CODEWITHSUNDEEP
c#.netxmlserialization
peon
peon

Reputation: 21

how can I replace the deprecated SoapFormatter?

I have a legacy app that uses SoapFormatter to persist a graph of objects (maybe 50 different classes). I want to move away from using this as it is deprecated, and increasingly hard to continue to support deserializing from old files as the classes change.

I want to use DataContractSerializer going forward. Does anyone have any suggestions as to a good strategy for migration? I need to continue to be able to deserializing old files written by SoapFormatter...

Thanks

Upvotes: 2

Views: 851

Answers (2)

Nekresh
Nekresh

Reputation: 2988

The simplest code would be to try deserialize with DataContractSerializer and fallback to SoapFormatter if it fails. The save part will always use the DataContractSerializer, so that your new objects or the updated ones will use your new supported version.

public MyContract Deserialize(string file)
{
  try
  {
    using (var stream = loadFile())
    {
      return loadWithDataContractSerializer(stream);
    }
  }
  catch (SerializationException)
  {
    using (var stream = openForRead(file))
    {
      return convertToContract(loadWithSoapFormatter(stream));
    }
  }
}

private MyContract loadWithDataContractSerializer(Stream s);
private MyOldObject loadWithSoapFormatter(Stream s);
private MyContract convertToContract(MyOldObject obj);

public void Serialize(string file, MyContract data)
{
  using (var stream = openForWrite(file))
  {
    writeWithDataContractSerializer(stream, data);
  }
}

Of course, it might be possible to implement a custom logic to allow DataContractSerializer to understant the SoapFormatter structure, but you will have to provide a lot more work.

Upvotes: 0

Henk Holterman
Henk Holterman

Reputation: 273581

I don't think you want to be limited to a backward-compatible format.

So you will need to distinguish old and new content. And easy method would be :

Old Format: <soapdata>
New Format: <header> <newdata>

And in your new Load() method:

  1. (Try to) Read the header
  2. If a header is found, continue to read the new format
  3. else re-position to begin and use the SOAP formatter to read.

Upvotes: 1

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