fix(@angular-devkit/build-angular): do not generate an index.html file in the browser directory when using SSR.

BREAKING CHANGE: By default, the index.html file is no longer emitted in the browser directory when using the application builder with SSR. Instead, an index.csr.html file is emitted. This change is implemented because in many cases server and cloud providers incorrectly treat the index.html file as a statically generated page. If you still require the old behavior, you can use the `index` option to specify the `output` file name.

```json
"architect": {
  "build": {
    "builder": "@angular-devkit/build-angular:application",
    "options": {
      "outputPath": "dist/my-app",
      "index": {
        "input": "src/index.html",
        "output": "index.html"
      }
    }
  }
}
```

Author: alan-agius4

packages/angular_devkit/build_angular/src/builders/application/options.ts

@@ -194,35 +194,6 @@ export async function normalizeOptions(
     ? undefined
     : await getTailwindConfig(searchDirectories, workspaceRoot, context);
 
-  const globalStyles = normalizeGlobalEntries(options.styles, 'styles');
-  const globalScripts = normalizeGlobalEntries(options.scripts, 'scripts');
-
-  let indexHtmlOptions;
-  // index can never have a value of `true` but in the schema it's of type `boolean`.
-  if (typeof options.index !== 'boolean') {
-    indexHtmlOptions = {
-      input: path.join(
-        workspaceRoot,
-        typeof options.index === 'string' ? options.index : options.index.input,
-      ),
-      // The output file will be created within the configured output path
-      output:
-        typeof options.index === 'string'
-          ? path.basename(options.index)
-          : options.index.output || 'index.html',
-      insertionOrder: [
-        ['polyfills', true],
-        ...globalStyles.filter((s) => s.initial).map((s) => [s.name, false]),
-        ...globalScripts.filter((s) => s.initial).map((s) => [s.name, false]),
-        ['main', true],
-        // [name, esm]
-      ] as [string, boolean][],
-      transformer: extensions?.indexHtmlTransformer,
-      // Preload initial defaults to true
-      preloadInitial: typeof options.index !== 'object' || (options.index.preloadInitial ?? true),
-    };
-  }
-
   let serverEntryPoint: string | undefined;
   if (options.server) {
     serverEntryPoint = path.join(workspaceRoot, options.server);
@@ -259,10 +230,57 @@ export async function normalizeOptions(
     };
   }
 
-  if ((appShellOptions || ssrOptions || prerenderOptions) && !serverEntryPoint) {
-    throw new Error(
-      'The "server" option is required when enabling "ssr", "prerender" or "app-shell".',
-    );
+  const globalStyles = normalizeGlobalEntries(options.styles, 'styles');
+  const globalScripts = normalizeGlobalEntries(options.scripts, 'scripts');
+  let indexHtmlOptions;
+  // index can never have a value of `true` but in the schema it's of type `boolean`.
+  if (typeof options.index !== 'boolean') {
+    let indexOutput: string;
+    // The output file will be created within the configured output path
+    if (typeof options.index === 'string') {
+      /**
+       * If SSR is activated, create a distinct entry file for the `index.html`.
+       * This is necessary because numerous server/cloud providers automatically serve the `index.html` as a static file
+       * if it exists (handling SSG).
+       * For instance, accessing `foo.com/` would lead to `foo.com/index.html` being served instead of hitting the server.
+       */
+      const indexBaseName = path.basename(options.index);
+      indexOutput = ssrOptions && indexBaseName === 'index.html' ? 'index.csr.html' : indexBaseName;
+    } else {
+      indexOutput = options.index.output || 'index.html';
+    }
+
+    indexHtmlOptions = {
+      input: path.join(
+        workspaceRoot,
+        typeof options.index === 'string' ? options.index : options.index.input,
+      ),
+      output: indexOutput,
+      insertionOrder: [
+        ['polyfills', true],
+        ...globalStyles.filter((s) => s.initial).map((s) => [s.name, false]),
+        ...globalScripts.filter((s) => s.initial).map((s) => [s.name, false]),
+        ['main', true],
+        // [name, esm]
+      ] as [string, boolean][],
+      transformer: extensions?.indexHtmlTransformer,
+      // Preload initial defaults to true
+      preloadInitial: typeof options.index !== 'object' || (options.index.preloadInitial ?? true),
+    };
+  }
+
+  if (appShellOptions || ssrOptions || prerenderOptions) {
+    if (!serverEntryPoint) {
+      throw new Error(
+        'The "server" option is required when enabling "ssr", "prerender" or "app-shell".',
+      );
+    }
+
+    if (!indexHtmlOptions) {
+      throw new Error(
+        'The "index" option cannot be set to false when enabling "ssr", "prerender" or "app-shell".',
+      );
+    }
   }
 
