feat: Enable importing CSS from node_modules

flow-server/src/main/resources/plugins/application-theme-plugin/application-theme-plugin.js

@@ -114,7 +114,7 @@ function handleThemes(themeName, themesFolder, projectStaticAssetsOutputFolder)
 
     copyStaticAssets(themeProperties, projectStaticAssetsOutputFolder, logger);
 
-    const themeFile = generateThemeFile(themeFolder, themeName);
+    const themeFile = generateThemeFile(themeFolder, themeName, themeProperties);
 
     fs.writeFileSync(path.resolve(themeFolder, themeName + '.js'), themeFile);
     return true;

flow-server/src/main/resources/plugins/application-theme-plugin/package.json

@@ -6,7 +6,7 @@
   ],
   "repository": "vaadin/flow",
   "name": "@vaadin/application-theme-plugin",
-  "version": "0.2.1",
+  "version": "0.2.2",
   "main": "application-theme-plugin.js",
   "author": "Vaadin Ltd",
   "license": "Apache-2.0",

flow-server/src/main/resources/plugins/application-theme-plugin/theme-generator.js

@@ -44,9 +44,10 @@ export const injectGlobalCss = (css, target) => {
  *
  * @param {string} themeFolder folder of the theme
  * @param {string} themeName name of the handled theme
+ * @param {JSON Object} themeProperties content of theme.json
  * @returns {string} theme file content
  */
-function generateThemeFile(themeFolder, themeName) {
+function generateThemeFile(themeFolder, themeName, themeProperties) {
   const globalFiles = glob.sync('*.css', {
     cwd: themeFolder,
     nodir: true,
@@ -79,6 +80,15 @@ function generateThemeFile(themeFolder, themeName) {
     }
   });
 
+  let i = 0;
+  if (themeProperties.importCss) {
+    themeProperties.importCss.forEach((cssPath) => {
+      const variable = 'module' + i++;
+      imports.push(`import ${variable} from '${cssPath}';\n`);
+      globalCssCode.push(`injectGlobalCss(${variable}.toString(), target);\n`);
+    });
+  }
+
   componentsFiles.forEach((componentCss) => {
     const filename = path.basename(componentCss);
     const tag = filename.replace('.css', '');

flow-server/src/main/resources/webpack.generated.js

@@ -212,6 +212,9 @@ module.exports = {
               if(urlResource.match(themePartRegex)){
                 return /^(\\|\/)theme\1[\s\S]*?\1(.*)/.exec(urlResource)[2].replace(/\\/, "/");
               }
+              if(urlResource.match(/(\\|\/)node_modules\1/)) {
+                return /(\\|\/)node_modules\1(?!.*node_modules)([\S]*)/.exec(urlResource)[2].replace(/\\/g, "/");
+              }
               return '[path][name].[ext]';
             }
           }

flow-tests/test-themes/frontend/theme/app-theme/theme.json

@@ -1,4 +1,5 @@
 {
+  "importCss": ["@fortawesome/fontawesome-free/css/all.css"],
   "assets": {
     "@fortawesome/fontawesome-free": {
       "svgs/regular/**": "fortawesome/icons"

flow-tests/test-themes/src/main/java/com/vaadin/flow/uitest/ui/theme/ThemeView.java

@@ -30,6 +30,7 @@ public class ThemeView extends Div {
     public static final String SNOWFLAKE_ID = "fortawesome";
     public static final String BUTTERFLY_ID = "butterfly";
     public static final String OCTOPUSS_ID = "octopuss";
+    public static final String FONTAWESOME_ID = "font-awesome";
     public static final String SUB_COMPONENT_ID = "sub-component";
 
     public ThemeView() {
@@ -45,12 +46,16 @@ public ThemeView() {
         Span octopuss = new Span();
         octopuss.setId(OCTOPUSS_ID);
 
+        Span faText = new Span("This test is FontAwesome.");
+        faText.setClassName("fas fa-coffee");
+        faText.setId(FONTAWESOME_ID);
+
         Image snowFlake = new Image(
             "VAADIN/static/fortawesome/icons/snowflake.svg", "snowflake");
         snowFlake.setHeight("1em");
         snowFlake.setId(SNOWFLAKE_ID);
 
-        add(textSpan, snowFlake, subCss, butterfly, octopuss);
+        add(textSpan, snowFlake, subCss, butterfly, octopuss, faText);
 
         add(new Div());
         add(new MyPolymerField().withId(MY_POLYMER_ID));

flow-tests/test-themes/src/test/java/com/vaadin/flow/uitest/ui/theme/ThemeIT.java

@@ -18,6 +18,7 @@
 import org.junit.Assert;
 import org.junit.Test;
 import org.openqa.selenium.By;
+import org.openqa.selenium.JavascriptExecutor;
 import org.openqa.selenium.WebElement;
 
 import com.vaadin.flow.component.html.testbench.ImageElement;
@@ -26,6 +27,7 @@
 import com.vaadin.testbench.TestBenchElement;
 
 import static com.vaadin.flow.uitest.ui.theme.ThemeView.BUTTERFLY_ID;
+import static com.vaadin.flow.uitest.ui.theme.ThemeView.FONTAWESOME_ID;
 import static com.vaadin.flow.uitest.ui.theme.ThemeView.MY_LIT_ID;
 import static com.vaadin.flow.uitest.ui.theme.ThemeView.MY_POLYMER_ID;
 import static com.vaadin.flow.uitest.ui.theme.ThemeView.SNOWFLAKE_ID;
@@ -79,6 +81,28 @@ public void applicationTheme_GlobalCss_isUsed() {
             driver.getPageSource().contains("Could not navigate"));
     }
 
+    @Test
+    public void applicationTheme_importCSS_isUsed() {
+        open();
+        checkLogsForErrors();
+
+        Assert.assertEquals(
+            "Imported FontAwesome css file should be applied.",
+            "\"Font Awesome 5 Free\"", $(SpanElement.class).id(FONTAWESOME_ID)
+                        .getCssValue("font-family"));
+
+        String iconUnicode = getCssPseudoElementValue(FONTAWESOME_ID,
+                                          "::before");
+        Assert.assertEquals(
+           "Font-Icon from FontAwesome css file should be applied.",
+           "\"\uf0f4\"", iconUnicode);
+
+        getDriver().get(getRootURL() +
+                "/path/VAADIN/static/@fortawesome/fontawesome-free/webfonts/fa-solid-900.svg");
+        Assert.assertFalse("Font resource should be available",
+                driver.getPageSource().contains("HTTP ERROR 404 Not Found"));
+    }
+
     @Test
     public void componentThemeIsApplied_forPolymerAndLit() {
         open();
@@ -160,4 +184,12 @@ protected String getTestPath() {
         return path.replace(view, "path/");
     }
 
+    private String getCssPseudoElementValue(String elementId,
+                                            String pseudoElement) {
+        String script = "return window.getComputedStyle(" +
+                                    "document.getElementById(arguments[0])" +
+                                ", arguments[1]).content";
+        JavascriptExecutor js = (JavascriptExecutor)driver;
+        return (String) js.executeScript(script, elementId, pseudoElement);
+    }
 }