fix: Store and reuse index.html modifications for dev bundles

flow-server/src/main/java/com/vaadin/flow/server/BootstrapHandler.java

@@ -25,7 +25,6 @@
 import java.io.OutputStreamWriter;
 import java.io.Serializable;
 import java.lang.annotation.Annotation;
-import java.net.URL;
 import java.nio.charset.StandardCharsets;
 import java.util.ArrayList;
 import java.util.Arrays;
@@ -49,7 +48,6 @@
 import java.util.stream.Collectors;
 import java.util.stream.Stream;
 
-import org.apache.commons.io.IOUtils;
 import org.jsoup.Jsoup;
 import org.jsoup.nodes.DataNode;
 import org.jsoup.nodes.Document;
@@ -70,6 +68,7 @@
 import com.vaadin.flow.function.DeploymentConfiguration;
 import com.vaadin.flow.internal.AnnotationReader;
 import com.vaadin.flow.internal.BootstrapHandlerHelper;
+import com.vaadin.flow.internal.JsonUtils;
 import com.vaadin.flow.internal.ReflectTools;
 import com.vaadin.flow.internal.UsageStatisticsExporter;
 import com.vaadin.flow.router.InvalidLocationException;
@@ -96,6 +95,7 @@
 import elemental.json.JsonObject;
 import elemental.json.JsonValue;
 import elemental.json.impl.JsonUtil;
+
 import static com.vaadin.flow.server.Constants.VAADIN_MAPPING;
 import static com.vaadin.flow.server.frontend.FrontendUtils.EXPORT_CHUNK;
 import static java.nio.charset.StandardCharsets.UTF_8;
@@ -1595,17 +1595,15 @@ protected static void setupPwa(Document document, VaadinService service) {
         setupPwa(document, service.getPwaRegistry());
     }
 
-    protected static void addJavaScriptEntryPoints(
+    protected static void addGeneratedIndexContent(
             DeploymentConfiguration config, Document targetDocument)
             throws IOException {
-        URL statsJsonUrl = DevBundleUtils
-                .findBundleFile(config.getProjectFolder(), "config/stats.json");
-        Objects.requireNonNull(statsJsonUrl,
+        String statsJson = DevBundleUtils
+                .findBundleStatsJson(config.getProjectFolder());
+        Objects.requireNonNull(statsJson,
                 "Frontend development bundle is expected to be in the project"
                         + " or on the classpath, but not found.");
-        String statsJson = IOUtils.toString(statsJsonUrl,
-                StandardCharsets.UTF_8);
-        addEntryScripts(targetDocument, Json.parse(statsJson));
+        addGeneratedIndexContent(targetDocument, Json.parse(statsJson));
     }
 
     /**
@@ -1676,31 +1674,30 @@ private static Element getStyleTag(String themeName, String fileName,
         return element;
     }
 
-    private static void addEntryScripts(Document targetDocument,
+    private static void addGeneratedIndexContent(Document targetDocument,
             JsonObject statsJson) {
-        boolean addIndexHtml = true;
-        Element indexHtmlScript = null;
-        JsonArray entryScripts = statsJson.getArray("entryScripts");
-        for (int i = 0; i < entryScripts.length(); i++) {
-            String entryScript = entryScripts.getString(i);
-            Element elm = new Element(SCRIPT_TAG);
-            elm.attr("type", "module");
-            elm.attr("src", entryScript);
-            targetDocument.head().appendChild(elm);
+        JsonArray indexHtmlGeneratedRows = statsJson
+                .getArray("indexHtmlGenerated");
+        List<String> toAdd = new ArrayList<>();
 
-            if (entryScript.contains("indexhtml")) {
-                indexHtmlScript = elm;
-            }
+        Optional<String> webComponentScript = JsonUtils
+                .stream(statsJson.getArray("entryScripts"))
+                .map(value -> value.asString())
+                .filter(script -> script.contains("webcomponenthtml"))
+                .findFirst();
 
