How to Upload to Azure Blob Storage using SAS Token, via Dynamics 365 Plugin

Adam Murchison, 28 October 2020

When writing code for Dynamics 365 online plugins, you are limited to assemblies you can use within the sandbox. Luckily you can use the HTTPClient, which allows you to upload a file to an Azure Blob Storage Container without using any of the Azure Blob Storage Nuget Packages found here. This blog will show you how to achieve this while using a SAS (shared access signature), you can find more information on SAS tokens here.

To do this, you will need your SAS token as mentioned above and a Blob Storage Container setup. My URL for the blob container is, ‘https://example.blob.core.windows.net/test-container’ while my SAS token example is ‘sv=2019-12-12&ss=b&srt=o&sp=rwdlacx&se=2025-10-08T06:00:03Z&st=2020-10-07T22:00:03Z&spr=xxxxx’.

Let’s say you want to upload a file ‘test.txt’ to your blob storage container using the SAS token above. The request URL is broken down like this:

Blob Storage Authenticated URL structure: {blobStorageUrl}/{blobContainer}/{fileName}?{sasToken}

Blob Storage Authenticated URL: https://example.blob.core.windows.net/test-container/test.txt?sv=2019-12-12&ss=b&srt=o&sp=rwdlacx&se=2025-10-08T06:00:03Z&st=2020-10-07T22:00:03Z&spr=xxxxx

To use this authenticated URL code, you simply pass the byteArray of the file you want to upload with the mimeType within the ‘Content-Type’ header and viola! You have successfully uploaded your file into the blob storage. Now check out the code below:

            byte[] dataByteArray = Convert.FromBase64String(base64Data);
            string blobAuthenticatedPath = "https://example.blob.core.windows.net/test-container/test.txt?sv=2019-12-12&ss=b&srt=o&sp=rwdlacx&se=2025-10-08T06:00:03Z&st=2020-10-07T22:00:03Z&spr=xxxxx";
            Uri blobUri = new Uri(blobAuthenticatedPath);

            try
            {
                using (HttpClient client = new HttpClient())
                {
                    var content = new StreamContent(new MemoryStream(dataByteArray));
                    content.Headers.Add("x-ms-blob-type", "BlockBlob");
                    string mimeType = "text/plain";
                    content.Headers.Add("Content-Type", mimeType);
                    var response = client.PutAsync(blobUri, content).Result;

                    if (!response.IsSuccessStatusCode)
                    {
                        throw new InvalidPluginExecutionException("Put request wasn't a success.");
                    }
                }
            }
            catch (Exception e)
            {
                throw new InvalidPluginExecutionException("Your file upload wasn't successful.");
            }

This is a simple example of how to upload any file to a blob storage container. To access the file you simply use the URL without the sasToken, i.e. https://example.blob.core.windows.net/test-container/test.txt. I hope this helps when you’re working with Azure Blob Storage in Dynamics 365.