WCF DataContact和代理WCF服务。

Question

I have two WCF services one on a Master server (Managed by a third party, don't have much access there) and another on my local server, basically the reason for the local service to exist is to store data locally in case the Master service is offline (for any reason) and then upload the data back whenever Master service becomes available.

To keep the client application transparent of where to hit with the data (Master service/local service) I am making the local service as proxy. ie, the client application would only call local service and then it in turns checks the health of the Master server to get/post data, in case it is offline it uses local cache, and pushes data back to server whenever available.

Now there are some complex DataContract in the master service (and they are loads of them), and I since don't have access to actual data contract attributed files (it is managed by a third party), and since any added reference (SOAP) creates complex types locally, but with XML Serialization attributes instead of DataMembers/DataContracts I won't be able to reuse the types as is or can I?

Is there a way around or do I just have to either get through the 3rd Party or create my contracts?

Answer 1

I have some queries :-

1. Well what do you mean by managed by third party? Is it a separate Organization providing/maintaining the WCF service and you don't have the code?

2. Is you're local service kind of wrapper?

If you by any means get hold of Data Contracts and Service contract that would be the best as you're local service can implement the same Service Contract using the same Data Contracts. Along with that you can have one more Service Contract which you can use to push data back when the master service is up.

Refer to the Example below :-

public interface IMasterService
{
    TResponse PersistData(TRequestObject request);
}

public interface ILocalService
{
    TResponse PushDataInBatch(TRequestObject[] requestBatch);

    //We can add more methods here if required
}

public MasterService : IMasterService
{
    public TResponse PersistData(TRequestObject request) 
    {
        //persist data in Master DB
    }
}

public LocalService : IMasterService, ILocalService
{
    public TResponse PersistData(TRequestObject request) 
    {
        //persist data in local cache
    }

    public TResponse PushDataInBatch(TRequestObject[] requestBatch) 
    {
        //persist data in local cache
    }
}

Let me know if the above thoughts helped you, feel free to give more information and then we can check it in detail.

---

Above implementation could have been the approach if you have access to their libraries, however if you don't then you are only left with one option to take a service reference of the MasterService and persist the data accordinlgly.

One more query, in your LocalService am assuming you are duplicating the persisting logic (in local datastore)?