-            if (entryScript.contains("webcomponenthtml")) {
-                addIndexHtml = false;
-            }
+        if (webComponentScript.isPresent()) {
+            Element elm = new Element(SCRIPT_TAG);
+            elm.attr("type", "module");
+            elm.attr("src", webComponentScript.get());
+            toAdd.add(elm.outerHtml());
+        } else {
+            toAdd.addAll(JsonUtils.stream(indexHtmlGeneratedRows)
+                    .map(value -> value.asString()).toList());
         }
 
-        // If a reference to webcomponenthtml is present, the embedded
-        // components are used, thus we don't need to serve indexhtml script
-        if (!addIndexHtml && indexHtmlScript != null) {
-            indexHtmlScript.remove();
+        for (String row : toAdd) {
+            targetDocument.head().append(row);
         }
     }
 

flow-server/src/main/java/com/vaadin/flow/server/communication/IndexHtmlRequestHandler.java

@@ -418,7 +418,7 @@ private static Document getIndexHtmlDocument(VaadinService service)
             // When running without a frontend server, the index.html comes
             // directly from the frontend folder and the JS entrypoint(s) need
             // to be added
-            addJavaScriptEntryPoints(config, indexHtmlDocument);
+            addGeneratedIndexContent(config, indexHtmlDocument);
         }
         modifyIndexHtmlForVite(indexHtmlDocument);
         return indexHtmlDocument;

flow-server/src/main/java/com/vaadin/flow/server/communication/WebComponentBootstrapHandler.java

@@ -135,7 +135,7 @@ public Document getBootstrapPage(BootstrapContext context) {
                     // directly from the frontend folder and the JS
                     // entrypoint(s) need
                     // to be added
-                    addJavaScriptEntryPoints(deploymentConfiguration, document);
+                    addGeneratedIndexContent(deploymentConfiguration, document);
                 }
 
                 // Specify the application ID for scripts of the

flow-server/src/main/resources/vite.generated.ts

@@ -55,6 +55,8 @@ const bundleSizeFile = path.resolve(statsFolder, 'bundle-size.html');
 const nodeModulesFolder = path.resolve(__dirname, 'node_modules');
 const webComponentTags = '#webComponentTags#';
 
+const projectIndexHtml = path.resolve(frontendFolder, 'index.html');
+
 const projectStaticAssetsFolders = [
   path.resolve(__dirname, 'src', 'main', 'resources', 'META-INF', 'resources'),
   path.resolve(__dirname, 'src', 'main', 'resources', 'static'),
@@ -229,15 +231,35 @@ function statsExtracterPlugin(): PluginOption {
         .sort()
         .filter((value, index, self) => self.indexOf(value) === index);
       const npmModuleAndVersion = Object.fromEntries(npmModules.map((module) => [module, getVersion(module)]));
-      const cvdls = Object.fromEntries(npmModules.filter((module) => getCvdlName(module) != null)
-          .map((module) => [module, {name: getCvdlName(module),version: getVersion(module)}]));
+      const cvdls = Object.fromEntries(
+        npmModules
+          .filter((module) => getCvdlName(module) != null)
+          .map((module) => [module, { name: getCvdlName(module), version: getVersion(module) }])
+      );
 
       mkdirSync(path.dirname(statsFile), { recursive: true });
       const projectPackageJson = JSON.parse(readFileSync(projectPackageJsonFile, { encoding: 'utf-8' }));
 
       const entryScripts = Object.values(bundle)
         .filter((bundle) => bundle.isEntry)
         .map((bundle) => bundle.fileName);
+
+      const generatedIndexHtml = path.resolve(buildOutputFolder, 'index.html');
+      const customIndexData: string = readFileSync(projectIndexHtml, { encoding: 'utf-8' });
+      const generatedIndexData: string = readFileSync(generatedIndexHtml, {
+        encoding: 'utf-8'
+      });
+
+      const customIndexRows = new Set(customIndexData.split(/[\r\n]/).filter((row) => row.trim() !== ''));
+      const generatedIndexRows = generatedIndexData.split(/[\r\n]/).filter((row) => row.trim() !== '');
+
+      const rowsGenerated: string[] = [];
+      generatedIndexRows.forEach((row) => {
+        if (!customIndexRows.has(row)) {
+          rowsGenerated.push(row);
+        }
+      });
+
       //After dev-bundle build add used Flow frontend imports JsModule/JavaScript/CssImport
 
