A Developer's Guide to Session Management in React

Sessions can be a challenging topic for developers of all skill levels. Many React developers never consider the internals of session management because so much of the work is abstracted away. But, it is important to understand what sessions are, how they work, and how best to manage and manipulate them.

There are several different strategies for session management in React. In this article, you will learn the basics about sessions, how to manage them in React, and see some examples using common packages.

Session Management Overview

The first thing you should know is what exactly a “session” is. In its simplest terms, a session is some data that is stored on the server. The server then provides an ID to the client, which the client can use to make requests back to the server. For example, if you needed access to a user’s email address, you could store it against the session, then return an ID to the client. The client could then request an email be sent using the ID, rather than passing his/her email back to the server. The ID field is opaque, meaning that the client knows nothing about what is saved against the ‘ID’ field. The ID can also contain validation and encryption. And, the server can return client data, which would typically be encrypted, to the client that he/she would frequently need.

In this article, I consider a range of server scenarios, as many times when working in React, developers don’t have control over what the server does. For example, when passing session data, the server will include the data in a cookie. The server may also expect a cookie to be present when making a request. Therefore, as a react developer, you will be required to include this cookie in your requests. You may also choose to store the data in localStorage, however then the server doesn’t have access to it. Local storage allows for more storage and can persist over browsing sessions, making it ideal for situations where you want to remember user actions across multiple browsing sessions.

Another situation where you may receive a cookie from the server, is when it is marked HttpOnly. When a cookie is marked HttpOnly, it cannot be read by the client in javascript. This helps minimize the risk of attack against the cookie. For example, if your site has a cross-site scripting vulnerability, marking the cookie HttpOnly will protect the cookie’s contents. Of course, you still need the data that the cookie represents, so you should make a request to the server for the resource you need and present the cookie to the server.

Along these same lines, you should also understand cookie validation. The server you are attempting to access should validate the cookie before processing any request on it. There are many validation tools to help server-side developers, such as signing and expiring cookies. Many times, the server will provide a way for you to check the state of a cookie without requesting a resource.

Manage Sessions in React

There are many packages for helping manage sessions in React. If you are using Redux, redux-react-session is a popular choice. If you are not, react-session-api is another helpful package found on npm.

Focusing on redux-react-session, the first thing you need to do is add your session reducer.

import { combineReducers } from 'redux';
import { sessionReducer } from 'redux-react-session';
 
const reducers = {
  // ... your other reducers here ...
  session: sessionReducer
};

const reducer = combineReducers(reducers);

Next, you need to initialize your session service.

import { createStore } from 'redux';
import { sessionService } from 'redux-react-session';
const store = createStore(reducer)

sessionService.initSessionService(store);

Once you are set up, you have access to the full API by the session service. There are several key benefits to this.

First, you have initSessionService. As the name implies, this call will initiate the session service. Below you can see an example of a call:

import { createStore } from 'redux';
import { sessionService } from 'redux-react-session';
 
const store = createStore(reducer)

const validateSession = (session) => {
  // check if your session is still valid
  return true;
}

const options = { refreshOnCheckAuth: true, redirectPath: '/home', driver: 'COOKIES', validateSession };
 
sessionService.initSessionService(store, options)
  .then(() => console.log('Redux React Session is ready and a session was refreshed from your storage'))
  .catch(() => console.log('Redux React Session is ready and there is no session in your storage'));

To understand this call, you should understand the options that are passed in. First is refreshOnCheckAuth. This option defaults to false, but if set to true, will refresh the Redux store in the checkAuth() function. The checkAuth() function is provided by the sessionService object from the redux-react-session.

redirectPath defaults to /login. This is the path used when the session is rejected or doesn’t exist. Suppose a new user attempts to access a secured page by browsing to the URL directly. Because there is no session, the user will be re-routed to /login by default, or /home in the example above.

Next is the driver option. The two you have already learned about are COOKIES and LOCALSTORAGE, however redux-react-session also accepts INDEXEDDB or WEBSQL. IndexedDB is a database that is built into the browser. Applications that require a lot of client-side data storage should consider this option. Web SQL is also a browser based database, however it is not supported in HTML5 and is deprecated. IndexedDB is considered the default alternative to Web SQL.

Finally, there is the validateSession() function. This will pass the logic for session validation to the sessionService. As discussed before, this is largely dependent on your server functionality. If you can validate the session from the client-side, you can implement the logic here. Otherwise, you can use axios or fetch to make a call to the server to request session validation.

Two other useful functions are saveSession() and deleteSession(). It is a best practice to enforce some rules for deleting the session, though these rules will vary based on your use cases. These functions return promises, as does the entire API. To save the session, you need to pass your custom session object. Setting the session also changes the authenticated flag to true in the Redux store.

Learn More About Sessions and React

Managing sessions in React is an immense topic. In this article, you learned the basics of session management and how to apply them to React. You also learned how to use one of the most common react session management packages available. But this is just a start. I encourage you to look into more react session packages and continue to learn and understand how to properly manage the session. Doing so will make your applications more secure and performant.

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