README
Negroni
Notice: This is the library formerly known as
github.com/codegangsta/negroni
-- Github will automatically redirect requests
to this repository, but we recommend updating your references for clarity.
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:
Getting Started
After installing Go and setting up your
GOPATH, create your first .go
file.
We'll call it server.go
.
package main
import (
"fmt"
"net/http"
"github.com/urfave/negroni"
)
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() // Includes some default middlewares
n.UseHandler(mux)
http.ListenAndServe(":3000", n)
}
Then install the Negroni package (NOTE: >= go 1.1 is required):
go get github.com/urfave/negroni
Then run your server:
go run server.go
You will now have a Go net/http
webserver running on localhost:3000
.
Packaging
If you are on Debian, negroni
is also available as a
package that
you can install via apt install golang-github-urfave-negroni-dev
(at the time
of writing, it is in the sid
repositories).
Is Negroni a Framework?
Negroni is not a framework. It is a middleware-focused 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, and 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)
http.ListenAndServe(":3001", n)
negroni.Classic()
negroni.Classic()
provides some default middleware that is useful for most
applications:
negroni.Recovery
- Panic Recovery Middleware.negroni.Logger
- Request/Response Logger 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.Handler
s:
n := negroni.New()
mux := http.NewServeMux()
// map your routes
n.UseHandler(mux)
http.ListenAndServe(":3000", n)
With()
Negroni has a convenience function called With
. With
takes one or more
Handler
instances and returns a new Negroni
with the combination of the
receiver's handlers and the new handlers.
// middleware we want to reuse
common := negroni.New()
common.Use(MyMiddleware1)
common.Use(MyMiddleware2)
// `specific` is a new negroni with the handlers from `common` combined with the
// the handlers passed in
specific := common.With(
SpecificMiddleware1,
SpecificMiddleware2
)
Run()
Negroni has a convenience function called Run
. Run
takes an addr string
identical to http.ListenAndServe
.
package main
import (
"github.com/urfave/negroni"
)
func main() {
n := negroni.Classic()
n.Run(":8080")
}
If no address is provided, the PORT
environment variable is used instead.
If the PORT
environment variable is not defined, the default address will be used.
See Run for a complete description.
In general, you will want to use net/http
methods and pass negroni
as a
Handler
, as this is more flexible, e.g.:
package main
import (
"fmt"
"log"
"net/http"
"time"
"github.com/urfave/negroni"
)
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() // Includes some default middlewares
n.UseHandler(mux)
s := &http.Server{
Addr: ":8080",
Handler: n,
ReadTimeout: 10 * time.Second,
WriteTimeout: 10 * time.Second,
MaxHeaderBytes: 1 << 20,
}
log.Fatal(s.ListenAndServe())
}
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.PathPrefix("/admin").Handler(negroni.New(
Middleware1,
Middleware2,
negroni.Wrap(adminRoutes),
))
If you are using Gorilla Mux, here is an example using a subrouter:
router := mux.NewRouter()
subRouter := mux.NewRouter().PathPrefix("/subpath").Subrouter().StrictSlash(true)
subRouter.HandleFunc("/", someSubpathHandler) // "/subpath/"
subRouter.HandleFunc("/:id", someSubpathHandler) // "/subpath/:id"
// "/subpath" is necessary to ensure the subRouter and main router linkup
router.PathPrefix("/subpath").Handler(negroni.New(
Middleware1,
Middleware2,
negroni.Wrap(subRouter),
))
With()
can be used to eliminate redundancy for middlewares shared across
routes.
router := mux.NewRouter()
apiRoutes := mux.NewRouter()
// add api routes here
webRoutes := mux.NewRouter()
// add web routes here
// create common middleware to be shared across routes
common := negroni.New(
Middleware1,
Middleware2,
)
// create a new negroni for the api middleware
// using the common middleware as a base
router.PathPrefix("/api").Handler(common.With(
APIMiddleware1,
negroni.Wrap(apiRoutes),
))
// create a new negroni for the web middleware
// using the common middleware as a base
router.PathPrefix("/web").Handler(common.With(
WebMiddleware1,
negroni.Wrap(webRoutes),
))
Bundled Middleware
Static
This middleware will serve files on the filesystem. If the files do not exist,
it proxies the request to the next middleware. If you want the requests for
non-existent files to return a 404 File Not Found
to the user you should look
at using http.FileServer as
a handler.
