Implement server-side validation to enhance security and user assistance, preventing client-side bypass. Customize error messages for a seamless design.

Master server-side form validation for data integrity and user-friendly error messages. Enhance UX by securely validating input before server processing.

Server-Side Form Validation and Error Handling

[00:00] Let's open up the editor route and our action is where server code runs. So the user cannot circumvent this no matter what they do, this server code is the code that they're calling and so it will run. So we can do some validation here. So let's create an errors object and then we can say

[00:17] if the title is equal to an empty string, then we know that they did not submit the title. So we can say errors.title. Now here Copilot is saying, hey, why don't you just set errors.title to this string. But it's pretty common to actually have multiple errors per field. So what I'm going to do is turn that into an array

[00:35] and we're going to push onto that error. So let's clean this up a little bit. We'll say title and content on our errors. There's actually a pretty common case where sometimes you've got multiple fields that are in error, or maybe the entire form is an error, like you're not even authorized to submit this form.

[00:53] What are you doing? So what I like to do as just a regular convention, is I say form errors and that's going to be an array. Then we have field errors and that will be an object. So here we'll say errors.field, errors.title.push.

[01:11] This is complaining because it doesn't know what type of this is. So we can say as array of string on all of these and now we are set. Okay, great. If we take a look at the type there, that's exactly what we're hoping for. We can get auto-complete and all that for that.

[01:28] Okay, so if the title is an empty string, it's required. Then we can say if the title.length is greater than 100, then we can say title must be 100 characters or less. Now, we have a magic number here.

[01:45] Magic numbers are basically like a hard-coded number that doesn't communicate really its intent. It's pretty clear to us looking at this that 100 is fine. But the other problem with magic numbers is keeping them in sync with other places that they need to be. So what we're going to do is I'm going to extract this to

[02:03] a variable that we can use that I'm just simply going to call title.max.length. Then we can come up here and we can say title.max.length is 100, and we can do a content.max.length of 10,000. Let's do the same thing there,

[02:21] content.max.length. Awesome. Then we can use title.max.length, and we can even use title.max.length in here as well if we want. That works. Awesome. Then we do the same thing for the content.

[02:38] Content is required, and if it's greater than the max.length, then we'll do that. Okay, so we've done some validation, but we're not sending those errors back to the user. We need to show those errors and definitely not update the note. So we need to return early or skip updating that note. We don't want to redirect either.

[02:56] We want to make sure that we send those errors back so they can finish submitting the form. So we're going to send back some JSON. So to determine whether we have errors, we're going to say has errors, and Copilot could probably fix this for us. Here we go. So we've got form errors, length is greater than zero. So if there are any form errors,

[03:14] and then or take all the values of the field errors, and if some of those have a length of greater than zero, then we know that we've got an error there too. That works just fine for me. Thanks, Copilot. So if it has errors, then we're going to return JSON of those errors. I like to use an object for this.

[03:33] So I'm going to put that inside of an object, and we can say the status is 400. So the submission was incorrect. Status of 400 is basically like, if you try this again, same thing's going to happen. So don't try it again. You got to change the way that you're submitting that. So we'll save all that, and then actually we can come in here,

[03:52] we can try that, and we're going to get the police fill out this field. So what we're going to do is just to test this out. We're going to say no validate. We're going to say browser. I know that we've got these attributes, but we're going to ignore those for now. It's still important to keep those attributes, even if you do no validate because of the screen reader and other implications there. So we're going to leave those on there,

[04:12] but add no validate so that we can test out this server interaction, and then we're going to have our own custom validation anyway. So with that, we hit Submit. Here, let's try refreshing and make sure that it's happening. There we go. Great. So we're not getting any validation showing up,

[04:31] but you'll notice that I hit Submit and it's not actually redirecting the user. It's not working. If we open up our DevTools, go to the Network tab, and then we try this submission again, we're going to see that 400 status response. So we see the title is empty. If we look at the preview of the response,

[04:50] we're going to see field errors, title is required. Perfect. That's exactly what we're looking for. So the next part of this is the client-side to make this actually work and feel nice. So we're going to grab that error list component and stick it right here,

[05:06] and then we need to get that action data. So that data that we're sending back, this is going to come from the UseActionData hook. So ActionData equals UseActionData, we'll say type of action, and that's going to come from RemixRunReact. Then we're going to get the field errors.

