clair/vendor/github.com/codegangsta/negroni

Negroni

Negroni is an idiomatic approach to web middleware in Go. It is tiny, non-intrusive, and encourages use of net/http Handlers.

If you like the idea of Martini, but you think it contains too much magic, then Negroni is a great fit.

Language Translations:

• Português Brasileiro (pt_BR)

Getting Started

After installing Go and setting up your GOPATH, create your first .go file. We'll call it server.go.

package main

import (
  "github.com/codegangsta/negroni"
  "net/http"
  "fmt"
)

func main() {
  mux := http.NewServeMux()
  mux.HandleFunc("/", func(w http.ResponseWriter, req *http.Request) {
    fmt.Fprintf(w, "Welcome to the home page!")
  })

  n := negroni.Classic()
  n.UseHandler(mux)
  n.Run(":3000")
}

Then install the Negroni package (go 1.1 and greater is required):

go get github.com/codegangsta/negroni

Then run your server:

go run server.go

You will now have a Go net/http webserver running on localhost:3000.

Need Help?

If you have a question or feature request, go ask the mailing list. The GitHub issues for Negroni will be used exclusively for bug reports and pull requests.

Is Negroni a Framework?

Negroni is not a framework. It is a library that is designed to work directly with net/http.

Routing?

Negroni is BYOR (Bring your own Router). The Go community already has a number of great http routers available, Negroni tries to play well with all of them by fully supporting net/http. For instance, integrating with Gorilla Mux looks like so:

router := mux.NewRouter()
router.HandleFunc("/", HomeHandler)

n := negroni.New(Middleware1, Middleware2)
// Or use a middleware with the Use() function
n.Use(Middleware3)
// router goes last
n.UseHandler(router)

n.Run(":3000")

negroni.Classic()

negroni.Classic() provides some default middleware that is useful for most applications:

• negroni.Recovery - Panic Recovery Middleware.
• negroni.Logging - Request/Response Logging Middleware.
• negroni.Static - Static File serving under the "public" directory.

This makes it really easy to get started with some useful features from Negroni.

Handlers

Negroni provides a bidirectional middleware flow. This is done through the negroni.Handler interface:

type Handler interface {
  ServeHTTP(rw http.ResponseWriter, r *http.Request, next http.HandlerFunc)
}

If a middleware hasn't already written to the ResponseWriter, it should call the next http.HandlerFunc in the chain to yield to the next middleware handler. This can be used for great good:

func MyMiddleware(rw http.ResponseWriter, r *http.Request, next http.HandlerFunc) {
  // do some stuff before
  next(rw, r)
  // do some stuff after
}

And you can map it to the handler chain with the Use function:

n := negroni.New()
n.Use(negroni.HandlerFunc(MyMiddleware))

You can also map plain old http.Handlers:

n := negroni.New()

mux := http.NewServeMux()
// map your routes

n.UseHandler(mux)

n.Run(":3000")

Run()

Negroni has a convenience function called Run. Run takes an addr string identical to http.ListenAndServe.

n := negroni.Classic()
// ...
log.Fatal(http.ListenAndServe(":8080", n))

Route Specific Middleware

If you have a route group of routes that need specific middleware to be executed, you can simply create a new Negroni instance and use it as your route handler.

router := mux.NewRouter()
adminRoutes := mux.NewRouter()
// add admin routes here

// Create a new negroni for the admin middleware
router.Handle("/admin", negroni.New(
  Middleware1,
  Middleware2,
  negroni.Wrap(adminRoutes),
))

Third Party Middleware

Here is a current list of Negroni compatible middlware. Feel free to put up a PR linking your middleware if you have built one:

Middleware	Author	Description
RestGate	Prasanga Siripala	Secure authentication for REST API endpoints
Graceful	Tyler Bunnell	Graceful HTTP Shutdown
secure	Cory Jacobsen	Middleware that implements a few quick security wins
JWT Middleware	Auth0	Middleware checks for a JWT on the Authorization header on incoming requests and decodes it
binding	Matt Holt	Data binding from HTTP requests into structs
logrus	Dan Buch	Logrus-based logger
render	Cory Jacobsen	Render JSON, XML and HTML templates
gorelic	Jingwen Owen Ou	New Relic agent for Go runtime
gzip	phyber	GZIP response compression
oauth2	David Bochenski	oAuth2 middleware
sessions	David Bochenski	Session Management
permissions2	Alexander Rødseth	Cookies, users and permissions
onthefly	Alexander Rødseth	Generate TinySVG, HTML and CSS on the fly
cors	Olivier Poitrey	Cross Origin Resource Sharing (CORS) support
xrequestid	Andrea Franz	Middleware that assigns a random X-Request-Id header to each request
VanGoH	Taylor Wrobel	Configurable AWS-Style HMAC authentication middleware
stats	Florent Messa	Store information about your web application (response time, etc.)

Examples

Alexander Rødseth created mooseware, a skeleton for writing a Negroni middleware handler.

Live code reload?

gin and fresh both live reload negroni apps.

Essential Reading for Beginners of Go & Negroni

• Using a Context to pass information from middleware to end handler
• Understanding middleware

About

Negroni is obsessively designed by none other than the Code Gangsta