YouTube C# API V3, how do you resume an interrupted upload?

Question

I can\'t work out how to resume an interrupted upload in V3 of the C# YouTube API.

My existing code uses V1 and works fine but I\'m switching to V3.

If I cal

Answer 1

After a fair bit of deliberation, I've decided to modify the API code. My solution maintains backwards compatibility.

I've documented my changes below but I don't recommend using them.

In the UploadAsync() method in the ResumableUpload Class in "Google.Apis.Upload", I replaced this code.

BytesServerReceived = 0;
UpdateProgress(new ResumableUploadProgress(UploadStatus.Starting, 0));
// Check if the stream length is known.
StreamLength = ContentStream.CanSeek ? ContentStream.Length : UnknownSize;
UploadUri = await InitializeUpload(cancellationToken).ConfigureAwait(false);

with this code

UpdateProgress(new ResumableUploadProgress(
    BytesServerReceived == 0 ? UploadStatus.Starting : UploadStatus.Resuming, BytesServerReceived));
StreamLength = ContentStream.CanSeek ? ContentStream.Length : UnknownSize;
if (UploadUri == null) UploadUri = await InitializeUpload(cancellationToken).ConfigureAwait(false);

I also made the UploadUri and BytesServerReceived properties public. This allows an upload to be continued after the ResumableUpload object has been destroyed or after an application restart.

You just recreate the ResumableUpload as per normal, set these two fields and call UploadAsync() to resume an upload. Both fields need to be saved during the original upload.

public Uri UploadUri { get; set; }
public long BytesServerReceived { get; set; }

I also added "Resuming" to the UploadStatus enum in the IUploadProgress class.

public enum UploadStatus
{
    /// 

    /// The upload has not started.
    /// 
    NotStarted,

    /// 

    /// The upload is initializing.
    /// 
    Starting,

    /// 

    /// Data is being uploaded.
    /// 
    Uploading,

    /// 

    /// Upload is being resumed.
    /// 
    Resuming,

    /// 

    /// The upload completed successfully.
    /// 
    Completed,

    /// 

    /// The upload failed.
    /// 
    Failed
};

Nothing has changed for starting an upload.

Provided the ResumableUpload Oject and streams have not been destroyed, call UploadAsync() again to resume an interrupted upload.

If they have been destroyed, create new objects and set the UploadUri and BytesServerReceived properties. These two properties can be saved during the original upload. The video details and content stream can be configured as per normal.

These few changes allow an upload to be resumed even after restarting your application or rebooting. I'm not sure how long before an upload expires but I'll report back when I've done some more testing with my real application.

Just for completeness, this is the test code I've been using, which happily resumes an interrupted upload after restarting the application multiple times during an upload. The only difference between resuming and restarting, is setting the UploadUri and BytesServerReceived properties.

resumableUploadTest = youTubeService.Videos.Insert(video, "snippet,status,contentDetails", fileStream, "video/*");
if (resume)
{
    resumableUploadTest.UploadUri = Settings.Default.UploadUri;
    resumableUploadTest.BytesServerReceived = Settings.Default.BytesServerReceived;                 
}                                               
resumableUploadTest.ChunkSize = ResumableUpload

I hope this helps someone. It took me much longer than expected to work it out and I'm still hoping I've missed something simple. I messed around for ages trying to add my own error handlers but the API does all that for you. The API does recover from minor short hiccups but not from an application restart, reboot or prolonged outage.

Cheers. Mick.