A quick and easy way to setup a RESTful JSON API
Go-Json-Rest is a thin layer on top of net/http that helps building RESTful JSON APIs easily. It provides fast and scalable request routing using a Trie based implementation, helpers to deal with JSON requests and responses, and middlewares for functionalities like CORS, Auth, Gzip, Status ...
- Features
- Install
- Vendoring
- Middlewares
- Examples
- External Documentation
- Version 3 release notes
- Migration guide from v2 to v3
- Version 2 release notes
- Migration guide from v1 to v2
- Thanks
- Many examples.
- Fast and scalable URL routing. It implements the classic route description syntax using a Trie data structure.
- Architecture based on a router(App) sitting on top of a stack of Middlewares.
- The Middlewares implement functionalities like Logging, Gzip, CORS, Auth, Status, ...
- Implemented as a
net/httpHandler. This standard interface allows combinations with other Handlers. - Test package to help writing tests for your API.
- Monitoring statistics inspired by Memcached.
This package is "go-gettable", just do:
go get github.com/ant0ine/go-json-rest/rest
The recommended way of using this library in your project is to use the "vendoring" method, where this library code is copied in your repository at a specific revision. This page is a good summary of package management in Go.
Core Middlewares:
| Name | Description |
|---|---|
| AccessLogApache | Access log inspired by Apache mod_log_config |
| AccessLogJson | Access log with records as JSON |
| AuthBasic | Basic HTTP auth |
| ContentTypeChecker | Verify the request content type |
| Cors | CORS server side implementation |
| Gzip | Compress the responses |
| If | Conditionally execute a Middleware at runtime |
| JsonIndent | Easy to read JSON |
| Jsonp | Response as JSONP |
| PoweredBy | Manage the X-Powered-By response header |
| Recorder | Record the status code and content length in the Env |
| Status | Memecached inspired stats about the requests |
| Timer | Keep track of the elapsed time in the Env |
Third Party Middlewares:
| Name | Description |
|---|---|
| Statsd | Send stats to a statsd server |
| JWT | Provides authentication via Json Web Tokens |
| AuthToken | Provides a Token Auth implementation |
| ForceSSL | Forces SSL on requests |
| SecureRedirect | Redirect clients from HTTP to HTTPS |
If you have a Go-Json-Rest compatible middleware, feel free to submit a PR to add it in this list, and in the examples.
All the following examples can be found in dedicated examples repository: https://github.com/ant0ine/go-json-rest-examples
First examples to try, as an introduction to go-json-rest.
Tradition!
curl demo:
curl -i http://127.0.0.1:8080/code:
package main
import (
"github.com/ant0ine/go-json-rest/rest"
"log"
"net/http"
)
func main() {
api := rest.NewApi()
api.Use(rest.DefaultDevStack...)
api.SetApp(rest.AppSimple(func(w rest.ResponseWriter, r *rest.Request) {
w.WriteJson(map[string]string{"Body": "Hello World!"})
}))
log.Fatal(http.ListenAndServe(":8080", api.MakeHandler()))
}Demonstrate how to use the relaxed placeholder (notation #paramName).
This placeholder matches everything until the first /, including .
curl demo:
curl -i http://127.0.0.1:8080/lookup/google.com
curl -i http://127.0.0.1:8080/lookup/notadomain
code:
package main
import (
"github.com/ant0ine/go-json-rest/rest"
"log"
"net"
"net/http"
)
func main() {
api := rest.NewApi()
api.Use(rest.DefaultDevStack...)
router, err := rest.MakeRouter(
rest.Get("/lookup/#host", func(w rest.ResponseWriter, req *rest.Request) {
ip, err := net.LookupIP(req.PathParam("host"))
if err != nil {
rest.Error(w, err.Error(), http.StatusInternalServerError)
return
}
w.WriteJson(&ip)
}),
)
if err != nil {
log.Fatal(err)
}
api.SetApp(router)
log.Fatal(http.ListenAndServe(":8080", api.MakeHandler()))
}Demonstrate simple POST GET and DELETE operations
curl demo:
curl -i -H 'Content-Type: application/json' \
-d '{"Code":"FR","Name":"France"}' http://127.0.0.1:8080/countries
curl -i -H 'Content-Type: application/json' \
-d '{"Code":"US","Name":"United States"}' http://127.0.0.1:8080/countries
curl -i http://127.0.0.1:8080/countries/FR
curl -i http://127.0.0.1:8080/countries/US
curl -i http://127.0.0.1:8080/countries
curl -i -X DELETE http://127.0.0.1:8080/countries/FR
curl -i http://127.0.0.1:8080/countries
curl -i -X DELETE http://127.0.0.1:8080/countries/US
curl -i http://127.0.0.1:8080/countries
code:
package main
import (
"github.com/ant0ine/go-json-rest/rest"
"log"
"net/http"
"sync"
)
func main() {
api := rest.NewApi()
api.Use(rest.DefaultDevStack...)
