reverse proxy example

gistfile1.go

package main

import (
	"file-api/oid"
	c "file-api/proxy/controllers"
	"file-api/proxy/models"
	. "file-api/proxy/utils"
	"github.com/3d0c/martini-contrib/binding"
	"github.com/3d0c/martini-contrib/config"
	"github.com/3d0c/martini-contrib/encoder"
	"github.com/codegangsta/martini"
	"log"
	"net/http"
	"net/http/httputil"
	"net/url"
	"strings"
)

func init() {
	log.SetFlags(log.Lshortfile | log.Ldate | log.Ltime)

	config.Init("./proxy.json")
	config.LoadInto(ProxyCfg)

	oid.Nodes = &oid.NodesCounter{Total: ProxyCfg.NodesCount()}
}

// Cache-Control: max-age=2592000
// Pragma: public
// Cache-Control: public
func main() {
	m := martini.New()
	route := martini.NewRouter()

	m.Use(func(c martini.Context, w http.ResponseWriter) {
		c.MapTo(encoder.JsonEncoder{}, (*encoder.Encoder)(nil))
		w.Header().Set("Content-Type", "application/json")
	})

	// some CORS stuff
	m.Use(func(w http.ResponseWriter, req *http.Request) {
		if origin := req.Header.Get("Origin"); origin != "" {
			w.Header().Add("Access-Control-Allow-Origin", origin)
		} else {
			w.Header().Add("Access-Control-Allow-Origin", "*")
		}

		w.Header().Add("Access-Control-Allow-Methods", "POST, GET, OPTIONS, PUT, DELETE")
		w.Header().Add("Access-Control-Allow-Headers", "Content-Type, Content-Length, Accept-Encoding, X-CSRF-Token")
		w.Header().Add("Access-Control-Expose-Headers", "Mv-Length, Mv-Dim, Mv-Dim-Max")
		w.Header().Add("Cache-Control", "max-age=2592000")
		w.Header().Add("Pragma", "public")
		w.Header().Add("Cache-Control", "public")
	})

	// Preflight - 200 OK.
	route.Options("/**")

	route.Get("/files", binding.Form(models.UrlOptions{}), c.FilesFind)

	route.Post("/files", proxyMap, func(p *httputil.ReverseProxy, w http.ResponseWriter, r *http.Request) {
		p.ServeHTTP(w, r)
	})

	m.Action(route.Handle)

	log.Printf("Proxy waiting for connections on %v...\n", ProxyCfg.ListenOn())

	go func() {
		if err := http.ListenAndServe(ProxyCfg.ListenOn(), m); err != nil {
			log.Fatal(err)
		}
	}()

	if err := http.ListenAndServeTLS(ProxyCfg.HttpsOn(), ProxyCfg.SSLCert(), ProxyCfg.SSLKey(), m); err != nil {
		log.Fatal(err)
	}
}

func proxyMap(ctx martini.Context, req *http.Request) {
	var nodeId int32 = oid.NewObjectId().NodeId()

	if strings.HasPrefix(req.URL.Path, "/files/") {
		p := strings.Split(req.URL.Path, "/")
		if len(p) == 3 && oid.IsObjectIdHex(p[2]) {
			nodeId = oid.ObjectIdHex(p[2]).NodeId()
		}
	}

	remote, err := url.Parse(ProxyCfg.Node(nodeId).GetAddress())
	if err != nil {
		panic(err)
	}

	proxy := httputil.NewSingleHostReverseProxy(remote)
	ctx.Map(proxy)
}