直接从 html5 上传文件到 Azure 存储容器

Question

对于我的场景，我试图允许用户使用 javascript 将文件拖放到网页，这些文件将被上传到容器，上传文件类似于 wordpress 媒体上传的工作方式行政方面。我遇到的问题是我找到了为容器创建 SAS url 的代码，

        //Set the expiry time and permissions for the container.
        //In this case no start time is specified, so the shared access signature becomes valid immediately.
        SharedAccessBlobPolicy sasConstraints = new SharedAccessBlobPolicy();
        sasConstraints.SharedAccessExpiryTime = DateTime.UtcNow.AddHours(24);
        sasConstraints.Permissions = SharedAccessBlobPermissions.Write;

        //Generate the shared access signature on the container, setting the constraints directly on the signature.
        string sasContainerToken = container.GetSharedAccessSignature(sasConstraints);

        //Return the URI string for the container, including the SAS token.
        return container.Uri + sasContainerToken;

但我发现的所有示例似乎都表明我必须为每个 blob

生成一个 sas url

        Microsoft.WindowsAzure.Storage.Blob.CloudBlobClient blobClient = storageAccount.CreateCloudBlobClient();

        //Get a reference to a container to use for the sample code, and create it if it does not exist.
        Microsoft.WindowsAzure.Storage.Blob.CloudBlobContainer container = blobClient.GetContainerReference(containerName);
        container.CreateIfNotExists();

        //Create a new stored access policy and define its constraints.
        Microsoft.WindowsAzure.Storage.Blob.SharedAccessBlobPolicy sharedPolicy = new Microsoft.WindowsAzure.Storage.Blob.SharedAccessBlobPolicy()
        {
            SharedAccessExpiryTime = DateTime.UtcNow.AddMinutes(10),
            Permissions = Microsoft.WindowsAzure.Storage.Blob.SharedAccessBlobPermissions.Write
        };

        //Get the container's existing permissions.
        Microsoft.WindowsAzure.Storage.Blob.BlobContainerPermissions permissions = container.GetPermissions();//new Microsoft.WindowsAzure.Storage.Blob.BlobContainerPermissions();

        Microsoft.WindowsAzure.Storage.Blob.CloudBlockBlob blob = container.GetBlockBlobReference(fileName);

        return blob.Uri.AbsoluteUri + blob.GetSharedAccessSignature(sharedPolicy);

而不是好像我正在上传一个文件。

管理员可以上传任意数量的文件，因此必须通过 Web api 为这些文件中的每一个调用生成 blob sas 似乎效率很低。我更愿意为容器生成一个 SAS，并允许用户在指定的时间（比如 3 小时）内上传到该容器。另外，我想使用分块来上传每个文件。这是可能的还是我必须为每个文件生成一个 blob sas url？

Answer 1

An administrator can upload any number of files, so to have to generate a blob sas via web api call for each one of these files seems to be very inefficient. I would prefer to generate a SAS for the container and allow the user to upload to that container for a specified time, say 3 hours.

当然可以。当您在具有 Write 权限（用于上传目的）的 blob 容器上创建 SAS 时，同样可用于在该容器中上传多个 blob。您只需根据正在上传的文件构建 blob URI 并附加 SAS 令牌。因此，例如，您在 myaccount 存储帐户中为 mycontainer 容器创建了一个 SAS 令牌并上传了一个文件 myfile.png，您的 SAS URL 将是 https://myaccount.blob.core.windows.net/mycontainer/myfile.png?SAS-Token。

我在您的代码中注意到您正在返回带有 SAS 令牌的容器 URI。在这种情况下，您只需在容器名称后插入文件名即可获取 blob 上传 URI。

Also, I would like to use chunking to upload each file.

又是可能的。前段时间我写了一些关于这个的博客 posts，你可能会发现它们有用：

http://gauravmantri.com/2013/02/16/uploading-large-files-in-windows-azure-blob-storage-using-shared-access-signature-html-and-javascript/（这是在 Azure 存储支持 CORS 之前写的，所以请忽略我在 post 中关于 CORS 的评论）。

http://gauravmantri.com/2013/12/01/windows-azure-storage-and-cors-lets-have-some-fun/

直接从 html5 上传文件到 Azure 存储容器

Uploading files to Azure storage container from html5 directly

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