Golang : Web routing/multiplex example


Tags : golang http mux web-route multiplex gorilla

Routing based on the URL's path can be useful in some cases like build RESTful API server.

Problem :

You need to route/multiplex to different function/handler based on the URL's path. For example :

 "/someresource/:id" ---> "code to do something with the resource"

 "/users/:name/profile" ---> "code to do something with the profile"

Solution :

Use "net/http" NewServeMux() function. It compares incoming requests against a list of predefined URL paths, and calls the associated handler for the path whenever a match is found.

Code example ;

 package main

 import (
 "net/http"
 "strings"
 )

 func SayHelloWorld(w http.ResponseWriter, r *http.Request) {
 w.Write([]byte("Hello, World!"))
 }

 func ReplyName(w http.ResponseWriter, r *http.Request) {
 URISegments := strings.Split(r.URL.Path, "/")
 w.Write([]byte(URISegments[1]))
 }

 func main() {
 // http.Handler
 mux := http.NewServeMux()
 mux.HandleFunc("/", SayHelloWorld)
 mux.HandleFunc("/replyname", ReplyName)

 http.ListenAndServe(":8080", mux)
 }

there are couple of third parties packages that provides more features when come to routing. For example, Gorilla Mux for path pattern matching (useful for RESTful APIs)

In this example, we will use Gorilla's Mux. Go get from github.com/gorilla/mux before trying out the codes below.

 package main

 import (
 "fmt"
 "github.com/gorilla/mux"
 "net/http"
 )

 func SayHelloWorld(w http.ResponseWriter, r *http.Request) {
 w.Write([]byte("Hello, World!"))
 }

 func ReplyNameGorilla(w http.ResponseWriter, r *http.Request) {
 name := mux.Vars(r)["name"] // variable name is case sensitive
 w.Write([]byte(fmt.Sprintf("Hello %s !", name)))
 }

 func main() {
 mx := mux.NewRouter()
 mx.HandleFunc("/", SayHelloWorld)
 mx.HandleFunc("/{name}", ReplyNameGorilla)  // variable name is case sensitive

 http.ListenAndServe(":8080", mx)
 }

Reference :

http://golang.org/pkg/net/http/#NewServeMux

http://www.gorillatoolkit.org/pkg/mux

  See also : Golang : Get URI segments by number and assign as variable example



Tags : golang http mux web-route multiplex gorilla

By Adam Ng

IF you gain some knowledge or the information here solved your programming problem. Please consider donating to the less fortunate or some charities that you like. Apart from donation, planting trees, volunteering or reducing your carbon footprint will be great too.


Advertisement