path-router-go

path router is a http router for go using a trie data structure for routing

r := pathrouter.NewRouter()

r.Get("/", func(w http.ResponseWriter, req *http.Request, ps *pathrouter.Params) {
    fmt.Fprintf(w, "Hello, World!")
})

log.Fatal(http.ListenAndServe(":8000", r))

• middleware

middleware can be added using the use method

middleware is applied when the route is inserted and won't change if the use function is called again

func logger(next HandlerFunc) HandlerFunc {
    return func(w http.ResponseWriter, r *http.Request, ps *pathrouter.Params) {
        log.Println(r.Method, r.URL.String())
        next(w, r)
    }
}

r := pathrouter.NewRouter()
r.Use(logger)

• groups

groups in path router allow url path prefixing and middleware scoped to urls

r := pathrouter.NewRouter()

api := r.Scope("/api")
api.Use(logger)

usersAPI := api.Scope("/users")
usersAPI.Use(auth)

usersAPI.Get("/", getUsers)
usersAPI.Post("/", postUsers)
usersAPI.Delete("/", postUsers)

• url params

url parameters can be specified by prefixing the url element with a :

the maximum number of url parameters is limited to 32

/hello/:user

/hello/hehaowen00

the matched values will be stored in the parameter struct in the request context

func (w http.ResponseWriter, r *http.Request, ps *pathrouter.Params) {
    value := ps.Get(r.URL.Path, ":user") // hehaowen00
}

url parameters will only match one url segment unlike wildcards

• wildcards

wildcards are specified using * and must be at the end of the url

urls with wildcards will terminate matching and consume the rest of the url

/static/js/*

/static/js/app/index.min.js

wildcards are stored in the parameter struct in the request context

func (w http.ResponseWriter, r *http.Request, ps *pathrouter.Params) {
    value := ps.Get(r.URL.Path, "*") // app/index.min.js
}

• error handling

error handlers can be registered using HandleErr

currently router only uses http.StatusNotFound handler

r.HandleErr(http.StatusNotFound, func (w http.ResponseWriter, r *http.Request, ps *pathrouter.Params) {
    fmt.Fprintf(w, "Page Not Found\n")
})

• routing conflicts

when a parameter and wildcard node are in the same position within the URL, only the parameter node will be matched and the wildcard route ignored

/special/:id
/special/*

adding another route with the same special path segment will overwrite the previous

/special/:a
/special/:b

• compatibility

path router implements the Handle method to add http.Handler routes

r := pathrouter.NewRouter()

r.Handle("GET", "/handle", http.HandleFunc(func (w http.ResponseWriter, r *http.Request) {
    ps := r.Context().Value(pathrouter.ParamsKey).(*pathrouter.Params)
})