Example:
package main
import (
"fmt"
"net/http"
"github.com/urfave/negroni"
)
func main() {
mux := http.NewServeMux()
mux.HandleFunc("/", func(w http.ResponseWriter, req *http.Request) {
fmt.Fprintf(w, "Welcome to the home page!")
})
// Example of using a http.FileServer if you want "server-like" rather than "middleware" behavior
// mux.Handle("/public", http.FileServer(http.Dir("/home/public")))
n := negroni.New()
n.Use(negroni.NewStatic(http.Dir("/tmp")))
n.UseHandler(mux)
http.ListenAndServe(":3002", n)
}
Will serve files from the /tmp
directory first, but proxy calls to the next
handler if the request does not match a file on the filesystem.
Recovery
This middleware catches panic
s and responds with a 500
response code. If
any other middleware has written a response code or body, this middleware will
fail to properly send a 500 to the client, as the client has already received
the HTTP response code. Additionally, an PanicHandlerFunc
can be attached
to report 500's to an error reporting service such as Sentry or Airbrake.
Example:
package main
import (
"net/http"
"github.com/urfave/negroni"
)
func main() {
mux := http.NewServeMux()
mux.HandleFunc("/", func(w http.ResponseWriter, req *http.Request) {
panic("oh no")
})
n := negroni.New()
n.Use(negroni.NewRecovery())
n.UseHandler(mux)
http.ListenAndServe(":3003", n)
}
Will return a 500 Internal Server Error
to each request. It will also log the
stack traces as well as print the stack trace to the requester if PrintStack
is set to true
(the default).
Example with error handler:
package main
import (
"net/http"
"github.com/urfave/negroni"
)
func main() {
mux := http.NewServeMux()
mux.HandleFunc("/", func(w http.ResponseWriter, req *http.Request) {
panic("oh no")
})
n := negroni.New()
recovery := negroni.NewRecovery()
recovery.PanicHandlerFunc = reportToSentry
n.Use(recovery)
n.UseHandler(mux)
http.ListenAndServe(":3003", n)
}
func reportToSentry(info *negroni.PanicInformation) {
// write code here to report error to Sentry
}
The middleware simply output the informations on STDOUT by default.
You can customize the output process by using the SetFormatter()
function.
You can use also the HTMLPanicFormatter
to display a pretty HTML when a crash occurs.
package main
import (
"net/http"
"github.com/urfave/negroni"
)
func main() {
mux := http.NewServeMux()
mux.HandleFunc("/", func(w http.ResponseWriter, req *http.Request) {
panic("oh no")
})
n := negroni.New()
recovery := negroni.NewRecovery()
recovery.Formatter = &negroni.HTMLPanicFormatter{}
n.Use(recovery)
n.UseHandler(mux)
http.ListenAndServe(":3003", n)
}
Logger
This middleware logs each incoming request and response.
Example:
package main
import (
"fmt"
"net/http"
"github.com/urfave/negroni"
)
func main() {
mux := http.NewServeMux()
mux.HandleFunc("/", func(w http.ResponseWriter, req *http.Request) {
fmt.Fprintf(w, "Welcome to the home page!")
})
n := negroni.New()
n.Use(negroni.NewLogger())
n.UseHandler(mux)
http.ListenAndServe(":3004", n)
}
Will print a log similar to:
[negroni] 2017-10-04T14:56:25+02:00 | 200 | 378µs | localhost:3004 | GET /
on each request.
