5. URL Routing

# URL Routing For some simple applications, the default `http.ServeMux` can take you prettyfar. If you need more power in how you parse URL endpoints and route them tothe proper handler, you may need to pull in a third party routing framework.For this tutorial, we will use the popular`github.com/julienschmidt/httprouter` library as our router.`github.com/julienschmidt/httprouter` is a great choice for a router as it is avery simple implementation with one of the best performance benchmarks out ofall the third party Go routers. In this example, we will create some routing for a RESTful resource called"posts". Below we define mechanisms to view index, show, create, update,destroy, and edit posts. ~~~ package main import ( "fmt" "net/http" "github.com/julienschmidt/httprouter" ) func main() { r := httprouter.New() r.GET("/", HomeHandler) // Posts collection r.GET("/posts", PostsIndexHandler) r.POST("/posts", PostsCreateHandler) // Posts singular r.GET("/posts/:id", PostShowHandler) r.PUT("/posts/:id", PostUpdateHandler) r.GET("/posts/:id/edit", PostEditHandler) fmt.Println("Starting server on :8080") http.ListenAndServe(":8080", r) } func HomeHandler(rw http.ResponseWriter, r *http.Request, p httprouter.Params) { fmt.Fprintln(rw, "Home") } func PostsIndexHandler(rw http.ResponseWriter, r *http.Request, p httprouter.Params) { fmt.Fprintln(rw, "posts index") } func PostsCreateHandler(rw http.ResponseWriter, r *http.Request, p httprouter.Params) { fmt.Fprintln(rw, "posts create") } func PostShowHandler(rw http.ResponseWriter, r *http.Request, p httprouter.Params) { id := p.ByName("id") fmt.Fprintln(rw, "showing post", id) } func PostUpdateHandler(rw http.ResponseWriter, r *http.Request, p httprouter.Params) { fmt.Fprintln(rw, "post update") } func PostDeleteHandler(rw http.ResponseWriter, r *http.Request, p httprouter.Params) { fmt.Fprintln(rw, "post delete") } func PostEditHandler(rw http.ResponseWriter, r *http.Request, p httprouter.Params) { fmt.Fprintln(rw, "post edit") } ~~~ ## Exercises 1. Explore the documentation for `github.com/julienschmidt/httprouter`. 1. Find out how well `github.com/julienschmidt/httprouter` plays nicely with existing `http.Handler`s like `http.FileServer` 1. `httprouter` has a very simple interface. Explore what kind of abstractions can be built on top of this fast router to make building things like RESTful routing easier.