wrouter/router.go

package wrouter

import (
	"fmt"
	"net/http"
	"strings"
	"time"

	"git.aiterp.net/gisle/wrouter/auth"
)

// Route is an interface for a request handler.
type Route interface {
	Handle(path string, w http.ResponseWriter, req *http.Request, user *auth.User) bool
}

// Router is the main structure of the wrouter package. It routes requests to the appropriate
// Route
type Router struct {
	paths  map[Route]string
	routes []Route
}

// Mount a router to the router, prefixing all the paths of it
func (router *Router) Mount(path string, subRouter *Router) {
	for _, route := range subRouter.routes {
		router.Route(strings.Replace(path+subRouter.paths[route], "//", "/", 1), route)
	}
}

// Route mounts a route interface to a path
func (router *Router) Route(path string, route Route) {
	if router.paths == nil {
		router.paths = make(map[Route]string, 16)
	}

	router.paths[route] = path
	router.routes = append(router.routes, route)
}

// ServeHTTP serves a HTTP request using the router's routes
func (router *Router) ServeHTTP(w http.ResponseWriter, req *http.Request) {
	req.ParseForm()
	defer req.Body.Close()

	// Allow REST for clients of yore
	if req.Header.Get("X-Method") != "" {
		req.Method = strings.ToUpper(req.Header.Get("X-Method"))
	}

	// Resolve session cookies
	var user *auth.User
	var sess *auth.Session
	cookie, err := req.Cookie(auth.SessionCookieName)

	if cookie != nil && err == nil {
		sess = auth.FindSession(cookie.Value)
		if sess != nil {
			user, _ = auth.FindUser(sess.UserID)

			if user != nil {
				user.Session = sess
			}
		}
	}

	for index, route := range router.routes {
		path := router.paths[route]

		if strings.HasPrefix(strings.ToLower(req.URL.Path), path) {
			// Just so the handler can replace the path properly in case of case
			// insensitive clients getting fancy on it.
			path = req.URL.Path[:len(path)]

			// Attach a little something for testing
			w.Header().Set("X-Route-Path", path)
			w.Header().Set("X-Route-Index", fmt.Sprint(index))

			if route.Handle(path, w, req, user) {
				if user != nil && user.LoggedOut() {
					auth.CloseSession(sess.ID)
				}

				return
			}
		}
	}

	w.Header().Set("Content-Type", "text/plain; charset=utf-8")
	w.WriteHeader(404)
	w.Write([]byte("Not Found: " + req.URL.Path))
}

// Resource is a shorthand for creating and adding a new REST resource to the router
func (router *Router) Resource(mount string, list, create ResourceFunc, get, update, delete ResourceIDFunc) {
	router.Route(mount, NewResource(list, create, get, update, delete))
}

// Static is a shorthand for creating a static file server on the following path
func (router *Router) Static(mount string, filePath string) {
	router.Route(mount, NewStatic(filePath))
}

// Function creates a simple bare-bones handler that just runs a function, prevents
// the need for dummy interfaces
func (router *Router) Function(mount string, function FunctionHandlerFunc) {
	router.Route(mount, &functionHandler{function})
}

// Listen creates a http.Server with some sane defaults and pointing to this structure
// for request handling.
func (router *Router) Listen(host string, port int) (*http.Server, error) {
	srv := &http.Server{
		Addr:         fmt.Sprintf("%s:%d", host, port),
		ReadTimeout:  5 * time.Second,
		WriteTimeout: 10 * time.Second,
		IdleTimeout:  120 * time.Second,
		Handler:      router,
	}

	return srv, srv.ListenAndServe()
}