Question

我有一个azure函数，它将文件下载到临时文件路径，然后将临时文件保存到blob。我有两个问题：

1）是否有办法管理该功能创建的临时文件 Path.GetTempFileName（）。即在函数范围之后删除临时文件名？

2）将文件从网址下载到blob是否有更好的做法？

var filename = Path.GetTempFileName();
WebClient myWebClient = new WebClient();
myWebClient.DownloadFile(url, filename);
using (var fileStream = System.IO.File.OpenRead(filename))
{
    blob.UploadFromStream(fileStream);
}

Answer 1

更有效的方法是将URL内容直接流式传输到blob流，而不是下载到本地文件系统。像这样：

HttpWebRequest request = HttpWebRequest.CreateHttp(url);
using (WebResponse response = await request.GetResponseAsync())
using (Stream dataStream = response.GetResponseStream())
{
    await blob.UploadFromStreamAsync(dataStream);
}

Answer 2

实际上，您可以通过CloudBlob.StartCopy直接从源URL执行服务器端副本，而不是下载然后下载：

var account = new CloudStorageAccount(new StorageCredentials(accountName, accountKey), true);
var blobClient = account.CreateCloudBlobClient();
var blobContainer = blobClient.GetContainerReference(destinationContainer);
blobContainer.CreateIfNotExists();
var newBlockBlob = blobContainer.GetBlockBlobReference(newFileName);
newBlockBlob.StartCopy(new Uri(sourceUrl));

// Monitor the copy state
while (true)
{
    newBlockBlob.FetchAttributes();
    Console.WriteLine("Copy state: {0}", newBlockBlob.CopyState);
    if (newBlockBlob.CopyState.Status != CopyStatus.Pending)
    {
        break;
    }

    Thread.Sleep(waitTime);
}

从url下载文件并保存到blob

2 个答案: