org.apache.struts2.interceptor
Class TokenInterceptor

java.lang.Object
  com.opensymphony.xwork2.interceptor.AbstractInterceptor
      com.opensymphony.xwork2.interceptor.MethodFilterInterceptor
          org.apache.struts2.interceptor.TokenInterceptor

All Implemented Interfaces:

Interceptor, Serializable

Direct Known Subclasses:

TokenSessionStoreInterceptor

public class TokenInterceptor
extends MethodFilterInterceptor

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 invalid.token, which can be mapped in your action configuration. A more complex implementation, TokenSessionStoreInterceptor, can provide much better logic for when invalid tokens are found.

Note: To set a token in your form, you should use the token tag. 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.

Internationalization Note: The following key could be used to internationalized the action errors generated by this token interceptor

• struts.messages.invalid.token

NOTE: As this method extends off MethodFilterInterceptor, it is capable of deciding if it is applicable only to selective methods in the action class. See MethodFilterInterceptor for more info.

Interceptor parameters:

• None

Extending the interceptor:

While not very common for users to extend, this interceptor is extended by the TokenSessionStoreInterceptor. The handleInvalidToken(com.opensymphony.xwork2.ActionInvocation) and handleValidToken(com.opensymphony.xwork2.ActionInvocation) methods are protected and available for more interesting logic, such as done with the token session interceptor.

Example code:

 

 <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>

 
 

See Also:

TokenSessionStoreInterceptor, TokenHelper, Serialized Form

Field Summary

static String

INVALID_TOKEN_CODE

Fields inherited from class com.opensymphony.xwork2.interceptor.MethodFilterInterceptor

excludeMethods, includeMethods, log

Constructor Summary

TokenInterceptor()

Method Summary

protected String	doIntercept(ActionInvocation invocation)
protected String	handleInvalidToken(ActionInvocation invocation) Determines what to do if an invalid token is provided.
protected String	handleValidToken(ActionInvocation invocation) Called when a valid token is found.

Methods inherited from class com.opensymphony.xwork2.interceptor.MethodFilterInterceptor

applyInterceptor, getExcludeMethodsSet, getIncludeMethodsSet, intercept, setExcludeMethods, setIncludeMethods

Methods inherited from class com.opensymphony.xwork2.interceptor.AbstractInterceptor

destroy, init

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

INVALID_TOKEN_CODE

public static final String INVALID_TOKEN_CODE

See Also:

Constant Field Values

Constructor Detail

TokenInterceptor

public TokenInterceptor()

Method Detail

doIntercept

protected String doIntercept(ActionInvocation invocation)
                      throws Exception

Specified by:

doIntercept in class MethodFilterInterceptor

Throws:

Exception

See Also:

MethodFilterInterceptor.doIntercept(com.opensymphony.xwork2.ActionInvocation)

handleInvalidToken

protected String handleInvalidToken(ActionInvocation invocation)
                             throws Exception

Determines what to do if an invalid token is provided. If the action implements ValidationAware

Parameters:

invocation - the action invocation where the invalid token failed

Returns:

the return code to indicate should be processed

Throws:

Exception - when any unexpected error occurs.

handleValidToken

protected String handleValidToken(ActionInvocation invocation)
                           throws Exception

Called when a valid token is found. This method invokes the action by can be changed to do something more interesting.

Parameters:

invocation - the action invocation

Throws:

Exception - when any unexpected error occurs.