[05:26] So we'll have field errors is going to come from the action data. You'll notice the Elvis operator right there, that's because the action data could potentially be undefined. It will be undefined when the user first appears on the page. They haven't submitted an action, so it will be undefined in that case.

[05:45] If it is defined, we'll grab the errors property and then the field errors. If that doesn't exist, then we'll fall back to null. Then we'll have our form errors, and we'll say ActionData errors form errors or fall back to null. Awesome. Then from there,

[06:04] we can simply add the errors for each one of these. So I've actually gave you an example so that it can be nicely formatted, so we'll just use that. We've got a div with the class name and all that, and then we have our errors for the title. Then we'll do the same thing for our content.

[06:24] Then finally, we do the same thing for the form errors, which will just be form errors. There we go. Now, if I try to submit, we see we've got that there now. We hit Submit. Titles required, and oh-oh, titles required. You got to watch out for those copy-paste errors.

[06:44] So let's try that again and get rid of that. Submit. It's working awesome. Then if we do too many characters, we actually can't because the browser is not going to let us, so we're going to cheat and inspect element and increase the max length because we just want to test this out. Add more characters and then hit Submit.

[07:03] Title must be 100 characters or less. I'm going to assume that the content is going to work just the same. We don't actually have any errors that are going to show up for the form error, but if you want to go ahead and try to add one and just see how that ends up looking.

[07:24] But it is pretty common to have those types of errors on lots of different forms. We're not going to do that for this exercise, but it is something that I recommend doing on all your forms. In the future, we're actually going to have an abstraction that will handle a lot of this stuff for us. So to review things really quickly,

[07:42] by having an action that runs only on the server, we can safely do all the validation that we want and not worry about users being able to circumvent that. Once we've done that validation, if we determine that there are errors, we can return those errors,

[07:59] and then those errors can be sent over to our UI via this action data. Then we can grab those errors and render them appropriately in the different areas of our form. Now, there are a couple other small things that I want to do to make some adjustments to this.

[08:19] Like one thing we could do is move these types a little bit just to make that nicer. You can feel free to do that yourself, the next step of the exercise that will be done. Then another thing that I like to do is I like to really communicate very clearly what the different return types of my action are,

[08:37] and so I almost always will have a status of error. Then I add as const, so that's the status type is literally the string error rather than just being a type of string. This can be really useful, and you'll see this later on as we work through these exercises where we have

[08:57] different status types that we return from our action. Then we can key off of that and say, action data.status is error, that now we know for sure that there is action data and it does have an errors value there.

[09:14] Then otherwise, we'll say null. To me, this just is a little bit more explicit, and so you'll see in the code that I'm writing in these exercises, that's how I do things is I'll add the status error and as const.

[09:30] That is getting some error validation logic that the user cannot circumvent and giving the user a nice error message to boot. It's a good thing.

Server-side Validation and Custom Error Messages

[00:00] Even though the browser supports built-in validation and you can even customize that validation with JavaScript, this is really easy to circumvent. Users can literally just open up the DevTools and go down to here and say, you know what, I think it should have a max length

[00:15] of thousands and then they can circumvent our validation that way. Or they could just hit the endpoint directly, just look at what the network is doing and do that same thing and do whatever they want to with it. So we absolutely always, no matter what, you should have validation on

[00:32] the server. So that's what we're going to do in this exercise. I want you to add some validation for the title and the content on the server side. And I also want you to display error messages. So while we do have some error message right here, we want to be able to customize that to

[00:48] match our aesthetic. And so I'm going to give you a component that you can render for those error messages. And I want you to render those error messages that the server sends back so that we can give the user not only some protection against themselves, but also some help as they

[01:05] work through this stuff and then match our own design and totally customize that. So there are a couple of things that you're going to be doing in this step of the exercise and it's going to be awesome. Have a good time. We'll see you when you're done.

