Download raw content of email attachment using Microsoft Graph SDK

Is there a method that allows to download the email attachment content bytes using the SDK?

Basically, it should just append /$value the request URL according to https://learn.microsoft.com/en-us/graph/api/attachment-get?view=graph-rest-1.0&tabs=csharp#example-6-get-the-raw-contents-of-a-file-attachment-on-a-message , but I don't see such feature in SDK

The closest I could get is

await graphClient.Users[userId].Messages[messageId].Attachments[attachmentId].GetAsync()

I would expect Attachments[attachmentId].Content.GetAsync() or something

Microsoft.Graph 5.13.0

It's still not supported by SDK v5 to download message's attachment. The workaround can be

var requestInfo = graphClient.Users["{user_id}"]
                             .Messages["{message_id}"]
                             .Attachments["{attachment_id}"]
                             .ToGetRequestInformation();
requestInfo.UrlTemplate = requestInfo.UrlTemplate
                           .Insert(requestInfo.UrlTemplate.LastIndexOf('{'), "/$value");
var attachmentStream = await graphClient.RequestAdapter.SendPrimitiveAsync<Stream>(requestInfo);

I could not find a snippet to do it via SDK, so I wrote my own by combining Graph client and custom HttpClient calls.

AttachmentsRequestBuilder GetAttachmentsList(string id) =>
    graphClient.Users[userId].Messages[id].Attachments;

var attachmentList = await GetAttachmentsList(messageId)
    .GetAsync(cancellationToken: cancellationToken);

if (attachmentList?.Value != null)
{
    foreach (var attachmentItem in attachmentList.Value)
    {
        var attachmentRequest = GetAttachmentsList(messageId)[attachmentItem.Id];
        var getRequestInfo = attachmentRequest.ToGetRequestInformation();
        var attachmentUri = getRequestInfo.URI + "/$value";

        using var client = httpClientFactory.CreateClient();

        client.DefaultRequestHeaders.Authorization =
            new AuthenticationHeaderValue("Bearer", await GetToken());
        var response = await client.GetAsync(attachmentUri, cancellationToken);

        var file = await response.Content.ReadAsByteArrayAsync(cancellationToken);
    }
}

GetToken method

private async Task<string> GetToken()
{
    using var client = httpClientFactory.CreateClient();

    var @params = new Dictionary<string, string>()
    {
        { "client_id", clientId },
        { "client_secret", clientSecret },
        { "scope", "https://graph.microsoft.com/.default" },
        { "grant_type", "client_credentials" },
    };

    var response = await
        client.PostAsync($"https://login.microsoftonline.com/{tenantId}/oauth2/v2.0/token",
            new FormUrlEncodedContent(@params));

    response.EnsureSuccessStatusCode();

    using var sr = new StreamReader(await response.Content.ReadAsStreamAsync());
    var body = await sr.ReadToEndAsync();
    var jobject = JObject.Parse(body);

    return jobject["access_token"]!.ToString();
}