Ability to cancel the store request in C-Get #1810

enasbond · 2024-06-09T10:25:11Z

I implemented the Dicom-Get operation exactly as demonstrated in your SDK. Additionally, my application utilizes the NativeTranscoderManager. When a store request sends a large DICOM file that requires compression and takes about 2 or 3 minutes, my server does not receive the connection request until the compression is complete if the remote host suddenly closes the connection.

I recommend supporting a cancellation token to be sent with the SendRequestAsync method of the DicomService. This would allow the operation to be terminated when the remote host closes the connection, thereby saving server resources.

amoerie · 2024-06-19T18:15:00Z

DicomServer and DicomService are indeed lacking in cooperative cancellation support. I think we should do better here.
I might take a stab at this if I find the time.

amoerie · 2024-06-19T19:10:51Z

I took a quick stab at it. It's far from finished though, and this will need to be discussed. See the PR for more details!

gofal · 2025-04-16T05:20:21Z

You can setup your own cancellation token if you need one.
Your class implementing the c-get is inheriting from DicomService, this means that you always have access to properties that tell you about the state of the underlying connection.

For example there is the property IsConnected. In Order to avoid errors your OnCGetRequestAsync could look like that:

   public async IAsyncEnumerable<DicomCGetResponse> OnCGetRequestAsync(DicomCGetRequest request)
   {
       // some logic to evaluate the request params and to find the matchinf files

       foreach (var matchingFile in matchingFiles)
       {
           // add this line of code, to quit this loop if the connection was closed, to avoid errors in your log when trying to send data
           if (!IsConnected) break;

           var storeRequest = new DicomCStoreRequest(matchingFile);
           await SendRequestAsync(storeRequest);
       }

       yield return new DicomCGetResponse(request, DicomStatus.Success);
   }

gofal · 2025-04-16T05:28:00Z

But as I understand, you have some long-lasting compression method, that only can be canceled by a cancellationToken?
Whenever the connection is closed (intentionally, or not), the virtual method OnConnectionClosed is injected. So you could add your own cancellation token source, that you use for your compression method, and that you can inject if the OnConnectionClosed is injected.

    private CancellationTokenSource _connectionClosedToken = new CancellationTokenSource();

    public void OnConnectionClosed(Exception exception)
    {
        // whenever the connection is closed, you can trigger the cancellationtokensource
        _connectionClosedToken.Cancel();
        Clean();
    }

    public async IAsyncEnumerable<DicomCGetResponse> OnCGetRequestAsync(DicomCGetRequest request)
    {
         // some logic to evaluate the request params and to find the matchinf files

        foreach (var matchingFile in matchingFiles)
        {
            // here in this long-lasting operation you can pass this cancellationtoken
           //  depending how your method reacs on cancellation token (if it throws an exception, or if it terminates fine but returns null) you have to add more code, to quit the foreach loop
            var compressed = await DoLongLastingCompression(matchingFile, _connectionClosedToken.Token);

            var storeRequest = new DicomCStoreRequest(compressed);
            await SendRequestAsync(storeRequest);
        }

        yield return new DicomCGetResponse(request, DicomStatus.Success);
    }

enasbond added the new label Jun 9, 2024

amoerie added enhancement and removed new labels Jun 19, 2024

amoerie mentioned this issue Jun 19, 2024

Add cancellation token support to DicomService #1813

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gofal added question and removed enhancement labels Apr 22, 2025

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Ability to cancel the store request in C-Get #1810

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Ability to cancel the store request in C-Get #1810

Ability to cancel the store request in C-Get #1810

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