Forms are the primary mechanism for interactivity on the web.

But for all of their importance, forms can be incredibly frustrating for developers and users alike.

There are a lot of moving parts to consider: 

You need to validate user input and handle complex data structures, while being secure from bots and data-stealing attacks. The UI should inform users of any issues as quickly as possible, and be accessible for all.

The Professional Web Forms Workshop will equip you with the tools to handle all of these challenges and more.

## Form Validation

HTML has several attributes built-in that help with form element validation. Unfortunately, they're not enough on their own. On the client-side, bad actors can bypass checks by manually adding the `novalidate` attribute or making requests directly. On the server side, there's no standard way to respond to validation errors other than a generic 400 status code.

In this section, you'll implement a base level of form validation:

- Essential HTML attributes for validation
- Server-side validation with JSON responses
- Displaying errors with the `useActionData` hook
- Disabling default browser validation messages with `useHydrated`

## Accessibility

Accessibility is often an afterthought, but should be a priority. While forms are just one part of the accessibility equation, they're a big one. In this section, you'll learn how to make sure your forms accessible and usable by all of your application's users:

- Properly associating labels with input fields
- Adding appropriate ARIA attributes when necessary
- Manage keyboard focus in response to errors and user interactions
- Creating and using a `useFocus` hook to direct the user’s focus
- Considerations for accessibility testing

## Schema-Based Validation

Manually writing conditional checks for every field in every form is tedious and error-prone: *Is there content in the field? Is it the right type? Is it within the acceptable range? There must be a better way!*

Fortunately, the combination of the Zod and Conform libraries makes it easy to define reusable declarative schemas to validate form data on the client and server:

- Safely replace HTML validation attributes with schemas
- Zod error handling & message customization
- Progressively enhanced validation with Conform
- Share type-safe validation logic between client and server

## File Uploads

Forms need to support more than just text. Images, videos, audio files, and other documents need a different type of input. Depending on the size of the file, you'll have considerations for how and where it is uploaded. In this section, you'll learn how to handle file uploads in a secure and efficient way:

- Uploading images from an `ImageChooser` component
- Handling file uploads on the server
- Schema validation for file uploads with Zod

## Complex Data Structures

The `FormData` API does not support representing objects or arrays– only key/value pairs. It also won't allow you to nest forms within each other. This makes representing complex data structures difficult without jumping through some hoops. Luckily for us, Conform has a great solution when your forms get complex. Here you'll practice:

- Infer field types with Zod
- Nesting objects as a form
- Represent arrays of fields with the `useFieldList` utility
- Add and remove items with Conform's `intent` buttons

## Spam Prevention with Honeypots

Spam bots are constantly crawling the web, looking for forms to submit junk data to boost their client’s search engine rankings and find holes in your security. This can strain server resources, contaminate databases, and cause other unforeseen consequences. One way to combat this is by using a "honeypot", which will prevent a form from being submitted by a bot. This section will teach you how to:

- Create a simple hidden-field validation
- Add a configurable honeypot instance to an action
- Prevent form submissions that are too fast
- Use environment variables for encryption seeds

## CSRF Protection

Cross-Site Request Forgery (CSRF) attacks are a type of malicious exploit where a user is tricked into performing an action they did not intend to. This is usually done by embedding a link or form in a page that the user is already authenticated to. Think of a user logged into their bank account clicking a link that transfers money from their bank account to the attacker's. To prevent this type of attack, you'll want to:

- Create a signed cookie in the user's browser
- Include unique user tokens in forms
- Validate tokens on the server via request headers

## Rate Limiting

You definitely want to prevent bad actors from making tons of requests to try to brute-force their way into your app or cause general chaos. However, malicious intent and spam aren't the only reasons you need to protect your site. Even too many legitimate requests can cause problems. Rate limiting is a way to prevent users from overloading your server with requests. Here you'll learn:

- Considerations for different limits for `GET` vs. `POST` requests
- Implementing basic rate limiting with Express middleware
- Tiered rate limiting depending on which form is being submitted

The Professional Web Forms Workshop will equip you for building complex, fully accessible forms that handle validation and file uploads while preventing spam.