router, err := rest.MakeRouter(
rest.Get("/countries", GetAllCountries),
rest.Post("/countries", PostCountry),
rest.Get("/countries/:code", GetCountry),
rest.Delete("/countries/:code", DeleteCountry),
)
if err != nil {
log.Fatal(err)
}
api.SetApp(router)
log.Fatal(http.ListenAndServe(":8080", api.MakeHandler()))
}
type Country struct {
Code string
Name string
}
var store = map[string]*Country{}
var lock = sync.RWMutex{}
func GetCountry(w rest.ResponseWriter, r *rest.Request) {
code := r.PathParam("code")
lock.RLock()
var country *Country
if store[code] != nil {
country = &Country{}
*country = *store[code]
}
lock.RUnlock()
if country == nil {
rest.NotFound(w, r)
return
}
w.WriteJson(country)
}
func GetAllCountries(w rest.ResponseWriter, r *rest.Request) {
lock.RLock()
countries := make([]Country, len(store))
i := 0
for _, country := range store {
countries[i] = *country
i++
}
lock.RUnlock()
w.WriteJson(&countries)
}
func PostCountry(w rest.ResponseWriter, r *rest.Request) {
country := Country{}
err := r.DecodeJsonPayload(&country)
if err != nil {
rest.Error(w, err.Error(), http.StatusInternalServerError)
return
}
if country.Code == "" {
rest.Error(w, "country code required", 400)
return
}
if country.Name == "" {
rest.Error(w, "country name required", 400)
return
}
lock.Lock()
store[country.Code] = &country
lock.Unlock()
w.WriteJson(&country)
}
func DeleteCountry(w rest.ResponseWriter, r *rest.Request) {
code := r.PathParam("code")
lock.Lock()
delete(store, code)
lock.Unlock()
w.WriteHeader(http.StatusOK)
}Demonstrate how to use Method Values.
Method Values have been introduced in Go 1.1.
This shows how to map a Route to a method of an instantiated object (i.e: receiver of the method)
curl demo:
curl -i -H 'Content-Type: application/json' \
-d '{"Name":"Antoine"}' http://127.0.0.1:8080/users
curl -i http://127.0.0.1:8080/users/0
curl -i -X PUT -H 'Content-Type: application/json' \
-d '{"Name":"Antoine Imbert"}' http://127.0.0.1:8080/users/0
curl -i -X DELETE http://127.0.0.1:8080/users/0
curl -i http://127.0.0.1:8080/users
code:
package main
import (
"fmt"
"github.com/ant0ine/go-json-rest/rest"
"log"
"net/http"
"sync"
)
func main() {
users := Users{
Store: map[string]*User{},
}
api := rest.NewApi()
api.Use(rest.DefaultDevStack...)
router, err := rest.MakeRouter(
rest.Get("/users", users.GetAllUsers),
rest.Post("/users", users.PostUser),
rest.Get("/users/:id", users.GetUser),
rest.Put("/users/:id", users.PutUser),
rest.Delete("/users/:id", users.DeleteUser),
)
if err != nil {
log.Fatal(err)
}
api.SetApp(router)
log.Fatal(http.ListenAndServe(":8080", api.MakeHandler()))
}
type User struct {
Id string
Name string
}
type Users struct {
sync.RWMutex
Store map[string]*User
}
func (u *Users) GetAllUsers(w rest.ResponseWriter, r *rest.Request) {
u.RLock()
users := make([]User, len(u.Store))
i := 0
for _, user := range u.Store {
users[i] = *user
i++
}
u.RUnlock()
w.WriteJson(&users)
}
func (u *Users) GetUser(w rest.ResponseWriter, r *rest.Request) {
id := r.PathParam("id")
u.RLock()
var user *User
if u.Store[id] != nil {
user = &User{}
*user = *u.Store[id]
}
u.RUnlock()
if user == nil {
rest.NotFound(w, r)
return
}
w.WriteJson(user)
}
func (u *Users) PostUser(w rest.ResponseWriter, r *rest.Request) {
user := User{}
err := r.DecodeJsonPayload(&user)
if err != nil {
rest.Error(w, err.Error(), http.StatusInternalServerError)
return
}
u.Lock()
id := fmt.Sprintf("%d", len(u.Store)) // stupid
user.Id = id
u.Store[id] = &user
u.Unlock()
w.WriteJson(&user)
}
func (u *Users) PutUser(w rest.ResponseWriter, r *rest.Request) {
id := r.PathParam("id")
u.Lock()
if u.Store[id] == nil {
rest.NotFound(w, r)
u.Unlock()
return
}
user := User{}
err := r.DecodeJsonPayload(&user)
if err != nil {
rest.Error(w, err.Error(), http.StatusInternalServerError)
u.Unlock()
return
}
user.Id = id
u.Store[id] = &user
u.Unlock()
w.WriteJson(&user)
}
func (u *Users) DeleteUser(w rest.ResponseWriter, r *rest.Request) {
id := r.PathParam("id")
u.Lock()
delete(u.Store, id)
u.Unlock()
w.WriteHeader(http.StatusOK)
}Common use cases, found in many applications.
Combine Go-Json-Rest with other handlers.
api.MakeHandler() is a valid http.Handler, and can be combined with other handlers.
