001/*
002 * The contents of this file are subject to the terms of the Common Development and
003 * Distribution License (the License). You may not use this file except in compliance with the
004 * License.
005 *
006 * You can obtain a copy of the License at legal/CDDLv1.0.txt. See the License for the
007 * specific language governing permission and limitations under the License.
008 *
009 * When distributing Covered Software, include this CDDL Header Notice in each file and include
010 * the License file at legal/CDDLv1.0.txt. If applicable, add the following below the CDDL
011 * Header, with the fields enclosed by brackets [] replaced by your own identifying
012 * information: "Portions copyright [year] [name of copyright owner]".
013 *
014 * Copyright 2014-2016 ForgeRock AS.
015 */
016
017package org.forgerock.http.oauth2;
018
019/** OAuth2 utility class. */
020public final class OAuth2 {
021
022    private static final String BEARER_TOKEN_KEY = "BEARER";
023
024    /**
025     * Extracts the bearer token from the request's authorization header.
026     * <p>
027     * Expected ABNF format (as per RFC 6750):
028     * <pre>
029     *     {@code
030     *     b64token    = 1*( ALPHA / DIGIT / "-" / "." / "_" / "~" / "+" / "/" ) *"="
031     *     credentials = "Bearer" 1*SP b64token
032     *     }
033     * </pre>
034     *
035     * @param authorizationHeader
036     *         The authorization header from the request.
037     * @return The access token, or {@code null} if the access token was not present or was not using Bearer
038     * authorization.
039     */
040    public static String getBearerAccessToken(final String authorizationHeader) {
041
042        if (authorizationHeader == null) {
043            return null;
044        }
045        String authorization = authorizationHeader.trim();
046        final int index = authorization.indexOf(' ');
047        if (index <= 0) {
048            return null;
049        }
050
051        final String tokenType = authorization.substring(0, index);
052
053        if (BEARER_TOKEN_KEY.equalsIgnoreCase(tokenType)) {
054            return authorization.substring(index + 1);
055        }
056
057        return null;
058    }
059
060    private OAuth2() {
061        /* utility class */
062    }
063}