Professional Web Forms

Kent C. Dodds

Developers working on modern web applications today face a myriad of challenges.

The apps we build are expected to be good looking, fast, and secure. They need to be interactive, responsive, and accessible. They need to be SEO-friendly, and they need to be resilient to errors.

In order to be successful, you need to ensure you have a solid foundation to build on.

Full Stack Foundations is a comprehensive, in-depth workshop that sets the stage for the rest of the Epic Web series. It's designed to equip you with the current best practices for handling CSS, routing, data loading, and more.

This isn't some basic "intro" workshop! Even if you're an experienced developer, you'll learn new skills and techniques that will help you build better apps.

<Testimonial author={{name: "Gwen Shapira"}}>

It was 🤯. A lot of fun, and I learned so much in one day. Even with 23 years as a software engineer, I have a much clearer understanding of how the web actually works. Now, months after this workshop, I’m working on a web project and this gave me the mental framework I needed to quickly ramp up and feel competent. I’m not even using the same tools Kent uses in the workshops! 13/10.

</Testimonial>

## Styling

In recent years, CSS has seen a lot of evolution in its usage and tooling. There are new best practices for importing stylesheets, managing assets, and optimizing styles. Failing to follow them can lead to slow-loading pages and a maintenance nightmare.

Here, you'll learn how to handle styling right:

- Loading external stylesheets & other resources
- Managing assets with fingerprinting and caching
- Compilation with PostCSS and Tailwind CSS
- Bundling CSS for libraries and components

## Routing

The URL is critical for the web, and is closely tied to your application's routing. Making suboptimal decisions affects loading performance, navigation, and overall experience.

This section is a deep dive into routing, from the basic filesystem structure through nested routes and dynamic parameters:

- Conventions for signifying routes
- Layout and URL nesting
- Navigation and linking
- Dynamic route params
- Resource routes

## Data Loading

The web is all about data, and nothing frustrates users more than when loading is slow or broken. This section introduces you to AJAX/fetch and Remix loading features, giving you the tools to build stable, fast-loading applications:

- Working with `Request` and `Response` objects
- Fetching data for initial and subsequent loads
- Accessing environment variables
- Connecting routes to loaders

## Mutations

Interactivity makes apps engaging, but also introduces complexity. You need to ensure that the thing that happens when a form is submitted is what the user expects. Here you will use form methods and actions to mutate existing data in a mock database:

- Creating forms with `method` and `action`
- Storing and extracting form data
- Handling invalid submissions
- Form state management
- Specifying intent

*This module sets the stage for the complete Professional Web Forms workshop.*

## Scripting

The browser is capable of quite a lot on its own. Up until this point of the workshop, the Epic Notes application will work without any JavaScript. However, scripting allows us to enhance the user experience in ways that would otherwise be impossible.

In this section, you'll incrementally add in features like client-side pending UI, prefetching, and optimistic updates:

- Scroll position restoration
- Considerations when overriding default browser functionality
- Server and client bundles & entry files
- Preloading data & code for anticipated actions
- Transitions with the `useNavigation` hook

## Search Engine Optimization

Ignoring SEO is like building a store without a sign— people simply won't find you. If you want to be successful, your site needs to be discoverable and optimized for presentation on those platforms.

SEO is a very broad topic, but this section will get you set up on the technical side of the equation:

- Essential tags and attributes
- Overriding default metadata for specific pages
- Dynamically set metadata for social sharing
- Reusing parent data for nested routes

## Error Handling

Even the best apps can break, but what separates the good from the great is how they recover. Lack of proper error handling can lead to frustrated users and lost business.

This section will teach you how to anticipate, handle, and recover from errors, making your application resilient and user-friendly.

