C# 在Azure存储客户端2.0中将一个Azure blob复制到另一个blob

在旧的1.7存储客户端中有一个CloudBlob.CopyFromBlob（otherBlob）方法，但在2.0版本中似乎没有。复制BLOB的推荐最佳实践是什么？我确实看到了ICloudBlob.BeginStartCopyFromBlob方法。如果这是合适的方法，我该如何使用它？

已经写了一系列关于2.0版Azure存储的文章。我从他的博客文章for Blob Copy中摘录了这段代码

CloudStorageAccount storageAccount = new CloudStorageAccount(new StorageCredentials(accountName, accountKey), true);
CloudBlobClient cloudBlobClient = storageAccount.CreateCloudBlobClient();
CloudBlobContainer sourceContainer = cloudBlobClient.GetContainerReference(containerName);
CloudBlobContainer targetContainer = cloudBlobClient.GetContainerReference(targetContainerName);
string blobName = "<Blob Name e.g. myblob.txt>";
CloudBlockBlob sourceBlob = sourceContainer.GetBlockBlobReference(blobName);
CloudBlockBlob targetBlob = targetContainer.GetBlockBlobReference(blobName);
targetBlob.StartCopyFromBlob(sourceBlob);

CloudStorageAccount-storageAccount=new-CloudStorageAccount（new-StorageCredentials（accountName，accountKey），true）；
CloudBlobClient CloudBlobClient=storageAccount.CreateCloudBlobClient（）；
CloudBlobContainer sourceContainer=cloudBlobClient.GetContainerReference（containerName）；
CloudBlobContainer targetContainer=cloudBlobClient.GetContainerReference（targetContainerName）；
字符串blobName=“”；
CloudBlockBlob sourceBlob=sourceContainer.GetBlockBlobReference（blobName）；
CloudBlockBlob targetBlob=targetContainer.GetBlockBlobReference（blobName）；
targetBlob.StartCopyFromBlob（sourceBlob）；

Naveen已经解释了使用

StartCopyFromBlob

（同步方法）的正确语法。您提到的方法（

BeginStartCopyFromBlob

）是一种异步替代方法，可以与

任务

结合使用，例如：

    var blobClient = account.CreateCloudBlobClient();

    // Upload picture.
    var picturesContainer = blobClient.GetContainerReference("pictures");
    picturesContainer.CreateIfNotExists();
    var myPictureBlob = picturesContainer.GetBlockBlobReference("me.png");
    using (var fs = new FileStream(@"C:\Users\Public\Pictures\Sample Pictures\Chrysanthemum.jpg", FileMode.Open))
        myPictureBlob.UploadFromStream(fs);

    // Backup picture.
    var backupContainer = blobClient.GetContainerReference("backup");
    backupContainer.CreateIfNotExists();
    var backupBlob = picturesContainer.GetBlockBlobReference("me.png");

    var task = Task.Factory.FromAsync<string>(backupBlob.BeginStartCopyFromBlob(myPictureBlob, null, null), backupBlob.EndStartCopyFromBlob);
    task.ContinueWith((t) =>
    {
        if (!t.IsFaulted)
        {
            while (true)
            {
                Console.WriteLine("Copy state for {0}: {1}", backupBlob.Uri, backupBlob.CopyState.Status);
                Thread.Sleep(500);
            }
        }
        else
        {
            Console.WriteLine("Error: " + t.Exception);
        }
    });

var blobClient=account.CreateCloudBlobClient（）；
//上传图片。
var picturesContainer=blobClient.GetContainerReference（“图片”）；
picturesContainer.CreateIfNotExists（）；
var myPictureBlob=picturesContainer.GetBlockBlobReference（“me.png”）；
使用（var fs=newfilestream（@“C:\Users\Public\Pictures\Sample Pictures\jummy.jpg”，FileMode.Open））
myPictureBlob.UploadFromStream（fs）；
//备份图片。
var backupContainer=blobClient.GetContainerReference（“备份”）；
backupContainer.CreateIfNotExists（）；
var backupBlob=picturesContainer.GetBlockBlobReference（“me.png”）；
var task=task.Factory.fromsync（backupBlob.begintartcopyfromblob（myPictureBlob，null，null），backupBlob.EndStartCopyFromBlob）；
任务。继续（（t）=>
{
如果（！t.IsFaulted）
{
while（true）
{
WriteLine（“复制状态为{0}:{1}”，backuplob.Uri，backuplob.CopyState.Status）；
睡眠（500）；
}
}
其他的
{
Console.WriteLine（“错误：+t.Exception”）；
}
});

