Removed event chain caused by settings date update

refs https://linear.app/tryghost/issue/CORE-104/decouple-frontend-routing-events-from-urlserver-events

- The 'settings.timezone.edited' event triggers a roundtrip chain of calls in the frontend routing to the url services. It was all handled by event listeners and handler that clearly don't belong there.
- Extracted event realted listeners/handlers into methods and moved most of the logic to the "bootstrap" module, which soon is going to become a "RoutesManger"
- The result of this refactor - no more events going back and forth between frontend routing and the backend!

core/bridge.js

@@ -16,6 +16,7 @@ const config = require('./shared/config');
 const logging = require('@tryghost/logging');
 const tpl = require('@tryghost/tpl');
 const themeEngine = require('./frontend/services/theme-engine');
+const frontendRouting = require('./frontend/services/routing/bootstrap');
 const settingsCache = require('./shared/settings-cache');
 
 // Listen to settings.lang.edited, similar to the member service and models/base/listeners
@@ -35,6 +36,13 @@ class Bridge {
             debug('Active theme init18n');
             this.getActiveTheme().initI18n({locale: model.get('value')});
         });
+
+        // NOTE: eventually this event should somehow be listened on and handled by the URL Service
+        //       for now this eliminates the need for the frontend routing to listen to
+        //       server events
+        events.on('settings.timezone.edited', (model) => {
+            frontendRouting.handleTimezoneEdit(model);
+        });
     }
 
     getActiveTheme() {

core/frontend/services/routing/CollectionRouter.js

@@ -7,9 +7,6 @@ const middlewares = require('./middlewares');
 const RSSRouter = require('./RSSRouter');
 const bootstrap = require('./bootstrap');
 
-// This emits its own routing events AND listens to settings.timezone.edited :(
-const events = require('../../../server/lib/common/events');
-
 /**
  * @description Collection Router for post resource.
  *
@@ -60,7 +57,6 @@ class CollectionRouter extends ParentRouter {
         debug(this.name, this.route, this.permalinks);
 
         this._registerRoutes();
-        this._listeners();
     }
 
     /**
@@ -128,43 +124,6 @@ class CollectionRouter extends ParentRouter {
         next();
     }
 
-    /**
-     * @description This router has listeners to react on changes which happen in Ghost.
-     * @private
-     */
-    _listeners() {
-        /**
-         * CASE: timezone changes
-         *
-         * If your permalink contains a date reference, we have to regenerate the urls.
-         *
-         * e.g. /:year/:month/:day/:slug/ or /:day/:slug/
-         */
-        this._onTimezoneEditedListener = this._onTimezoneEdited.bind(this);
-        events.on('settings.timezone.edited', this._onTimezoneEditedListener);
-    }
-
-    /**
-     * @description Helper function to handle a timezone change.
-     * @param settingModel
-     * @private
-     */
-    _onTimezoneEdited(settingModel) {
-        const newTimezone = settingModel.attributes.value;
-        const previousTimezone = settingModel._previousAttributes.value;
-
-        if (newTimezone === previousTimezone) {
-            return;
-        }
-
-        if (this.getPermalinks().getValue().match(/:year|:month|:day/)) {
-            debug('_onTimezoneEdited: trigger regeneration');
-
-            // @NOTE: The connected url generator will listen on this event and regenerate urls.
-            this.emit('updated');
-        }
-    }
-
     /**
      * @description Get resource type of this router (always "posts")
      * @returns {string}
@@ -197,12 +156,6 @@ class CollectionRouter extends ParentRouter {
 
         return urlUtils.createUrl(urlUtils.urlJoin(this.route.value, this.rssRouter.route.value), options.absolute, options.secure);
     }
-
-    reset() {
-        if (this._onTimezoneEditedListener) {
-            events.removeListener('settings.timezone.edited', this._onTimezoneEditedListener);
-        }
-    }
 }
 
 module.exports = CollectionRouter;

core/frontend/services/routing/bootstrap.js

@@ -14,6 +14,8 @@ const events = require('../../../server/lib/common/events');
 
 const defaultApiVersion = 'v4';
 
+// This registry thing should be passed into here as a dependency once the module
+// is rewritten into the class + DI pattern
 const registry = require('./registry');
 let siteRouter;
 let _urlService;
@@ -119,6 +121,38 @@ const start = (apiVersion, routerSettings) => {
     debug('Routes:', registry.getAllRoutes());
 };
 
