add decoder for HTTP Basic auth

plugins/src/opengrok/auth/plugin/decoders/UserPrincipalDecoder.java

@@ -0,0 +1,58 @@
+/*
+ * CDDL HEADER START
+ *
+ * The contents of this file are subject to the terms of the
+ * Common Development and Distribution License (the "License").
+ * You may not use this file except in compliance with the License.
+ *
+ * See LICENSE.txt included in this distribution for the specific
+ * language governing permissions and limitations under the License.
+ *
+ * When distributing Covered Code, include this CDDL HEADER in each
+ * file and include the License file at LICENSE.txt.
+ * If applicable, add the following below this CDDL HEADER, with the
+ * fields enclosed by brackets "[]" replaced with your own identifying
+ * information: Portions Copyright [yyyy] [name of copyright owner]
+ *
+ * CDDL HEADER END
+ */
+
+/*
+ * Copyright (c) 2019, Oracle and/or its affiliates. All rights reserved.
+ */
+
+package opengrok.auth.plugin.decoders;
+
+import opengrok.auth.plugin.entity.User;
+
+import javax.servlet.http.HttpServletRequest;
+import java.util.logging.Level;
+import java.util.logging.Logger;
+
+/**
+ * Get authenticated user principal and use it to create User object.
+ * This works e.g. with HTTP Basic authentication headers as per RFC 7617.
+ *
+ * @author Vladimir Kotal
+ */
+public class UserPrincipalDecoder implements IUserDecoder {
+
+    private static final Logger LOGGER = Logger.getLogger(UserPrincipalDecoder.class.getName());
+
+    @Override
+    public User fromRequest(HttpServletRequest request) {
+        if (request.getUserPrincipal() == null) {
+            return null;
+        }
+
+        String username = request.getUserPrincipal().getName();
+        if (username == null || username.isEmpty()) {
+            LOGGER.log(Level.WARNING,
+                    "Can not construct User object: cannot get user principal from: {0}",
+                    request);
+            return null;
+        }
+
+        return new User(username);
+    }
+}

plugins/test/opengrok/auth/plugin/decoders/UserPrincipalDecoderTest.java

@@ -0,0 +1,60 @@
+/*
+ * CDDL HEADER START
+ *
+ * The contents of this file are subject to the terms of the
+ * Common Development and Distribution License (the "License").
+ * You may not use this file except in compliance with the License.
+ *
+ * See LICENSE.txt included in this distribution for the specific
+ * language governing permissions and limitations under the License.
+ *
+ * When distributing Covered Code, include this CDDL HEADER in each
+ * file and include the License file at LICENSE.txt.
+ * If applicable, add the following below this CDDL HEADER, with the
+ * fields enclosed by brackets "[]" replaced with your own identifying
+ * information: Portions Copyright [yyyy] [name of copyright owner]
+ *
+ * CDDL HEADER END
+ */
+
+/*
+ * Copyright (c) 2019, Oracle and/or its affiliates. All rights reserved.
+ */
+
+package opengrok.auth.plugin.decoders;
+
+import opengrok.auth.plugin.entity.User;
+import opengrok.auth.plugin.util.DummyHttpServletRequestUser;
+import org.junit.Assert;
+import org.junit.Before;
+import org.junit.Test;
+
+import static org.junit.Assert.assertNull;
+
+public class UserPrincipalDecoderTest {
+    DummyHttpServletRequestUser dummyRequest;
+    UserPrincipalDecoder decoder = new UserPrincipalDecoder();
+
+    @Before
+    public void setUp() {
+        dummyRequest = new DummyHttpServletRequestUser();
+    }
+
+    @Test
+    public void testHttpBasicDecoding() {
+        dummyRequest.setHeader("authorization", "Basic Zm9vOmJhcg==");
+
+        User result = decoder.fromRequest(dummyRequest);
+
+        Assert.assertNotNull(result);
+        Assert.assertEquals("foo", result.getUsername());
+        assertNull(result.getId());
+        Assert.assertFalse(result.isTimeouted());
+    }
+
+    @Test
+    public void testMissingHeader() {
+        assertNull(decoder.fromRequest(new DummyHttpServletRequestUser()));
+    }
+}
+

plugins/test/opengrok/auth/plugin/util/DummyHttpServletRequestUser.java

@@ -26,6 +26,7 @@
 import java.io.IOException;
 import java.io.UnsupportedEncodingException;
 import java.security.Principal;
+import java.util.Base64;
 import java.util.Collection;
 import java.util.Collections;
 import java.util.Enumeration;
@@ -217,7 +218,24 @@ public boolean isUserInRole(String string) {
 
     @Override
     public Principal getUserPrincipal() {
-        throw new UnsupportedOperationException("Not supported yet.");
+        String authHeader = getHeader("authorization");
+        if (authHeader == null) {
+            return null;
+        }
+
+        if (!authHeader.startsWith("Basic")) {
+            return null;
+        }
+
+        String encodedValue = authHeader.split(" ")[1];
+        Base64.Decoder decoder = Base64.getDecoder();
+        String username = new String(decoder.decode(encodedValue)).split(":")[0];
+        return new Principal() {
+            @Override
+            public String getName() {
+                return username;
+            }
+        };
     }
 
     @Override