fix(service-worker): detect new version even if files are identical t…

…o an old one

Previously, if an app version contained the same files as an older
version (e.g. making a change, then rolling it back), the SW would not
detect it as the latest version (and update clients).

This commit fixes it by adding a `timestamp` field in `ngsw.json`, which
makes each build unique (with sufficiently high probability).

Fixes #24338

packages/service-worker/config/src/generator.ts

@@ -32,6 +32,7 @@ export class Generator {
 
     return {
       configVersion: 1,
+      timestamp: Date.now(),
       appData: config.appData,
       index: joinUrls(this.baseHref, config.index), assetGroups,
       dataGroups: this.processDataGroups(config),

packages/service-worker/config/test/generator_spec.ts

@@ -11,6 +11,8 @@ import {MockFilesystem} from '../testing/mock';
 
 {
   describe('Generator', () => {
+    beforeEach(() => spyOn(Date, 'now').and.returnValue(1234567890123));
+
     it('generates a correct config', done => {
       const fs = new MockFilesystem({
         '/index.html': 'This is a test',
@@ -71,6 +73,7 @@ import {MockFilesystem} from '../testing/mock';
       res.then(config => {
            expect(config).toEqual({
              configVersion: 1,
+             timestamp: 1234567890123,
              appData: {
                test: true,
              },
@@ -138,6 +141,7 @@ import {MockFilesystem} from '../testing/mock';
       res.then(config => {
            expect(config).toEqual({
              configVersion: 1,
+             timestamp: 1234567890123,
              appData: undefined,
              index: '/test/index.html',
              assetGroups: [],

packages/service-worker/test/integration_spec.ts

@@ -32,6 +32,7 @@ function obsToSinglePromise<T>(obs: Observable<T>): Promise<T> {
 
 const manifest: Manifest = {
   configVersion: 1,
+  timestamp: 1234567890123,
   appData: {version: '1'},
   index: '/only.txt',
   assetGroups: [{
@@ -47,6 +48,7 @@ const manifest: Manifest = {
 
 const manifestUpdate: Manifest = {
   configVersion: 1,
+  timestamp: 1234567890123,
   appData: {version: '2'},
   index: '/only.txt',
   assetGroups: [{

packages/service-worker/worker/src/manifest.ts

@@ -12,6 +12,7 @@ export type ManifestHash = string;
 
 export interface Manifest {
   configVersion: number;
+  timestamp: number;
   appData?: {[key: string]: string};
   index: string;
   assetGroups?: AssetGroupConfig[];

packages/service-worker/worker/test/data_spec.ts

@@ -39,6 +39,7 @@ const distUpdate = new MockFileSystemBuilder()
 
 const manifest: Manifest = {
   configVersion: 1,
+  timestamp: 1234567890123,
   index: '/index.html',
   assetGroups: [
     {

packages/service-worker/worker/test/happy_spec.ts

@@ -50,6 +50,7 @@ const brokenFs = new MockFileSystemBuilder().addFile('/foo.txt', 'this is foo').
 
 const brokenManifest: Manifest = {
   configVersion: 1,
+  timestamp: 1234567890123,
   index: '/foo.txt',
   assetGroups: [{
     name: 'assets',
@@ -67,6 +68,7 @@ const brokenManifest: Manifest = {
 
 const manifest: Manifest = {
   configVersion: 1,
+  timestamp: 1234567890123,
   appData: {
     version: 'original',
   },
@@ -114,6 +116,7 @@ const manifest: Manifest = {
 
 const manifestUpdate: Manifest = {
   configVersion: 1,
+  timestamp: 1234567890123,
   appData: {
     version: 'update',
   },
@@ -166,12 +169,21 @@ const manifestUpdate: Manifest = {
   hashTable: tmpHashTableForFs(distUpdate),
 };
 
-const server = new MockServerStateBuilder()
-                   .withStaticFiles(dist)
-                   .withManifest(manifest)
-                   .withRedirect('/redirected.txt', '/redirect-target.txt', 'this was a redirect')
-                   .withError('/error.txt')
-                   .build();
+const serverBuilderBase =
+    new MockServerStateBuilder()
+        .withStaticFiles(dist)
+        .withRedirect('/redirected.txt', '/redirect-target.txt', 'this was a redirect')
+        .withError('/error.txt');
+
+const server =
+    serverBuilderBase
+        .withManifest(manifest)
+        .build();
+
+const serverRollback =
+    serverBuilderBase
+        .withManifest({...manifest, timestamp: manifest.timestamp + 1})
+        .build();
 
 const serverUpdate =
     new MockServerStateBuilder()
@@ -309,6 +321,19 @@ const manifestUpdateHash = sha1(JSON.stringify(manifestUpdate));
       serverUpdate.assertNoOtherRequests();
     });
 
+    async_it('detects new version even if only `manifest.timestamp` is different', async() => {
+      expect(await makeRequest(scope, '/foo.txt', 'newClient')).toEqual('this is foo');
+      await driver.initialized;
+
+      scope.updateServerState(serverUpdate);
+      expect(await driver.checkForUpdate()).toEqual(true);
+      expect(await makeRequest(scope, '/foo.txt', 'newerClient')).toEqual('this is foo v2');
+
+      scope.updateServerState(serverRollback);
+      expect(await driver.checkForUpdate()).toEqual(true);
+      expect(await makeRequest(scope, '/foo.txt', 'newestClient')).toEqual('this is foo');
+    });
+
     async_it('updates a specific client to new content on request', async() => {
       expect(await makeRequest(scope, '/foo.txt')).toEqual('this is foo');
       await driver.initialized;

packages/service-worker/worker/testing/mock.ts

@@ -88,7 +88,13 @@ export class MockServerStateBuilder {
     return this;
   }
 
-  build(): MockServerState { return new MockServerState(this.resources, this.errors); }
+  build(): MockServerState {
+    // Take a "snapshot" of the current `resources` and `errors`.
+    const resources = new Map(this.resources.entries());
+    const errors = new Set(this.errors.values());
+
+    return new MockServerState(resources, errors);
+  }
 }
 
 export class MockServerState {
@@ -187,6 +193,7 @@ export function tmpManifestSingleAssetGroup(fs: MockFileSystem): Manifest {
   files.forEach(path => { hashTable[path] = fs.lookup(path) !.hash; });
   return {
     configVersion: 1,
+    timestamp: 1234567890123,
     index: '/index.html',
     assetGroups: [
       {

packages/service-worker/worker/testing/scope.ts

@@ -290,6 +290,7 @@ export class ConfigBuilder {
     const hashTable = {};
     return {
       configVersion: 1,
+      timestamp: 1234567890123,
       index: '/index.html', assetGroups,
       navigationUrls: [], hashTable,
     };