Develop Reference

How to modularize Javascript authentication code in MFE context in a VueJS

I'm working on a large,single-page VueJS application that's been broken down into several micro front-ends, and I'm currently implementing the authentication for communication with the orchestration layer and it's stumping me. The application is organized as a container application that bootstraps and mounts several other VueJS applications underneath it using single-spa
We use Azure-AD and the MSAL library for authentication and to refresh the Bearer token before each API request, and currently the application I'm working had previously stored the AD client info itself and created the authenticationContext on initialization, something like
export class Authentiation {
authenticationContext;
refreshToken;
constructor() {
this.authenticationContext = new msal.PublicClientApplication(msalConfig)
// code to initialize the
}
async acquireToken() {
// code which refreshes the token
}
}
Now, the initial authentication code has been moved into the container application since it will authenticate the user first and only then mount the apps once the user is inside. Each application, though, needs to be able to refresh the Bearer token whenever it communicates with its OL layer. Currently, it's just running the initialization again and pulling the AuthenticationContext out of local storage using the supplied keys
The goal is to modify it so that a the authentication context from the container is passed down to whatever application is being mounted up, without the need to store the AD client and context information in the app itself
What's required is that every repository within the application would have an API object injected into it, and would use this API when making requests, and the API would contain the authentication context for being able to refresh the Bearer token on each call, and this is where I'm stumped
I had thought about creating an Authentication Singleton that the API could use when being injected into a repository, but since the authenticationContext is unknown at the time, it feels weird to set it after the fact, ie something like
let authContext = new Authentication()
// setup single-spa bootstrap code
// this function is called when the container application bootstraps this Vue application
export const bootstrap = (props) =>
vueLifecycles.bootstrap(props).then(async () => {
authContext.setContext(props.authentication)
})
Then when the API gets intialized, it would have an authContext that would invoke authContext.acquireToken() to get a Bearer token to set for each refresh. But, something feels incorrect about doing this way and I'm not 100% if it's the way to go.
To summarize, applications that were once handling authentication on their own are now being passed the authentication context as a prop during load, and I'm confused about how to implement this to properly set this context as part of the API
Another team had actually stored the acquireToken function in the a Vuex store but that, to me, does not seem appropriate since it ties this code specifically to Vue

Best way to create dynamic navigation on NextJS with firebase?

I'm looking forward to create a web app with NextJS and Google's Firebase. The app has an admin panel and a public site. In the admin panel should have options to edit the public site's navigation.
So I was thinking is it wise to have client-side fetching navigation data on each refresh or is there a better way to get dynamic and up-to date navigation data with as little API request as possible?

This really depends on your use case. In Next.js there are 3 diffrent types for data fetching.
Static site generation - SSG
This fetches the data and renders the pages on build time. This is greate for Pages that don't change to often. Like a blog for example.
Server site rendering - SSR
This fetches the data and renders the pages on each request from a user. This is usefull for data that changes quickly and has to be up to date.
Increment static regeneration - ISR
This allows for a compromise between the 2 types i described above and might be what your looking for if you want to use as little API requests as possiblie. With it you can staticly regenerate the page at a certain time interval.
export async function getStaticProps(){
//fetch data from firebase ...
return {
props: { data },
revalidate: 60,
}
}

Getting initial state using HTML5 history api

Everything I've been searching for is just a tutorial how to use pushState, replaceState, history.state, etc. Those concepts are simple but one thing I'm wondering how people solve is how to know what the initial state is.
Say you SPA is hosted at https://example.com/en-us/myapp/. Go there and your home page of the app is loaded, click around and it does a pushState to see you to https://example.com/en-us/myapp/get/users. Great, now you see a list of users and thanks to the history api, it wasn't an actual page load.
But now let's pretend a user had that https://example.com/en-us/myapp/get/users state bookmarked and the started the app off at this URL. Ok, so your server listens to that and serves up the app. My question is, how do you know that get/users is the current state and you need to show the associated view? Do you just know that your app is hosted at https://example.com/en-us/myapp/ and so you get whatever is after that to know?
Something like this:
function getState (uri) {
return uri.match(/^https:\/{2}(?:w{3}\.)?example.com\/en-us\/myapp\/?(.*)/i)[1];
}
var state = getState(location.href);
and if state is falsey then load the initial view, otherwise handle the state and show the list of users when state === 'get/users'?