       const parseImports = (filename: string, result: Set<string>): void => {
@@ -343,7 +365,8 @@ function statsExtracterPlugin(): PluginOption {
         entryScripts,
         webComponents,
         cvdlModules: cvdls,
-        packageJsonHash: projectPackageJson?.vaadin?.hash
+        packageJsonHash: projectPackageJson?.vaadin?.hash,
+        indexHtmlGenerated: rowsGenerated
       };
       writeFileSync(statsFile, JSON.stringify(stats, null, 1));
     }
@@ -663,7 +686,7 @@ export const vaadinConfig: UserConfigFn = (env) => {
       assetsDir: 'VAADIN/build',
       rollupOptions: {
         input: {
-          indexhtml: path.resolve(frontendFolder, 'index.html'),
+          indexhtml: projectIndexHtml,
 
           ...(hasExportedWebComponents ? { webcomponenthtml: path.resolve(frontendFolder, 'web-component.html') } : {})
         },

flow-server/src/test/java/com/vaadin/tests/util/TestUtil.java

@@ -110,7 +110,8 @@ public static void createStatsJsonStub(File projectRootFolder)
             throws IOException {
         String content = "{\"npmModules\": {}, "
                 + "\"entryScripts\": [\"foo.js\"], "
-                + "\"packageJsonHash\": \"42\"}";
+                + "\"packageJsonHash\": \"42\","
+                + "\"indexHtmlGenerated\": []}";
         createStubFile(projectRootFolder,
                 Constants.DEV_BUNDLE_LOCATION + "/config/stats.json", content);
     }

flow-tests/test-express-build/test-dev-bundle-frontend-add-on/src/main/webapp/imported-by-vite-plugin.css

@@ -0,0 +1,3 @@
+body {
+  background: rgba(173, 216, 230, 1);
+}

flow-tests/test-express-build/test-dev-bundle-frontend-add-on/src/test/java/com/vaadin/flow/frontend/ViteImportedCSSIT.java

@@ -0,0 +1,50 @@
+/*
+ * Copyright 2000-2023 Vaadin Ltd.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not
+ * use this file except in compliance with the License. You may obtain a copy of
+ * the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+ * License for the specific language governing permissions and limitations under
+ * the License.
+ */
+package com.vaadin.flow.frontend;
+
+import java.io.File;
+import java.io.IOException;
+import java.nio.charset.StandardCharsets;
+
+import org.apache.commons.io.FileUtils;
+import org.junit.Assert;
+import org.junit.Test;
+import org.openqa.selenium.By;
+import org.openqa.selenium.WebElement;
+
+import com.vaadin.flow.server.Constants;
+import com.vaadin.flow.testutil.ChromeBrowserTest;
+
+import elemental.json.Json;
+import elemental.json.JsonArray;
+import elemental.json.JsonObject;
+
+public class ViteImportedCSSIT extends ChromeBrowserTest {
+
+    @Override
+    protected String getTestPath() {
+        return "/view/";
+    }
+
+    @Test
+    public void cssImportedByVite_availableInApp() throws IOException {
+        open();
+        WebElement body = $("body").first();
+
+        Assert.assertEquals("rgba(173, 216, 230, 1)",
+                body.getCssValue("background-color"));
+    }
+}

flow-tests/test-express-build/test-dev-bundle-frontend-add-on/vite.config.ts

@@ -0,0 +1,29 @@
+import { PluginOption, UserConfigFn } from 'vite';
+import { overrideVaadinConfig } from './vite.generated';
+
+function addCssToIndex(): PluginOption {
+  return {
+    name: 'generate-css',
+    transformIndexHtml: (_html, _conf) => {
+      const tags = [
+        {
+          tag: 'link',
+          attrs: {
+            rel: 'stylesheet',
+            href: '/imported-by-vite-plugin.css'
+          }
+        }
+      ];
+
+      return tags;
+    }
+  };
+}
+
+const customConfig: UserConfigFn = (env) => ({
+  // Here you can add custom Vite parameters
+  // https://vitejs.dev/config/
+  plugins: [addCssToIndex()]
+});
+
+export default overrideVaadinConfig(customConfig);