In this example the api handler is used under the /api/ prefix, while a FileServer is instantiated under the /static/ prefix.
curl demo:
curl -i http://127.0.0.1:8080/api/message
curl -i http://127.0.0.1:8080/static/main.go
code:
package main
import (
"github.com/ant0ine/go-json-rest/rest"
"log"
"net/http"
)
func main() {
api := rest.NewApi()
api.Use(rest.DefaultDevStack...)
router, err := rest.MakeRouter(
rest.Get("/message", func(w rest.ResponseWriter, req *rest.Request) {
w.WriteJson(map[string]string{"Body": "Hello World!"})
}),
)
if err != nil {
log.Fatal(err)
}
api.SetApp(router)
http.Handle("/api/", http.StripPrefix("/api", api.MakeHandler()))
http.Handle("/static/", http.StripPrefix("/static", http.FileServer(http.Dir("."))))
log.Fatal(http.ListenAndServe(":8080", nil))
}Demonstrate basic CRUD operation using a store based on MySQL and GORM
GORM is simple ORM library for Go. In this example the same struct is used both as the GORM model and as the JSON model.
curl demo:
curl -i -H 'Content-Type: application/json' \
-d '{"Message":"this is a test"}' http://127.0.0.1:8080/reminders
curl -i http://127.0.0.1:8080/reminders/1
curl -i http://127.0.0.1:8080/reminders
curl -i -X PUT -H 'Content-Type: application/json' \
-d '{"Message":"is updated"}' http://127.0.0.1:8080/reminders/1
curl -i -X DELETE http://127.0.0.1:8080/reminders/1
code:
package main
import (
"github.com/ant0ine/go-json-rest/rest"
_ "github.com/go-sql-driver/mysql"
"github.com/jinzhu/gorm"
"log"
"net/http"
"time"
)
func main() {
i := Impl{}
i.InitDB()
i.InitSchema()
api := rest.NewApi()
api.Use(rest.DefaultDevStack...)
router, err := rest.MakeRouter(
rest.Get("/reminders", i.GetAllReminders),
rest.Post("/reminders", i.PostReminder),
rest.Get("/reminders/:id", i.GetReminder),
rest.Put("/reminders/:id", i.PutReminder),
rest.Delete("/reminders/:id", i.DeleteReminder),
)
if err != nil {
log.Fatal(err)
}
api.SetApp(router)
log.Fatal(http.ListenAndServe(":8080", api.MakeHandler()))
}
type Reminder struct {
Id int64 `json:"id"`
Message string `sql:"size:1024" json:"message"`
CreatedAt time.Time `json:"createdAt"`
UpdatedAt time.Time `json:"updatedAt"`
DeletedAt time.Time `json:"-"`
}
type Impl struct {
DB *gorm.DB
}
func (i *Impl) InitDB() {
var err error
i.DB, err = gorm.Open("mysql", "gorm:gorm@/gorm?charset=utf8&parseTime=True")
if err != nil {
log.Fatalf("Got error when connect database, the error is '%v'", err)
}
i.DB.LogMode(true)
}
func (i *Impl) InitSchema() {
i.DB.AutoMigrate(&Reminder{})
}
func (i *Impl) GetAllReminders(w rest.ResponseWriter, r *rest.Request) {
reminders := []Reminder{}
i.DB.Find(&reminders)
w.WriteJson(&reminders)
}
func (i *Impl) GetReminder(w rest.ResponseWriter, r *rest.Request) {
id := r.PathParam("id")
reminder := Reminder{}
if i.DB.First(&reminder, id).Error != nil {
rest.NotFound(w, r)
return
}
w.WriteJson(&reminder)
}
func (i *Impl) PostReminder(w rest.ResponseWriter, r *rest.Request) {
reminder := Reminder{}
if err := r.DecodeJsonPayload(&reminder); err != nil {
rest.Error(w, err.Error(), http.StatusInternalServerError)
return
}
if err := i.DB.Save(&reminder).Error; err != nil {
rest.Error(w, err.Error(), http.StatusInternalServerError)
return
}
w.WriteJson(&reminder)
}
func (i *Impl) PutReminder(w rest.ResponseWriter, r *rest.Request) {
id := r.PathParam("id")
reminder := Reminder{}
if i.DB.First(&reminder, id).Error != nil {
rest.NotFound(w, r)
return
}
updated := Reminder{}
if err := r.DecodeJsonPayload(&updated); err != nil {
rest.Error(w, err.Error(), http.StatusInternalServerError)
return
}
reminder.Message = updated.Message
if err := i.DB.Save(&reminder).Error; err != nil {
rest.Error(w, err.Error(), http.StatusInternalServerError)
return
}
w.WriteJson(&reminder)
}
func (i *Impl) DeleteReminder(w rest.ResponseWriter, r *rest.Request) {
id := r.PathParam("id")
reminder := Reminder{}
if i.DB.First(&reminder, id).Error != nil {
rest.NotFound(w, r)
return
}
if err := i.DB.Delete(&reminder).Error; err != nil {
rest.Error(w, err.Error(), http.StatusInternalServerError)
return
}
w.WriteHeader(http.StatusOK)
}Demonstrate how to setup CorsMiddleware around all the API endpoints.
curl demo:
curl -i http://127.0.0.1:8080/countries
code:
package main
import (
"github.com/ant0ine/go-json-rest/rest"
"log"
"net/http"
)
func main() {
api := rest.NewApi()
api.Use(rest.DefaultDevStack...)
