From 50a5f792477308ef1e4ce458aca730c6fcc49593 Mon Sep 17 00:00:00 2001
From: Kai Moritz <kai@juplo.de>
Date: Mon, 25 Jan 2016 02:23:20 +0100
Subject: [PATCH] Refactored authorization from HomeController to
 UserCookieInterceptor

The educationally authorization-concept now roughly resembles the behavior
of Spring-Security.
---
 .../de/juplo/yourshouter/HomeController.java  | 16 ------------
 .../SecurityContextUserIdSource.java          | 26 +++++--------------
 .../yourshouter/UserCookieInterceptor.java    | 13 +++++++++-
 3 files changed, 18 insertions(+), 37 deletions(-)

diff --git a/src/main/java/de/juplo/yourshouter/HomeController.java b/src/main/java/de/juplo/yourshouter/HomeController.java
index c5ece60..c74316e 100644
--- a/src/main/java/de/juplo/yourshouter/HomeController.java
+++ b/src/main/java/de/juplo/yourshouter/HomeController.java
@@ -37,22 +37,6 @@ public class HomeController
   @RequestMapping(method = RequestMethod.GET)
   public String home(Model model)
   {
-    boolean authorized = true;
-    try
-    {
-      authorized = facebook.isAuthorized();
-    }
-    catch (NullPointerException e)
-    {
-      LOG.debug("NPE while acessing Facebook: {}", e);
-      authorized = false;
-    }
-    if (!authorized)
-    {
-      LOG.info("no authorized user, redirecting to /signin.html");
-      return "redirect:/signin.html";
-    }
-
     User user = facebook.userOperations().getUserProfile();
     LOG.info("authorized user {}, id: {}", user.getName(), user.getId());
     model.addAttribute("user", user);
diff --git a/src/main/java/de/juplo/yourshouter/SecurityContextUserIdSource.java b/src/main/java/de/juplo/yourshouter/SecurityContextUserIdSource.java
index 9fae323..662da57 100644
--- a/src/main/java/de/juplo/yourshouter/SecurityContextUserIdSource.java
+++ b/src/main/java/de/juplo/yourshouter/SecurityContextUserIdSource.java
@@ -1,8 +1,7 @@
 package de.juplo.yourshouter;
 
-import org.slf4j.Logger;
-import org.slf4j.LoggerFactory;
 import org.springframework.social.UserIdSource;
+import org.springframework.util.Assert;
 
 
 /**
@@ -13,30 +12,17 @@ import org.springframework.social.UserIdSource;
  */
 public class SecurityContextUserIdSource implements UserIdSource
 {
-  private final static Logger LOG =
-      LoggerFactory.getLogger(SecurityContextUserIdSource.class);
-
-
   /**
    * Retrieves the ID of the current user from the {@link SecurityContext}.
+   * If no ID is found, an exception is thrown.
    *
-   * @return
-   *     The ID of the current user, or the special ID <code>anonymous</code>,
-   *     if no current user is present.
+   * @return The ID of the current user
+   * @throws IllegalStateException, if no current user is found.
    */
   @Override
   public String getUserId()
   {
-    String user = SecurityContext.getCurrentUser();
-    if (user != null)
-    {
-      LOG.debug("found user \"{}\" in the security-context", user);
-    }
-    else
-    {
-      LOG.info("found no user in the security-context, using \"anonymous\"");
-      user = "anonymous";
-    }
-    return user;
+    Assert.state(SecurityContext.userSignedIn(), "No user signed in!");
+    return SecurityContext.getCurrentUser();
   }
 }
diff --git a/src/main/java/de/juplo/yourshouter/UserCookieInterceptor.java b/src/main/java/de/juplo/yourshouter/UserCookieInterceptor.java
index 6a6cba6..c72ef41 100644
--- a/src/main/java/de/juplo/yourshouter/UserCookieInterceptor.java
+++ b/src/main/java/de/juplo/yourshouter/UserCookieInterceptor.java
@@ -1,6 +1,7 @@
 package de.juplo.yourshouter;
 
 
+import java.io.IOException;
 import java.util.Collections;
 import javax.servlet.http.HttpServletRequest;
 import javax.servlet.http.HttpServletResponse;
@@ -52,6 +53,9 @@ public final class UserCookieInterceptor extends HandlerInterceptorAdapter
    * @return
    *     Always <code>true</code>, to indicate, that the intercepted request
    *     should be handled normally.
+   * @throws java.io.IOException
+   *     if something wents wrong, while sending the redirect to the
+   *     sign-in-page.
    */
   @Override
   public boolean preHandle(
@@ -59,7 +63,12 @@ public final class UserCookieInterceptor extends HandlerInterceptorAdapter
       HttpServletResponse response,
       Object handler
       )
+      throws
+        IOException
   {
+    if (request.getServletPath().startsWith("/signin"))
+      return true;
+
     String user = UserCookieGenerator.INSTANCE.readCookieValue(request);
     if (user != null)
     {
@@ -78,7 +87,9 @@ public final class UserCookieInterceptor extends HandlerInterceptorAdapter
         UserCookieGenerator.INSTANCE.removeCookie(response);
       }
     }
-    return true;
+
+    response.sendRedirect("/signin.html");
+    return false;
   }
 
   /**
-- 
2.20.1