Downloading an attachment from Teams across a Bot Nodejs - botframework

Question

I'm facing the following error when I try to get the attachment in Microsoft Teams with Bot Builder v4:
{"message":"Authorization has been denied for this request."}
everything works fine with the version 3, as far as I know in Teams is necessary a token in order get the binary array of the file.
In the v3 I'm able to get the jwt token in this way:
connector.getAccessToken.bind(connector)
and then I use it in the header of the GET request =>
headers: {
'Authorization': 'Bearer ' + token,
'Content-Type': 'application/octet-stream'
}
In the v4:
context.adapter.getUserToken(step.context, CONNECTION_SETTING_NAME);
is there another way to get a valid token in the v4?

Answer 1

To get the token just call the prompt again. You can find the auth sample here for node. The sample happens to use a waterfall dialog, which may not be needed in your case
let prompt = await step.prompt(OAUTH_PROMPT);
If the token is valid and not expired you can get the token like below, if the token is not valid or the user does not have a token they will be prompted to log in. Otherwise the token will be in the prompt result.
var tokenResponse = prompt.result;
if (tokenResponse != null) {
await step.context.sendActivity(`Here is your token: ${ tokenResponse.token }`);
}
These comments from the sample should help explain
// Call the prompt again because we need the token. The reasons for this are:
// 1. If the user is already logged in we do not need to store the token locally in the bot and worry
// about refreshing it. We can always just call the prompt again to get the token.
// 2. We never know how long it will take a user to respond. By the time the
// user responds the token may have expired. The user would then be prompted to login again.
//
// There is no reason to store the token locally in the bot because we can always just call
// the OAuth prompt to get the token or get a new token if needed.

Answer 2

these are the steps
/**
* WaterfallDialogStep to process the user's picture.
* #param {WaterfallStepContext} step WaterfallStepContext
*/
async processPhotoStep(step) {
await this.writeLogInTheStorage('Start downloading picture....');
await this.handleIncomingAttachment(step);
return await step.endDialog();
};
/**
* responds to the user with information about the saved attachment or an error.
* #param {Object} turnContext
*/
async handleIncomingAttachment(step) {
// Prepare Promises to download each attachment and then execute each Promise.
const attachment = step.context.activity.attachments[0];
const tokenIsRequired = await this.checkRequiresToken(step.context);
const dc = await this.dialogs.createContext(step.context);
const token = await dc.beginDialog(LOGIN_PROMPT); //await step.context.adapter.getUserToken(step.context, CONNECTION_SETTING_NAME);
let file = undefined;
if (tokenIsRequired) {
file = await this.downloadAttachment(token.result.token, attachment.contentUrl);
}
else {
file = await requestX(attachment.contentUrl);
}
await OAuthHelpers.postPhoto(step.context, token.result, file);
}
async downloadAttachment(token, url) {
const p = new Promise((resolve, reject) => {
request({
url: url,
headers: {
'Authorization': 'Bearer ' + token,
'Content-Type': 'application/octet-stream'
}
}, async function (err, response, body) {
const result = body
if (err) {
console.log(err);
//await this.writeLogInTheStorage('err 1 : ' + err);
reject(err);
} else if (result.error) {
console.log(result.error);
//await this.writeLogInTheStorage('err 2 : ' + err);
reject(result.error.message);
} else {
// The value of the body will be an array.
console.log(result);
//await this.writeLogInTheStorage('success : ' + result);
resolve(result);
}
});
});
return p;
}