Cookie session storage in Remix - Mini Project: Build & Apply

Cookie Session Storage with Remix

📖 Scenario: You are building a simple web app using Remix where users can log in and their session is stored securely in cookies.

🎯 Goal: Create a cookie session storage in Remix that stores a user's username and allows reading and updating this session data.

📋 What You'll Learn

Create a cookie session storage using Remix's createCookieSessionStorage

Set a secret string for cookie encryption

Write a function to get the session from the request

Write a function to commit the session with updated data

💡 Why This Matters

🌍 Real World

Web apps often need to remember who a user is between page visits. Cookie session storage lets you save small data securely on the user's browser.

💼 Career

Understanding session management is key for web developers to build secure and user-friendly applications that keep users logged in.

1

Create cookie session storage

Import createCookieSessionStorage from @remix-run/node and create a cookie session storage called sessionStorage with a cookie named my_session and a secret string 'my_super_secret'.

Remix

// Import createCookieSessionStorage and create sessionStorage
// Your code here

Hint

Use createCookieSessionStorage with a cookie config object including name and secrets.

2

Create a function to get the session

Write an async function called getUserSession that takes a request parameter and returns the session by calling sessionStorage.getSession(request.headers.get('Cookie')).

Remix

import { createCookieSessionStorage } from '@remix-run/node';

export const sessionStorage = createCookieSessionStorage({
  cookie: {
    name: 'my_session',
    secrets: ['my_super_secret'],
    sameSite: 'lax',
    path: '/',
    httpOnly: true,
    secure: process.env.NODE_ENV === 'production'
  }
});

// Write async function getUserSession(request) to get session
// Your code here

Hint

Use sessionStorage.getSession with the cookie header from the request.

3

Create a function to commit session changes

Write an async function called commitUserSession that takes a session parameter and returns the result of sessionStorage.commitSession(session).

Remix

import { createCookieSessionStorage } from '@remix-run/node';

export const sessionStorage = createCookieSessionStorage({
  cookie: {
    name: 'my_session',
    secrets: ['my_super_secret'],
    sameSite: 'lax',
    path: '/',
    httpOnly: true,
    secure: process.env.NODE_ENV === 'production'
  }
});

export async function getUserSession(request) {
  return sessionStorage.getSession(request.headers.get('Cookie'));
}

// Write async function commitUserSession(session) to commit session
// Your code here

Hint

Use sessionStorage.commitSession to save session changes.

4

Set and get username in session

Write an async function called setUsername that takes request and username parameters. Inside, get the session using getUserSession(request), set the username in the session, and return the result of commitUserSession(session).

Remix

import { createCookieSessionStorage } from '@remix-run/node';

export const sessionStorage = createCookieSessionStorage({
  cookie: {
    name: 'my_session',
    secrets: ['my_super_secret'],
    sameSite: 'lax',
    path: '/',
    httpOnly: true,
    secure: process.env.NODE_ENV === 'production'
  }
});

export async function getUserSession(request) {
  return sessionStorage.getSession(request.headers.get('Cookie'));
}

export async function commitUserSession(session) {
  return sessionStorage.commitSession(session);
}

// Write async function setUsername(request, username) to set username in session
// Your code here

Hint

Use session.set to store the username and commit the session.

Practice

1. What is the main purpose of using cookie session storage in Remix Framework?

easy

A. To keep user data between page visits using browser cookies

B. To store large files on the server

C. To speed up database queries

D. To change the website's layout dynamically

Solution

1. Step 1: Understand cookie session storage role

   Cookie session storage saves small pieces of user data in browser cookies to remember users across visits.

2. Step 2: Identify correct purpose in Remix

   Remix uses cookie sessions to keep user info safely between page loads, not for server files or layout changes.

3. Final Answer:

   To keep user data between page visits using browser cookies -> Option A

4. Quick Check:

   Cookie session storage = keep user data [OK]

Hint: Remember: cookie sessions store user info in browser cookies [OK]

Common Mistakes:

• Confusing cookie storage with server file storage
• Thinking cookie sessions speed up database queries
• Assuming cookie sessions change page layout

2. Which of the following is the correct way to create a cookie session in Remix?

easy

A. import { cookieSession } from 'remix-framework';

B. import { createSessionCookie } from 'remix';

C. import { sessionCookieCreate } from '@remix-run/server';

D. import { createCookieSessionStorage } from '@remix-run/node';

Solution

1. Step 1: Recall Remix cookie session import syntax

   Remix uses createCookieSessionStorage from '@remix-run/node' to handle cookie sessions.