You can also set your own log format by calling the SetFormat
function. The format is a template string with fields as mentioned in the LoggerEntry
struct. So, as an example -
l.SetFormat("[{{.Status}} {{.Duration}}] - {{.Request.UserAgent}}")
will show something like - [200 18.263µs] - Go-User-Agent/1.1
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 |
---|---|---|
authz | Yang Luo | ACL, RBAC, ABAC Authorization middlware based on Casbin |
binding | Matt Holt | Data binding from HTTP requests into structs |
cloudwatch | Colin Steele | AWS cloudwatch metrics middleware |
cors | Olivier Poitrey | Cross Origin Resource Sharing (CORS) support |
csp | Awake Networks | Content Security Policy (CSP) support |
delay | Jeff Martinez | Add delays/latency to endpoints. Useful when testing effects of high latency |
New Relic Go Agent | Yadvendar Champawat | Official New Relic Go Agent (currently in beta) |
gorelic | Jingwen Owen Ou | New Relic agent for Go runtime |
Graceful | Tyler Bunnell | Graceful HTTP Shutdown |
gzip | phyber | GZIP response compression |
JWT Middleware | Auth0 | Middleware checks for a JWT on the Authorization header on incoming requests and decodes it |
JWT Middleware | Marcelo Fuentes | JWT middleware for golang |
logrus | Dan Buch | Logrus-based logger |
oauth2 | David Bochenski | oAuth2 middleware |
onthefly | Alexander Rødseth | Generate TinySVG, HTML and CSS on the fly |
permissions2 | Alexander Rødseth | Cookies, users and permissions |
prometheus | Rene Zbinden | Easily create metrics endpoint for the prometheus instrumentation tool |
render | Cory Jacobsen | Render JSON, XML and HTML templates |
RestGate | Prasanga Siripala | Secure authentication for REST API endpoints |
secure | Cory Jacobsen | Middleware that implements a few quick security wins |
sessions | David Bochenski | Session Management |
stats | Florent Messa | Store information about your web application (response time, etc.) |
VanGoH | Taylor Wrobel | Configurable AWS-Style HMAC authentication middleware |
xrequestid | Andrea Franz | Middleware that assigns a random X-Request-Id header to each request |
mgo session | Joel James | Middleware that handles creating and closing mgo sessions per request |
digits | Bilal Amarni | Middleware that handles Twitter Digits authentication |
stats | Chirag Gupta | Middleware that manages qps and latency stats for your endpoints and asynchronously flushes them to influx db |
Chaos | Marc Falzon | Middleware for injecting chaotic behavior into application in a programmatic way |
Examples
Alexander Rødseth created mooseware, a skeleton for writing a Negroni middleware handler.
Prasanga Siripala created an effective skeleton structure for web-based Go/Negroni projects: Go-Skeleton
Live code reload?
gin and fresh both live reload negroni apps.
Essential Reading for Beginners of Go & Negroni
About
Negroni is obsessively designed by none other than the Code Gangsta
Documentation
Overview ¶
Package 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.
For a full guide visit http://github.com/urfave/negroni
package main import ( "github.com/urfave/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") }
Index ¶
- Constants
- Variables
- type ALogger
- type HTMLPanicFormatter
- type Handler
- type HandlerFunc
- type Logger
- type LoggerEntry
- type Negroni
- func (n *Negroni) Handlers() []Handler
- func (n *Negroni) Run(addr ...string)
- func (n *Negroni) ServeHTTP(rw http.ResponseWriter, r *http.Request)
- func (n *Negroni) Use(handler Handler)
- func (n *Negroni) UseFunc(...)
- func (n *Negroni) UseHandler(handler http.Handler)
- func (n *Negroni) UseHandlerFunc(handlerFunc func(rw http.ResponseWriter, r *http.Request))
- func (n *Negroni) With(handlers ...Handler) *Negroni
- type PanicFormatter
- type PanicInformation
- type Recovery
- type ResponseWriter
- type Static
- type TextPanicFormatter
Constants ¶
const (
// DefaultAddress is used if no other is specified.
