// Register a middleware handler (or few) on the middleware stack
Use(middlewares ...interface{})

// Register a new middleware stack
Group(fn func(r Router)) Router

// Mount an inline sub-router
Route(pattern string, fn func(r Router)) Router

// Mount a sub-router
Mount(pattern string, handlers ...interface{})

// Register routing handler for all http methods
Handle(pattern string, handlers ...interface{})

// Register routing handler for CONNECT http method
Connect(pattern string, handlers ...interface{})

// Register routing handler for HEAD http method
Head(pattern string, handlers ...interface{})

// Register routing handler for GET http method
Get(pattern string, handlers ...interface{})

// Register routing handler for POST http method
Post(pattern string, handlers ...interface{})

// Register routing handler for PUT http method
Put(pattern string, handlers ...interface{})

// Register routing handler for PATCH http method
Patch(pattern string, handlers ...interface{})

// Register routing handler for DELETE http method
Delete(pattern string, handlers ...interface{})

// Register routing handler for TRACE http method
Trace(pattern string, handlers ...interface{})

// Register routing handler for OPTIONS http method
Options(pattern string, handlers ...interface{})

// Standard HTTP middleware. Compatible and friendly for when a request context isn't needed.
func StdMiddleware(next http.Handler) http.Handler {
  return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
    next.ServeHTTP(w, r)
  })
}

// net/context HTTP middleware. Useful for signaling to stop processing, adding a timeout,
// cancellation, or passing data down the middleware chain.
func CtxMiddleware(next chi.Handler) chi.Handler {
  return chi.HandlerFunc(func(ctx context.Context, w http.ResponseWriter, r *http.Request) {
    ctx = context.WithValue(ctx, "key", "value")
    next.ServeHTTPC(ctx, w, r)
  })
}

// Standard HTTP handler
func StdHandler(w http.ResponseWriter, r *http.Request) {
  w.Write([]byte("hi"))
}

// net/context HTTP request handler
func CtxHandler(ctx context.Context, w http.ResponseWriter, r *http.Request) {
  userID := chi.URLParams(ctx)["userID"] // from a route like /users/:userID
  key := ctx.Value("key").(string)
  w.Write([]byte(fmt.Sprintf("hi %v, %v", userID, key)))
}

import (
  //...
  "github.com/pressly/chi"
  "github.com/pressly/chi/middleware"
  "golang.org/x/net/context"
)

func main() {
  r := chi.NewRouter()

  // A good base middleware stack
  r.Use(middleware.RequestID)
  r.Use(middleware.RealIP)
  r.Use(middleware.Logger)
  r.Use(middleware.Recoverer)

  // When a client closes their connection midway through a request, the
  // http.CloseNotifier will cancel the request context (ctx).
  r.Use(middleware.CloseNotify)

  // Set a timeout value on the request context (ctx), that will signal
  // through ctx.Done() that the request has timed out and further
  // processing should be stopped.
  r.Use(middleware.Timeout(60 * time.Second))

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

  // RESTy routes for "articles" resource
  r.Route("/articles", func(r chi.Router) {
    r.Get("/", paginate, listArticles)  // GET /articles
    r.Post("/", createArticle)          // POST /articles

    r.Route("/:articleID", func(r chi.Router) {
      r.Use(ArticleCtx)
      r.Get("/", getArticle)            // GET /articles/123
      r.Put("/", updateArticle)         // PUT /articles/123
      r.Delete("/", deleteArticle)      // DELETE /articles/123
    })
  })

  // Mount the admin sub-router
  r.Mount("/admin", adminRouter())

  http.ListenAndServe(":3333", r)
}

func ArticleCtx(next chi.Handler) chi.Handler {
  return chi.HandlerFunc(func(ctx context.Context, w http.ResponseWriter, r *http.Request) {
    articleID := chi.URLParams(ctx)["articleID"]
    article, err := dbGetArticle(articleID)
    if err != nil {
      http.Error(w, http.StatusText(404), 404)
      return
    }
    ctx = context.WithValue(ctx, "article", article)
    next.ServeHTTPC(ctx, w, r)
  })
}

func getArticle(ctx context.Context, w http.ResponseWriter, r *http.Request) {
  article, ok := ctx.Value("article").(*Article)
  if !ok {
    http.Error(w, http.StatusText(422), 422)
    return
  }
  w.Write([]byte(fmt.Sprintf("title:%s", article.Title)))
}

// A completely separate router for administrator routes
func adminRouter() chi.Router {
  r := chi.NewRouter()
  r.Use(AdminOnly)
  r.Get("/", adminIndex)
  r.Get("/accounts", adminListAccounts)
  return r
}

func AdminOnly(next chi.Handler) chi.Handler {
  return chi.HandlerFunc(func(ctx context.Context, w http.ResponseWriter, r *http.Request) {
    perm, ok := ctx.Value("acl.permission").(YourPermissionType)
    if !ok || !perm.IsAdmin() {
      http.Error(w, http.StatusText(403), 403)
      return
    }
    next.ServeHTTPC(ctx, w, r)
  })
}