C# – Unable to serialize the session state

asp.netciisiis-6

We have reasonably large scale application and recently experiencing issues with random logouts. Upon investigation we've found app pool is recycling after physical memory limit of (1GB)is reached. I m now trying to save session state in out of process as below

<sessionState mode="StateServer" stateConnectionString="tcpip=127.0.0.1:42424" cookieless="false" timeout="20"/>

After changing the session state mode to "StateServer" and running the asp.net state service on server. I m getting the following error message

"Unable to serialize the session state. In 'StateServer' and 'SQLServer' mode, ASP.NET will serialize the session state objects, and as a result non-serializable objects or MarshalByRef objects are not permitted. The same restriction applies if similar serialization is done by the custom session state store in 'Custom' mode."

Apparently i have to mark session related objects with [Serializable] attribute but the application is quite big. Is there a way around this issue?

thanks

Best Answer

Is there a way around this issue?

No, you have to analyze all the objects that are participating in the object graph that you are storing into the session and decorate them with the [Serializable] attribute.

The alternative's not gonna like you: write a custom session state provider where you will have control over the serialization of your session state objects but that's usually an overkill.

This is the style that Microsoft tends to use in their examples.

It appears that the guidance in this area may have changed, as StyleCop now enforces the use of the C# specific aliases.

C# – Unable to serialize the session state. Part 2

When using BinaryFormatter (which includes this session-state provider), all types in the graph must be serializable via [Serializable] or ISerializable. The most common "gotcha" here is events. Normally you might add:

[field:NonSerialized]

to any field-like event declarations, i.e.

[field:NonSerialized]
public event EventHandler FooChanged;

but obviously this is not convenient in generated code.

IMO, the real problem here is using rich objects in state. Session-state and cache objects should really be bare-bones versions - basic DTOs with minimum fuss and complexity - just data (I would consider full-immutability or popsicle-immutability a nice-to-have, too). I would refactor to add a DTO for the things you want to store, and just store that.

Another approach is to change your state implementation, in the process swapping the serializer. In the DBML designer you can make LINQ models "unidirectional", meaning DataContractSerializer will work with them; so DataContractSerializer might make a reasonable swap out; but writing a provider is hard work and nothing to do with your business needs. I would just write the DTO ;p

One final option is to implement ISerializable in your partial class, and only store/fetch the values you actually need.

(in addition to events, any other fields that lead to objects that are not serializable by BinaryFormatter will also fail)

Best Answer

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This is the style that Microsoft tends to use in their examples.

C# – Unable to serialize the session state. Part 2

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