Express middleware using loopback 4 models

[BillyCottrell]

Hi there,

I am currently developing a service that is responsible to communicate with Microsoft Graph, which uses passport to serialize and deserialize the user. Problem is that I need to find the user from my MongoDB database, in loopback 3 this was possible by doing "server.models.User".

What about loopback 4, how can we access this model, do I need to do a call to one of my loopback paths or can I easily access this model using a different method?

Any ideas on this?

Thanks in advance!

PS: This is the code I'm trying to convert from loopback 3 to loopback 4:

'use strict';
const express = require('express');
const erouter = require('express').Router();
var session = require('express-session');
var passport = require('passport');
var OIDCStrategy = require('passport-azure-ad').OIDCStrategy;
const request = require('request');
var querystring = require('querystring');
const graph = require('./graph.service');
const getBookings = require('./getBookings.service');
const cors = require('cors');
var compression = require('compression');

module.exports = function(server) {
    // Install a `/` route that returns server status
    var router = server.loopback.Router();
    router.get('/', server.loopback.status());

    // Configure simple-oauth2
    const oauth2 = require('simple-oauth2').create({
        client: {
            id: process.env.OAUTH_APP_ID,
            secret: process.env.OAUTH_APP_PASSWORD
        },
        auth: {
            tokenHost: process.env.OAUTH_AUTHORITY,
            authorizePath: process.env.OAUTH_AUTHORIZE_ENDPOINT,
            tokenPath: process.env.OAUTH_TOKEN_ENDPOINT
        }
    });

    passport.serializeUser(function(user, done) {
        var MSUser = server.models.MSUser;
        var id = user.profile.oid;
        MSUser.find({ where: { oid: id } }, function(err, msu) {
            if (err) return done(err, null);
            if (!msu) {
                MSUser.create(user);
            } else {
                done(null, id);
            }
        });
    });

    passport.deserializeUser(function(id, done) {
        var MSUser = server.models.MSUser;
        MSUser.findById(id, function(err, user) {
            if (err) return next(err);
            done(null, user);
        });
    });


    async function signInComplete(iss, sub, profile, accessToken, refreshToken, params, done) {
        if (!profile.oid) {
            return done(new Error("No OID found in user profile."), null);
        }
        try {
            const user = await graph.getUserDetails(accessToken);
            if (user) {
                profile['email'] = user.mail ? user.mail.toLowerCase() : user.userPrincipalName.toLowerCase();
            }
        } catch (err) {
            done(err, null);
        }
        let oauthToken = oauth2.accessToken.create(params);
        var AuthUser = server.models.AuthUser;
        var user = {};
        AuthUser.find({ where: { email: profile['email'] } }, function(err, au) {
            if (err) return done(err, null);
            if (au.length != 1) return done(new Error("User was not found with that email address."), null);
            user = au[0];
            const dataMsAuth = querystring.stringify({
                "created": new Date().toDateString(),
                "token_type": oauthToken.token.token_type,
                "expires_in": oauthToken.token.expires_in,
                "access_token": oauthToken.token.access_token,
                "scope": oauthToken.token.scope,
                "ext_expires_in": oauthToken.token.ext_expires_in,
                "refresh_token": oauthToken.token.refresh_token,
                "id_token": oauthToken.token.id_token,
                "expires_at": new Date(oauthToken.token.expires_at).toDateString()
            });
            const postMSAuth = {
                url: process.env.API_URL + "api/Companies/" + user.companyId + "/msauth",
                method: 'POST',
                body: dataMsAuth,
                headers: {
                    'Content-Type': 'application/x-www-form-urlencoded'
                }
            }
            request(postMSAuth, function(err, resp, body) {
                if (err) return done(err, null);
                var MSUser = server.models.MSUser;
                var id = profile.oid;
                var msuser = { profile, oauthToken, oid: id, email: profile.email }
                MSUser.findById(id, function(err, msu) {
                    if (err) return done(err, null);
                    if (!msu) {
                        MSUser.create(msuser);
                    }
                });
                return done(null, msuser);
            });
        });
    }

    passport.use(new OIDCStrategy({
            identityMetadata: `${process.env.OAUTH_AUTHORITY}${process.env.OAUTH_ID_METADATA}`,
            clientID: process.env.OAUTH_APP_ID,
            responseType: 'code id_token',
            responseMode: 'form_post',
            redirectUrl: process.env.OAUTH_REDIRECT_URI,
            allowHttpForRedirectUrl: true,
            clientSecret: process.env.OAUTH_APP_PASSWORD,
            validateIssuer: false,
            passReqToCallback: false,
            scope: process.env.OAUTH_SCOPES.split(' ')
        },
        signInComplete
    ));

    var app = express();
    app.use(compression());
    app.use(session({
        secret: process.env.BOOKINGS_LOOPBACK_SECRET,
        resave: false,
        saveUninitialized: false,
        unset: 'destroy'
    }));
    app.use("/result", express.static('client'));

    app.use(passport.initialize());
    app.use(passport.session());
    app.use(cors({
        origin: '*'
    }));

    erouter.get('/API/bookings/:companyid', getBookings());

    erouter.get('/auth/signin',
        function(req, res, next) {
            passport.authenticate('azuread-openidconnect', {
                response: res,
                prompt: 'login',
                state: req.query.state,
                failureRedirect: process.env.WEBSITE_URL + 'settings?error=incorrect_request',
                successRedirect: process.env.WEBSITE_URL + 'settings?auth=success'
            })(req, res, next);
        }
    );

    erouter.post('/auth/callback',
        function(req, res, next) {
            passport.authenticate('azuread-openidconnect', {
                response: res,
                failureRedirect: process.env.WEBSITE_URL + 'settings?error=permission_denied',
                successRedirect: process.env.WEBSITE_URL + 'settings?auth=success'
            })(req, res, next);
        }
    );

    app.use(erouter);
    server.use(app);
    server.use(router);
};