api.Use(&rest.CorsMiddleware{
RejectNonCorsRequests: false,
OriginValidator: func(origin string, request *rest.Request) bool {
return origin == "http://my.other.host"
},
AllowedMethods: []string{"GET", "POST", "PUT"},
AllowedHeaders: []string{
"Accept", "Content-Type", "X-Custom-Header", "Origin"},
AccessControlAllowCredentials: true,
AccessControlMaxAge: 3600,
})
router, err := rest.MakeRouter(
rest.Get("/countries", GetAllCountries),
)
if err != nil {
log.Fatal(err)
}
api.SetApp(router)
log.Fatal(http.ListenAndServe(":8080", api.MakeHandler()))
}
type Country struct {
Code string
Name string
}
func GetAllCountries(w rest.ResponseWriter, r *rest.Request) {
w.WriteJson(
[]Country{
Country{
Code: "FR",
Name: "France",
},
Country{
Code: "US",
Name: "United States",
},
},
)
}Demonstrate how to use the JSONP middleware.
curl demo:
curl -i http://127.0.0.1:8080/
curl -i http://127.0.0.1:8080/?cb=parseResponsecode:
package main
import (
"github.com/ant0ine/go-json-rest/rest"
"log"
"net/http"
)
func main() {
api := rest.NewApi()
api.Use(rest.DefaultDevStack...)
api.Use(&rest.JsonpMiddleware{
CallbackNameKey: "cb",
})
api.SetApp(rest.AppSimple(func(w rest.ResponseWriter, r *rest.Request) {
w.WriteJson(map[string]string{"Body": "Hello World!"})
}))
log.Fatal(http.ListenAndServe(":8080", api.MakeHandler()))
}Demonstrate how to setup AuthBasicMiddleware as a pre-routing middleware.
curl demo:
curl -i http://127.0.0.1:8080/
curl -i -u admin:admin http://127.0.0.1:8080/
code:
package main
import (
"github.com/ant0ine/go-json-rest/rest"
"log"
"net/http"
)
func main() {
api := rest.NewApi()
api.Use(rest.DefaultDevStack...)
api.Use(&rest.AuthBasicMiddleware{
Realm: "test zone",
Authenticator: func(userId string, password string) bool {
if userId == "admin" && password == "admin" {
return true
}
return false
},
})
api.SetApp(rest.AppSimple(func(w rest.ResponseWriter, r *rest.Request) {
w.WriteJson(map[string]string{"Body": "Hello World!"})
}))
log.Fatal(http.ListenAndServe(":8080", api.MakeHandler()))
}Demonstrate how to use the ForceSSL Middleware to force HTTPS on requests to a go-json-rest API.
For the purposes of this demo, we are using HTTP for all requests and checking the X-Forwarded-Proto header to see if it is set to HTTPS (many routers set this to show what type of connection the client is using, such as Heroku). To do a true HTTPS test, make sure and use http.ListenAndServeTLS with a valid certificate and key file.
Additional documentation for the ForceSSL middleware can be found here.
curl demo:
curl -i 127.0.0.1:8080/
curl -H "X-Forwarded-Proto:https" -i 127.0.0.1:8080/code:
package main
import (
"github.com/ant0ine/go-json-rest/rest"
"github.com/jadengore/go-json-rest-middleware-force-ssl"
"log"
"net/http"
)
func main() {
api := rest.NewApi()
api.Use(&forceSSL.Middleware{
TrustXFPHeader: true,
Enable301Redirects: false,
})
api.SetApp(rest.AppSimple(func(w rest.ResponseWriter, r *rest.Request) {
w.WriteJson(map[string]string{"body": "Hello World!"})
}))
// For the purposes of this demo, only HTTP connections accepted.
// For true HTTPS, use ListenAndServeTLS.
// https://golang.org/pkg/net/http/#ListenAndServeTLS
log.Fatal(http.ListenAndServe(":8080", api.MakeHandler()))
}Demonstrate how to setup a /.status endpoint
Inspired by memcached "stats", this optional feature can be enabled to help monitoring the service.
This example shows how to enable the stats, and how to setup the /.status route.
curl demo:
curl -i http://127.0.0.1:8080/.status
curl -i http://127.0.0.1:8080/.status
...
Output example:
{
"Pid": 21732,
"UpTime": "1m15.926272s",
"UpTimeSec": 75.926272,
"Time": "2013-03-04 08:00:27.152986 +0000 UTC",
"TimeUnix": 1362384027,
"StatusCodeCount": {
"200": 53,
"404": 11
},
"TotalCount": 64,
"TotalResponseTime": "16.777ms",
"TotalResponseTimeSec": 0.016777,
"AverageResponseTime": "262.14us",
"AverageResponseTimeSec": 0.00026214
}
code:
package main
import (
"github.com/ant0ine/go-json-rest/rest"
"log"
"net/http"
)
func main() {
api := rest.NewApi()
statusMw := &rest.StatusMiddleware{}
api.Use(statusMw)
api.Use(rest.DefaultDevStack...)
router, err := rest.MakeRouter(
rest.Get("/.status", func(w rest.ResponseWriter, r *rest.Request) {
w.WriteJson(statusMw.GetStatus())
}),
)
if err != nil {
log.Fatal(err)
}
api.SetApp(router)
log.Fatal(http.ListenAndServe(":8080", api.MakeHandler()))
}Demonstrate how to setup a /.status endpoint protected with basic authentication.
