Azure存储:BlobClient在上载大文件时不断重置自身

问题描述

我正在尝试从连接到快速Wifi连接的手机上载200 MB的视频文件.我使用的是适用于.NET的Azure存储SDK的v12，但以下代码会在上载进度达到30％左右后自行重置.发生重置时，进度从0开始，并且不会引发异常.

I'm trying to upload a 200 MB video file from a mobile phone that's connected to a fast Wifi connection. I'm using v12 of Azure Storage SDK for .NET, but the below code keeps resetting itself after about 30% upload progress. When the reset occurs, progress begins from 0 and there is no exception thrown.

await blobClient.UploadAsync(stream, progressHandler: new Progress<long>(progress =>
{
     // show progress bar
}), cancellationToken: cancellationToken);

v12是否支持上传大文件?如果我没记错的话，旧的API可以上传单个块.我的印象是上述上传方法将隐式处理分块.

Does v12 support uploading large files? If I remember correctly, the old APIs had the ability to upload individual blocks. I was under the impression that the above upload method would handle chunking implicitly.

如何使用最新的sdk上传大文件?

How can I upload large files using the latest sdk?

P.S.我尝试传递具有很高的并发性和1 MB传输大小的 StorageTransferOptions ，但这没什么区别.

P.S. I tried passing a StorageTransferOptions with very high concurrency and 1 MB transfer size, but it made no difference.

编辑:等待了很长一段时间后，我才能引发异常.我看到由于以下原因，多个任务被取消了:

After waiting for a long time, I was able to get an exception thrown. I see that multiple tasks get canceled because of

Cannot access a disposed object.
Object name: 'MobileAuthenticatedStream'.

  at Mono.Net.Security.MobileAuthenticatedStream.StartOperation (Mono.Net.Security.MobileAuthenticatedStream+OperationType type, Mono.Net.Security.AsyncProtocolRequest asyncRequest, System.Threading.CancellationToken cancellationToken) [0x00245] in /Users/builder/jenkins/workspace/archive-mono/2020-02/android/release/mcs/class/System/Mono.Net.Security/MobileAuthenticatedStream.cs:410
  at System.Net.Http.HttpConnection.WriteAsync (System.ReadOnlyMemory`1[T] source) [0x00118] in /Users/builder/jenkins/workspace/archive-mono/2020-02/android/release/external/corefx/src/System.Net.Http/src/System/Net/Http/SocketsHttpHandler/HttpConnection.cs:1008
  at System.IO.Stream.CopyToAsyncInternal (System.IO.Stream destination, System.Int32 bufferSize, System.Threading.CancellationToken cancellationToken) [0x000e7] in /Users/builder/jenkins/workspace/archive-mono/2020-02/android/release/external/corert/src/System.Private.CoreLib/shared/System/IO/Stream.cs:152
  at Azure.Core.RequestContent+StreamContent.WriteToAsync (System.IO.Stream stream, System.Threading.CancellationToken cancellation) [0x00094] in <7b1dc95b0b4841539beb48023c1128d3>:0
  at Azure.Core.Pipeline.HttpClientTransport+PipelineRequest+PipelineContentAdapter.SerializeToStreamAsync (System.IO.Stream stream, System.Net.TransportContext context) [0x0007c] in <7b1dc95b0b4841539beb48023c1128d3>:0
  at System.Net.Http.HttpContent.CopyToAsyncCore (System.Threading.Tasks.ValueTask copyTask) [0x00022] in /Users/builder/jenkins/workspace/archive-mono/2020-02/android/release/external/corefx/src/System.Net.Http/src/System/Net/Http/HttpContent.cs:361

因此，似乎在 blobClient 中内置了并行化，但是仍然失败.此外，我不能使用 https://www.nuget.org/packages/Microsoft.Azure.Storage.DataMovement ，因为它不适用于 Xamarin Forms .

So it seems there is parallelization built into blobClient, but it's failing still. Additionally, I cannot use https://www.nuget.org/packages/Microsoft.Azure.Storage.DataMovement because it doesn't work with Xamarin Forms.

推荐答案

如果要将文件分块上传到Azure blob存储，请参考以下代码

If you want to upload file to Azure blob storage in chunk, please refer to the following code

public async Task upload(Stream stream){
            string connectionString = "";
            string containerName = "upload";
            string blobName = "";
            BlockBlobClient blobClient = new BlockBlobClient(connectionString, containerName, blobName);

            List<string> blockList = new List<string>();

                while (true) {
                    byte[] b = new byte[1024 * 1024];
                    var n = await stream.ReadAsync(b, 0, 1024 * 1024);
                    if (n == 0) break;
                    string blockId = Guid.NewGuid().ToString();
                    string base64BlockId = Convert.ToBase64String(Encoding.UTF8.GetBytes(blockId));
                    await blobClient.StageBlockAsync(base64BlockId, new MemoryStream(b, true));
                    blockList.Add(base64BlockId);
                }

                await blobClient.CommitBlockListAsync(blockList);


}

---

更新

如果要使用sas令牌，请参考以下代码

If you want to use sas token, please refer to the following code

var uri = new Uri($"https://{storageAccountName}.blob.core.windows.net/{containerName}/{blobName}?{sasToken}");
BlockBlobClient blobClient = new BlockBlobClient(uri);

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