Example "injecting" services into a HTTP handler using gorilla.pat and negroni

handlers.go

package web

func contactHandler(
	res http.ResponseWriter,
	req *http.Request,
	csrf csrf.TokenManager,
	nodeRepository node.Repository,
) {
	
}

server.go

package web

import (
	"github.com/codegangsta/negroni"
	"github.com/goincremental/negroni-sessions"
	"github.com/goincremental/negroni-sessions/cookiestore"
	"github.com/gorilla/pat"
)

// init because this is app engine
func init() {
  // create services
	store := cookiestore.New([]byte(appConfig.Secret))
	templateEngine := template.NewEngine()
  userRepository := user.NewCachingRepository(user.NewMemoryRepository())
	nodeRepository := node.NewCachingRepository(node.NewDatastoreRepository())
	
	router := pat.New()
	router.NewRoute().Methods("HEAD", "GET").PathPrefix("/contact").Handler(http.HandlerFunc(func(res http.ResponseWriter, req *http.Request) {
		session := sessions.GetSession(req)

		contactHandler(
			res,
			req,
			csrf.NewTokenManager(session),
			nodeRepository,
		)
		// could use some sort of DI-type container too but haven't had a need yet
		contactHandler(
			res,
			req,
			container.Get("node_repository"), // the container can determine what "node_repository" implementation gets returned, maybe it can even lazy-create it
		)
	}))

	n := negroni.New()
	n.UseHandler(router)
}