+/**
+ * This is a glue code to keep the implementation of routers away from
+ * this sort of logic. Ideally this method should not be ever called
+ * and handled completely on the URL Service layer without touching the frontend
+ * @param {Object} settingModel instance of the settings model
+ * @returns {void}
+ */
+const handleTimezoneEdit = (settingModel) => {
+    const newTimezone = settingModel.attributes.value;
+    const previousTimezone = settingModel._previousAttributes.value;
+
+    if (newTimezone === previousTimezone) {
+        return;
+    }
+
+    /**
+     * CASE: timezone changes
+     *
+     * If your permalink contains a date reference, we have to regenerate the urls.
+     *
+     * e.g. /:year/:month/:day/:slug/ or /:day/:slug/
+     */
+
+    // NOTE: timezone change only affects the collection router with dated permalinks
+    const collectionRouter = registry.getRouterByName('CollectionRouter');
+    if (collectionRouter.getPermalinks().getValue().match(/:year|:month|:day/)) {
+        debug('handleTimezoneEdit: trigger regeneration');
+
+        this.internal.routerUpdated(collectionRouter);
+    }
+};
+
 module.exports.internal = {
     owns: (routerId, id) => {
         return _urlService.owns(routerId, id);
@@ -135,7 +169,13 @@ module.exports.internal = {
         events.emit('router.created', this);
 
         _urlService.onRouterAddedType(router);
+    },
+    routerUpdated: (router) => {
+        _urlService.onRouterUpdated(router);
     }
 };
+
+// Public API methods called out by the backend
 module.exports.init = init;
 module.exports.start = start;
+module.exports.handleTimezoneEdit = handleTimezoneEdit;

core/frontend/services/routing/registry.js

@@ -41,6 +41,19 @@ module.exports = {
         return routers[name];
     },
 
+    /**
+     * Gets a router by it's internal router name
+     * @param {String} name internal router name
+     * @returns {Express-Router}
+     */
+    getRouterByName(name) {
+        for (let routerKey in routers) {
+            if (routers[routerKey].name === name) {
+                return routers[routerKey];
+            }
+        }
+    },
+
     /**
      *
      *

core/frontend/services/url/UrlGenerator.js

@@ -67,25 +67,25 @@ class UrlGenerator {
         this._listeners();
     }
 
+    /**
+     * @NOTE: currently only used if the permalink setting changes and it's used for this url generator.
+     * @TODO: https://github.com/TryGhost/Ghost/issues/10699
+     */
+    regenerateResources() {
+        const myResources = this.urls.getByGeneratorId(this.uid);
+
+        myResources.forEach((object) => {
+            this.urls.removeResourceId(object.resource.data.id);
+            object.resource.release();
+            this._try(object.resource);
+        });
+    }
+
     /**
      * @description Helper function to register listeners for each url generator instance.
      * @private
      */
     _listeners() {
-        /**
-         * @NOTE: currently only used if the permalink setting changes and it's used for this url generator.
-         * @TODO: https://github.com/TryGhost/Ghost/issues/10699
-         */
-        this.router.addListener('updated', () => {
-            const myResources = this.urls.getByGeneratorId(this.uid);
-
-            myResources.forEach((object) => {
-                this.urls.removeResourceId(object.resource.data.id);
-                object.resource.release();
-                this._try(object.resource);
-            });
-        });
-
         /**
          * Listen on two events:
          *

core/frontend/services/url/UrlService.js

@@ -89,6 +89,15 @@ class UrlService {
         this.urlGenerators.push(urlGenerator);
     }
 
+    /**
+     * @description Router update handler - regenerates it's resources
+     * @param {ExpressRouter} router
+     */
+    onRouterUpdated(router) {
+        const generator = this.urlGenerators.find(g => g.router.id === router.id);
+        generator.regenerateResources();
+    }
+
     /**
      * @description If the API version in the theme config changes, we have to reset urls and resources.
      * @private

test/unit/frontend/services/routing/CollectionRouter.test.js

@@ -179,62 +179,4 @@ describe('UNIT - services/routing/CollectionRouter', function () {
             });
         });
     });
-
-    describe('timezone changes', function () {
-        describe('no dated permalink', function () {
-            it('default', function () {
-                const collectionRouter = new CollectionRouter('/magic/', {permalink: '/:slug/'}, RESOURCE_CONFIG);
-
-                sinon.stub(collectionRouter, 'emit');
-
-                events.on.args[0][1]({
-                    attributes: {value: 'America/Los_Angeles'},
-                    _previousAttributes: {value: 'Europe/London'}
-                });
-
-                collectionRouter.emit.called.should.be.false();
-            });
-
-            it('tz has not changed', function () {
-                const collectionRouter = new CollectionRouter('/magic/', {permalink: '/:slug/'}, RESOURCE_CONFIG);
-
-                sinon.stub(collectionRouter, 'emit');
-
-                events.on.args[0][1]({
-                    attributes: {value: 'America/Los_Angeles'},
-                    _previousAttributes: {value: 'America/Los_Angeles'}
-                });
-
-                collectionRouter.emit.called.should.be.false();
-            });
-        });
-
-        describe('with dated permalink', function () {
-            it('default', function () {
-                const collectionRouter = new CollectionRouter('/magic/', {permalink: '/:year/:slug/'}, RESOURCE_CONFIG);
-
-                sinon.stub(collectionRouter, 'emit');
-
-                events.on.args[0][1]({
-                    attributes: {value: 'America/Los_Angeles'},
-                    _previousAttributes: {value: 'Europe/London'}
-                });
-
-                collectionRouter.emit.calledOnce.should.be.true();
-            });
-
-            it('tz has not changed', function () {
-                const collectionRouter = new CollectionRouter('/magic/', {permalink: '/:year/:slug/'}, RESOURCE_CONFIG);
-
-                sinon.stub(collectionRouter, 'emit');
-
-                events.on.args[0][1]({
-                    attributes: {value: 'America/Los_Angeles'},
-                    _previousAttributes: {value: 'America/Los_Angeles'}
-                });
-
-                collectionRouter.emit.called.should.be.false();
-            });
-        });
-    });
 });