- HTTP status codes
- Using `ErrorBoundary` components to contain errors
- Handle thrown errors when fetching data
- Error bubbling from child routes to parent routes
- Implement useful 404 pages

Full Stack Foundations

Data modeling is as a critical skill for the full stack developer. After all, data is the foundation of your application.

If you don't do it right, you'll find yourself stuck before you even get started. A poorly designed database schema can lead to a lot of headaches down the road when you need to make changes or add new features. Inefficient queries can slow down your application, leading to a poor user experience. Analyzing root causes to issues like these can be a time-consuming and frustrating process.

Web developers spend a ton of time into making their UI handle a slow backend well which is great and you should do that too (you don’t control network latency after all). But *****great***** web developers put effort into making it so their users hardly ever experience that great pending UI by making the backend as fast as possible. Your UI can’t be any faster than your slowest database query.

The Data Modeling Deep Dive Workshop will help you develop a keen understanding of databases and how to manage them. You'll learn the same tools and techniques used at the top tech companies to design robust database architectures and optimize query performance.

We'll be using production grade tools like Prisma and SQLite, but the concepts you learn in this workshop will be applicable to other database systems as well.

## Database Schema

A well-designed database schema is the foundation of your application. It's critical to get it right from the start, as it can be difficult to make changes down the road. This section provides a background on SQL before introducing Prisma's suite of tools. You'll learn:

- SQLite database initialization with Prisma
- Prisma's Object Relational Mapper (ORM)
- Defining a schema with Prisma's declarative schema language
- Converting a schema to SQL with the Prisma CLI
- Viewing and editing your database in Prisma Studio

## Relationships

Poorly planned relationships between database models can lead to data inconsistencies and increased query complexities and performance problems. To avoid these issues, you need to understand the different types of relationships and how to implement them. This section provides you with practical experience in recognizing relationships:

- One-to-many relationships (User has many Notes)
- One-to-one relationships (User has one UserImage)
- Updating the database with Prisma
- Planning models for the future
- Generate an Entity Relationship Diagram (ERD) for visualization

## Migrations

As your application evolves, so will your database schema. It's not uncommon for there to be "breaking changes" that affects one or more of your database models. This is where migrations come in.

Migrations allow you to track and synchronize schema changes across environments. Traditionally migrations have been tricky to manage, but this section will teach you how to use migrations to ensure your development, staging, and production environments are always in sync:

- Generating SQL migration code with Prisma
- Best practices for documenting & tracking migrations
- The "widen then narrow" approach for eliminating downtime
- Experimenting with migrations before permanently applying them

## Seeding Data

Manually adding data to a database is not only time-consuming but also prone to errors. Scripting to the rescue!

Here you'll learn how to populate your databases with consistent data for development and testing purposes:

- Initializing a SQLite database
- Idempotent scripting
- Resetting the database with Prisma
- Nesting SQL queries to simplify foreign key connections

## Generating Seed Data

Using hardcoded seed data works great for small applications, but it won't provide the best idea of how your application will perform at scale. You also shouldn't use real user data during development for plenty of obvious reasons.

A better approach is to use a library like Faker.js. This section will teach you how to use Faker.js to generate seed data for your database:

- Balancing realism with practicality when generating data
- Creating realistic user information
- Varying data quantities and randomness
- Validating against the schema
- Enforce data uniqueness

## Querying Data

In SQL, queries are written with the `SELECT` statement. This is one of the most powerful statements available, but it can also be one of the most complex. This is where tools like Object Relational Mappers (ORMs) come in, helping developers write SQL in a more intuitive way. Although it isn't a traditional ORM, the Prisma Client is an indispensable tool for modern web development. In this section, you'll learn how to get the most out of it:

- Understanding how Prisma's API maps to SQL
- Handling Hot Module Replacement (HMR)
- Logging slow queries
- Pre-connecting the client to the database

## Updating Data

Data mutation is a common task, but doing it incorrectly can lead to data corruption or loss. Especially when a single user action results in multiple database changes (for example, transferring money between user’s bank accounts). Getting mutations wrong can be a serious problem for your app’s success. This section will walk you through techniques for working safely:

