hitch: middleware + routing for vanilla go http.Handlers — https://github.com/nbio/hitch

hitch-example.go

package main

import (
	"fmt"
	"net/http"

	"github.com/nbio/hitch"
	"github.com/nbio/httpcontext"
	"github.com/nbio/httpgzip"
)

func main() {
	h := hitch.New()
	h.Use(Logger, httpgzip.GzipResponse, SetUser)
	h.Get("/", http.HandlerFunc(Home))

	items := hitch.New()
	items.Use(NestedMiddleware)
	items.Get("/items", http.HandlerFunc(Items))
	items.Get("/items/:id", http.HandlerFunc(Item))
	h.Next(items)

	http.ListenAndServe(":8000", h)
}

func Logger(next http.Handler) http.Handler {
	return http.HandlerFunc(func(w http.ResponseWriter, req *http.Request) {
		fmt.Printf("%s %s\n", req.Method, req.URL.String())
		next.ServeHTTP(w, req)
	})
}

type key int

const userKey key = 0

// SetUser middleware sets the User member of a RequestContext for
// subsequent handlers to depend on.
func SetUser(next http.Handler) http.Handler {
	return http.HandlerFunc(func(w http.ResponseWriter, req *http.Request) {
		req.ParseForm()
		user := req.Form.Get("user")
		w.Header().Set("X-User", user)
		httpcontext.Set(req, userKey, user)
		next.ServeHTTP(w, req)
	})
}

func Home(w http.ResponseWriter, req *http.Request) {
	w.Header().Set("Content-Type", "text/plain")
	fmt.Fprintf(w, "Welcome home, %s!\n", httpcontext.GetString(req, userKey))
}

func NestedMiddleware(next http.Handler) http.Handler {
	return http.HandlerFunc(func(w http.ResponseWriter, req *http.Request) {
		w.Header().Set("X-Nested-Middleware", "active")
		next.ServeHTTP(w, req)
	})
}

func Items(w http.ResponseWriter, req *http.Request) {
	w.Header().Set("Content-Type", "text/plain")
	fmt.Fprintf(w, "Showing all items\n")
}

func Item(w http.ResponseWriter, req *http.Request) {
	w.Header().Set("Content-Type", "text/plain")
	fmt.Fprintf(w, "Showing item: %s\n", hitch.Params(req).ByName("id"))
}

$ go build hitch-example.go

./hitch.go:21: cannot use items (type *hitch.Hitch) as type http.Handler in argument to h.Next:
*hitch.Hitch does not implement http.Handler (missing ServeHTTP method)
./hitch.go:23: cannot use h (type *hitch.Hitch) as type http.Handler in argument to http.ListenAndServe:
*hitch.Hitch does not implement http.Handler (missing ServeHTTP method)

Should be:

12 func main() {
13     h := hitch.New()
14     h.Use(Logger, httpgzip.GzipResponse, SetUser)
15     h.Get("/", http.HandlerFunc(Home))
16 
17     items := hitch.New()
18     items.Use(NestedMiddleware)
19     items.Get("/items", http.HandlerFunc(Items))
20     items.Get("/items/:id", http.HandlerFunc(Item))
21     h.Next(items.Handler())
22 
23     http.ListenAndServe(":8000", h.Handler())
24 }