使用Storage 6.3（比原始问题中更新得多的库）和异步方法使用StartCoyAsync（）

---

仅供参考，从最新版本（7.x）的

SDK

开始，由于

begintartcopyblob

功能不再存在，此功能不再有效

您可以这样做：

// this tunnels the data via your program,
// so it reuploads the blob instead of copying it on service side
using (var stream = await sourceBlob.OpenReadAsync())
{
  await destinationBlob.UploadFromStreamAsync(stream);
}

如@（Alexey Shcherbak）所述，这是一种更好的方式：

---

等待targetCloudBlob.startCopySync（sourceCloudBlob.Uri）；
while（targetCloudBlob.CopyState.Status==CopyStatus.Pending）
{
等待任务。延迟（500）；
//需要获取，否则“CopyState”将永远不会更新
等待targetCloudBlob.FetchAttributesAsync（）；
}
if（targetCloudBlob.CopyState.Status！=CopyStatus.Success）
{
抛出新异常（“复制失败：+targetCloudBlob.CopyState.Status”）；
}

这是我的简单答案

public void Copy(CloudBlockBlob srcBlob, CloudBlobContainer destContainer)
{
    CloudBlockBlob destBlob;

    if (srcBlob == null)
    {
        throw new Exception("Source blob cannot be null.");
    }

    if (!destContainer.Exists())
    {
        throw new Exception("Destination container does not exist.");
    }

    //Copy source blob to destination container
    string name = srcBlob.Uri.Segments.Last();
    destBlob = destContainer.GetBlockBlobReference(name);
    destBlob.StartCopyAsync(srcBlob);                
}

---

对于我，WindowsAzure.Storage 8.0.1，James Hancock的解决方案执行了服务器端拷贝，但客户端拷贝状态一直处于

挂起状态（永远循环）。解决方案是在
Thread.sleep（500）
之后调用
targetCloudBlob
上的
FetchAttributes（）

启动Azure Storage 8，要在存储帐户之间移动Blob，我使用类似于下面的代码，希望它能帮助某些人：

//copy blobs - from
CloudStorageAccount sourceStorageAccount = new CloudStorageAccount(new StorageCredentials(storageFromName, storageFromKey), true);
CloudBlobClient sourceCloudBlobClient = sourceStorageAccount.CreateCloudBlobClient();
CloudBlobContainer sourceContainer = sourceCloudBlobClient.GetContainerReference(containerFromName);

//copy blobs - to
CloudStorageAccount targetStorageAccount = new CloudStorageAccount(new StorageCredentials(storageToName, storageToKey), true);
CloudBlobClient targetCloudBlobClient = targetStorageAccount.CreateCloudBlobClient();
CloudBlobContainer targetContainer = targetCloudBlobClient.GetContainerReference(containerToName);

//create target container if didn't exists
try{
    await targetContainer.CreateIfNotExistsAsync();
}
catch(Exception e){
    log.Error(e.Message);
}

CloudBlockBlob sourceBlob = sourceContainer.GetBlockBlobReference(blobName);
CloudBlockBlob targetBlob = targetContainer.GetBlockBlobReference(blobName);

try{
    //initialize copying
    await targetBlob.StartCopyAsync(sourceBlob.Uri);
}
catch(Exception ex){
    log.Error(ex.Message);
    //return error, in my case HTTP
    return req.CreateResponse(HttpStatusCode.BadRequest, "Error, source BLOB probably has private access only: " +ex.Message);
} 

//fetch current attributes
targetBlob.FetchAttributes();

//waiting for completion
while (targetBlob.CopyState.Status == CopyStatus.Pending){
    log.Info("Status: " + targetBlob.CopyState.Status);
    Thread.Sleep(500);
    targetBlob.FetchAttributes();
}

//check status
if (targetBlob.CopyState.Status != CopyStatus.Success){
    //return error, in my case HTTP
    return req.CreateResponse(HttpStatusCode.BadRequest, "Copy failed with status: " + targetBlob.CopyState.Status);
}

//finally remove source in case Copy Status was Success
sourceBlob.Delete();

//and return success (in my case HTTP)
return req.CreateResponse(HttpStatusCode.OK, "Done.");