Yes, that is quite right. However, you could try using location.pathname to fetch the state, so that your regex does not need to include the domain name.
For example:
function getState (uri){
var path = uri.split("myapp", 2)[1]; // This will split the pathname after 'myapp'
console.log(path) // Just for debugging purposes
// Now we can decide what to do with the path (i.e. "/get/users")
// For example, we can use a switch or a simple if statement
if (path === '/get/users'){
return true
} else {
return false
}
}
var state = getState(location.pathname);
That is just a simple example of a router. You can now try building your very own router for your SPA. Also, there are many libraries out there for you to use if you would like a different approach. You can take a look at these ones if you would like.
navigo
router.js
Also, if you are using a framework to build your SPA, they often have their own routing ability built in. These are just some of the many frameworks that have routers built in. (Sorry, I've <10 reputation so I'm not allowed more than two links).
Vue.js — vuejs.org/v2/guide/routing.html
Mithril.js — mithril.js.org/#routing
Ember.js — guides.emberjs.com/v2.13.0/routing/
Of course, it is ultimately your choice which to use. You could expand upon the example I've provided, by simply implementing a switch for different links/pages in your SPA. I wish you the best with your app!

Communicating with a web widget-Meteor, React, Node

I'm building a chat dashboard and widget with which a customer should be able to put the widget into their page. Some similar examples would be Intercom or Drift.
Currently, the "main" application is written in Meteor.js (it's front end is in React). I've written a <Widget /> component and thrown it inside a /widget directory. Inside this directory, I also have an index.jsx file, which simply contains the following:
import React from 'react';
import ......
ReactDOM.render(
<Widget/>,
document.getElementById('widget-target')
);
I then setup a webpack configuration with an entry point at index.jsx and when webpack is run spits out a bundle.js in a public directory.
This can then be included on another page by simply including a script and div:
<script src="http://localhost:3000/bundle.js" type="text/javascript"></script>
<div id="widget-target"></div>
A few questions:
What is wrong with this implementation? Are their any security issues to be aware of? Both the examples linked earlier seem make use of an iframe in one form or another.
What is the best way to communicate with my main meteor application? A REST API? Emit events with Socket.io? The widget is a chat widget, so I need to send messages back and forth.
How can I implement some sort of unique identifier/user auth for the user and the widget? Currently, the widget is precompiled.

1 What is wrong with this implementation? Are their any security issues to be aware of? Both the examples linked earlier seem make use of an iframe in one form or another.
As #JeremyK mentioned, you're safer within an iFrame. That being said, there's a middle route that many third parties (Facebook, GA, ...) are using, including Intercom:
ask users to integrate your bundled code within their webpage. It's then up to you to ensure you're not introducing a security vulnerability on their site. This code will do two things:
take care of setting up an iframe, where the main part of your service is going to happen. You can position it, style it etc. This ensure that all the logic happening in the iframe is safe and you're not exposed.
expose some API between your customer webpage and your iframe, using window messaging.
the main code (the iframe code) is then loaded by this first script asynchronously, and not included in it.
For instance Intercom ask customers to include some script on their page: https://developers.intercom.com/docs/single-page-app#section-step-1-include-intercom-js-library that's pretty small (https://js.intercomcdn.com/shim.d97a38b5.js). This loads extra code that sets the iFrame and expose their API that will make it easy to interact with the iFrame, like closing it, setting user properties etc.
2 What is the best way to communicate with my main meteor application? A REST API? Emit events with Socket.io? The widget is a chat widget, so I need to send messages back and forth.
You've three options:
Build your widget as an entire Meteor app. This will increase the size of the code that needs to be loaded. In exchange for the extra code, you can communicate with your backend through the Meteor API, like Meteor.call, get the reactivity of all data (for instance if you send a response to a user through your main Meteor application, the response would pop up on the client with no work to do as long as they are on the same database (no need to be on the same server)), and the optimistic UI. In short you've all what Meteor offers here, and it's probably going to be easier to integrate with your existing backend that I assume is Meteor.
Don't include Meteor. Since you're building a chat app, you'll probably need socket.io over a traditional REST API. For sure you can do a mix of both
Use Meteor DDP. (it's kind of like socket.io, but for Meteor. Meteor app use that for all requests to the server) This will include less things that the full Meteor and probably be easier to integrate to your Meteor backend than a REST API / socket.io, and will be some extra work over the full Meteor.
3 How can I implement some sort of unique identifier/user auth for the user and the widget?
This part should probably do some work on the customer website (vs in your iframe) so that you can set cookies on his page, and send that data to your iframe that's gonna talk to your server and identify the user. Wether you use artwells:accounts-guest (that's based on meteor:accounts-base) is going to depend on wether you decide to include Meteor in your iframe.
If you don't have Meteor in your iframe, you can do something like:
handle user creation yourself, by simply doing on your server
.
const token = createToken();
Users.insert({ tokens: [token] });
// send the token back to your iframe
// and set is as a cookie on your customer website
then for each call to your server, on your iframe:
.
let token;
const makeRequest = async (request) => {
token = token || getCookieFromCustomerWebsite();
// pass the token to your HTTP / socket.io / ... request.
// in the header of whatever
return await callServer(token, request);
};
in the server have a middleware that sets the user. Mine looks like:
.
const loginAs = (userId, cb) => {
DDP._CurrentInvocation.withValue(new DDPCommon.MethodInvocation({
isSimulation: false,
userId,
}), cb);
};
// my middleware that run on all API requests for a non Meteor client
export const identifyUserIfPossible = (req, res, next) => {
const token = req.headers.authorization;
if (!token) {
return next();
}
const user = Users.findOne({ tokens: token });
if (!user) {
return next();
}
loginAs(user._id, () => {
next();
// Now Meteor.userId() === user._id from all calls made on that request
// So you can do Meteor.call('someMethod') as you'd do on a full Meteor stack
});
};

