090-Julien-Schimdt-Router

README

Third-party ServeMux

You can search godoc.org for third-party packages.

Here is a good third-party ServeMux that allows easy access to methods for routing & path parameters.

julienschmidt/httprouter

Match method & path

The router matches incoming requests by the request method and the path.

func main() {
    router := httprouter.New()
    router.GET("/apply", apply)
    router.POST("/apply", applyProcess) 
    http.ListenAndServe(":8080", router)
}

Named path parameters

The registered path, against which the router matches incoming requests, can also contain parameters. Parameters are dynamic path segments. They match anything until the next '/' or the path end.

func main() {
    router := httprouter.New()
    router.GET("/blog/:category/:article", blog)
    http.ListenAndServe(":8080", router)
}

Requests:
 /blog/go/request-routers            match: category="go", article="request-routers"
 /blog/go/request-routers/           no match, but the router would redirect
 /blog/go/                           no match
 /blog/go/request-routers/comments   no match

Catch-all path parameters

Catch-all parameters match anything until the path end, including the directory index (the '/' before the catch-all). Since they match anything until the end, catch-all parameters must always be the final path element.

func main() {
    router := httprouter.New()
    router.GET("/files/*filepath", loadFile)
    http.ListenAndServe(":8080", router)
}

Requests:
 /files/                             match: filepath="/"
 /files/LICENSE                      match: filepath="/LICENSE"
 /files/templates/article.html       match: filepath="/templates/article.html"
 /files                              no match

Using path parameters

The value of parameters is saved as a []Param

type Param struct {
    Key   string
    Value string
}

The slice is passed to the Handle func as a third parameter.

func Index(w http.ResponseWriter, r *http.Request, _ httprouter.Params) {
    fmt.Fprint(w, "Welcome!\n")
}

func Hello(w http.ResponseWriter, r *http.Request, ps httprouter.Params) {
    fmt.Fprintf(w, "hello, %s!\n", ps.ByName("user"))
}

func main() {
    router := httprouter.New()
    router.GET("/", Index)
    router.GET("/hello/:user", Hello)

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

Retrieve the value of a parameter:

user := ps.ByName("user") // defined by :user or *user

Performance

Julien Schmidt's router is nicely performant