自从以前的帖子发布以来，API似乎已经被清理了一点

/\u客户端是通过构造函数中的DI注入的BlobServiceClient。
BlobContainerClient sourceContainerClient=\u client.GetBlobContainerClient（sourceContainerName）；
BlobClient sourceClient=sourceContainerClient.GetBlobClient（blobName）；
BlobContainerClient destContainerClient=\u client.GetBlobContainerClient（destContainerName）；
BlobClient destClient=destContainerClient.GetBlobClient（blobName）；
//假设如果下面的代码没有抛出异常，那么它是成功的。
CopyFromUriOperation操作=等待destClient.StartCopyFromUriSync（sourceClient.Uri）；
等待操作。WaitForCompletionAsync（）；

operation.WaitForCompletionAsync
的文档说明：

定期调用服务器，直到长时间运行的操作完成。此方法将定期调用UpdateStatusAsync，直到HasCompleted为true，然后返回操作的最终结果

查看此方法的源代码似乎调用了
BlobBaseClient.GetProperties
（或异步版本），这将在出错时抛出
RequestFailureException
。
我正试图使用它在同一存储帐户内复制blob，但我得到了一个409冲突错误。消息是“blob类型对此操作无效”。我试着把它当作一个页面blob和一个块blob（我很确定我是一个页面blob）来解决它。结果表明，源是一个页面blob，但目标已作为块blob创建（在上次失败的尝试中）。删除目标并重试成功。这是服务器端副本吗？StartCopyFromBlob也是一个异步操作，因为这将重新上载blob。正如Aaron Sherman所提到的，对于较新的库，如果可以添加Vangaorth的FetchAttributes（）修订内联，则应该使用StartCoyAsync，这可能会很有用-我在经过一段时间的调试后才看到。启动Windows Azure Storage 8.0时，还需要不断地获取属性（targetCloudBlob.FetchAttributes（））。上面的代码段将由于超时而失败（无止境
// Aaron Sherman's code 

targetCloudBlob.StartCopy(sourceCloudBlob.Uri);

while (targetCloudBlob.CopyState.Status == CopyStatus.Pending)
{
    Thread.Sleep(500);
    targetCloudBlob.FetchAttributes();
}

// James Hancock's remaining code

//copy blobs - from
CloudStorageAccount sourceStorageAccount = new CloudStorageAccount(new StorageCredentials(storageFromName, storageFromKey), true);
CloudBlobClient sourceCloudBlobClient = sourceStorageAccount.CreateCloudBlobClient();
CloudBlobContainer sourceContainer = sourceCloudBlobClient.GetContainerReference(containerFromName);

//copy blobs - to
CloudStorageAccount targetStorageAccount = new CloudStorageAccount(new StorageCredentials(storageToName, storageToKey), true);
CloudBlobClient targetCloudBlobClient = targetStorageAccount.CreateCloudBlobClient();
CloudBlobContainer targetContainer = targetCloudBlobClient.GetContainerReference(containerToName);

//create target container if didn't exists
try{
    await targetContainer.CreateIfNotExistsAsync();
}
catch(Exception e){
    log.Error(e.Message);
}

CloudBlockBlob sourceBlob = sourceContainer.GetBlockBlobReference(blobName);
CloudBlockBlob targetBlob = targetContainer.GetBlockBlobReference(blobName);

try{
    //initialize copying
    await targetBlob.StartCopyAsync(sourceBlob.Uri);
}
catch(Exception ex){
    log.Error(ex.Message);
    //return error, in my case HTTP
    return req.CreateResponse(HttpStatusCode.BadRequest, "Error, source BLOB probably has private access only: " +ex.Message);
} 

//fetch current attributes
targetBlob.FetchAttributes();

//waiting for completion
while (targetBlob.CopyState.Status == CopyStatus.Pending){
    log.Info("Status: " + targetBlob.CopyState.Status);
    Thread.Sleep(500);
    targetBlob.FetchAttributes();
}

//check status
if (targetBlob.CopyState.Status != CopyStatus.Success){
    //return error, in my case HTTP
    return req.CreateResponse(HttpStatusCode.BadRequest, "Copy failed with status: " + targetBlob.CopyState.Status);
}

//finally remove source in case Copy Status was Success
sourceBlob.Delete();

//and return success (in my case HTTP)
return req.CreateResponse(HttpStatusCode.OK, "Done.");