Downloading from Blob Azure redirects wrong

Question

When I press download and call this action, I get the result

The resource you are looking for has been removed, had its name changed, or is temporarily unavailable.

and directed to

http://integratedproject20170322032906.azurewebsites.net/MyDocumentUps/Download/2020Resume.pdf

Why does it link to above and not to

https://filestorageideagen.blob.core.windows.net/documentuploader/2020Resume.pdf

as shown in the controller?

Here is my actionlink in the view

@Html.ActionLink("Download", "Download", "MyDocumentUps", new { id = item.DocumentId.ToString() + item.RevisionId.ToString() + item.Attachment }, new { target="_blank"}) |

public ActionResult Download(string id)
        {

            string path = @"https://filestorageideagen.blob.core.windows.net/documentuploader/";

            return View(path + id);

        }

score 2 · Answer 1 · edited May 23 '17 at 12:25

I can think of 2 ways by which you can force download a file in the client browser.

Return aFileResultorFileStreamResultfrom your controller. Here's an example of doing so: How can I present a file for download from an MVC controller?. Please note that this will download the file first on your server and then stream the contents to the client browser from there. For smaller files/low load this approach may work but as your site grows or the files to be downloaded becomes bigger in size, it will create more stress on your web server.
Use a Shared Access Signature (SAS) for the blob with Content-Disposition response header set. In this approach you will simply create a SAS token for the blob to be downloaded and using that create a SAS URL. Your controller will simply return a RedirectResult with this URL. The advantage with this approach is that all the downloads are happening directly from Azure Storage and not through your server.

When creating SAS, please ensure that

You have at least Read permission in the SAS.
Content-Disposition header is overridden in the SAS.
The expiry of SAS should be sufficient for the file to download.

Here's the sample code to create a Shared Access Signature.

        var sasToken = blob.GetSharedAccessSignature(new SharedAccessBlobPolicy()
        {
            Permissions = SharedAccessBlobPermissions.Read,
            SharedAccessExpiryTime = DateTime.UtcNow.AddHours(1),

        }, new SharedAccessBlobHeaders()
        {
            ContentDisposition = "attachment;filename=" + blob.Name
        });
        var blobUrl = string.Format("{0}{1}", blob.Uri.AbsoluteUri, sasToken);
        return Redirect(blobUrl);

P.S. While I was answering the question, the question got edited so the answer may seem a bit out of whack :) :).

Milen · Answer 2 · 2017-03-27T13:53:52.923

1

Given that you have the image url as part of your Model and blob has no restrictions:

<img src=@Model.YourImageUri>

var image = new BitmapImage(new Uri("https://your_storage_account_name.blob.core.windows.net/your_container/your_image.jpg"));

edited Mar 27 '17 at 13:53

answered Mar 27 '17 at 13:45

Milen

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What are you talking about, image url? – Captain Canada Mar 27 '17 at 13:47
When you save a file (for example image) to blob storage you get a url of the saved file, you can use it to access your image.. – Milen Mar 27 '17 at 13:50
Where is the url saved? – Captain Canada Mar 27 '17 at 13:53
Useful article that goes in to a bit more detail: https://learn.microsoft.com/en-us/azure/storage/storage-dotnet-how-to-use-blobs – Milen Mar 27 '17 at 13:54
the link you gave is pretty much what I have and doesn't explain anymore than I already know – Captain Canada Mar 27 '17 at 14:46
I have changed my question, could you take another look? – Captain Canada Mar 27 '17 at 15:30

Downloading from Blob Azure redirects wrong

2 Answers2