auth0 get users endpoint invocation server side (trusted server)

getUser.js

function getManagementApiToken() {
    const cachedToken = cache.get('managementApi');
    if (cachedToken) {
        return Promise.resolve(cachedToken);
    } else {
        return request.post({
            url: `https://${process.env.AUTH0_DOMAIN}/oauth/token`,
            body: {
                client_id: process.env.CLIENT_ID,
                client_secret: process.env.CLIENT_SECRET,
                audience: `https://${process.env.AUTH0_DOMAIN}/api/v2/`,
                grant_type: 'client_credentials'
            },
            json: true
        }).then(apiResponse => {
            // Tokens should be cached based on the expires_in response from Auth0,
            // but this is not currently implemented for client credentials. Instead,
            // we hardcode the expiration time configured in the dashboard, because
            // we cannot depend on the contents of this token for anything.
            cache.put('managementApi', apiResponse.access_token, 86400 * 1000);
            return apiResponse.access_token;
        });
    }
}

// Given a user ID, fetches the full user profile from the Auth0 Management API.
// This request is authenticated with client credentials, and tokens are stored
// in an in-memory cache.
function getUser(id) {
    return getManagementApiToken().then(token => {
        return request.get({
            url: `https://${process.env.AUTH0_DOMAIN}/api/v2/users/${id}`,
            headers: {
                Authorization: `Bearer ${token}`
            },
            json: true
        });
    });
}