This is a good use case of middleware applied to only one API endpoint.
curl demo:
curl -i http://127.0.0.1:8080/countries
curl -i http://127.0.0.1:8080/.status
curl -i -u admin:admin http://127.0.0.1:8080/.status
...
code:
package main
import (
"github.com/ant0ine/go-json-rest/rest"
"log"
"net/http"
)
func main() {
api := rest.NewApi()
statusMw := &rest.StatusMiddleware{}
api.Use(statusMw)
api.Use(rest.DefaultDevStack...)
auth := &rest.AuthBasicMiddleware{
Realm: "test zone",
Authenticator: func(userId string, password string) bool {
if userId == "admin" && password == "admin" {
return true
}
return false
},
}
router, err := rest.MakeRouter(
rest.Get("/countries", GetAllCountries),
rest.Get("/.status", auth.MiddlewareFunc(
func(w rest.ResponseWriter, r *rest.Request) {
w.WriteJson(statusMw.GetStatus())
},
)),
)
if err != nil {
log.Fatal(err)
}
api.SetApp(router)
log.Fatal(http.ListenAndServe(":8080", api.MakeHandler()))
}
type Country struct {
Code string
Name string
}
func GetAllCountries(w rest.ResponseWriter, r *rest.Request) {
w.WriteJson(
[]Country{
Country{
Code: "FR",
Name: "France",
},
Country{
Code: "US",
Name: "United States",
},
},
)
}More advanced use cases.
Demonstrates how to use the Json Web Token Auth Middleware to authenticate via a JWT token.
curl demo:
curl -d '{"username": "admin", "password": "admin"}' -H "Content-Type:application/json" http://localhost:8080/api/login
curl -H "Authorization:Bearer TOKEN_RETURNED_FROM_ABOVE" http://localhost:8080/api/auth_test
curl -H "Authorization:Bearer TOKEN_RETURNED_FROM_ABOVE" http://localhost:8080/api/refresh_tokencode:
package main
import (
"log"
"net/http"
"time"
"github.com/StephanDollberg/go-json-rest-middleware-jwt"
"github.com/ant0ine/go-json-rest/rest"
)
func handle_auth(w rest.ResponseWriter, r *rest.Request) {
w.WriteJson(map[string]string{"authed": r.Env["REMOTE_USER"].(string)})
}
func main() {
jwt_middleware := &jwt.JWTMiddleware{
Key: []byte("secret key"),
Realm: "jwt auth",
Timeout: time.Hour,
MaxRefresh: time.Hour * 24,
Authenticator: func(userId string, password string) bool {
return userId == "admin" && password == "admin"
}}
api := rest.NewApi()
api.Use(rest.DefaultDevStack...)
// we use the IfMiddleware to remove certain paths from needing authentication
api.Use(&rest.IfMiddleware{
Condition: func(request *rest.Request) bool {
return request.URL.Path != "/login"
},
IfTrue: jwt_middleware,
})
api_router, _ := rest.MakeRouter(
rest.Post("/login", jwt_middleware.LoginHandler),
rest.Get("/auth_test", handle_auth),
rest.Get("/refresh_token", jwt_middleware.RefreshHandler),
)
api.SetApp(api_router)
http.Handle("/api/", http.StripPrefix("/api", api.MakeHandler()))
log.Fatal(http.ListenAndServe(":8080", nil))
}Demonstrate a streaming REST API, where the data is "flushed" to the client ASAP.
The stream format is a Line Delimited JSON.
curl demo:
curl -i http://127.0.0.1:8080/stream
Output:
HTTP/1.1 200 OK
Content-Type: application/json
Date: Sun, 16 Feb 2014 00:39:19 GMT
Transfer-Encoding: chunked
{"Name":"thing #1"}
{"Name":"thing #2"}
{"Name":"thing #3"}
code:
package main
import (
"fmt"
"github.com/ant0ine/go-json-rest/rest"
"log"
"net/http"
"time"
)
func main() {
api := rest.NewApi()
api.Use(&rest.AccessLogApacheMiddleware{})
api.Use(rest.DefaultCommonStack...)
router, err := rest.MakeRouter(
rest.Get("/stream", StreamThings),
)
if err != nil {
log.Fatal(err)
}
api.SetApp(router)
log.Fatal(http.ListenAndServe(":8080", api.MakeHandler()))
}
type Thing struct {
Name string
}
func StreamThings(w rest.ResponseWriter, r *rest.Request) {
cpt := 0
for {
cpt++
w.WriteJson(
&Thing{
Name: fmt.Sprintf("thing #%d", cpt),
},
)
w.(http.ResponseWriter).Write([]byte("\n"))
// Flush the buffer to client
w.(http.Flusher).Flush()
// wait 3 seconds
time.Sleep(time.Duration(3) * time.Second)
}
}Exceptional use of non JSON payloads.
The ResponseWriter implementation provided by go-json-rest is designed to build JSON responses. In order to serve different kind of content, it is recommended to either: a) use another server and configure CORS (see the cors/ example) b) combine the api.MakeHandler() with another http.Handler (see api-and-static/ example)
That been said, exceptionally, it can be convenient to return a different content type on a JSON endpoint. In this case, setting the Content-Type and using the type assertion to access the Write method is enough. As shown in this example.
curl demo:
curl -i http://127.0.0.1:8080/message.txt
code:
package main
import (
"github.com/ant0ine/go-json-rest/rest"
"log"
"net/http"
)
func main() {
api := rest.NewApi()
api.Use(rest.DefaultDevStack...)
router, err := rest.MakeRouter(
rest.Get("/message.txt", func(w rest.ResponseWriter, req *rest.Request) {
w.Header().Set("Content-Type", "text/plain")
w.(http.ResponseWriter).Write([]byte("Hello World!"))
