callback function

callback.js

app.get('/callback', function (req, res) {
	/* Retrieve authorization code from request */
	let code = req.query.code;
	let requestId = req.query.state;

	/* Set options with required paramters */
	let requestOptions = {
		uri: `https://api.dropboxapi.com/oauth2/token?grant_type=authorization_code&code=${code}&client_id=${dropboxApiKey}&client_secret=${dropboxApiSecret}&redirect_uri=${publicUrl}/callback`,
		method: 'POST',
		json: true
	}

	/* Send a POST request using the request library */
	request(requestOptions)
		.then(function (response) {
			/* Store the token in req.session.token */
			req.session.token = response.access_token;

			/* Simulating writing to a database */
			requestIds[requestId]["accessToken"] = response.access_token;
			res.send('Authentication successful. You can close this tab');
		})
		.catch(function (error) {
			res.json({ 'response': 'Log in failed!' });
		});
})