feat: Open tab in dev mode less often

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

@@ -271,4 +271,12 @@ public class InitParameters implements Serializable {
  * Configuration name for cleaning or leaving frontend files in build.
  */
  public static final String CLEAN_BUILD_FRONTEND_FILES = "vaadin.clean.build.frontend.files";
+
+ /**
+ * Configuration name for how long since last browser open before we open a
+ * new tab for the application in development mode.
+ *
+ * Time is given in minutes.
+ */
+ public static final String LAUNCH_BROWSER_DELAY = "launch-browser-delay";
 }

vaadin-dev-server/src/main/java/com/vaadin/base/devserver/BrowserLauncher.java

@@ -1,12 +1,19 @@
 package com.vaadin.base.devserver;
 
+import java.io.File;
+import java.io.IOException;
+import java.nio.file.Files;
+import java.util.concurrent.TimeUnit;
+
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
 import com.vaadin.flow.server.VaadinContext;
 import com.vaadin.flow.server.startup.ApplicationConfiguration;
 import com.vaadin.open.Open;
 
+import static com.vaadin.flow.server.InitParameters.LAUNCH_BROWSER_DELAY;
+
 /**
  * Util for launching a browser instance.
  */
@@ -52,11 +59,43 @@ private boolean isProductionMode() {
  return applicationConfiguration.isProductionMode();
  }
 
- private static boolean isLaunched() {
+ private boolean isLaunched() {
+ File launchFile = getLaunchFile();
+ ApplicationConfiguration applicationConfiguration = ApplicationConfiguration
+ .get(context);
+ int lastModifiedDelay = Integer.parseInt(applicationConfiguration
+ .getStringProperty(LAUNCH_BROWSER_DELAY, "30"));
+ // If launch file exists and is younger than time update file content
+ // and modified stamp
+ if (launchFile.exists()
+ && TimeUnit.MILLISECONDS.toMinutes(System.currentTimeMillis()
+ - launchFile.lastModified()) < lastModifiedDelay) {
+ writeLaunchFile(launchFile);
+ return true;
+ }
  return LAUNCHED_VALUE.equals(System.getProperty(LAUNCH_TRACKER));
  }
 
- private static void setLaunched() {
+ private void writeLaunchFile(File launchFile) {
+ try {
+ Files.writeString(launchFile.toPath(),
+ Long.toString(System.currentTimeMillis()));
+ } catch (IOException e) {
+ getLogger().debug("Failed to write browser launched file.", e);
+ }
+ }
+
+ private File getLaunchFile() {
+ ApplicationConfiguration applicationConfiguration = ApplicationConfiguration
+ .get(context);
+ File buildFolder = new File(applicationConfiguration.getProjectFolder(),
+ applicationConfiguration.getBuildFolder());
+ return new File(buildFolder, "tab.launch");
+ }
+
+ private void setLaunched() {
+ // write launch file and update modified timestamp.
+ writeLaunchFile(getLaunchFile());
  System.setProperty(LAUNCH_TRACKER, LAUNCHED_VALUE);
  }
 

vaadin-spring/src/main/java/com/vaadin/flow/spring/VaadinConfigurationProperties.java

@@ -121,6 +121,12 @@ public static List<String> getExcludedUrls(Environment environment) {
  */
  private boolean launchBrowser = false;
 
+ /**
+ * Timeout until a new browser should be launched on startup when in
+ * development mode.
+ */
+ private int launchBrowserDelay = 30;
+
  /**
  * URL patterns that should not be handled by the Vaadin servlet when mapped
  * to the context root.
@@ -399,6 +405,30 @@ public void setLaunchBrowser(boolean launchBrowser) {
  this.launchBrowser = launchBrowser;
  }
 
+ /**
+ * Returns timout after which a browser should be launched again on startup
+ * when in development mode.
+ * <p>
+ *
+ * @return if a browser should be launched on startup when in development
+ * mode
+ */
+ public int getLaunchBrowserDelay() {
+ return launchBrowserDelay;
+ }
+
+ /**
+ * Sets timout for launching a new browser on startup when in development
+ * mode.
+ *
+ * @param launchBrowser
+ * {@code true} to launch a browser on startup when in
+ * development mode, {@code false} otherwise
+ */
+ public void setLaunchBrowserDelay(int launchBrowser) {
+ this.launchBrowserDelay = launchBrowser;
+ }
+
  /**
  * Returns whether class scan caching between reloads when using Spring Boot
  * DevTools should be enabled.