}),
)
if err != nil {
log.Fatal(err)
}
api.SetApp(router)
log.Fatal(http.ListenAndServe(":8080", api.MakeHandler()))
}First, API versioning is not easy and you may want to favor a mechanism that uses only backward compatible changes and deprecation cycles.
That been said, here is an example of API versioning using Semver
It defines a middleware that parses the version, checks a min and a max, and makes it available in the request.Env.
curl demo:
curl -i http://127.0.0.1:8080/api/1.0.0/message
curl -i http://127.0.0.1:8080/api/2.0.0/message
curl -i http://127.0.0.1:8080/api/2.0.1/message
curl -i http://127.0.0.1:8080/api/0.0.1/message
curl -i http://127.0.0.1:8080/api/4.0.1/message
code:
package main
import (
"github.com/ant0ine/go-json-rest/rest"
"github.com/coreos/go-semver/semver"
"log"
"net/http"
)
type SemVerMiddleware struct {
MinVersion string
MaxVersion string
}
func (mw *SemVerMiddleware) MiddlewareFunc(handler rest.HandlerFunc) rest.HandlerFunc {
minVersion, err := semver.NewVersion(mw.MinVersion)
if err != nil {
panic(err)
}
maxVersion, err := semver.NewVersion(mw.MaxVersion)
if err != nil {
panic(err)
}
return func(writer rest.ResponseWriter, request *rest.Request) {
version, err := semver.NewVersion(request.PathParam("version"))
if err != nil {
rest.Error(
writer,
"Invalid version: "+err.Error(),
http.StatusBadRequest,
)
return
}
if version.LessThan(*minVersion) {
rest.Error(
writer,
"Min supported version is "+minVersion.String(),
http.StatusBadRequest,
)
return
}
if maxVersion.LessThan(*version) {
rest.Error(
writer,
"Max supported version is "+maxVersion.String(),
http.StatusBadRequest,
)
return
}
request.Env["VERSION"] = version
handler(writer, request)
}
}
func main() {
svmw := SemVerMiddleware{
MinVersion: "1.0.0",
MaxVersion: "3.0.0",
}
api := rest.NewApi()
api.Use(rest.DefaultDevStack...)
router, err := rest.MakeRouter(
rest.Get("/#version/message", svmw.MiddlewareFunc(
func(w rest.ResponseWriter, req *rest.Request) {
version := req.Env["VERSION"].(*semver.Version)
if version.Major == 2 {
// https://en.wikipedia.org/wiki/Second-system_effect
w.WriteJson(map[string]string{
"Body": "Hello broken World!",
})
} else {
w.WriteJson(map[string]string{
"Body": "Hello World!",
})
}
},
)),
)
if err != nil {
log.Fatal(err)
}
api.SetApp(router)
http.Handle("/api/", http.StripPrefix("/api", api.MakeHandler()))
log.Fatal(http.ListenAndServe(":8080", nil))
}Demonstrate how to use the Statsd Middleware to collect statistics about the requests/reponses. This middleware is based on the g2s statsd client.
curl demo:
# start statsd server
# monitor network
ngrep -d any port 8125
curl -i http://127.0.0.1:8080/message
curl -i http://127.0.0.1:8080/doesnotexist
code:
package main
import (
"github.com/ant0ine/go-json-rest-middleware-statsd"
"github.com/ant0ine/go-json-rest/rest"
"log"
"net/http"
"time"
)
func main() {
api := rest.NewApi()
api.Use(&statsd.StatsdMiddleware{})
api.Use(rest.DefaultDevStack...)
api.SetApp(rest.AppSimple(func(w rest.ResponseWriter, req *rest.Request) {
// take more than 1ms so statsd can report it
time.Sleep(100 * time.Millisecond)
w.WriteJson(map[string]string{"Body": "Hello World!"})
}))
log.Fatal(http.ListenAndServe(":8080", api.MakeHandler()))
}NewRelic integration based on the GoRelic plugin: github.com/yvasiyarov/gorelic
curl demo:
curl -i http://127.0.0.1:8080/code:
package main
import (
"github.com/ant0ine/go-json-rest/rest"
"github.com/yvasiyarov/go-metrics"
"github.com/yvasiyarov/gorelic"
"log"
"net/http"
"time"
)
type NewRelicMiddleware struct {
License string
Name string
Verbose bool
agent *gorelic.Agent
}
func (mw *NewRelicMiddleware) MiddlewareFunc(handler rest.HandlerFunc) rest.HandlerFunc {
mw.agent = gorelic.NewAgent()
mw.agent.NewrelicLicense = mw.License
mw.agent.HTTPTimer = metrics.NewTimer()
mw.agent.Verbose = mw.Verbose
mw.agent.NewrelicName = mw.Name
mw.agent.CollectHTTPStat = true
mw.agent.Run()
return func(writer rest.ResponseWriter, request *rest.Request) {
handler(writer, request)
// the timer middleware keeps track of the time
startTime := request.Env["START_TIME"].(*time.Time)
mw.agent.HTTPTimer.UpdateSince(*startTime)
}
}
func main() {
api := rest.NewApi()
api.Use(rest.DefaultDevStack...)
