[jira] Issue Comment Edited: (WW-1831) Common use case for stranded messages in MessageStoreInterceptor

["James Holmes (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/struts/browse/WW-1831?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel#action_41834 ] 

jholmes edited comment on WW-1831 at 8/13/07 8:15 PM:
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I also ran into this same issue. I fixed the problem by not having my main action always be in RETRIEVE operation mode. Instead I passed the operation mode to the main action. I have an example of this below using your original configuration

<action name="home" class="com.mycompany.action.HomeAction">
    <result>home.ftl</result>
    <interceptor-ref name="store"/>
    <interceptor-ref name="basicStack"/>
</action>

<action name="updateEmail" class="com.mycompany.action.ChangeEmailAction" method="updateEmail">
    <result type="redirect-action">
        <param name="actionName">home</param>
        <param name="operationMode">RETRIEVE</param>
    </result>
    <result name="input">editEmail.ftl</result>
    <interceptor-ref name="store">
        <param name="operationMode">STORE</param>
    </interceptor-ref> 
    <interceptor-ref name="validationStack"/>
</action>

Notice that the operation mode of RETRIEVE is passed as parameter on the redirect-action result.

      was (Author: jholmes):
    I also ran into this same issue. I fixed the problem by not having my main action always be in RETRIEVE operation mode. Instead I passed the operation mode to the main action. I have an example of this below using your original configuration

<action name="home" class="com.mycompany.action.HomeAction">
    <result>home.ftl</result>
    <interceptor-ref name="store"/>
    <interceptor-ref name="basicStack"/>
</action>

<action name="updateEmail" class="com.mycompany.action.ChangeEmailAction" method="updateEmail">
    <result type="redirect-action">
        <param name="actionName">home</param>
        <param name="operationMode">RETRIEVE</param>
    </result>
    <result name="input">editEmail.ftl</result>
    <interceptor-ref name="store">
        <param name="operationMode">STORE</param>
    </interceptor-ref> 
    <interceptor-ref name="validationStack"/>
</action>

Notice that the operation mode of RETRIEVE is passed as parameter on the redirect-action result.

I still believe this should be fixed though and I will work on that.
  
> Common use case for stranded messages in MessageStoreInterceptor 
> -----------------------------------------------------------------
>
>                 Key: WW-1831
>                 URL: https://issues.apache.org/struts/browse/WW-1831
>             Project: Struts 2
>          Issue Type: Improvement
>          Components: Interceptors
>    Affects Versions: 2.0.6, 2.0.7, 2.0.8, 2.0.9
>            Reporter: Jasper Rosenberg
>            Assignee: James Holmes
>             Fix For: Future
>
>
> I have what I think would be a pretty common use case for the MessageStoreInterceptor where, under some circumstances, messages could be left in the session, taking up memory unncessarily.
> The sample use case is that when someone submits an email change, on success I want to redirect them back to their home action, passing any messages (i.e. "Your email has been successfully changed") along for display.  I used to do this with action chaining which worked but was sub-optimal since the user would end up back at their home page with an url like "updateEmail.action" rather than "home.action".
> MessageStoreInterceptor seems like the right solution for this case as now I can have the updateEmail store the message, redirect to the home page, and then have home page retrieve it:
> <action name="home"
>         class="com.mycompany.action.HomeAction">
>     <result>home.ftl</result>
>     <interceptor-ref name="store">
>         <param name="operationMode">RETRIEVE</param>
>     </interceptor-ref>
>     <interceptor-ref name="basicStack"/>
> </action>
> <action name="updateEmail"
>         class="com.mycompany.action.ChangeEmailAction" method="updateEmail">
>     <result type="redirect-action">
>         <param name="actionName">home</param>
>     </result>
>     <result name="input">editEmail.ftl</result>
>     <interceptor-ref name="store">
>         <param name="operationMode">STORE</param>
>     </interceptor-ref>                
>     <interceptor-ref name="validationStack"/>
> </action>
> The problem is the case when the result of updateEmail is "input" rather than "success".  In this case, I just redisplay the change email form, but any validation errors will have been stored in the session.  If the user then navigates away or closes the browser, these messages will be stranded in the session.
> I think there is a pretty simple fix for this:
> In MessageStoreInterceptor.before(), simply move the lines:
>             session.remove(actionErrorsSessionKey);
>             session.remove(actionMessagesSessionKey);
>             session.remove(fieldErrorsSessionKey);
> out of the nested ifs so that they are always the last operations in the method.
> This will handle any case other than a redirect/chain to an action that doesn't have the interceptor at all (which can't be helped).
> Another option to this is to explictly support an additional parameter for the Interceptor like "clearStoredMessages" which defaults to false, but if true always calls the session.remove()s at the end of the before().

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