Asking your customers to embed your code like this doesn't follow the principles of Security by Design.
From their point of view, you are asking them to embed your prebundled code into their website, exposing their site up to any hidden security risks (inadvertent or deliberately malicious) that exist in your code which would have unrestricted access to their website's DOM, localstorage, etc.
This is why using an iframe is the prefered method to embed third party content in a website, as that content is sandboxed from the rest of it's host site.
Further, following the security principle of 'Least Privilege' they (with your guidance/examples) can set the sandbox attribute on the iframe, and explicitly lockdown via a whitelist the privileges the widget will have.
Loading your widget in an iframe will also give you more flexibility in how it communicates with your servers. This could now be a normal meteor client, using meteor's ddp to communicate with your servers. Your other suggestions are also possible.
User auth/identification depends on the details of your system. This could range from using Meteor Accounts which would give you either password or social auth solutions. Or you could try an anonymous accounts solution such as artwells:accounts-guest.
html5rocks article on sandboxed-iframes

How to build authorization based systems with React?

I'm about to develop a application which will have some pages/components based on the authenticated user authorization/roles/permissions.
First of all: how to avoid having components different of <Login /> (for example) when a unauthenticated user access the app?
Them how to properly load different sets of components based on user's authorization? For example: only the users with manager role would be able to see <ManageUsers /> component. Only admins will see <Dashboard /> and so on.
This MUST to be handled by the server? I guess.
How is role-based apps built with React?(and I think the question extends for other client-side frameworks like Angular as well).

You can solve this problems either on the server-side or on the client. The main idea is to determine a user status and handle it. For example, you can redirect the user to the login page, show a warning message or allow the user to open the page.
On a server: you determine the user (through cookies, token etc) and his status. If it's okay then pass him on, if not - redirect e.g. to the login page.
About React and other frameworks/libraries: again you need to determine the user status. You can do this by sending API request or getting stored data in localstorage etc. There're several approaches how to do it (the 1st way is better in my opinion):
Through the router. In a React app you can use react-router and onEnter hook. Here an example. In short, when route is matched the onEnter hook will be called and there you can do whatever you want
By server response. If it's a SPA then you probably need to load some data to show the page. So, if the user isn't authenticated or can't get this data the server should return 401 (not authenticated/not logged in) or 403 (not authorized) status. And again you just need to handle this.
That's all about allowing a user to open a page. But what about displaying different blocks on the page for different users? Let's say we need to show different set of links in the header for authenticated user and admin. How it might look with React:
const Header = React.createClass({
render() {
return (
<header>
<a className="logo" href="/">Logo</a>
// here you get the user role from the Flux store, localstorage or whatever you want
{user.role === 'admin' ? this.renderAdminLinks() : this.renderAuthLinks()}
</header>
);
},
renderAuthLinks() {
return (
<ul>
Dashboard
Profile
</ul>
);
},
renderAdminLinks() {
return (
<ul>
Admin Panel
Statistics
</ul>
);
}
});
It's just an example but for more complicated things you can define new components like <AdminLinks/>, <UserLinks> and so on.
The the same idea will work with Angular/Backbone/etc in the component/view you should decide what you want to show to the user based on his status.