Add HTTP/2 push

.travis.yml

@@ -1,9 +1,6 @@
 language: go
 
 go:
-  - 1.5.4
-  - 1.6.4
-  - 1.7.5
   - 1.8.1
   - tip
 

README.md

@@ -21,12 +21,7 @@ There is a few different ways of getting it:
 - [Other versions](https://github.com/khlieng/dispatch/releases)
 
 ### 2. Go
-This requires a [Go environment](http://golang.org/doc/install).
+This requires a [Go environment](http://golang.org/doc/install), version 1.8 or greater.
-
-If running go 1.5 this environment variable is needed, versions <1.5 are not supported:
-```bash
-export GO15VENDOREXPERIMENT=1
-```
 
 Fetch, compile and run dispatch:
 ```bash

server/serve_files.go

@@ -28,6 +28,7 @@ type File struct {
 	Path         string
 	Asset        string
 	GzipAsset    []byte
+	Hash         string
 	ContentType  string
 	CacheControl string
 	Compressed   bool
@@ -69,7 +70,8 @@ func initFileServer() {
 		}
 
 		hash := md5.Sum(data)
-		files[0].Path = "bundle." + base64.RawURLEncoding.EncodeToString(hash[:]) + ".js"
+		files[0].Hash = base64.RawURLEncoding.EncodeToString(hash[:])
+		files[0].Path = "bundle." + files[0].Hash + ".js"
 
 		br, err := brotli.NewReader(bytes.NewReader(data), nil)
 		if err != nil {
@@ -92,7 +94,8 @@ func initFileServer() {
 		}
 
 		hash = md5.Sum(data)
-		files[1].Path = "bundle." + base64.RawURLEncoding.EncodeToString(hash[:]) + ".css"
+		files[1].Hash = base64.RawURLEncoding.EncodeToString(hash[:])
+		files[1].Path = "bundle." + files[1].Hash + ".css"
 
 		br.Reset(bytes.NewReader(data))
 		buf = &bytes.Buffer{}
@@ -196,6 +199,36 @@ func serveIndex(w http.ResponseWriter, r *http.Request) {
 		w.Header().Set("Strict-Transport-Security", hstsHeader)
 	}
 
+	if pusher, ok := w.(http.Pusher); ok {
+		options := &http.PushOptions{
+			Header: http.Header{
+				"Accept-Encoding": r.Header["Accept-Encoding"],
+			},
+		}
+
+		cookie, err := r.Cookie("push")
+		if err != nil {
+			err = pusher.Push("/"+files[1].Path, options)
+			err = pusher.Push("/"+files[0].Path, options)
+			setPushCookie(w, r)
+		} else {
+			pushed := false
+
+			if files[1].Hash != cookie.Value[22:] {
+				pusher.Push("/"+files[1].Path, options)
+				pushed = true
+			}
+			if files[0].Hash != cookie.Value[:22] {
+				pusher.Push("/"+files[0].Path, options)
+				pushed = true
+			}
+
+			if pushed {
+				setPushCookie(w, r)
+			}
+		}
+	}
+
 	if strings.Contains(r.Header.Get("Accept-Encoding"), "gzip") {
 		w.Header().Set("Content-Encoding", "gzip")
 
@@ -207,6 +240,17 @@ func serveIndex(w http.ResponseWriter, r *http.Request) {
 	}
 }
 
+func setPushCookie(w http.ResponseWriter, r *http.Request) {
+	http.SetCookie(w, &http.Cookie{
+		Name:     "push",
+		Value:    files[0].Hash + files[1].Hash,
+		Path:     "/",
+		Expires:  time.Now().AddDate(1, 0, 0),
+		HttpOnly: true,
+		Secure:   r.TLS != nil,
+	})
+}
+
 func serveFile(w http.ResponseWriter, r *http.Request, file *File) {
 	info, err := assets.AssetInfo(file.Asset)
 	if err != nil {

server/server.go

@@ -1,6 +1,7 @@
 package server
 
 import (
+	"crypto/tls"
 	"log"
 	"net"
 	"net/http"
@@ -10,7 +11,6 @@ import (
 
 	"github.com/gorilla/websocket"
 	"github.com/spf13/viper"
-	"golang.org/x/net/http2"
 
 	"github.com/khlieng/dispatch/letsencrypt"
 	"github.com/khlieng/dispatch/storage"
@@ -59,8 +59,6 @@ func startHTTP() {
 			Handler: http.HandlerFunc(serve),
 		}
 
-		http2.ConfigureServer(server, nil)
-
 		if certExists() {
 			log.Println("[HTTPS] Listening on port", portHTTPS)
 			server.ListenAndServeTLS(viper.GetString("https.cert"), viper.GetString("https.key"))
@@ -79,10 +77,12 @@ func startHTTP() {
 				log.Fatal(err)
 			}
 
-			server.TLSConfig.GetCertificate = letsEncrypt.GetCertificate
+			server.TLSConfig = &tls.Config{
+				GetCertificate: letsEncrypt.GetCertificate,
+			}
 
 			log.Println("[HTTPS] Listening on port", portHTTPS)
-			log.Fatal(listenAndServeTLS(server))
+			log.Fatal(server.ListenAndServeTLS("", ""))
 		} else {
 			log.Fatal("Could not locate SSL certificate or private key")
 		}

server/tls.go

@@ -1,43 +1,11 @@
 package server
 
 import (
-	"crypto/tls"
-	"net"
-	"net/http"
 	"os"
-	"time"
 
 	"github.com/spf13/viper"
 )
 
-func listenAndServeTLS(srv *http.Server) error {
-	if srv.TLSConfig.NextProtos == nil {
-		srv.TLSConfig.NextProtos = []string{"http/1.1"}
-	}
-
-	ln, err := net.Listen("tcp", srv.Addr)
-	if err != nil {
-		return err
-	}
-
-	tlsListener := tls.NewListener(tcpKeepAliveListener{ln.(*net.TCPListener)}, srv.TLSConfig)
-	return srv.Serve(tlsListener)
-}
-
-type tcpKeepAliveListener struct {
-	*net.TCPListener
-}
-
-func (ln tcpKeepAliveListener) Accept() (c net.Conn, err error) {
-	tc, err := ln.AcceptTCP()
-	if err != nil {
-		return
-	}
-	tc.SetKeepAlive(true)
-	tc.SetKeepAlivePeriod(3 * time.Minute)
-	return tc, nil
-}
-
 func certExists() bool {
 	cert := viper.GetString("https.cert")
 	key := viper.GetString("https.key")