我有一个 SAS 令牌,它将在 2 分钟内到期。
SAS = AzureClient.GetCloudContainer().GetSharedAccessSignature(new SharedAccessPolicy()
{
SharedAccessExpiryTime = DateTime.UtcNow + TimeSpan.FromMinutes(1)
}, "readonly");
var sasCreds = new StorageCredentialsSharedAccessSignature(SAS);
CloudStorageAccount _storageAccount = AzureClient.GetCloudStorageAccount();
CloudBlobClient sasBlobClient = new CloudBlobClient(_storageAccount.BlobEndpoint, sasCreds);
CloudBlob sasBlob = sasBlobClient.GetBlobReference("blobname");
其中 readonly 是策略名称。
现在我正在执行以下操作:
using (BlobStream stream = sasBlob.OpenRead())
{
using (FileStream fileStream = File.OpenWrite(@"Smething.txt"))
{
BlobStreamReader(stream,fileStream);
}
}
private void BlobStreamReader(BlobStream blob,Stream OutputStream)
{
int buffersize = 4194304; // 4MB
byte[] data = new byte[buffersize];
do
{
int bytesRead = blob.Read(data,0,buffersize);
if (bytesRead == 0) break;
OutputStream.Write(data,0,bytesRead);
}
while (true);
}
问题是 SAS 过期时下载失败。我的理解是,SAS 令牌仅用于身份验证,如果在到期时间开始下载,那么即使 SAS 到期,下载也会继续。