UY-1256 add & document user control of favicon, add default ones

Author: golbi

documentation/src/main/doc/branding-v2x.txt

@@ -83,3 +83,17 @@ Example panel with a simple header added:
 ----
 
 
+==== Controlling favicon
+
+Configuration of favicon shall be provided in a file located in the default web contents directory (which is by default the +webContents/+ 
+directory of distribution), in a file under path: +VAADIN/favicon.html+.
+
+The file may look like the default one found in Unity's distribution:
+
+----
+<link rel="icon" type="image/png" sizes="16x16" href="./VAADIN/themes/common/img/favicon/favicon-16.png">
+<link rel="icon" type="image/png" sizes="24x24" href="./VAADIN/themes/common/img/favicon/favicon-24.png">
+---- 
+
+Note that contents of this file will be placed as-is in the HTML header section of the web pages generated by Unity.
+

integration-tests/src/test/resources/webContents/VAADIN/favicon.html

@@ -0,0 +1,2 @@
+<link rel="icon" type="image/png" sizes="16x16" href="./VAADIN/themes/common/img/favicon/favicon-16.png">
+<link rel="icon" type="image/png" sizes="24x24" href="./VAADIN/themes/common/img/favicon/favicon-24.png">

web-common/src/main/resources/VAADIN/favicon.html

@@ -0,0 +1,2 @@
+<link rel="icon" type="image/png" sizes="16x16" href="./VAADIN/themes/common/img/favicon/favicon-16.png">
+<link rel="icon" type="image/png" sizes="24x24" href="./VAADIN/themes/common/img/favicon/favicon-24.png">

web-upman/src/main/java/io/imunity/upman/front/UnityShellConfigurator.java

@@ -5,20 +5,66 @@
 
 package io.imunity.upman.front;
 
+import java.io.File;
+import java.io.IOException;
+import java.nio.file.Files;
+import java.nio.file.Path;
+
+import org.apache.logging.log4j.Logger;
+import org.springframework.beans.factory.annotation.Autowired;
+
 import com.vaadin.flow.component.page.AppShellConfigurator;
+import com.vaadin.flow.component.page.Inline.Wrapping;
 import com.vaadin.flow.component.page.Push;
 import com.vaadin.flow.server.AppShellSettings;
 import com.vaadin.flow.shared.ui.Transport;
 import com.vaadin.flow.theme.Theme;
 import com.vaadin.flow.theme.lumo.Lumo;
 
+import pl.edu.icm.unity.base.utils.Log;
+import pl.edu.icm.unity.engine.api.config.UnityServerConfiguration;
+
 @Push(transport = Transport.LONG_POLLING)
 @Theme(themeClass = Lumo.class)
 public class UnityShellConfigurator implements AppShellConfigurator
 {
+	private static final Logger log = Log.getLogger(Log.U_SERVER_WEB, UnityShellConfigurator.class);
+	private final UnityServerConfiguration config;
+	
+
+	@Autowired
+	UnityShellConfigurator(UnityServerConfiguration config)
+	{
+		this.config = config;
+	}
+
 	@Override
 	public void configurePage(AppShellSettings settings)
 	{
-		settings.addLink("shortcut icon", "/unitygw/VAADIN/favicon.ico");
+		setupFavicon(settings);
+	}
+
+	private void setupFavicon(AppShellSettings settings)
+	{
+		File webContentsFile = config.getFileValue(UnityServerConfiguration.DEFAULT_WEB_CONTENT_PATH, true);
+		Path faviconDefFile = webContentsFile.toPath().resolve(Path.of("VAADIN", "favicon.html"));
+		log.debug("Trying to read favicon definitions from {}", faviconDefFile);
+		if (Files.isReadable(faviconDefFile))
+		{
+			String faviconDefContents = readFile(faviconDefFile);
+			log.debug("Installing favicon definition from {}", faviconDefFile);
+			settings.addInlineWithContents(faviconDefContents, Wrapping.NONE);
+		}
+	}
+
+	private String readFile(Path faviconDefFile)
+	{
+		try
+		{
+			return Files.readString(faviconDefFile);
+		} catch (IOException e)
+		{
+			throw new IllegalStateException("Unable to read favicon file " + faviconDefFile, e);
+		}
 	}
 }