Hi. I'm currently trying to use the pending_attachment API provided by Yammer (Endpoint: https://www.yammer.com/api/v1/pending_attachments).

I contacted Yammer support, and this is the code they provided me with in C#:

public static async Task<PendingAttachment> Upload(string FilePath)
    {
        byte[] byteFile = System.IO.File.ReadAllBytes(FilePath);
        FileInfo fi = new FileInfo(FilePath);
 
        PendingAttachment pa = null;
        using (var client = new HttpClient())
        {
            string token = "XXXXXXXXXXXXX";
            client.DefaultRequestHeaders.Add("Authorization", "Bearer" + token);
            using (var content = new MultipartFormDataContent("Upload----" + DateTime.Now.ToString(CultureInfo.InvariantCulture)))
            {
                content.Add(new StreamContent(new MemoryStream(byteFile)), "attachment", fi.Name);
 
                using (var message = await client.PostAsync("https://www.yammer.com/api/v1/pending_attachments", content))
                {
                    if (message.IsSuccessStatusCode)
                    {
                        var result = await message.Content.ReadAsStringAsync();
                        pa = Newtonsoft.Json.JsonConvert.DeserializeObject<PendingAttachment>(result);
                        return pa;
                    }
                }
            }
        }
        return null;
    }
 
    var FilePath = @"<FILE PATH>";
    var pa = await Upload(FilePath);
 
    MessageParam message = new MessageParam()
    {
            body = "posting attachment",
            group_id = XXXXXXX,
            pending_attachment1 = pa.id
    };
    var result = await CreateMessageAsync(message);

I tried doing this on Outsystems but to no avail. I referenced the Box File upload.

Here's the OML file: 

Attachment.oml

Can someone please help me out?