http_util.go

//  Copyright (c) 2014 Couchbase, Inc.
//  Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file
//  except in compliance with the License. You may obtain a copy of the License at
//    http://www.apache.org/licenses/LICENSE-2.0
//  Unless required by applicable law or agreed to in writing, software distributed under the
//  License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND,
//  either express or implied. See the License for the specific language governing permissions
//  and limitations under the License.
package main

import (
	"encoding/json"
	"flag"
	"io"
	"net/http"
	"time"

	"github.com/gorilla/mux"
)

var staticEtag = flag.String("staticEtag", "", "A static etag value.")
var staticPath = flag.String("static", "static/", "Path to the static content")

func staticFileRouter() *mux.Router {
	r := mux.NewRouter()
	r.StrictSlash(true)

	// static
	r.PathPrefix("/static/").Handler(http.StripPrefix("/static/",
		myFileHandler{http.FileServer(http.Dir(*staticPath))}))

	// application pages
	appPages := []string{
		"/overview",
		"/search",
	}

	for _, p := range appPages {
		// if you try to use index.html it will redirect...poorly
		r.PathPrefix(p).Handler(RewriteURL("/",
			http.FileServer(http.Dir(*staticPath))))
	}

	r.Handle("/", http.RedirectHandler("/static/index.html", 302))

	return r
}

type myFileHandler struct {
	h http.Handler
}

func (mfh myFileHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
	if *staticEtag != "" {
		w.Header().Set("Etag", *staticEtag)
	}
	mfh.h.ServeHTTP(w, r)
}

func RewriteURL(to string, h http.Handler) http.Handler {
	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		r.URL.Path = to
		h.ServeHTTP(w, r)
	})
}

func mustEncode(w io.Writer, i interface{}) {
	if headered, ok := w.(http.ResponseWriter); ok {
		headered.Header().Set("Cache-Control", "no-cache")
		headered.Header().Set("Content-type", "application/json")
	}

	e := json.NewEncoder(w)
	if err := e.Encode(i); err != nil {
		panic(err)
	}
}

type lastUpdatedHandler struct {
}

func (h *lastUpdatedHandler) ServeHTTP(w http.ResponseWriter, req *http.Request) {
	rv := struct {
		LastUpdated time.Time `json:"last_updated"`
	}{
		LastUpdated: lastUpdated,
	}
	mustEncode(w, rv)
}