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*
* 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.struts2.interceptor;
import com.opensymphony.xwork2.ActionInvocation;
import com.opensymphony.xwork2.TextProvider;
import com.opensymphony.xwork2.ValidationAware;
import com.opensymphony.xwork2.inject.Inject;
import com.opensymphony.xwork2.interceptor.MethodFilterInterceptor;
import org.apache.struts2.ServletActionContext;
import org.apache.struts2.util.TokenHelper;
import javax.servlet.http.HttpSession;
/**
* <!-- START SNIPPET: description -->
*
* Ensures that only one request per token is processed. This interceptor can make sure that back buttons and double
* clicks don't cause un-intended side affects. For example, you can use this to prevent careless users who might double
* click on a "checkout" button at an online store. This interceptor uses a fairly primitive technique for when an
* invalid token is found: it returns the result <b>invalid.token</b>, which can be mapped in your action configuration.
* A more complex implementation, {@link TokenSessionStoreInterceptor}, can provide much better logic for when invalid
* tokens are found.
*
* <p/>
*
* <b>Note:</b> To set a token in your form, you should use the <b>token tag</b>. This tag is required and must be used
* in the forms that submit to actions protected by this interceptor. Any request that does not provide a token (using
* the token tag) will be processed as a request with an invalid token.
*
* <p/>
*
* <b>Internationalization Note:</b> The following key could be used to internationalized the action errors generated
* by this token interceptor
*
* <ul>
* <li>struts.messages.invalid.token</li>
* </ul>
*
* <p/>
*
* <b>NOTE:</b> As this method extends off MethodFilterInterceptor, it is capable of
* deciding if it is applicable only to selective methods in the action class. See
* <code>MethodFilterInterceptor</code> for more info.
*
* <!-- END SNIPPET: description -->
*
* <p/> <u>Interceptor parameters:</u>
*
* <!-- START SNIPPET: parameters -->
*
* <ul>
*
* <li>None</li>
*
* </ul>
*
* <!-- END SNIPPET: parameters -->
*
* <p/> <u>Extending the interceptor:</u>
*
* <p/>
*
* <!-- START SNIPPET: extending -->
*
* While not very common for users to extend, this interceptor is extended by the {@link TokenSessionStoreInterceptor}.
* The {@link #handleInvalidToken} and {@link #handleValidToken} methods are protected and available for more
* interesting logic, such as done with the token session interceptor.
*
* <!-- END SNIPPET: extending -->
*
* <p/> <u>Example code:</u>
*
* <pre>
* <!-- START SNIPPET: example -->
*
* <action name="someAction" class="com.examples.SomeAction">
* <interceptor-ref name="token"/>
* <interceptor-ref name="basicStack"/>
* <result name="success">good_result.ftl</result>
* </action>
*
* <-- In this case, myMethod of the action class will not
* get checked for invalidity of token -->
* <action name="someAction" class="com.examples.SomeAction">
* <interceptor-ref name="token">
* <param name="excludeMethods">myMethod</param>
* </interceptor-ref name="token"/>
* <interceptor-ref name="basicStack"/>
* <result name="success">good_result.ftl</result>
* </action>
*
* <!-- END SNIPPET: example -->
* </pre>
*
* @see TokenSessionStoreInterceptor
* @see TokenHelper
*/
public class TokenInterceptor extends MethodFilterInterceptor {
private static final long serialVersionUID = -6680894220590585506L;
public static final String INVALID_TOKEN_CODE = "invalid.token";
private static final String INVALID_TOKEN_MESSAGE_KEY = "struts.messages.invalid.token";
private static final String DEFAULT_ERROR_MESSAGE = "The form has already been processed or no token was supplied, please try again.";
private TextProvider textProvider;
@Inject
public void setTextProvider(TextProvider textProvider) {
this.textProvider = textProvider;
}
/**
* @see com.opensymphony.xwork2.interceptor.MethodFilterInterceptor#doIntercept(com.opensymphony.xwork2.ActionInvocation)
*/
@Override
protected String doIntercept(ActionInvocation invocation) throws Exception {
if (log.isDebugEnabled()) {
log.debug("Intercepting invocation to check for valid transaction token.");
}
return handleToken(invocation);
}
protected String handleToken(ActionInvocation invocation) throws Exception {
//see WW-2902: we need to use the real HttpSession here, as opposed to the map
//that wraps the session, because a new wrap is created on every request
HttpSession session = ServletActionContext.getRequest().getSession(true);
synchronized (session) {
if (!TokenHelper.validToken()) {
return handleInvalidToken(invocation);
}
}
return handleValidToken(invocation);
}
/**
* Determines what to do if an invalid token is provided. If the action implements {@link ValidationAware}
*
* @param invocation the action invocation where the invalid token failed
* @return the return code to indicate should be processed
* @throws Exception when any unexpected error occurs.
*/
protected String handleInvalidToken(ActionInvocation invocation) throws Exception {
Object action = invocation.getAction();
String errorMessage = getErrorMessage(invocation);
if (action instanceof ValidationAware) {
((ValidationAware) action).addActionError(errorMessage);
} else {
log.warn(errorMessage);
}
return INVALID_TOKEN_CODE;
}
protected String getErrorMessage(ActionInvocation invocation) {
Object action = invocation.getAction();
if (action instanceof TextProvider) {
return ((TextProvider) action).getText(INVALID_TOKEN_MESSAGE_KEY, DEFAULT_ERROR_MESSAGE);
}
return textProvider.getText(INVALID_TOKEN_MESSAGE_KEY, DEFAULT_ERROR_MESSAGE);
}
/**
* Called when a valid token is found. This method invokes the action by can be changed to do something more
* interesting.
*
* @param invocation the action invocation
* @throws Exception when any unexpected error occurs.
*/
protected String handleValidToken(ActionInvocation invocation) throws Exception {
return invocation.invoke();
}
}