Rest API attachment error

Question

I've problems sending attachments through a Skype channel using the bot framework REST API.

I'm able to correctly send images using a json message like this:

{  
   "type":"message",
   "timestamp":"2017-05-22T11:31:36.2281894Z",
   "from":{  
      "name":"MyBot"
   },
   "recipient":{  
      "id":"29:1-Dl1xMx6G2qGya5O5BgTZJhc0fUKOiQLctt74CmwJ3PVJNgkocpf3LY626py9UIO"
   },
   "text":"It works!",
   "attachments": [
        {
            "contentType": "image/jpg",
            "contentUrl": "https://g87a2173.ngrok.io/content/attachments/65f2be10-e61e-424e-9ea1-e05f1002fd19",
            "name": "image.jpg"
        }
    ]
}

But if I send files with any content type other than image I have an error.

For example, if I send

{  
   "type":"message",
   "timestamp":"2017-05-22T11:31:36.2281894Z",
   "from":{  
      "name":"MyBot"
   },
   "recipient":{  
      "id":"29:1-Dl1xMx6G2qGya5O5BgTZJhc0fUKOiQLctt74CmwJ3PVJNgkocpf3LY626py9UIO"
   },
   "text":"Not working!",
   "attachments": [
        {
            "contentType": "audio/wav",
            "contentUrl": "https://g87a2173.ngrok.io/content/attachments/e58bcefa-7060-464f-96ee-78d2795ec80f",
            "name": "audio.wav"
        }
    ]
}

I get a 400 error

{
    "error": {
        "code": "BadArgument",
        "message": "Unknown attachment type"
    }
}

The rest endpoint used for these tests is https://smba.trafficmanager.net/apis/v3/conversations/29%3A1-Dl1xMx6G2qGya5O5BgTZJhc0fUKOiQLctt74CmwJ3PVJNgkocpf3LY626py9UIO/activities

The API reference documentation states that

An attachment may be a media file (e.g., audio, video, image, file) or a rich card

so where am I wrong?

Thank you

Nicolas R · Accepted Answer · 2017-06-07T16:02:09.253

1

I tried the same with C# code and got the same conclusion: on Skype Channel, we got an Unknown attachment type exception for this. Working on emulator and Slack (got a link to download the wav file)

There must be a channel limitation yes, or a bug.

Anyway you may try to use AudioCard: I tested it (in C# code) and it's working on Skype:

Sample code here: https://github.com/Microsoft/BotBuilder-Samples/tree/master/CSharp/cards-RichCards

edited Jun 07 '17 at 16:02

answered Jun 06 '17 at 13:13

Nicolas R

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Same error. I've tried several contentType. It seems to accept only `image*`, `video*` and the various `application/vnd.microsoft.card.*`. Could it be a channel limitation? – Francesco Maria Milizia Jun 07 '17 at 15:07
I edited my answer with more tests and a possible solution – Nicolas R Jun 07 '17 at 16:02
@FrancescoMariaMilizia was that useful? – Nicolas R Jun 14 '17 at 11:42
Yes, thank you. Unfortunately I have to send other kind of files (like pdf) so the AudioCard does not fit my needs, but I appreciated your help. – Francesco Maria Milizia Jun 15 '17 at 12:34
If it was helpul in this context please validate the answer. If you have other problems, post another question ;) – Nicolas R Jun 15 '17 at 12:35

score 0 · Answer 2 · answered May 04 '20 at 21:51

The best general solution I've found is to send an Adaptive card with an AdaptiveOpenUrlAction pointing at the URI of the file, like so:

var card = new AdaptiveCard("1.0");
card.Actions.Add(new AdaptiveOpenUrlAction{
  Title = "myDocument.docx",
  Url = "https://example.com/documents/myDocument.docx"
});
var attachment = new Attachment(AdaptiveCard.ContentType, content:card);

Rest API attachment error

2 Answers2

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