Respond to a bot call in Microsoft Teams with Graph API

Question

I trying to respond to a call in Teams but actually I'm not getting a respond from the bot.

First I get access_token from Graph API.

Then I have a route that intercept bot calls.

app.post("/api/call", function(req, res) {
  if (j === 1) {
    j = j + 1;
    res.status(204).send();
  } else {
    var answerbody = {
      callbackUri: "https://8a73b7ad.ngrok.io/api/call",
      acceptedModalities: ["audio"],
      mediaConfig: {
        "@odata.type": "#microsoft.graph.serviceHostedMediaConfig",
        preFetchMedia: [
          {
            uri: "https://cdn.contoso.com/beep.wav",
            resourceId: "1D6DE2D4-CD51-4309-8DAA-70768651088E"
          },
          {
            uri: "https://cdn.contoso.com/cool.wav",
            resourceId: "1D6DE2D4-CD51-4309-8DAA-70768651088F"
          }
        ]
      }
    };
    POST(
      "https://graph.microsoft.com/beta/" + req.body.resource + "/answer",
      answerbody
    )
      .then(
        data => console.log(data) // I get undefined
      )
      .catch(function(err) {
        console.log("err   " + err);
        res.status(200).send();
      });
  }
});

Here's POST function

function POST(url, BB) {
  return new Promise(function(resolve, reject) {
    var options = {
      url: url,
      method: "POST",
      headers: {
        Accept: "application/json",
        Authorization: "Bearer " + token
      },
      body: BB,
      json: true
    };
    request(options)
      .then(function(body) {
        resolve(body);
      })
      .catch(function(err) {
        reject(err);
      });
  });
}

As mentionned in documentation , Server sould first reply 204 in order to get response in Graph API protocol.

Actually I don't get a response. Bot still ringing until It gets voice message : " You can't talk to the bot just yet , we are working on it".

As mentioned in Teams API documentation, I should get callback with the ressource id and other information to be able to answer to the call.

So I use my POST function to answer. but here I don't get any 202 Accepted response as indicated in docs, instead I get more than one callback with different ressource ids, then after some seconds I get the voice message.

Answer 1

The solution is to change acceptedModalities: ["audio"] to acceptedModalities: ["Audio"]