CODEWITHSUNDEEP
c#azureazure-storagebotframeworkazure-blob-storage
bertonc96
bertonc96

Reputation: 826

Save attachment in blob container - bot framework

I'm using Azure Storage to log the conversations between my bot and the users. I want to store the attachments the user sends inside an Azure Blob Container. I'm using the ContentUrl attributin this way:

foreach (Attachment item in message.Attachments)
        {
            /// creo una sottodirectory in cui verranno salvate tutte le immagini con quel conversation Id, quindi di quella conversazione
            CloudBlockBlob targetBlob = _alturasbotChatAttachmentBlobsContainer.GetBlockBlobReference("conv#" + message.Conversation.Id.ToLower() + "/" + item.Name);

            /// carico il file dall'url datomi dall'utente
            try
            {
                await targetBlob.StartCopyAsync(new Uri(item.ContentUrl));
            }
            catch (Exception e)
            {
                throw;
            }
        }

The problem is that inside the try-catch an exception is thrown if the url is not an absolute one (for example everything works if I insert a image url from google instead of the contentUrl). Maybe the ContentUrl is not usable in this way because it is a local address. There is a way to solve the problem? Do I have to use the Content attribute (if so, how?). Thanks

Upvotes: 0

Views: 1127

Answers (3)

bertonc96
bertonc96

Reputation: 826

Thanks to who replied. In the end I've found out that the Content of the attachment is null so I've to use a HttpClient for downloading the content and then I've uploaded the file on Azure Blob Container. Now it works. For the most curious:

using (HttpClient client = new HttpClient())
                {
                    using (HttpResponseMessage response = await client.GetAsync(item.ContentUrl))
                    using (Stream streamToReadFrom = await response.Content.ReadAsStreamAsync())
                    {
                        await targetBlob.UploadFromStreamAsync(streamToReadFrom);
                    }
                }

Upvotes: 2

Gaurav Mantri
Gaurav Mantri

Reputation: 136336

Part answer to your problem (because I haven't worked with Bot framework).

Essentially copy blob operation requires the source item's URL should be publicly accessible as copy operation is an asynchronous server-side operation and Azure Storage should be able to read from source once a request to copy blob has been submitted. That's why your code worked when you took a URL from google and used that instead of ContentUrl of the attachment.

Since I have not worked with Bot framework (thus I will be purely speculating), one thing you could do is read the content of attachment you're trying to save in your code as a stream (not sure how you would do that) and then use CloudBlockBlob.UploadFromStream method to upload the blob.

Upvotes: 3

Dave Anders
Dave Anders

Reputation: 847

If you read API reference it says directly that CloudBlockBlob does everything using an absolute URI to the blob.

You can find the URI in CloudBlob.StorageUri Property

https://learn.microsoft.com/en-gb/dotnet/api/microsoft.windowsazure.storage.blob.cloudblockblob?view=azure-dotnet

Upvotes: 0

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