add Mellon header decoder

fixes #2739

Author: Vladimir Kotal

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

@@ -0,0 +1,62 @@
+/*
+ * 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;
+
+/**
+ * Decode basic headers coming from the
+ * <a href="https://github.com/Uninett/mod_auth_mellon">mod_auth_mellon</a> module
+ * for Apache web server.
+ *
+ * This decoder assumes that the SAML Service Provider metadata was setup with
+ * {@code <NameIDFormat>urn:oasis:names:tc:SAML:1.1:nameid-format:emailAddress</NameIDFormat>}
+ * i.e. that Identity Provider will send back e-mail address of the authenticated user
+ * and that the {@code mod_auth_mellon} is setup to create Apache environment variable
+ * containing the e-mail address and the {@code mod_headers} Apache module is set to
+ * pass the value of this variable in HTTP header called {@code MELLON_email}, i.e.:
+ * {@code RequestHeader set email "%{MELLON_email}e" env=MELLON_email}
+ */
+public class MellonHeaderDecoder implements IUserDecoder {
+
+    private static final Logger LOGGER = Logger.getLogger(MellonHeaderDecoder.class.getName());
+
+    static String MELLON_EMAIL_HEADER = "MELLON_email";
+
+    @Override
+    public User fromRequest(HttpServletRequest request) {
+        String username = request.getHeader(MELLON_EMAIL_HEADER);
+        if (username == null || username.isEmpty()) {
+            LOGGER.log(Level.WARNING,
+                    "Can not construct an user: username could not be extracted");
+            return null;
+        }
+
+        return new User(username);
+    }
+}

plugins/src/opengrok/auth/plugin/entity/User.java

@@ -34,6 +34,10 @@ public class User {
     private boolean timeouted;
     private final Map<String, Object> attrs = new HashMap<>();
 
+    public User(String username) {
+        this.username = username;
+    }
+
     public User(String username, String id, Date cookieTimestamp, boolean timeouted) {
         this.id = id;
         this.username = username;

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

@@ -0,0 +1,53 @@
+/*
+ * 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 opengrok.auth.plugin.decoders.MellonHeaderDecoder.MELLON_EMAIL_HEADER;
+
+public class MellonDecoderTest {
+    DummyHttpServletRequestUser dummyRequest;
+    MellonHeaderDecoder decoder = new MellonHeaderDecoder();
+
+    @Before
+    public void setUp() {
+        dummyRequest = new DummyHttpServletRequestUser();
+        dummyRequest.setHeader(MELLON_EMAIL_HEADER, "[email protected]");
+    }
+
+    @Test
+    public void testAll() {
+        User result = decoder.fromRequest(dummyRequest);
+
+        Assert.assertNotNull(result);
+        Assert.assertEquals("[email protected]", result.getUsername());
+        Assert.assertNull(result.getId());
+        Assert.assertFalse(result.isTimeouted());
+    }
+}