From a24df5e9ef0900033b0e431a819432101bdb1fc4 Mon Sep 17 00:00:00 2001
From: Mathieu Baudier <mbaudier@argeo.org>
Date: Sat, 21 Jan 2017 16:12:19 +0100
Subject: [PATCH] Clarify CurrentUser API. Add doAs().

---
 .../src/org/argeo/cms/auth/CurrentUser.java   | 100 ++++++++++++------
 1 file changed, 69 insertions(+), 31 deletions(-)

diff --git a/org.argeo.cms/src/org/argeo/cms/auth/CurrentUser.java b/org.argeo.cms/src/org/argeo/cms/auth/CurrentUser.java
index a23822b21..33a226737 100644
--- a/org.argeo.cms/src/org/argeo/cms/auth/CurrentUser.java
+++ b/org.argeo.cms/src/org/argeo/cms/auth/CurrentUser.java
@@ -17,6 +17,9 @@ package org.argeo.cms.auth;
 
 import java.security.AccessController;
 import java.security.Principal;
+import java.security.PrivilegedAction;
+import java.security.PrivilegedActionException;
+import java.security.PrivilegedExceptionAction;
 import java.security.acl.Group;
 import java.util.HashSet;
 import java.util.Set;
@@ -30,10 +33,18 @@ import org.argeo.node.NodeConstants;
 import org.argeo.node.security.NodeAuthenticated;
 import org.osgi.service.useradmin.Authorization;
 
-/** Static utilities */
+/**
+ * Programmatic access to the currently authenticated user, within a CMS
+ * context.
+ */
 public final class CurrentUser {
+	/*
+	 * CURRENT USER API
+	 */
 
 	/**
+	 * Technical username of the currently authenticated user.
+	 * 
 	 * @return the authenticated username or null if not authenticated /
 	 *         anonymous
 	 */
@@ -41,41 +52,59 @@ public final class CurrentUser {
 		return getUsername(currentSubject());
 	}
 
+	/**
+	 * Human readable name of the currently authenticated user (typically first
+	 * name and last name).
+	 */
 	public static String getDisplayName() {
 		return getDisplayName(currentSubject());
 	}
 
+	/** Whether a user is currently authenticated. */
 	public static boolean isAnonymous() {
 		return isAnonymous(currentSubject());
 	}
 
+	/**
+	 * Whether a user is currently authenticated. @deprecate User !isAnonymous()
+	 * instead.
+	 */
+	@Deprecated
 	public static boolean isRegistered() {
 		return !isAnonymous();
 	}
 
-	public static boolean isAnonymous(Subject subject) {
-		if (subject == null)
-			return true;
-		String username = getUsername(subject);
-		return username == null
-				|| username.equalsIgnoreCase(NodeConstants.ROLE_ANONYMOUS);
+	/** Roles of the currently logged-in user */
+	public final static Set<String> roles() {
+		return roles(currentSubject());
 	}
 
-	/**
-	 * The node authenticated component (typically a CMS view) related to this
-	 * display, or null if none is available from this call.
-	 */
-	public static NodeAuthenticated getNodeAuthenticated() {
-		return UiContext.getData(NodeAuthenticated.KEY);
+	/** Returns true if the current user is in the specified role */
+	public static boolean isInRole(String role) {
+		Set<String> roles = roles();
+		return roles.contains(role);
+	}
+
+	/** Executes as the current user */
+	public final static <T> T doAs(PrivilegedAction<T> action) {
+		return Subject.doAs(currentSubject(), action);
 	}
 
+	/** Executes as the current user */
+	public final static <T> T doAs(PrivilegedExceptionAction<T> action) throws PrivilegedActionException {
+		return Subject.doAs(currentSubject(), action);
+	}
+
+	/*
+	 * WRAPPERS
+	 */
+
 	public final static String getUsername(Subject subject) {
 		if (subject == null)
 			throw new CmsException("Subject cannot be null");
 		if (subject.getPrincipals(X500Principal.class).size() != 1)
 			return NodeConstants.ROLE_ANONYMOUS;
-		Principal principal = subject.getPrincipals(X500Principal.class)
-				.iterator().next();
+		Principal principal = subject.getPrincipals(X500Principal.class).iterator().next();
 		return principal.getName();
 	}
 
@@ -83,14 +112,25 @@ public final class CurrentUser {
 		return getAuthorization(subject).toString();
 	}
 
-	private static Authorization getAuthorization(Subject subject) {
-		return subject.getPrivateCredentials(Authorization.class).iterator()
-				.next();
+	public final static Set<String> roles(Subject subject) {
+		Set<String> roles = new HashSet<String>();
+		roles.add(getUsername(subject));
+		for (Principal group : subject.getPrincipals(Group.class)) {
+			roles.add(group.getName());
+		}
+		return roles;
 	}
 
-	public final static Set<String> roles() {
-		return roles(currentSubject());
+	/** Whether this user is currently authenticated. */
+	public static boolean isAnonymous(Subject subject) {
+		if (subject == null)
+			return true;
+		String username = getUsername(subject);
+		return username == null || username.equalsIgnoreCase(NodeConstants.ROLE_ANONYMOUS);
 	}
+	/*
+	 * HELPERS
+	 */
 
 	private static Subject currentSubject() {
 		NodeAuthenticated cmsView = getNodeAuthenticated();
@@ -102,19 +142,17 @@ public final class CurrentUser {
 		throw new CmsException("Cannot find related subject");
 	}
 
-	/** Returns true if the current user is in the specified role */
-	public static boolean isInRole(String role) {
-		Set<String> roles = roles();
-		return roles.contains(role);
+	/**
+	 * The node authenticated component (typically a CMS view) related to this
+	 * display, or null if none is available from this call. <b>Not API: Only
+	 * for low-level access.</b>
+	 */
+	private static NodeAuthenticated getNodeAuthenticated() {
+		return UiContext.getData(NodeAuthenticated.KEY);
 	}
 
-	public final static Set<String> roles(Subject subject) {
-		Set<String> roles = new HashSet<String>();
-		roles.add(getUsername(subject));
-		for (Principal group : subject.getPrincipals(Group.class)) {
-			roles.add(group.getName());
-		}
-		return roles;
+	private static Authorization getAuthorization(Subject subject) {
+		return subject.getPrivateCredentials(Authorization.class).iterator().next();
 	}
 
 	private CurrentUser() {
-- 
2.30.2