DefaultAddress = ":8080"
)
Variables ¶
var LoggerDefaultDateFormat = time.RFC3339
LoggerDefaultDateFormat is the format used for date by the default Logger instance.
var LoggerDefaultFormat = "{{.StartTime}} | {{.Status}} | \t {{.Duration}} | {{.Hostname}} | {{.Method}} {{.Path}}"
LoggerDefaultFormat is the format logged used by the default Logger instance.
Functions ¶
Types ¶
type ALogger ¶
type ALogger interface { Println(v ...interface{}) Printf(format string, v ...interface{}) }
ALogger interface
type HTMLPanicFormatter ¶
type HTMLPanicFormatter struct{}
HTMLPanicFormatter output the stack inside an HTML page. This has been largely inspired by https://github.com/go-martini/martini/pull/156/commits.
func (*HTMLPanicFormatter) FormatPanicError ¶
func (t *HTMLPanicFormatter) FormatPanicError(rw http.ResponseWriter, r *http.Request, infos *PanicInformation)
type Handler ¶
type Handler interface {
ServeHTTP(rw http.ResponseWriter, r *http.Request, next http.HandlerFunc)
}
Handler handler is an interface that objects can implement to be registered to serve as middleware in the Negroni middleware stack. ServeHTTP should yield to the next middleware in the chain by invoking the next http.HandlerFunc passed in.
If the Handler writes to the ResponseWriter, the next http.HandlerFunc should not be invoked.
func Wrap ¶
Wrap converts a http.Handler into a negroni.Handler so it can be used as a Negroni middleware. The next http.HandlerFunc is automatically called after the Handler is executed.
func WrapFunc ¶
func WrapFunc(handlerFunc http.HandlerFunc) Handler
WrapFunc converts a http.HandlerFunc into a negroni.Handler so it can be used as a Negroni middleware. The next http.HandlerFunc is automatically called after the Handler is executed.
type HandlerFunc ¶
type HandlerFunc func(rw http.ResponseWriter, r *http.Request, next http.HandlerFunc)
HandlerFunc is an adapter to allow the use of ordinary functions as Negroni handlers. If f is a function with the appropriate signature, HandlerFunc(f) is a Handler object that calls f.
func (HandlerFunc) ServeHTTP ¶
func (h HandlerFunc) ServeHTTP(rw http.ResponseWriter, r *http.Request, next http.HandlerFunc)
type Logger ¶
type Logger struct { // ALogger implements just enough log.Logger interface to be compatible with other implementations ALogger // contains filtered or unexported fields }
Logger is a middleware handler that logs the request as it goes in and the response as it goes out.
func (*Logger) ServeHTTP ¶
func (l *Logger) ServeHTTP(rw http.ResponseWriter, r *http.Request, next http.HandlerFunc)
func (*Logger) SetDateFormat ¶
type LoggerEntry ¶
type LoggerEntry struct { StartTime string Status int Duration time.Duration Hostname string Method string Path string Request *http.Request }
LoggerEntry is the structure passed to the template.
type Negroni ¶
type Negroni struct {
// contains filtered or unexported fields
}
Negroni is a stack of Middleware Handlers that can be invoked as an http.Handler. Negroni middleware is evaluated in the order that they are added to the stack using the Use and UseHandler methods.
func Classic ¶
func Classic() *Negroni
Classic returns a new Negroni instance with the default middleware already in the stack.
Recovery - Panic Recovery Middleware Logger - Request/Response Logging Static - Static File Serving
func (*Negroni) Handlers ¶
Returns a list of all the handlers in the current Negroni middleware chain.
func (*Negroni) Run ¶
Run is a convenience function that runs the negroni stack as an HTTP server. The addr string, if provided, takes the same format as http.ListenAndServe. If no address is provided but the PORT environment variable is set, the PORT value is used. If neither is provided, the address' value will equal the DefaultAddress constant.
func (*Negroni) Use ¶
Use adds a Handler onto the middleware stack. Handlers are invoked in the order they are added to a Negroni.
