Implemented a simple UserIdSource, that stores the user in a cookie

[examples/facebook-app] / src / main / java / de / juplo / yourshouter / UserCookieInterceptor.java

diff --git a/src/main/java/de/juplo/yourshouter/UserCookieInterceptor.java b/src/main/java/de/juplo/yourshouter/UserCookieInterceptor.java
new file mode 100644 (file)
index 0000000..6a6cba6
--- /dev/null
+++ b/src/main/java/de/juplo/yourshouter/UserCookieInterceptor.java
@@ -0,0 +1,107 @@
+package de.juplo.yourshouter;
+
+
+import java.util.Collections;
+import javax.servlet.http.HttpServletRequest;
+import javax.servlet.http.HttpServletResponse;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import org.springframework.social.connect.UsersConnectionRepository;
+import org.springframework.web.servlet.handler.HandlerInterceptorAdapter;
+
+
+/**
+ * Intercepts all requests to handle the user-cookie.
+ *
+ * @author Kai Moritz
+ */
+public final class UserCookieInterceptor extends HandlerInterceptorAdapter
+{
+  private final static Logger LOG =
+      LoggerFactory.getLogger(UserCookieInterceptor.class);
+
+
+  private final UsersConnectionRepository repository;
+
+
+  /**
+   * Creates an instance of this class, that uses the given instance of
+   * {@link UsersConnectionRepository}.
+   *
+   * @param repository
+   *     The instance of {@link UsersConnectionRepository} to use.
+   */
+  public UserCookieInterceptor(UsersConnectionRepository repository)
+  {
+    this.repository = repository;
+  }
+
+
+  /**
+   * Before a request is handled, the current user is loaded from the cookie,
+   * if the cookie is present and the user is known. If the user is not known,
+   * the cookie is removed.
+   *
+   * @param request
+   *     The {@link HttpServletRequest} that is intercepted.
+   * @param response
+   *     The {@link HttpServletResponse} that is intercepted.
+   * @param handler
+   *     The handler, that handles the intercepted request.
+   * @return
+   *     Always <code>true</code>, to indicate, that the intercepted request
+   *     should be handled normally.
+   */
+  @Override
+  public boolean preHandle(
+      HttpServletRequest request,
+      HttpServletResponse response,
+      Object handler
+      )
+  {
+    String user = UserCookieGenerator.INSTANCE.readCookieValue(request);
+    if (user != null)
+    {
+      if (!repository
+          .findUserIdsConnectedTo("facebook", Collections.singleton(user))
+          .isEmpty()
+          )
+      {
+        LOG.info("loading user {} from cookie", user);
+        SecurityContext.setCurrentUser(user);
+        return true;
+      }
+      else
+      {
+        LOG.warn("user {} is not known!", user);
+        UserCookieGenerator.INSTANCE.removeCookie(response);
+      }
+    }
+    return true;
+  }
+
+  /**
+   * After a request, the user is removed from the security-context.
+   *
+   * @param request
+   *     The {@link HttpServletRequest} that is intercepted.
+   * @param response
+   *     The {@link HttpServletResponse} that is intercepted.
+   * @param handler
+   *     The handler, that handles the intercepted request.
+   * @param exception
+   *     If an exception was thrown during the handling of this request, it is
+   *     handed in through this parameter.
+   */
+  @Override
+  public void afterCompletion(
+      HttpServletRequest request,
+      HttpServletResponse response,
+      Object handler,
+      Exception exception
+      )
+  {
+    SecurityContext.remove();
+  }
+}