值不能为null。 （参数; sharedKeykeyCredential;）

Question

我们正在从V11迁移代码以使用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，请获取以下提到的例外。
异常：“值不能为null。（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

您还可以使用所谓的用户代表团键为广告验证（包含托管服务身份）用户创建SAS URI。

从这里阅读更多：
创建一个用户代表团SAS对于带有.NET的容器，目录或BLOB

示例代码（从上面的链接缩写）：

var blobServiceClient = blobClient
    .GetParentBlobContainerClient()
    .GetParentBlobServiceClient();

var userDelegationKey = await blobServiceClient
    .GetUserDelegationKeyAsync(DateTimeOffset.UtcNow, DateTimeOffset.UtcNow.AddDays(7));

var sasBuilder = new BlobSasBuilder()
{
    BlobContainerName = blobClient.BlobContainerName,
    BlobName = blobClient.Name,
    Resource = "b",
    StartsOn = DateTimeOffset.UtcNow,
    ExpiresOn = DateTimeOffset.UtcNow.AddDays(7)
};

sasBuilder.SetPermissions(BlobSasPermissions.Read);

var blobUriBuilder = new BlobUriBuilder(blobClient.Uri)
{
    Sas = sasBuilder.ToSasQueryParameters(
            userDelegationKey, 
            blobServiceClient.AccountName)
};

var uri = blobUriBuilder.ToUri();

请注意，用户代表键不能像共享键一样长。我认为UDK的最高持续时间是几天或几周的规模，而您可以使用几个月的SAS URL，并带有共享键。

Answer 2

托马斯指出了这一问题的原因。代码中最好处理的最好是检查您的blobclinet是否能够使用 cangenerate> cangeneratesasulate

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;
    }