api.Use(&NewRelicMiddleware{
License: "<REPLACE WITH THE LICENSE KEY>",
Name: "<REPLACE WITH THE APP NAME>",
Verbose: true,
})
api.SetApp(rest.AppSimple(func(w rest.ResponseWriter, r *rest.Request) {
w.WriteJson(map[string]string{"Body": "Hello World!"})
}))
log.Fatal(http.ListenAndServe(":8080", api.MakeHandler()))
}This example uses https://github.com/tylerb/graceful to try to be nice with the clients waiting for responses during a server shutdown (or restart). The HTTP response takes 10 seconds to be completed, printing a message on the wire every second. 10 seconds is also the timeout set for the graceful shutdown. You can play with these numbers to show that the server waits for the responses to complete.
curl demo:
curl -i http://127.0.0.1:8080/messagecode:
package main
import (
"fmt"
"github.com/ant0ine/go-json-rest/rest"
"gopkg.in/tylerb/graceful.v1"
"log"
"net/http"
"time"
)
func main() {
api := rest.NewApi()
api.Use(rest.DefaultDevStack...)
router, err := rest.MakeRouter(
rest.Get("/message", func(w rest.ResponseWriter, req *rest.Request) {
for cpt := 1; cpt <= 10; cpt++ {
// wait 1 second
time.Sleep(time.Duration(1) * time.Second)
w.WriteJson(map[string]string{
"Message": fmt.Sprintf("%d seconds", cpt),
})
w.(http.ResponseWriter).Write([]byte("\n"))
// Flush the buffer to client
w.(http.Flusher).Flush()
}
}),
)
if err != nil {
log.Fatal(err)
}
api.SetApp(router)
server := &graceful.Server{
Timeout: 10 * time.Second,
Server: &http.Server{
Addr: ":8080",
Handler: api.MakeHandler(),
},
}
log.Fatal(server.ListenAndServe())
}Demonstrate how to use SPDY with https://github.com/shykes/spdy-go
For a command line client, install spdycat from: https://github.com/tatsuhiro-t/spdylay
spdycat demo:
spdycat -v --no-tls -2 http://localhost:8080/users/0
code:
package main
import (
"github.com/ant0ine/go-json-rest/rest"
"github.com/shykes/spdy-go"
"log"
)
type User struct {
Id string
Name string
}
func GetUser(w rest.ResponseWriter, req *rest.Request) {
user := User{
Id: req.PathParam("id"),
Name: "Antoine",
}
w.WriteJson(&user)
}
func main() {
api := rest.NewApi()
api.Use(rest.DefaultDevStack...)
router, err := rest.MakeRouter(
rest.Get("/users/:id", GetUser),
)
if err != nil {
log.Fatal(err)
}
api.SetApp(router)
log.Fatal(spdy.ListenAndServeTCP(":8080", api.MakeHandler()))
}Demonstrate a simple Google App Engine app
Here are my steps to make it work with the GAE SDK. (Probably not the best ones)
Assuming that go-json-rest is installed using "go get" and that the GAE SDK is also installed.
Setup:
- copy this examples/gae/ dir outside of the go-json-rest/ tree
- cd gae/
- mkdir -p github.com/ant0ine
- cp -r $GOPATH/src/github.com/ant0ine/go-json-rest github.com/ant0ine/go-json-rest
- rm -rf github.com/ant0ine/go-json-rest/examples/
- path/to/google_appengine/dev_appserver.py .
curl demo:
curl -i http://127.0.0.1:8080/message
code:
package gaehelloworld
import (
"github.com/ant0ine/go-json-rest/rest"
"log"
"net/http"
)
func init() {
api := rest.NewApi()
api.Use(rest.DefaultDevStack...)
router, err := rest.MakeRouter(
&rest.Get("/message", func(w rest.ResponseWriter, req *rest.Request) {
w.WriteJson(map[string]string{"Body": "Hello World!"})
}),
)
if err != nil {
log.Fatal(err)
}
api.SetApp(router)
http.Handle("/", api.MakeHandler())
}Demonstrate how to run websocket in go-json-rest
go client demo:
origin := "http://localhost:8080/"
url := "ws://localhost:8080/ws"
ws, err := websocket.Dial(url, "", origin)
if err != nil {
log.Fatal(err)
}
if _, err := ws.Write([]byte("hello, world\n")); err != nil {
log.Fatal(err)
}
var msg = make([]byte, 512)
var n int
if n, err = ws.Read(msg); err != nil {
log.Fatal(err)
}
log.Printf("Received: %s.", msg[:n])code:
package main
import (
"io"
"log"
"net/http"
"github.com/ant0ine/go-json-rest/rest"
"golang.org/x/net/websocket"
)
func main() {
wsHandler := websocket.Handler(func(ws *websocket.Conn) {
io.Copy(ws, ws)
})
router, err := rest.MakeRouter(
rest.Get("/ws", func(w rest.ResponseWriter, r *rest.Request) {
wsHandler.ServeHTTP(w.(http.ResponseWriter), r.Request)
}),
)
if err != nil {
log.Fatal(err)
}
api := rest.NewApi()
api.Use(rest.DefaultDevStack...)
api.SetApp(router)
log.Fatal(http.ListenAndServe(":8080", api.MakeHandler()))
}Old v1 blog posts:
- Public Middlewares. (12 included in the package)
- A new App interface. (the router being the provided App)
- A new Api object that manages the Middlewares and the App.