test/unit/frontend/services/routing/bootstrap.test.js

@@ -0,0 +1,74 @@
+const should = require('should');
+const sinon = require('sinon');
+const CollectionRouter = require('../../../../../core/frontend/services/routing/CollectionRouter');
+const bootstrap = require('../../../../../core/frontend/services/routing/bootstrap');
+const registry = require('../../../../../core/frontend/services/routing/registry');
+
+const RESOURCE_CONFIG = {QUERY: {post: {controller: 'posts', resource: 'posts'}}};
+
+describe('UNIT: services/routing/bootstrap', function () {
+    let routesUpdatedStub;
+
+    beforeEach(function () {
+        sinon.stub(bootstrap.internal, 'routerCreated').returns();
+        routesUpdatedStub = sinon.stub(bootstrap.internal, 'routerUpdated').returns();
+    });
+
+    afterEach(function () {
+        sinon.restore();
+    });
+
+    describe('timezone changes', function () {
+        describe('no dated permalink', function () {
+            it('default', function () {
+                const collectionRouter = new CollectionRouter('/magic/', {permalink: '/:slug/'}, RESOURCE_CONFIG);
+                sinon.stub(registry, 'getRouterByName').withArgs('CollectionRouter').returns(collectionRouter);
+
+                bootstrap.handleTimezoneEdit({
+                    attributes: {value: 'America/Los_Angeles'},
+                    _previousAttributes: {value: 'Europe/London'}
+                });
+
+                routesUpdatedStub.called.should.be.false();
+            });
+
+            it('tz has not changed', function () {
+                const collectionRouter = new CollectionRouter('/magic/', {permalink: '/:slug/'}, RESOURCE_CONFIG);
+                sinon.stub(registry, 'getRouterByName').withArgs('CollectionRouter').returns(collectionRouter);
+
+                bootstrap.handleTimezoneEdit({
+                    attributes: {value: 'America/Los_Angeles'},
+                    _previousAttributes: {value: 'America/Los_Angeles'}
+                });
+
+                routesUpdatedStub.called.should.be.false();
+            });
+        });
+
+        describe('with dated permalink', function () {
+            it('default', function () {
+                const collectionRouter = new CollectionRouter('/magic/', {permalink: '/:year/:slug/'}, RESOURCE_CONFIG);
+                sinon.stub(registry, 'getRouterByName').withArgs('CollectionRouter').returns(collectionRouter);
+
+                bootstrap.handleTimezoneEdit({
+                    attributes: {value: 'America/Los_Angeles'},
+                    _previousAttributes: {value: 'Europe/London'}
+                });
+
+                routesUpdatedStub.called.should.be.true();
+            });
+
+            it('tz has not changed', function () {
+                const collectionRouter = new CollectionRouter('/magic/', {permalink: '/:year/:slug/'}, RESOURCE_CONFIG);
+                sinon.stub(registry, 'getRouterByName').withArgs('CollectionRouter').returns(collectionRouter);
+
+                bootstrap.handleTimezoneEdit({
+                    attributes: {value: 'America/Los_Angeles'},
+                    _previousAttributes: {value: 'America/Los_Angeles'}
+                });
+
+                routesUpdatedStub.called.should.be.false();
+            });
+        });
+    });
+});

test/unit/frontend/services/url/UrlGenerator.test.js

@@ -61,7 +61,6 @@ describe('Unit: services/url/UrlGenerator', function () {
         const urlGenerator = new UrlGenerator(router, queue);
 
         queue.register.calledTwice.should.be.true();
-        router.addListener.calledOnce.should.be.true();
         should.not.exist(urlGenerator.filter);
     });
 
@@ -94,7 +93,8 @@ describe('Unit: services/url/UrlGenerator', function () {
             id: 'object-id-1'
         };
 
-        router.addListener.args[0][1]();
+        urlGenerator.regenerateResources();
+
         urls.removeResourceId.calledTwice.should.be.true();
         resource.release.calledOnce.should.be.true();
         resource2.release.calledOnce.should.be.true();