(ApiKeyMiddleware)

// Admin group with auth middleware
admin := r.Group("/admin")
admin.Use(AuthMiddleware)

// Users endpoints with versioning
users := api.Group("/v1/users")
users.Get("/", listUsersHandler)
users.Post("/", createUserHandler)
users.Get("/[id]", getUserHandler)
users.Put("/[id]", updateUserHandler)
users.Delete("/[id]", deleteUserHandler)

// Special case with route-specific middleware
api.WithMiddleware(CacheMiddleware).Get("/cached-resource", cachedResourceHandler)
```

## Error Handling

```go
r := router.New()

err := r.Get("/users/[id]", getUserHandler)
if err != nil {
	// Handle error
}

// Custom NotFound handler
oldServeHTTP := r.ServeHTTP
r.ServeHTTP = func(w http.ResponseWriter, req *http.Request) {
	h, params, ok := r.Lookup(req.Method, req.URL.Path)
	if !ok {
		// Custom 404 handler
		w.WriteHeader(http.StatusNotFound)
		fmt.Fprintf(w, "Custom 404: %s not found", req.URL.Path)
		return
	}
	h(w, req, params)
}
```

## Complete Application Example

```go
package main

import (
	"fmt"
	"log"
	"net/http"
	"github.com/yourusername/router"
)

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

	// Global middleware
	r.Use(LoggingMiddleware)

	// Basic routes
	r.Get("/", homeHandler)
	r.Get("/about", aboutHandler)

	// API routes
	api := r.Group("/api")
	api.Use(ApiKeyMiddleware)

	// Users API
	users := api.Group("/users")
	users.Get("/", listUsersHandler)
	users.Post("/", createUserHandler)
	users.Get("/[id]", getUserHandler)
	users.Put("/[id]", updateUserHandler)
	users.Delete("/[id]", deleteUserHandler)

	// Admin routes with auth
	admin := r.Group("/admin")
	admin.Use(AuthMiddleware)
	admin.Get("/", adminDashboardHandler)
	admin.Get("/users", adminUsersHandler)

	// Start server
	log.Println("Server starting on :8080")
	log.Fatal(http.ListenAndServe(":8080", r))
}

// Handlers
func homeHandler(w http.ResponseWriter, r *http.Request, _ []string) {
	fmt.Fprintf(w, "Welcome to the home page")
}

func aboutHandler(w http.ResponseWriter, r *http.Request, _ []string) {
	fmt.Fprintf(w, "About us")
}

func listUsersHandler(w http.ResponseWriter, r *http.Request, _ []string) {
	fmt.Fprintf(w, "List of users")
}

func getUserHandler(w http.ResponseWriter, r *http.Request, params []string) {
	id := params[0]
	fmt.Fprintf(w, "User details for ID: %s", id)
}

func createUserHandler(w http.ResponseWriter, r *http.Request, _ []string) {
	// Parse form data or JSON body
	fmt.Fprintf(w, "User created")
}

func updateUserHandler(w http.ResponseWriter, r *http.Request, params []string) {
	id := params[0]
	fmt.Fprintf(w, "User updated: %s", id)
}

func deleteUserHandler(w http.ResponseWriter, r *http.Request, params []string) {
	id := params[0]
	fmt.Fprintf(w, "User deleted: %s", id)
}

func adminDashboardHandler(w http.ResponseWriter, r *http.Request, _ []string) {
	fmt.Fprintf(w, "Admin Dashboard")
}

func adminUsersHandler(w http.ResponseWriter, r *http.Request, _ []string) {
	fmt.Fprintf(w, "Admin Users Management")
}

// Middleware
func LoggingMiddleware(next router.Handler) router.Handler {
	return router.Handler(func(w http.ResponseWriter, r *http.Request, params []string) {
		log.Printf("[%s] %s", r.Method, r.URL.Path)
		next(w, r, params)
	})
}

func ApiKeyMiddleware(next router.Handler) router.Handler {
	return router.Handler(func(w http.ResponseWriter, r *http.Request, params []string) {
		apiKey := r.Header.Get("X-API-Key")
		if apiKey == "" {
			http.Error(w, "API key required", http.StatusUnauthorized)
			return
		}
		next(w, r, params)
	})
}

func AuthMiddleware(next router.Handler) router.Handler {
	return router.Handler(func(w http.ResponseWriter, r *http.Request, params []string) {
		// Check session or JWT
		authorized := checkUserAuth(r)
		if !authorized {
			http.Redirect(w, r, "/login", http.StatusSeeOther)
			return
		}
		next(w, r, params)
	})
}

func checkUserAuth(r *http.Request) bool {
	// Implementation of auth check
	return r.Header.Get("Authorization") != ""
}
```