- Optional and interchangeable App/router.
api := rest.NewApi()
api.Use(rest.DefaultDevStack...)
api.SetApp(rest.AppSimple(func(w rest.ResponseWriter, r *rest.Request) {
w.WriteJson(map[string]string{"Body": "Hello World!"})
}))
http.ListenAndServe(":8080", api.MakeHandler())All 19 examples have been updated to use the new API. See here
V3 is about deprecating the ResourceHandler in favor of a new API that exposes the Middlewares. As a consequence, all the Middlewares are now public, and the new Api object helps putting them together as a stack. Some default stack configurations are offered. The router is now an App that sits on top of the stack of Middlewares. Which means that the router is no longer required to use Go-Json-Rest.
Design ideas and discussion See here
V3 introduces an API change (see Semver). But it was possible to maintain backward compatibility, and so, ResourceHandler still works. ResourceHandler does the same thing as in V2, but it is now considered as deprecated, and will be removed in a few months. In the meantime, it logs a deprecation warning.
EnableGzip bool: Just include GzipMiddleware in the stack of middlewares.DisableJsonIndent bool: Just don't include JsonIndentMiddleware in the stack of middlewares.EnableStatusService bool: Include StatusMiddleware in the stack and keep a reference to it to access GetStatus().EnableResponseStackTrace bool: Same exact option but moved to RecoverMiddleware.EnableLogAsJson bool: Include AccessLogJsonMiddleware, and possibly remove AccessLogApacheMiddleware.EnableRelaxedContentType bool: Just don't include ContentTypeCheckerMiddleware.OuterMiddlewares []Middleware: You are now building the full stack, OuterMiddlewares are the first in the list.PreRoutingMiddlewares []Middleware: You are now building the full stack, OuterMiddlewares are the last in the list.Logger *log.Logger: Same option but moved to AccessLogApacheMiddleware and AccessLogJsonMiddleware.LoggerFormat AccessLogFormat: Same exact option but moved to AccessLogApacheMiddleware.DisableLogger bool: Just don't include any access log middleware.ErrorLogger *log.Logger: Same exact option but moved to RecoverMiddleware.XPoweredBy string: Same exact option but moved to PoweredByMiddleware.DisableXPoweredBy bool: Just don't include PoweredByMiddleware.
-
Middlewares, the notion of middleware is now formally defined. They can be setup as global pre-routing Middlewares wrapping all the endpoints, or on a per endpoint basis. In fact the internal code of go-json-rest is itself implemented with Middlewares, they are just hidden behind configuration boolean flags to make these very common options even easier to use.
-
A new ResponseWriter. This is now an interface, and allows Middlewares to wrap the writer. The provided writer implements, in addition of rest.ResponseWriter, http.Flusher, http.CloseNotifier, http.Hijacker, and http.ResponseWriter. A lot more Go-ish, and very similar to
net/http. -
The AuthBasic and CORS Middlewares have been added. More to come in the future.
-
Faster, more tasks are performed at init time, and less for each request.
-
New documentation, with more examples.
-
A lot of other small improvements, See the Migration guide to v2
Go-Json-Rest follows Semver and a few breaking changes have been introduced with the v2.
This is more conform to Go style, and makes goimports work.
This:
import (
"github.com/ant0ine/go-json-rest"
)has to be changed to this:
import (
"github.com/ant0ine/go-json-rest/rest"
)This change allows the ResponseWriter to be wrapped, like the one of the net/http package.
This is much more powerful, and allows the creation of Middlewares that wrap the writer. The gzip option, for instance, uses this to encode the payload (see gzip.go).
This:
func (w *rest.ResponseWriter, req *rest.Request) {
...
}has to be changed to this:
func (w rest.ResponseWriter, req *rest.Request) {
...
}Instead of copying Route structures everywhere, pointers are now used. This is more elegant, more efficient, and will allow more sophisticated Route manipulations in the future (like reverse route resolution).
This:
handler.SetRoutes(
rest.Route{
// ...
},
)has to be changed to this:
handler.SetRoutes(
&rest.Route{
// ...
},
)A middleware is an object satisfying this interface:
type Middleware interface {
MiddlewareFunc(handler HandlerFunc) HandlerFunc
}Code using PreRoutingMiddleware will have to be adapted to provide a list of Middleware objects. See the Basic Auth example.
They used to be public methods of the ResponseWriter. The implementation is still there but a type assertion of the corresponding interface is now necessary. Regarding these features, a rest.ResponseWriter now behaves exactly as the http.ResponseWriter implementation provided by net/http.
This:
writer.Flush()has to be changed to this:
writer.(http.Flusher).Flush()The route has to be manually defined. See the Status example. This is more flexible (the route is customizable), and allows combination with Middlewarres. See for instance how to protect this status endpoint with the AuthBasic middleware.
Overall, they provide the same features, but with two methods instead of three, better names, and without the confusing UriForWithParams.
-
func (r *Request) UriBase() url.URLis nowfunc (r *Request) BaseUrl() *url.URL, Note the pointer as the returned value. -
func (r *Request) UriForWithParams(path string, parameters map[string][]string) url.URLis nowfunc (r *Request) UrlFor(path string, queryParams map[string][]string) *url.URL. -
func (r *Request) UriFor(path string) url.URLhas be removed.
- Franck Cuny
- Yann Kerhervé
- Ask Bjørn Hansen
- Paul Lam
- Thanabodee Charoenpiriyakij
- Sebastien Estienne
- Edward Bramanti
Copyright (c) 2013-2016 Antoine Imbert
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