func (*Negroni) UseFunc ¶
func (n *Negroni) UseFunc(handlerFunc func(rw http.ResponseWriter, r *http.Request, next http.HandlerFunc))
UseFunc adds a Negroni-style handler function onto the middleware stack.
func (*Negroni) UseHandler ¶
UseHandler adds a http.Handler onto the middleware stack. Handlers are invoked in the order they are added to a Negroni.
func (*Negroni) UseHandlerFunc ¶
func (n *Negroni) UseHandlerFunc(handlerFunc func(rw http.ResponseWriter, r *http.Request))
UseHandlerFunc adds a http.HandlerFunc-style handler function onto the middleware stack.
type PanicFormatter ¶
type PanicFormatter interface { // FormatPanicError output the stack for a given answer/response. // In case the the middleware should not output the stack trace, // the field `Stack` of the passed `PanicInformation` instance equals `[]byte{}`. FormatPanicError(rw http.ResponseWriter, r *http.Request, infos *PanicInformation) }
PanicFormatter is an interface on object can implement to be able to output the stack trace
type PanicInformation ¶
PanicInformation contains all elements for printing stack informations.
func (*PanicInformation) RequestDescription ¶
func (p *PanicInformation) RequestDescription() string
RequestDescription returns a printable description of the url
func (*PanicInformation) StackAsString ¶
func (p *PanicInformation) StackAsString() string
StackAsString returns a printable version of the stack
type Recovery ¶
type Recovery struct { Logger ALogger PrintStack bool PanicHandlerFunc func(*PanicInformation) StackAll bool StackSize int Formatter PanicFormatter // Deprecated: Use PanicHandlerFunc instead to receive panic // error with additional information (see PanicInformation) ErrorHandlerFunc func(interface{}) }
Recovery is a Negroni middleware that recovers from any panics and writes a 500 if there was one.
func (*Recovery) ServeHTTP ¶
func (rec *Recovery) ServeHTTP(rw http.ResponseWriter, r *http.Request, next http.HandlerFunc)
type ResponseWriter ¶
type ResponseWriter interface { http.ResponseWriter http.Flusher // Status returns the status code of the response or 0 if the response has // not been written Status() int // Written returns whether or not the ResponseWriter has been written. Written() bool // Size returns the size of the response body. Size() int // Before allows for a function to be called before the ResponseWriter has been written to. This is // useful for setting headers or any other operations that must happen before a response has been written. Before(func(ResponseWriter)) }
ResponseWriter is a wrapper around http.ResponseWriter that provides extra information about the response. It is recommended that middleware handlers use this construct to wrap a responsewriter if the functionality calls for it.
func NewResponseWriter ¶
func NewResponseWriter(rw http.ResponseWriter) ResponseWriter
NewResponseWriter creates a ResponseWriter that wraps an http.ResponseWriter
type Static ¶
type Static struct { // Dir is the directory to serve static files from Dir http.FileSystem // Prefix is the optional prefix used to serve the static directory content Prefix string // IndexFile defines which file to serve as index if it exists. IndexFile string }
Static is a middleware handler that serves static files in the given directory/filesystem. If the file does not exist on the filesystem, it passes along to the next middleware in the chain. If you desire "fileserver" type behavior where it returns a 404 for unfound files, you should consider using http.FileServer from the Go stdlib.
func NewStatic ¶
func NewStatic(directory http.FileSystem) *Static
NewStatic returns a new instance of Static
func (*Static) ServeHTTP ¶
func (s *Static) ServeHTTP(rw http.ResponseWriter, r *http.Request, next http.HandlerFunc)
type TextPanicFormatter ¶
type TextPanicFormatter struct{}
TextPanicFormatter output the stack as simple text on os.Stdout. If no `Content-Type` is set, it will output the data as `text/plain; charset=utf-8`. Otherwise, the origin `Content-Type` is kept.
func (*TextPanicFormatter) FormatPanicError ¶
func (t *TextPanicFormatter) FormatPanicError(rw http.ResponseWriter, r *http.Request, infos *PanicInformation)