How to use session scope variables in webservice

[wade]

I'm trying to put a User object in the session using web service, so after the client login, he needn't pass the user information any more.
I found the object has a property scope, and 'session' is an available value.
but after I set to scope="session" and reference it in the WebServiceExporter as the following:
<object id="CurrentUser" type="com.newgarman.domain.User, Newgarman.Service" scope="session">
</object>
<object id="demoWebTarget" type="com.newgarman.webservice.impl.DemoWebService ">
<property name="DemoService">
<ref object="demoService"/>
</property>
<property name="CurrentUser">
<ref object="CurrentUser"/>
</property>
</object>

<object id="demoWebService" type="Spring.Web.Services.WebServiceExporter, Spring.Web">
<property name="TargetName" value="demoWebTarget" />
<property name="Namespace" value="http://webservice/WebServices" />
<property name="Description" value="Spring Demo Web Services" />

<property name="MemberAttributes">
<dictionary>
<entry key="*">
<object type="System.Web.Services.WebMethodAttribute, System.Web.Services">
<property name="EnableSession" value="True"/>
</object>
</entry>
</dictionary>
</property>
</object>

it throws an exception that:
'session'-scoped objects require SessionState to be enabled.
Line 234: if (sessionCache == null)
Line 235: {
Line 236: throw ConfigurationUtils.CreateConfigurationException(
Line 237: "'session'-scoped objects require SessionState to be enabled.");
Line 238: }

Is there anything else I need to config or change? anyone can help? thanks in advance.

[Bruno Baia]

Hi,
This should be enough :

<object type="System.Web.Services.WebMethodAttribute, System.Web.Services">
   <property name="EnableSession" value="True"/>
</object>

As you can see, scope should not be used with WebServiceExporter.


Hth,
Bruno

[wade]

Hi, thanks for your reply.

I have enabled the session inside the WebServiceExporter, and I need to use CurrentUser object in DemoWebService which is a general class, so I added a property CurrentUser as the following:

public class DemoWebService : IDemoWebService
{
    private IDemoService demoService;
    public IDemoService DemoService
    {
        get
        {
            return demoService;
        }
        set
        {
            demoService = value;
        }
    }
    private User currentUser;

    public User CurrentUser
    {
        get { return currentUser; }
        set { currentUser = value; }
    }
    
    public Demo GetDemoById(int demo_id)
    {
        Demo demo = new Demo();
        
        if(CurrentUser == null){
            demo.UserName = "New user";
            CurrentUser = new User(); // generate a new User object
            CurrentUser.UserLoginName = "new user in spring";
        }else{
            demo.UserName = CurrentUser.UserLoginName;
        }
        
        return demo;
    }
}

Here's my configuration, I added a CurrentUser reference in DemoWebService. I made it more clear to read.

<object id="CurrentUser" type="com.newgarman.domain.User, Newgarman.Service" scope="session">
</object>

<object id="demoWebTarget" type="com.newgarman.webservice.impl.DemoWebService ">
    <property name="DemoService">
        <ref object="demoService"/>
    </property>
    <property name="CurrentUser">
        <ref object="CurrentUser"/>
    </property>
</object>

<object id="demoWebService" type="Spring.Web.Services.WebServiceExporter, Spring.Web">
    <property name="TargetName" value="demoWebTarget" />
    <property name="Namespace" value="http://webservice/WebServices" />
    <property name="Description" value="Spring Demo Web Services" />
    
    <property name="MemberAttributes">
        <dictionary>
            <entry key="*">
                <object type="System.Web.Services.WebMethodAttribute, System.Web.Services">
                    <property name="EnableSession" value="True"/>
                </object>
            </entry>
        </dictionary>
    </property>
</object>

Now it throws exception: 'session'-scoped objects require SessionState to be enabled.
And after I removed the CurrentUser reference in DemoWebService, there's no error, so I think maybe something need to do with the DemoWebService. But I didn't get any idea.

Then the question is how can I use the CurrentUser in my DemoWebService? thanks again.

[wade]

Anyone can help me?

Can I use the session variable in web service using injection?
If yes, then how can I do that?
thanks.

[wade]

Does this can't be done in spring?

[Bruno Baia]

Hi,

Can you try to set lazy-init=true for 'CurrentUser' and 'demoWebTarget' definitions.

HTH,
Bruno

[Erich Eichinger]

Hi,

Now it throws exception: 'session'-scoped objects require SessionState to be enabled.
And after I removed the CurrentUser reference in DemoWebService, there's no error, so I think maybe something need to do with the DemoWebService.

The problem here is that 'DemoWebService' is a singleton with implicit 'application' scope that gets created during container instantiation and 'CurrentUser' is of 'session' scope. This means you are injecting an object with a smaller lifetime into another with a larger lifetime. Furthermore during container instantiation there is no session available - but 'CurrentUser' is referenced, which causes the exception you are experiencing.

Then the question is how can I use the CurrentUser in my DemoWebService? thanks again.

You could make your DemoWebService 'IApplicationContextAware' (by implementing this interface) and obtain the 'CurrentUser' object from within your methods:

private IApplicationContext _applicationContext;
private string _currentUserObjectName;

void myServiceMethod()
{
  
  CurrentUser user = 
       _applicationContext.GetObject( _currentUserObjectName );
}

If you want to avoid implementing IApplicationContextAware, you could also leverage AOP to obtain a 'CurrentUser' instance from the applicationContext and place it e.g. into HttpContext.Items where your service methods can obtain it from.

hope this helps,
Erich

[wade]

Thanks for all, I Solved the problem by aop.
Now I'm storing the session level variable into httpsession instead of using a spring bean.

Now I'm using a IMethodInterceptor and inject it into a ProxyFactoryObject, then I can get the session in the advice, and that's just what I want since I can do any business logic there.

Thanks again. Spring.net is a great work.