/*

  * 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.shiro.web.filter.authc;

 import org.apache.shiro.authc.AuthenticationException;

 import org.apache.shiro.authc.AuthenticationToken;

 import org.apache.shiro.authc.UsernamePasswordToken;

 import org.apache.shiro.subject.Subject;

 import org.apache.shiro.web.util.WebUtils;

 import org.slf4j.Logger;

 import org.slf4j.LoggerFactory;

 import javax.servlet.ServletRequest;

 import javax.servlet.ServletResponse;

 import javax.servlet.http.HttpServletRequest;

 /**

  * Requires the requesting user to be authenticated for the request to continue, and if they are not, forces the user

  * to login via by redirecting them to the {@link #setLoginUrl(String) loginUrl} you configure.

  * <p/>

  * <p>This filter constructs a {@link UsernamePasswordToken UsernamePasswordToken} with the values found in

  * {@link #setUsernameParam(String) username}, {@link #setPasswordParam(String) password},

  * and {@link #setRememberMeParam(String) rememberMe} request parameters.  It then calls

  * {@link org.apache.shiro.subject.Subject#login(org.apache.shiro.authc.AuthenticationToken) Subject.login(usernamePasswordToken)},

  * effectively automatically performing a login attempt.  Note that the login attempt will only occur when the

  * {@link #isLoginSubmission(javax.servlet.ServletRequest, javax.servlet.ServletResponse) isLoginSubmission(request,response)}

  * is <code>true</code>, which by default occurs when the request is for the {@link #setLoginUrl(String) loginUrl} and

  * is a POST request.

  * <p/>

  * <p>If the login attempt fails, the resulting <code>AuthenticationException</code> fully qualified class name will

  * be set as a request attribute under the {@link #setFailureKeyAttribute(String) failureKeyAttribute} key.  This

  * FQCN can be used as an i18n key or lookup mechanism to explain to the user why their login attempt failed

  * (e.g. no account, incorrect password, etc).

  * <p/>

  * <p>If you would prefer to handle the authentication validation and login in your own code, consider using the

  * {@link PassThruAuthenticationFilter} instead, which allows requests to the

  * {@link #loginUrl} to pass through to your application's code directly.

  *

  * @see PassThruAuthenticationFilter

  * @since 0.9

  */

 public class FormAuthenticationFilter extends AuthenticatingFilter {

     //TODO - complete JavaDoc

     public static final String DEFAULT_ERROR_KEY_ATTRIBUTE_NAME = "shiroLoginFailure";

     public static final String DEFAULT_USERNAME_PARAM = "username";

     public static final String DEFAULT_PASSWORD_PARAM = "password";

     public static final String DEFAULT_REMEMBER_ME_PARAM = "rememberMe";

     private static final Logger log = LoggerFactory.getLogger(FormAuthenticationFilter.class);

     private String usernameParam = DEFAULT_USERNAME_PARAM;

     private String passwordParam = DEFAULT_PASSWORD_PARAM;

     private String rememberMeParam = DEFAULT_REMEMBER_ME_PARAM;

     private String failureKeyAttribute = DEFAULT_ERROR_KEY_ATTRIBUTE_NAME;

     public FormAuthenticationFilter() {

         setLoginUrl(DEFAULT_LOGIN_URL);

     }

     @Override

     public void setLoginUrl(String loginUrl) {

         String previous = getLoginUrl();

         if (previous != null) {

             this.appliedPaths.remove(previous);

         }

         super.setLoginUrl(loginUrl);

         if (log.isTraceEnabled()) {

             log.trace("Adding login url to applied paths.");

         }

         this.appliedPaths.put(getLoginUrl(), null);

     }

     public String getUsernameParam() {

         return usernameParam;

     }

     /**

      * Sets the request parameter name to look for when acquiring the username.  Unless overridden by calling this

      * method, the default is <code>username</code>.

      *

      * @param usernameParam the name of the request param to check for acquiring the username.

      */

     public void setUsernameParam(String usernameParam) {

         this.usernameParam = usernameParam;

     }

     public String getPasswordParam() {

         return passwordParam;

     }

     /**

      * Sets the request parameter name to look for when acquiring the password.  Unless overridden by calling this

      * method, the default is <code>password</code>.

