/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.apache.catalina.authenticator;

import java.io.IOException;

import jakarta.servlet.http.HttpServletResponse;

import org.apache.catalina.connector.Request;

/**
 * An <b>Authenticator</b> and <b>Valve</b> implementation that checks only security constraints not involving user
 * authentication.
 *
 * @author Craig R. McClanahan
 */
public final class NonLoginAuthenticator extends AuthenticatorBase {


    // --------------------------------------------------------- Public Methods


    /**
     * <p>
     * Authenticate the user making this request, based on the fact that no <code>login-config</code> has been defined
     * for the container.
     * </p>
     * <p>
     * This implementation means "login the user even though there is no self-contained way to establish a security
     * Principal for that user".
     * </p>
     * <p>
     * This method is called by the AuthenticatorBase super class to establish a Principal for the user BEFORE the
     * container security constraints are examined, i.e. it is not yet known whether the user will eventually be
     * permitted to access the requested resource. Therefore, it is necessary to always return <code>true</code> to
     * indicate the user has not failed authentication.
     * </p>
     * <p>
     * There are two cases:
     * </p>
     * <ul>
     * <li>without SingleSignon: a Session instance does not yet exist and there is no <code>auth-method</code> to
     * authenticate the user, so leave Request's Principal as null. Note: AuthenticatorBase will later examine the
     * security constraints to determine whether the resource is accessible by a user without a security Principal and
     * Role (i.e. unauthenticated).</li>
     * <li>with SingleSignon: if the user has already authenticated via another container (using its own login
     * configuration), then associate this Session with the SSOEntry so it inherits the already-established security
     * Principal and associated Roles. Note: This particular session will become a full member of the SingleSignOnEntry
     * Session collection and so will potentially keep the SSOE "alive", even if all the other properly authenticated
     * Sessions expire first... until it expires too.</li>
     * </ul>
     *
     * @param request  Request we are processing
     * @param response Response we are creating
     *
     * @return boolean to indicate whether the user is authenticated
     *
     * @exception IOException if an input/output error occurs
     */
    @Override
    protected boolean doAuthenticate(Request request, HttpServletResponse response) throws IOException {

        // Don't try and use SSO to authenticate since there is no auth
        // configured for this web application
        if (checkForCachedAuthentication(request, response, true)) {
            // Save the inherited Principal in this session so it can remain
            // authenticated until it expires.
            if (cache) {
                request.getSessionInternal(true).setPrincipal(request.getPrincipal());
            }
            return true;
        }

        // No Principal means the user is not already authenticated
        // and so will not be assigned any roles. It is safe to
        // to say the user is now authenticated because access to
        // protected resources will only be allowed with a matching role.
        // i.e. SC_FORBIDDEN (403 status) will be generated later.
        if (containerLog.isDebugEnabled()) {
            containerLog.debug("User authenticated without any roles");
        }
        return true;
    }


    /**
     * Return the authentication method, which is vendor-specific and not defined by HttpServletRequest.
     */
    @Override
    protected String getAuthMethod() {
        return "NONE";
    }
}
