Build and register service worker

apps/base/__init__.py

@@ -101,6 +101,18 @@ def favicon():
     )
 
 
+# Service worker has to be served from the route so that it can take
+# control of all pages, otherwise it only has control over files in
+# /js.
+@base.route("/serviceworker.js")
+def serviceworker():
+    return send_from_directory(
+        os.path.join(app.root_path, "static/js"),
+        "serviceworker.js",
+        mimetype="application/javascript",
+    )
+
+
 @base.route("/404")
 def raise_404():
     abort(404)

gulpfile.js

@@ -91,11 +91,19 @@ const main_js = (cb) => pump(jsBuild('main.js'), cb),
   line_up_js = (cb) => pump(jsBuild('line-up.js'), cb),
   schedule_js = (cb) => pump(jsBuild('schedule.js'), cb),
   volunteer_schedule_js = (cb) => pump(jsBuild('volunteer-schedule.js'), cb),
-  arrivals_js = (cb) => pump(jsBuild('arrivals.js'), cb);
+  arrivals_js = (cb) => pump(jsBuild('arrivals.js'), cb),
+  serviceworker_js = (cb) => pump(jsBuild('serviceworker.js'), cb),
 
 
 function js(cb) {
-  gulp.parallel(main_js, line_up_js, schedule_js, volunteer_schedule_js, arrivals_js)(cb);
+  gulp.parallel(
+    main_js,
+    line_up_js,
+    schedule_js,
+    volunteer_schedule_js,
+    arrivals_js,
+    serviceworker_js
+  )(cb);
 }
 
 function css(cb) {
@@ -109,7 +117,7 @@ function css(cb) {
       'css/schedule.scss',
       'css/volunteer_schedule.scss',
       'css/flask-admin.scss',
-      'css/dhtmlxscheduler_flat.css',
+      'css/dhtmlxscheduler_flat.css'
     ]),
     gulpif(!production, sourcemaps.init()),
     sass({ includePaths: ['../node_modules'] }).on('error', function (err) {

js/main.js

@@ -125,4 +125,20 @@ $(() => {
       return false;
     });
   });
-});
+});
+
+async function registerServiceWorker() {
+  if (!("serviceWorker" in navigator)) {
+    return
+  }
+
+  try {
+    await navigator.serviceWorker.register("/serviceworker.js", {
+      scope: "/",
+    });
+  } catch (error) {
+    console.error("Service worker registration failed:", error);
+  }
+}
+
+registerServiceWorker()

js/serviceworker.js

@@ -68,4 +68,4 @@ registerRoute(
             }),
         ],
     }),
-);
+);