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.

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()
n.Use(Middleware1)
n.Use(Middleware2)
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 middlware 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 ole http.Handler's:

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))

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
Graceful	Tyler Bunnell	Graceful HTTP Shutdown
secure	Cory Jacobsen	Middleware that implements a few quick security wins.
binding	Matt Holt	Data binding from HTTP requests into structs

Live code reload?

gin and fresh both live reload negroni apps.

About

Negroni is obsessively designed by none other than the Code Gangsta