Update chain.js handler

socket/client-js-config.go

@@ -1,41 +1,46 @@
 package socket
 
 import (
+	"bytes"
 	"embed"
 	"github.com/rs/zerolog/log"
 	"github.com/syntax-framework/chain"
+	"net/http"
+	"path"
 	"strconv"
+	"time"
 )
 
 var (
 	//go:embed client/chain.js
 	clientJsFS             embed.FS
 	clientJsContent        []byte
+	clientJsEtag           string
+	clientJsModTime, _     = time.Parse(time.DateTime, "2023-05-07 00:00:00")
 	configuredRouterClient = map[*chain.Router]bool{}
 )
 
 func init() {
-	var err error
-	if clientJsContent, err = clientJsFS.ReadFile("client/chain.js"); err != nil {
-		log.Panic().Err(err).Caller(1).
-			Stack().
-			Msg(_l("cannot load client/chain.js"))
+	if content, err := clientJsFS.ReadFile("client/chain.js"); err != nil {
+		log.Panic().Err(err).Caller(1).Stack().Msg(_l("cannot load client/chain.js"))
+	} else {
+		clientJsContent = content
+		clientJsEtag = chain.HashCrc32(clientJsContent)
 	}
 }
 
-func ClientJsAddHandler(router *chain.Router) {
-	if _, exist := configuredRouterClient[router]; exist {
+// ClientJsHandler add "/chain.js" endpoint
+func ClientJsHandler(r *chain.Router, route string) {
+	if _, exist := configuredRouterClient[r]; exist {
+		// @TODO: Permitir saber quando a instancia é destruida r.OnDestroy(func() { })
 		return
 	}
 
-	router.GET("/chain.js", func(ctx *chain.Context) {
-		ctx.SetHeader("Content-Type", "application/javascript")
+	jsPath := path.Join(route, "/chain.js")
+	r.GET(jsPath, func(ctx *chain.Context) {
+		ctx.SetHeader("Content-Type", "text/javascript; charset=utf-8")
 		ctx.SetHeader("Content-Length", strconv.Itoa(len(clientJsContent)))
-		// Etag
-		// Last-Modified
-		if _, err := ctx.Write(clientJsContent); err != nil {
-			log.Error().Stack().Err(err).Caller(1).
-				Msg(_l("it was not possible to deliver /chain.js"))
-		}
+		ctx.SetHeader("ETag", clientJsEtag)
+		http.ServeContent(ctx.Writer, ctx.Request, "/chain.js", clientJsModTime, bytes.NewReader(clientJsContent))
 	})
 }

socket/handler.go

@@ -44,7 +44,7 @@ type Handler struct {
 
 func (h *Handler) Configure(router *chain.Router, endpoint string) {
 
-	ClientJsAddHandler(router)
+	ClientJsHandler(router, endpoint)
 
 	if h.Options == nil {
 		h.Options = map[string]any{}

utils.go

@@ -2,8 +2,10 @@ package chain
 
 import (
 	"crypto/md5"
+	"encoding/base64"
 	"encoding/hex"
 	"encoding/json"
+	"hash/crc32"
 )
 
 type Serializer interface {
@@ -31,3 +33,11 @@ func HashMD5(text string) string {
 	h.Write([]byte(text))
 	return hex.EncodeToString(h.Sum(nil))
 }
+
+var crc32iSCSI = crc32.MakeTable(crc32.Castagnoli)
+
+func HashCrc32(content []byte) string {
+	h := crc32.New(crc32iSCSI)
+	h.Write(content)
+	return base64.StdEncoding.EncodeToString(h.Sum(nil))
+}