c# - 值不能为空。 (参数 'sharedKeyCredential')当我们尝试使用V12的GenerateSasUri()方法创建SAS Uri时

Question

我们正在将代码从 V11 迁移到使用 azure storage v12 客户端库 (Azure.Storage.Blobs 12.12.0)。当我们尝试使用GenerateSasUri()方法创建SAS Uri时，出现下面提到的异常。
异常:“值不能为空。(参数'sharedKeyCredential')”

this.blobContainerClient = new BlobContainerClient(
                new Uri($https://{storageAccountName}.blob.core.windows.net/{containerName}),
                new ManagedIdentityCredential(managedIdentityAppId));

var blobClient = blobContainerClient.GetBlobClient(blobName);

            BlobSasBuilder sasBuilder = new()
            {
                BlobContainerName = containerName,
                BlobName = blobName,
                Resource = "b", 
                StartsOn = DateTime.UtcNow.AddMinutes(-15),
                ExpiresOn = expirationTimeUtc
            };
            sasBuilder.SetPermissions(requestedPermission);            

            return blobClient.GenerateSasUri(sasBuilder);

Answer 1

Thomas指出了这个问题的原因。在代码中最好处理的是检查您的 blobclinet 是否能够使用 CanGenerateSasUri 创建 sas。

this.blobContainerClient = new BlobContainerClient(
                new Uri($https://{storageAccountName}.blob.core.windows.net/{containerName}),
                new ManagedIdentityCredential(managedIdentityAppId));

var blobClient = blobContainerClient.GetBlobClient(blobName);

    // Check whether this BlobClient object has been authorized with Shared Key.
    if (blobClient.CanGenerateSasUri)
    {
        
            BlobSasBuilder sasBuilder = new()
            {
                BlobContainerName = containerName,
                BlobName = blobName,
                Resource = "b", 
                StartsOn = DateTime.UtcNow.AddMinutes(-15),
                ExpiresOn = expirationTimeUtc
            };
            sasBuilder.SetPermissions(requestedPermission);            

            return blobClient.GenerateSasUri(sasBuilder);
    }
    else
    {
        Console.WriteLine(@"BlobClient must be authorized with Shared Key 
                          credentials to create a service SAS.");
        return null;
    }