Add auto-refresh logic for updates

api.go

@@ -1,7 +1,10 @@
 package main
 
 import (
+	"crypto/sha256"
+	"fmt"
 	"net/http"
+	"strings"
 	"sync"
 	"time"
 
@@ -27,10 +30,7 @@ func sendAllSockets(msgType string, msg interface{}) error {
 	defer socketSubscriptionsLock.RUnlock()
 
 	for _, hdl := range socketSubscriptions {
-		if err := hdl(map[string]interface{}{
-			"payload": msg,
-			"type":    msgType,
-		}); err != nil {
+		if err := hdl(compileSocketMessage(msgType, msg)); err != nil {
 			return errors.Wrap(err, "submit message")
 		}
 	}
@@ -52,6 +52,27 @@ func unsubscribeSocket(id string) {
 	delete(socketSubscriptions, id)
 }
 
+func compileSocketMessage(msgType string, msg interface{}) map[string]interface{} {
+	assetVersionsLock.RLock()
+	defer assetVersionsLock.RUnlock()
+
+	versionParts := []string{version}
+	for _, asset := range assets {
+		versionParts = append(versionParts, assetVersions[asset])
+	}
+
+	hash := sha256.New()
+	hash.Write([]byte(strings.Join(versionParts, "/")))
+
+	ver := fmt.Sprintf("%x", hash.Sum(nil))
+
+	return map[string]interface{}{
+		"payload": msg,
+		"type":    msgType,
+		"version": ver,
+	}
+}
+
 var upgrader = websocket.Upgrader{
 	ReadBufferSize:  1024,
 	WriteBufferSize: 1024,
@@ -87,10 +108,7 @@ func handleUpdateSocket(w http.ResponseWriter, r *http.Request) {
 		}
 	}()
 
-	if err := conn.WriteJSON(map[string]interface{}{
-		"payload": store,
-		"type":    msgTypeStore,
-	}); err != nil {
+	if err := conn.WriteJSON(compileSocketMessage(msgTypeStore, store)); err != nil {
 		log.WithError(err).Error("Unable to send initial state")
 		return
 	}

app.js

@@ -37,6 +37,7 @@ const app = new Vue({
     store: {},
     socket: null,
     time: new Date(),
+    version: null,
   },
 
   el: '#app',
@@ -68,9 +69,13 @@ const app = new Vue({
       this.socket.onmessage = evt => {
         const data = JSON.parse(evt.data)
 
+        if (data.version) {
+          this.version = data.version
+        }
+
         switch (data.type) {
           case 'store':
-            this.store = data
+            this.store = data.payload
             break
 
           default:
@@ -92,5 +97,12 @@ const app = new Vue({
       }
       this.showAlert('New Follower', `${to} just followed`)
     },
+
+    version(to, from) {
+      if (!from || !to || from === to) {
+        return
+      }
+      window.location.reload()
+    },
   },
 })

main.go

@@ -1,14 +1,19 @@
 package main
 
 import (
+	"crypto/sha256"
 	"fmt"
+	"io"
 	"net/http"
 	"os"
 	"path"
+	"strings"
+	"sync"
 	"time"
 
 	"github.com/gofrs/uuid"
 	"github.com/gorilla/mux"
+	"github.com/pkg/errors"
 	log "github.com/sirupsen/logrus"
 
 	"github.com/Luzifer/rconfig/v2"
@@ -16,6 +21,7 @@ import (
 
 var (
 	cfg = struct {
+		AssetCheckInterval    time.Duration `flag:"asset-check-interval" default:"1m" description:"How often to check asset files for updates"`
 		AssetDir              string        `flag:"asset-dir" default:"." description:"Directory containing assets"`
 		BaseURL               string        `flag:"base-url" default:"" description:"Base URL of this service" validate:"nonzero"`
 		ForceSyncInterval     time.Duration `flag:"force-sync-interval" default:"1m" description:"How often to force a sync without updates"`
@@ -30,9 +36,14 @@ var (
 		WebHookTimeout        time.Duration `flag:"webhook-timeout" default:"15m" description:"When to re-register the webhooks"`
 	}{}
 
-	version       = "dev"
+	assets            = []string{"app.js", "overlay.html"}
+	assetVersions     = map[string]string{}
+	assetVersionsLock = new(sync.RWMutex)
+
 	store         *storage
 	webhookSecret = uuid.Must(uuid.NewV4()).String()
+
+	version = "dev"
 )
 
 func init() {
@@ -59,13 +70,20 @@ func main() {
 		log.WithError(err).Fatal("Unable to load store")
 	}
 
+	if err := updateAssetHashes(); err != nil {
+		log.WithError(err).Fatal("Unable to read asset hashes")
+	}
+
 	router := mux.NewRouter()
 	registerAPI(router)
 
-	router.HandleFunc("/{file:(?:app.js|overlay.html)}", func(w http.ResponseWriter, r *http.Request) {
-		w.Header().Set("Cache-Control", "no-cache")
-		http.ServeFile(w, r, path.Join(cfg.AssetDir, mux.Vars(r)["file"]))
-	})
+	router.HandleFunc(
+		fmt.Sprintf("/{file:(?:%s)}", strings.Join(assets, "|")),
+		func(w http.ResponseWriter, r *http.Request) {
+			w.Header().Set("Cache-Control", "no-cache")
+			http.ServeFile(w, r, path.Join(cfg.AssetDir, mux.Vars(r)["file"]))
+		},
+	)
 
 	go func() {
 		if err := http.ListenAndServe(cfg.Listen, router); err != nil {
@@ -78,6 +96,7 @@ func main() {
 	}
 
 	var (
+		timerAssetCheck      = time.NewTicker(cfg.AssetCheckInterval)
 		timerForceSync       = time.NewTicker(cfg.ForceSyncInterval)
 		timerUpdateFromAPI   = time.NewTicker(cfg.UpdateFromAPIInterval)
 		timerWebhookRegister = time.NewTicker(cfg.WebHookTimeout)
@@ -85,6 +104,11 @@ func main() {
 
 	for {
 		select {
+		case <-timerAssetCheck.C:
+			if err := updateAssetHashes(); err != nil {
+				log.WithError(err).Error("Unable to update asset hashes")
+			}
+
 		case <-timerForceSync.C:
 			if err := sendAllSockets(msgTypeStore, store); err != nil {
 				log.WithError(err).Error("Unable to send store to all sockets")
@@ -103,3 +127,25 @@ func main() {
 		}
 	}
 }
+
+func updateAssetHashes() error {
+	assetVersionsLock.Lock()
+	defer assetVersionsLock.Unlock()
+
+	for _, asset := range assets {
+		hash := sha256.New()
+		f, err := os.Open(asset)
+		if err != nil {
+			return errors.Wrap(err, "open asset file")
+		}
+		defer f.Close()
+
+		if _, err = io.Copy(hash, f); err != nil {
+			return errors.Wrap(err, "read asset file")
+		}
+
+		assetVersions[asset] = fmt.Sprintf("%x", hash.Sum(nil))
+	}
+
+	return nil
+}