Added -forceReload flag which forces page reload on any file change

I'm developing a blog which is using fetch to lazy load html pages. So
currently it doesnt refresh whenever the lazy loaded html is changed
since origins html page won't ever be the same.

So this is a quick and dirty way of solving the problem, might also
solve some similar problems down the line.

cmd/serve/serve.go

@@ -23,12 +23,13 @@ type Fileserver interface {
 type command struct {
 	binPath string
 	// master, as in adjective 'master record' non-slavery kind
-	masterPath string
-	mirrorPath string
-	port       *int
-	wsPath     *string
-	flagset    *flag.FlagSet
-	fileserver Fileserver
+	masterPath  string
+	mirrorPath  string
+	port        *int
+	wsPath      *string
+	forceReload *bool
+	flagset     *flag.FlagSet
+	fileserver  Fileserver
 }
 
 func Command() *command {
@@ -52,7 +53,7 @@ func (c *command) Setup() error {
 	c.masterPath = path.Clean(relPath)
 
 	if c.masterPath != "" {
-		c.fileserver = wsinject.NewFileServer(*c.port, *c.wsPath)
+		c.fileserver = wsinject.NewFileServer(*c.port, *c.wsPath, *c.forceReload)
 		mirrorPath, err := c.fileserver.Setup(c.masterPath)
 		if err != nil {
 			return fmt.Errorf("failed to setup websocket injected mirror filesystem: %v", err)
@@ -121,6 +122,7 @@ func (c *command) Flagset() *flag.FlagSet {
 	fs := flag.NewFlagSet("server", flag.ExitOnError)
 	c.port = fs.Int("port", 8080, "port to serve http server on")
 	c.wsPath = fs.String("wsPort", "/delta-streamer-ws", "the path which the delta streamer websocket should be hosted on")
+	c.forceReload = fs.Bool("forceReload", false, "set to true if you wish to reload all attached browser pages on any file change")
 	c.flagset = fs
 	return fs
 }

internal/wsinject/delta_streamer.ws.go

@@ -1,6 +1,6 @@
 package wsinject
 
-const DeltaStreamerSourceCode = `/**
+const deltaStreamerSourceCode = `/**
 * This file has been injected by the wd-41 web development
 * hot reload tool. 
 */
@@ -33,7 +33,11 @@ function startWebsocket() {
     if(event.data === fileName ||
       // Always reload on js and css files since its difficult to know where these are used
       event.data.includes(".js") ||
-      event.data.includes(".css")) {
+      event.data.includes(".css") ||
+      // This funny-looking comparison is set using string interpolation from the -forceReload flag
+      // when writing this script
+      %v === true
+      ) {
       location.reload();
     }
   });

internal/wsinject/wsinject.go

@@ -19,11 +19,12 @@ import (
 )
 
 type Fileserver struct {
-	masterPath string
-	mirrorPath string
-	wsPort     int
-	wsPath     string
-	watcher    *fsnotify.Watcher
+	masterPath  string
+	mirrorPath  string
+	forceReload bool
+	wsPort      int
+	wsPath      string
+	watcher     *fsnotify.Watcher
 
 	pageReloadChan        chan string
 	wsDispatcher          sync.Map
@@ -36,7 +37,7 @@ var ErrNoHeaderTagFound = errors.New("no header tag found")
 const deltaStreamer = `<!-- This script has been injected by wd-41 and allows hot reloads -->
 <script type="module" src="delta-streamer.js"></script>`
 
-func NewFileServer(wsPort int, wsPath string) *Fileserver {
+func NewFileServer(wsPort int, wsPath string, forceReload bool) *Fileserver {
 	mirrorDir, err := os.MkdirTemp("", "wd-41_*")
 	if err != nil {
 		panic(err)
@@ -46,6 +47,7 @@ func NewFileServer(wsPort int, wsPath string) *Fileserver {
 		mirrorPath:            mirrorDir,
 		wsPort:                wsPort,
 		wsPath:                wsPath,
+		forceReload:           forceReload,
 		pageReloadChan:        make(chan string),
 		wsDispatcher:          sync.Map{},
 		wsDispatcherStarted:   &started,
@@ -95,7 +97,10 @@ func (fs *Fileserver) mirrorMaker(p string, info os.DirEntry, err error) error {
 }
 
 func (fs *Fileserver) writeDeltaStreamerScript() error {
-	err := os.WriteFile(path.Join(fs.mirrorPath, "delta-streamer.js"), []byte(fmt.Sprintf(DeltaStreamerSourceCode, fs.wsPort, fs.wsPath)), 0o755)
+	err := os.WriteFile(
+		path.Join(fs.mirrorPath, "delta-streamer.js"),
+		[]byte(fmt.Sprintf(deltaStreamerSourceCode, fs.wsPort, fs.wsPath, fs.forceReload)),
+		0o755)
 	if err != nil {
 		return fmt.Errorf("failed to write delta-streamer.js: %w", err)
 	}

internal/wsinject/wsinject_test.go

@@ -76,7 +76,7 @@ func Test_Setup(t *testing.T) {
 	}
 	nestedFile := path.Join(nestedDir, "nested.html")
 	os.WriteFile(nestedFile, []byte(mockHtml), 0o777)
-	fs := NewFileServer(8080, "/delta-streamer-ws.js")
+	fs := NewFileServer(8080, "/delta-streamer-ws.js", false)
 	_, err = fs.Setup(tmpDir)
 	if err != nil {
 		t.Fatalf("failed to setup: %v", err)
@@ -145,7 +145,7 @@ func Test_Start(t *testing.T) {
 		if err != nil {
 			t.Fatalf("failed to create temp dir: %v", err)
 		}
-		return NewFileServer(8080, "/delta-streamer-ws.js"), testFileSystem{
+		return NewFileServer(8080, "/delta-streamer-ws.js", false), testFileSystem{
 			root:      tmpDir,
 			nestedDir: nestedDir,
 		}