      *

      * @param passwordParam the name of the request param to check for acquiring the password.

      */

     public void setPasswordParam(String passwordParam) {

         this.passwordParam = passwordParam;

     }

     public String getRememberMeParam() {

         return rememberMeParam;

     }

     /**

      * Sets the request parameter name to look for when acquiring the rememberMe boolean value.  Unless overridden

      * by calling this method, the default is <code>rememberMe</code>.

      * <p/>

      * RememberMe will be <code>true</code> if the parameter value equals any of those supported by

      * {@link org.apache.shiro.web.util.WebUtils#isTrue(javax.servlet.ServletRequest, String) WebUtils.isTrue(request,value)}, <code>false</code>

      * otherwise.

      *

      * @param rememberMeParam the name of the request param to check for acquiring the rememberMe boolean value.

      */

     public void setRememberMeParam(String rememberMeParam) {

         this.rememberMeParam = rememberMeParam;

     }

     public String getFailureKeyAttribute() {

         return failureKeyAttribute;

     }

     public void setFailureKeyAttribute(String failureKeyAttribute) {

         this.failureKeyAttribute = failureKeyAttribute;

     }

     protected boolean onAccessDenied(ServletRequest request, ServletResponse response) throws Exception {

         if (isLoginRequest(request, response)) {

             if (isLoginSubmission(request, response)) {

                 if (log.isTraceEnabled()) {

                     log.trace("Login submission detected.  Attempting to execute login.");

                 }

                 return executeLogin(request, response);

             } else {

                 if (log.isTraceEnabled()) {

                     log.trace("Login page view.");

                 }

                 //allow them to see the login page ;)

                 return true;

             }

         } else {

             if (log.isTraceEnabled()) {

                 log.trace("Attempting to access a path which requires authentication.  Forwarding to the " +

                         "Authentication url [" + getLoginUrl() + "]");

             }

             saveRequestAndRedirectToLogin(request, response);

             return false;

         }

     }

     /**

      * This default implementation merely returns <code>true</code> if the request is an HTTP <code>POST</code>,

      * <code>false</code> otherwise. Can be overridden by subclasses for custom login submission detection behavior.

      *

      * @param request  the incoming ServletRequest

      * @param response the outgoing ServletResponse.

      * @return <code>true</code> if the request is an HTTP <code>POST</code>, <code>false</code> otherwise.

      */

     @SuppressWarnings({"UnusedDeclaration"})

     protected boolean isLoginSubmission(ServletRequest request, ServletResponse response) {

         return (request instanceof HttpServletRequest) && WebUtils.toHttp(request).getMethod().equalsIgnoreCase(POST_METHOD);

     }

     protected AuthenticationToken createToken(ServletRequest request, ServletResponse response) {

         String username = getUsername(request);

         String password = getPassword(request);

         return createToken(username, password, request, response);

     }

     protected boolean isRememberMe(ServletRequest request) {

         return WebUtils.isTrue(request, getRememberMeParam());

     }

     protected boolean onLoginSuccess(AuthenticationToken token, Subject subject,

                                      ServletRequest request, ServletResponse response) throws Exception {

         issueSuccessRedirect(request, response);

         //we handled the success redirect directly, prevent the chain from continuing:

         return false;

     }

     protected boolean onLoginFailure(AuthenticationToken token, AuthenticationException e,

                                      ServletRequest request, ServletResponse response) {

         if (log.isDebugEnabled()) {

             log.debug( "Authentication exception", e );

         }

         setFailureAttribute(request, e);

         //login failed, let request continue back to the login page:

         return true;

     }

     protected void setFailureAttribute(ServletRequest request, AuthenticationException ae) {

         String className = ae.getClass().getName();

         request.setAttribute(getFailureKeyAttribute(), className);

     }

     protected String getUsername(ServletRequest request) {

         return WebUtils.getCleanParam(request, getUsernameParam());

     }

     protected String getPassword(ServletRequest request) {

         return WebUtils.getCleanParam(request, getPasswordParam());

     }

 }