Step 6 - Proxy URL

Simple check to see if client is running in a proxy, and to call the
back-end servlet rather than the one running in angular. Also, we need
to let the server know we are running in a proxy.

src/main/java/org/kabir/quarkus/ui/SampleServlet.java

@@ -1,6 +1,7 @@
 package org.kabir.quarkus.ui;
 
 import java.io.IOException;
+import java.net.Socket;
 
 import javax.servlet.ServletException;
 import javax.servlet.annotation.WebServlet;
@@ -23,9 +24,23 @@ protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws Se
         } else if (path.equals("/callback")) {
             // Redirect back to a path controlled by the Angular client
             String redirectPath = "/clientCallback";
+
+            boolean proxy = Boolean.getBoolean("ui.proxy");
+            if (proxy && checkProxyIsRunning()) {
+                redirectPath = "http://localhost:4200" + redirectPath;
+            }
             resp.sendRedirect(redirectPath);
         } else {
             resp.sendError(404);
         }
     }
-}
+
+    private boolean checkProxyIsRunning() {
+        try (Socket s = new Socket("localhost", 4200)) {
+            return true;
+        } catch (IOException e) {
+            return false;
+        }
+    }
+}
+

webapp/src/app/app.component.ts

@@ -23,11 +23,19 @@ export class AppComponent {
     In <b>default</b> component. 
     <a [routerLink]="['/other']">Other</a> | 
     <a [routerLink]="['/rest']">Rest</a> |
-    <a href="/servlet/make-external-call">External</a>
+    <a href="{{externalUrl}}">External</a>
   `,
   styles: []
 })
 export class DefaultComponent {
+  externalUrl = '/servlet/make-external-call';
+
+  constructor() {
+    if (window.location.port === "4200") {
+      this.externalUrl = "http://localhost:8080" + this.externalUrl;
+    }
+  }
+
 }
 
 @Component({