livereload: Improve the livereload script build and update to v4.0.2

This script has very infrequent updates, but just copy pasting the minified source creates some potential trust issues.

This JS will now be pulled from a Git version and both the unminified and minified version gets written to disk.

This way it should be easier to reason about changes in the future.

To upgrade, change the commit hash and run `mage generate`.

Closes gohugoio#12451
Closes gohugoio#6290

livereload/gen/livereload-hugo-plugin.js

@@ -0,0 +1,34 @@
+/*
+Hugo adds a specific prefix, "__hugo_navigate", to the path in certain situations to signal
+navigation to another content page.
+*/
+function HugoReload() {}
+
+HugoReload.identifier = 'hugoReloader';
+HugoReload.version = '0.9';
+
+HugoReload.prototype.reload = function (path, options) {
+	var prefix = '__hugo_navigate';
+
+	if (path.lastIndexOf(prefix, 0) !== 0) {
+		return false;
+	}
+
+	path = path.substring(prefix.length);
+
+	var portChanged = options.overrideURL && options.overrideURL != window.location.port;
+
+	if (!portChanged && window.location.pathname === path) {
+		window.location.reload();
+	} else {
+		if (portChanged) {
+			window.location = location.protocol + '//' + location.hostname + ':' + options.overrideURL + path;
+		} else {
+			window.location.pathname = path;
+		}
+	}
+
+	return true;
+};
+
+LiveReload.addPlugin(HugoReload);

livereload/gen/main.go

@@ -0,0 +1,61 @@
+//go:generate go run main.go
+package main
+
+import (
+	_ "embed"
+	"fmt"
+	"io"
+	"log"
+	"net/http"
+	"os"
+
+	"github.com/evanw/esbuild/pkg/api"
+)
+
+//go:embed livereload-hugo-plugin.js
+var livereloadHugoPluginJS string
+
+func main() {
+	// 4.0.2
+	// To upgrade to a new version, change to the commit hash of the version you want to upgrade to
+	// then run mage generate from the root.
+	const liveReloadCommit = "d803a41804d2d71e0814c4e9e3233e78991024d9"
+	liveReloadSourceURL := fmt.Sprintf("https://raw.githubusercontent.com/livereload/livereload-js/%s/dist/livereload.js", liveReloadCommit)
+
+	func() {
+		resp, err := http.Get(liveReloadSourceURL)
+		must(err)
+		defer resp.Body.Close()
+
+		b, err := io.ReadAll(resp.Body)
+		must(err)
+
+		// Write the unminified livereload.js file.
+		err = os.WriteFile("../livereload.js", b, 0o644)
+		must(err)
+
+		// Bundle and minify with ESBuild.
+		result := api.Build(api.BuildOptions{
+			Stdin: &api.StdinOptions{
+				Contents: string(b) + livereloadHugoPluginJS,
+			},
+			Outfile:           "../livereload.min.js",
+			Bundle:            true,
+			Target:            api.ES2015,
+			Write:             true,
+			MinifyWhitespace:  true,
+			MinifyIdentifiers: true,
+			MinifySyntax:      true,
+		})
+
+		if len(result.Errors) > 0 {
+			log.Fatal(result.Errors)
+		}
+	}()
+}
+
+func must(err error) {
+	if err != nil {
+		log.Fatal(err)
+	}
+}

livereload/livereload.go

@@ -1,4 +1,4 @@
-// Copyright 2015 The Hugo Authors. All rights reserved.
+// Copyright 2024 The Hugo Authors. All rights reserved.
 //
 // Licensed under the Apache License, Version 2.0 (the "License");
 // you may not use this file except in compliance with the License.
@@ -50,6 +50,7 @@ import (
 )
 
 // Prefix to signal to LiveReload that we need to navigate to another path.
+// Do not change this.
 const hugoNavigatePrefix = "__hugo_navigate"
 
 var upgrader = &websocket.Upgrader{
@@ -144,48 +145,8 @@ func ServeJS(w http.ResponseWriter, r *http.Request) {
 }
 
 func liveReloadJS() []byte {
-	return []byte(livereloadJS + hugoLiveReloadPlugin)
+	return []byte(livereloadJS)
 }
 
-var (
-	// This is a patched version, see https://github.com/livereload/livereload-js/pull/84
-	//go:embed livereload.js
-	livereloadJS         string
-	hugoLiveReloadPlugin = fmt.Sprintf(`
-/*
-Hugo adds a specific prefix, "__hugo_navigate", to the path in certain situations to signal
-navigation to another content page.
-*/
-
-function HugoReload() {}
-
-HugoReload.identifier = 'hugoReloader';
-HugoReload.version = '0.9';
-
-HugoReload.prototype.reload = function(path, options) {
-	var prefix = %q;
-
-	if (path.lastIndexOf(prefix, 0) !== 0) {
-		return false
-	}
-	
-	path = path.substring(prefix.length);
-
-	var portChanged = options.overrideURL && options.overrideURL != window.location.port
-	
-	if (!portChanged && window.location.pathname === path) {
-		window.location.reload();
-	} else {
-		if (portChanged) {
-			window.location = location.protocol + "//" + location.hostname + ":" + options.overrideURL + path;
-		} else {
-			window.location.pathname = path;
-		}
-	}
-
-	return true;
-};
-
-LiveReload.addPlugin(HugoReload)
-`, hugoNavigatePrefix)
-)
+//go:embed livereload.min.js
+var livereloadJS string

magefile.go

@@ -79,8 +79,7 @@ func flagEnv() map[string]string {
 // Generate autogen packages
 func Generate() error {
 	generatorPackages := []string{
-		//"tpl/tplimpl/embedded/generate",
-		//"resources/page/generate",
+		"livereload/gen",
 	}
 
 	for _, pkg := range generatorPackages {