   // Initial options to keep

packages/angular_devkit/build_angular/src/builders/application/tests/behavior/index-preload-hints_spec.ts

@@ -38,13 +38,11 @@ describeBuilder(buildApplication, APPLICATION_BUILDER_INFO, (harness) => {
       await harness.modifyFile('src/tsconfig.app.json', (content) => {
         const tsConfig = JSON.parse(content);
         tsConfig.files ??= [];
-        tsConfig.files.push('main.server.ts', 'server.ts');
+        tsConfig.files.push('main.server.ts');
 
         return JSON.stringify(tsConfig);
       });
 
-      await harness.writeFile('src/server.ts', `console.log('Hello!');`);
-
       harness.useTarget('build', {
         ...BASE_OPTIONS,
         server: 'src/main.server.ts',
@@ -57,7 +55,7 @@ describeBuilder(buildApplication, APPLICATION_BUILDER_INFO, (harness) => {
       harness.expectFile('dist/server/main.server.mjs').toExist();
 
       harness
-        .expectFile('dist/browser/index.html')
+        .expectFile('dist/browser/index.csr.html')
         .content.not.toMatch(/<link rel="modulepreload" href="chunk-\.+\.mjs">/);
     });
   });

packages/angular_devkit/build_angular/src/builders/application/tests/behavior/rebuild-errors_spec.ts

@@ -315,7 +315,7 @@ describeBuilder(buildApplication, APPLICATION_BUILDER_INFO, (harness) => {
       });
 
       const buildCount = await harness
-        .execute({ outputLogsOnFailure: true })
+        .execute({ outputLogsOnFailure: false })
         .pipe(
           timeout(BUILD_TIMEOUT),
           concatMap(async ({ result, logs }, index) => {

packages/angular_devkit/build_angular/src/builders/application/tests/options/index_spec.ts

@@ -205,5 +205,27 @@ describeBuilder(buildApplication, APPLICATION_BUILDER_INFO, (harness) => {
       harness.expectFile('dist/browser/index.html').content.not.toContain('modulepreload');
       harness.expectFile('dist/browser/index.html').content.not.toContain('chunk-');
     });
+
+    it(`should generate 'index.csr.html' instead of 'index.html' by default when ssr is enabled.`, async () => {
+      await harness.modifyFile('src/tsconfig.app.json', (content) => {
+        const tsConfig = JSON.parse(content);
+        tsConfig.files ??= [];
+        tsConfig.files.push('main.server.ts');
+
+        return JSON.stringify(tsConfig);
+      });
+
+      harness.useTarget('build', {
+        ...BASE_OPTIONS,
+        server: 'src/main.server.ts',
+        ssr: true,
+      });
+
+      const { result } = await harness.executeOnce();
+      expect(result?.success).toBeTrue();
+      harness.expectDirectory('dist/server').toExist();
+      harness.expectFile('dist/browser/index.csr.html').toExist();
+      harness.expectFile('dist/browser/index.html').toNotExist();
+    });
   });
 });

packages/schematics/angular/ssr/files/application-builder/server.ts.template

@@ -20,12 +20,13 @@ export function app(): express.Express {
   // Example Express Rest API endpoints
   // server.get('/api/**', (req, res) => { });
   // Serve static files from /<%= browserDistDirectory %>
-  server.get('*.*', express.static(browserDistFolder, {
-    maxAge: '1y'
+  server.get('**', express.static(browserDistFolder, {
+    maxAge: '1y',
+    index: 'index.html',
   }));
 
   // All regular routes use the Angular engine
-  server.get('*', (req, res, next) => {
+  server.get('**', (req, res, next) => {
     const { protocol, originalUrl, baseUrl, headers } = req;
 
     commonEngine