取消 Google Drive API 中的文件上传

Question

我有用于上传适用于 UWP 的文件的代码。我一直在寻找取消上传的方法。没找到。有办法取消吗？我尝试添加

CancellationToken

但在

DriveAPI

属性中没有地方可以设置它。

try
{
    StorageFile file = StorageFile.GetFileFromPathAsync(path).AsTask().Result;
    String ID;

    var fileMetadata = new Google.Apis.Drive.v3.Data.File()
    {
        Name = Path.GetFileName(file.Path),
        MimeType = "application/octet-stream"
        
    };

    using (var stream = file.OpenStreamForReadAsync().Result)
    {
        

        var request = this.drive.Files.Create(fileMetadata, stream, "application/octet-stream");


        request.ProgressChanged += (IUploadProgress progressInfo) =>
        {
            if (progressInfo.Status == UploadStatus.Completed)
            {
                Debug.WriteLine($"done!");
                prog.Report(progressInfo);

            }
            else if (progressInfo.Status == UploadStatus.Failed)
            {
                Debug.WriteLine($"Failed To Upload Into Google Drive");
                prog.Report(progressInfo);
            }
            else
            {
                Debug.WriteLine(Convert.ToDouble(progressInfo.BytesSent/(1024*1024)) + " MB has sent");
                prog.Report(progressInfo);

            }
        };

        request.ChunkSize = 262144;
        request.Upload();
        

        var uploadedFile = request.ResponseBody;
        Debug.WriteLine($"File uploaded: {uploadedFile.Name} ({uploadedFile.Id})");

        ID = uploadedFile.Id;
        return ID;
    }

}

我尝试将

if(cancelationtoken)

放入

progressInfo.Status == UploadStatus.Uploading

中，但它并没有停止上传。它只会停止反驳“进度”。

有人知道如何处理整个

Task<>

？

这就是我尝试做的：

request.ProgressChanged += (IUploadProgress progressInfo) =>
        {
            if (progressInfo.Status == UploadStatus.Completed)
            {
                Debug.WriteLine($"done!");
                prog.Report(progressInfo);

            }
            else if (progressInfo.Status == UploadStatus.Failed)
            {
                Debug.WriteLine($"Failed To Upload Into Google Drive");
                prog.Report(progressInfo);
            }
            else if (progressInfo.Status == UploadStatus.Uploading)
            {
                //(if(canceltoken.iscancel)...){}
                Debug.WriteLine(Convert.ToDouble(progressInfo.BytesSent/(1024*1024)) + " MB has sent");
                prog.Report(progressInfo);

            }
        };

Answer 1

您希望能够取消文件上传，通过设置您的上传方法

async

可以使这变得更容易。然后您就可以正确使用 await 运算符，并可以按以下格式将取消令牌放入上传调用中：

await request.UploadAsync(cancellationToken)

---

我注意到代码中的几个地方您将

async

方法降级为阻止调用，例如

StorageFile.GetFileFromPathAsync(path).AsTask().Result

或

var stream = file.OpenStreamForReadAsync().Result

这在某种程度上违背了这些方法异步的目的，并且您可能会遇到一些死锁或其他线程问题。

---

所以我想说，像这样重新构建你的方法可能非常有利：

async Task<string> Upload(string path, CancellationToken cancellationToken, IProgress<IUploadProgress> prog)
{
    StorageFile file = await StorageFile.GetFileFromPathAsync(path);
    string ID;

    var fileMetadata = new Metadata()
    {
        Name = Path.GetFileName(file.Path),
        MimeType = "application/octet-stream"
    };

    using (var stream = await file.OpenStreamForReadAsync())
    {
        var request = this.drive.Files.Create(fileMetadata, stream, "application/octet-stream");

        request.ProgressChanged += (IUploadProgress progressInfo) =>
        {
            if (progressInfo.Status == UploadStatus.Completed)
            {
                Debug.WriteLine($"done!");
                prog.Report(progressInfo);

            }
            else if (progressInfo.Status == UploadStatus.Failed)
            {
                Debug.WriteLine($"Failed To Upload Into Google Drive");
                prog.Report(progressInfo);
            }
            else
            {
                Debug.WriteLine(Convert.ToDouble(progressInfo.BytesSent / (1024 * 1024)) + " MB has sent");
                prog.Report(progressInfo);

            }
        };

        request.ChunkSize = 262144;
        await request.UploadAsync(cancellationToken);

        var uploadedFile = request.ResponseBody;
        Debug.WriteLine($"File uploaded: {uploadedFile.Name} ({uploadedFile.Id})");

        ID = uploadedFile.Id;
        return ID;
    }
}