如何使用适用于.NET的Azure存储客户端库(BLOBS)列出所有虚拟目录和子目录 [英] How to list all virtual directories and subdirectories using Azure Storage Client Library for .NET (BLOBS)

问题描述

如何列出Blob容器中的所有目录和子目录?

这是我到目前为止所拥有的:

This is what I have so far:

public List<CloudBlobDirectory> Folders { get; set; }

public List<CloudBlobDirectory> GetAllFoldersAndSubFoldersFromBlobStorageContainer()
{
    CloudStorageAccount storageAccount = CloudStorageAccount.Parse(ConfigurationManager.ConnectionStrings["StorageConnectionString"].ConnectionString);
    CloudBlobClient blobClient = storageAccount.CreateCloudBlobClient();
    CloudBlobContainer container = blobClient.GetContainerReference("mycontainer");

    if (container.Exists())
    {
        Folders = new List<CloudBlobDirectory>();

        foreach (var item in container.ListBlobs())
        {
            if (item is CloudBlobDirectory)
            {
                var folder = (CloudBlobDirectory)item;
                Folders.Add(folder);
                GetSubFolders(folder);
            }
        }
    }

    return Folders;
}

private void GetSubFolders(CloudBlobDirectory folder)
{
    foreach (var item in folder.ListBlobs())
    {
        if (item is CloudBlobDirectory)
        {
            var subfolder = (CloudBlobDirectory)item;
            Folders.Add(subfolder);
            GetSubFolders(subfolder);
        }
    }
}

上面的代码片段为我提供了所需的列表，但是我不确定递归方法以及其他.NET/C#语法和最佳实践编程模式.简而言之，我希望最终结果尽可能优雅和高效.

The above code-snippet gives me the list that I want but I am unsure about the recursive method and other .NET/C# syntax and best practice programming patterns. Simply put, I would like the end result to be as elegant and as performant as possible.

如何改进上述代码段?

推荐答案

您本来非常优雅的代码唯一的问题是，它对存储服务的调用太多，无法获取数据.对于每个文件夹/子文件夹，它都转到存储服务并获取数据.

Only issue with your otherwise very elegant code is that it makes too many calls to storage service to fetch the data. For each folder/sub folder, it goes to the storage service and gets the data.

您可以通过列出容器中的所有blob，然后找出它是客户端上的目录还是blob来避免这种情况.例如，在此处查看以下代码(虽然您的代码不那么优雅，但希望它可以使您对我要传达的内容有所了解):

You could avoid that by list all blobs from a container and then figure out if it is a directory or blob on the client side. For example, take a look at this code here (It's not as elegant is yours but hopefully it should give you an idea about what I am trying to convey):

    static void FetchCloudBlobDirectories()
    {
        var account = new CloudStorageAccount(new StorageCredentials(accountName, accountKey), true);
        var containerName = "container-name";
        var blobClient = account.CreateCloudBlobClient();
        var container = blobClient.GetContainerReference(containerName);
        var containerUrl = container.Uri.AbsoluteUri;
        BlobContinuationToken token = null;
        List<string> blobDirectories = new List<string>();
        List<CloudBlobDirectory> cloudBlobDirectories = new List<CloudBlobDirectory>();
        do
        {
            var blobPrefix = "";//We want to fetch all blobs.
            var useFlatBlobListing = true;//This will ensure all blobs are listed.
            var blobsListingResult = container.ListBlobsSegmented(blobPrefix, useFlatBlobListing, BlobListingDetails.None, 500, token, null, null);
            token = blobsListingResult.ContinuationToken;
            var blobsList = blobsListingResult.Results;
            foreach (var item in blobsList)
            {
                var blobName = (item as CloudBlob).Name;
                var blobNameArray = blobName.Split(new string[] { "/" }, StringSplitOptions.RemoveEmptyEntries);
                //If the blob is in a virtual folder/sub folder, it will have a "/" in its name.
                //By splitting it, we are making sure that it is indeed the case.
                if (blobNameArray.Length > 1)
                {
                    StringBuilder sb = new StringBuilder();
                    //Since the blob name (somefile.png) will be the last element of this array and we're not interested in this,
                    //We only iterate through 2nd last element.
                    for (var i=0; i<blobNameArray.Length-1; i++)
                    {
                        sb.AppendFormat("{0}/", blobNameArray[i]);
                        var blobDirectory = sb.ToString();
                        if (blobDirectories.IndexOf(blobDirectory) == -1)//We check if we have already added this to our list or not
                        {
                            blobDirectories.Add(blobDirectory);
                            var cloudBlobDirectory = container.GetDirectoryReference(blobDirectory);
                            cloudBlobDirectories.Add(cloudBlobDirectory);
                            Console.WriteLine(cloudBlobDirectory.Uri);
                        }
                    }
                }
            }
        }
        while (token != null);
    }

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