2. Step 2: Compare options to correct import

   Only import { createCookieSessionStorage } from '@remix-run/node'; matches the official Remix import statement exactly.

3. Final Answer:

   import { createCookieSessionStorage } from '@remix-run/node'; -> Option D

4. Quick Check:

   Correct import = import { createCookieSessionStorage } from '@remix-run/node'; [OK]

Hint: Look for '@remix-run/node' and 'createCookieSessionStorage' keywords [OK]

Common Mistakes:

• Using wrong package names like 'remix-framework'
• Mixing function names like 'createSessionCookie'
• Importing from '@remix-run/server' instead of '@remix-run/node'

3. Given this Remix code snippet, what will be the value of userId after reading the session cookie?

const sessionStorage = createCookieSessionStorage({
  cookie: { name: 'mySession', secrets: ['s3cret'] }
});

const cookieHeader = 'mySession=eyJ1c2VySWQiOiIxMjM0NSJ9';
const session = await sessionStorage.getSession(cookieHeader);
const userId = session.get('userId');

medium

A. '12345'

B. undefined

C. null

D. Throws an error

Solution

1. Step 1: Decode the cookie value

   The cookie string 'mySession=eyJ1c2VySWQiOiIxMjM0NSJ9' is a base64-encoded JSON string representing {"userId":"12345"} but the session.get method expects keys set via session.set, not direct JSON parsing.

2. Step 2: Access session data with session.get('userId')

   Since the cookie is not properly signed/encrypted by Remix session storage, session.get('userId') returns undefined.

3. Final Answer:

   undefined -> Option B

4. Quick Check:

   session.get('userId') = undefined [OK]

Hint: Remember session.get(key) returns stored cookie value only if set via session.set [OK]

Common Mistakes:

• Assuming session.get returns undefined if cookie exists
• Confusing cookie string with session object
• Expecting an error from valid cookie data

4. Identify the error in this Remix cookie session code snippet:

const sessionStorage = createCookieSessionStorage({
  cookie: { name: 'session', secret: ['key1'] }
});

const session = await sessionStorage.getSession(request.headers.get('Cookie'));
session.set('token', 'abc123');
const cookieHeader = await sessionStorage.commitSession(session);
return new Response('OK', { headers: { 'Set-Cookie': cookieHeader } });

medium

A. session.set cannot be used to store values

B. Missing await before createCookieSessionStorage

C. The cookie option should use 'secrets' instead of 'secret'

D. Response headers should not include 'Set-Cookie'

Solution

1. Step 1: Check cookie options for session storage

   The correct option key is 'secrets' (plural), not 'secret'.

2. Step 2: Verify other code parts

   Await is not needed for createCookieSessionStorage, session.set is valid, and 'Set-Cookie' header is required to send cookie.

3. Final Answer:

   The cookie option should use 'secrets' instead of 'secret' -> Option C

4. Quick Check:

   Cookie option key = 'secrets' [OK]

Hint: Check cookie config keys carefully: 'secrets' not 'secret' [OK]

Common Mistakes:

• Using 'secret' instead of 'secrets' in cookie config
• Adding unnecessary await to createCookieSessionStorage
• Thinking session.set is invalid
• Removing 'Set-Cookie' header from response

5. You want to store a user's theme preference ('dark' or 'light') in a Remix cookie session and read it on page load. Which approach correctly sets and retrieves this value?

hard

A. Set the theme with session.set('theme', 'dark') before sending response; read with session.get('theme') after getting session from cookie

B. Store theme in localStorage and read it directly in the loader function

C. Use document.cookie to set theme and parse cookies manually in Remix loader

D. Save theme in a global variable and update it on each request

Solution

1. Step 1: Understand Remix cookie session usage

   Remix cookie sessions use session.set(key, value) to store data before sending response with Set-Cookie header.

2. Step 2: Retrieve stored data with session.get(key)

   On page load, get the session from cookie and read the theme with session.get('theme').

3. Final Answer:

   Set the theme with session.set('theme', 'dark') before sending response; read with session.get('theme') after getting session from cookie -> Option A

4. Quick Check:

   Use session.set and session.get for cookie session data [OK]

Hint: Use session.set before response and session.get after reading session [OK]

Common Mistakes:

• Using localStorage instead of cookie sessions in Remix loaders
• Manually parsing document.cookie instead of using session APIs
• Relying on global variables for per-user data