- Deleting and updating data
- Conditional upserts
- Combining multiple queries into a transaction
- Rolling back to a previous transaction

## SQL

No matter how great an ORM is, sometimes you have to write raw SQL. In this section, you'll learn how to write raw SQL queries and execute them with Prisma. You'll also practice with:

- Wildcard queries
- Runtime schema validation with Zod
- Using joins to enable more complex queries
- Specifying query result ordering for more efficient searching

## Query Optimization

Nobody likes a slow application.

There are many stories of companies spending millions of dollars on scaling hardware, adding multiple levels of caching, and even rewriting their entire application in pursuit of a faster performance– only to find out later that the solution was optimizing their database indexes and queries.

In this final section, you'll learn how to optimize your queries for maximum performance:

- Identifying the index
- Analyzing raw SQL queries
- Multi-column indexing
- Balancing premature optimization with practicality

Data Modeling Deep Dive

Most web applications feature user accounts in one form or another.

To the user, having a login form seems simple enough. But behind the scenes, there's a lot going on. You need to securely store and manage user sessions, handle authentication and authorization, and protect against malicious attacks.

Without knowledge of the underlying concepts, it's easy to make mistakes (even if you decide to use a third party service or library to do all the hard work for you). Weak authentication systems, misconfigured route protection, and flawed session management all lead to vulnerabilities and negative user experiences.

The Authentication Strategies & Implementation workshop is your guide to implementing industry standard user account flows in a modern web application.

Securely managing passwords, enabling two-factor authentication, and integrating with third-party providers are just some of the processes you will practice. You'll also learn how to handle user preferences, session data, and send emails to users. This will take you all the way to the point where you could easily add Single-Sign On (SSO) support–a must if you’re building a business-to-business application.

There are a lot of moving parts to consider, but this workshop will give you the confidence to tackle them all.

## Cookies

The workshop begins by diving into cookies. This fundamental part of web browsing is often misunderstood, but important to understand. We keep it simple to ramp you up slowly on the web’s original state management solution. This also introduces us to important UI patterns you’ll want to use in other areas of web development as well. It’s surprisingly deep! Topics include:

- Storing user theme preferences in a cookie
- Server-side cookie handling
- Using fetchers for non-navigation mutations
- Optimistic UI updating to apply changes immediately

## Session Storage

Storing user preferences in cookies is fine, but you need to be more careful when it comes to session data. It's vital that users with devtools or malicious client-side JavaScript can't access or modify the data inside of cookies. In this section, you'll learn:

- Cookie-based session data persistence
- Properly getting, setting, and updating session data
- Deleting data after reading
- The flash pattern for short-lived messages

## User Sessions

Depending on the amount of data you need to store, it may make sense to use a different storage mechanism for session data. For this workshop we will continue to use cookies, however we will switch to using a dedicated session cookie. This section will teach you:

- Create a session storage object for storing user data
- Transform form submissions into user objects for storage
- Retrieving user information from cookies then the database

## Passwords

Passwords are the most common way to authenticate that a user is who they say they are. Obviously, storing them in plain text is a bad idea, but even encryption isn't enough. You need to properly prepare to securely handle passwords:

- Create a Password model in the database
- Generate secure password hashes with the battle-tested bcrypt algorithm
- Protection against password attacks
- Update signup route to securely create records

## Login & Logout

At this point, you have the ability to create users and store their passwords. But how do you actually log them in? And how do you log them out? In this one we’re also going to learn about imperative mutations which you’ll definitely want to know for other app features. This section will teach you:

- Verify a user's password hash with bcrypt
- Handling optional vs. required user data
- Guard against timing attacks
- Clearing session data on logout
- Handle edge cases like deleted accounts
- Set expiration dates for session cookies
- Implement automatic logout after a set idle time

## Protecting Routes & Role-Based Access

Most web application have routes that you need to be logged in to access. It's one thing to prevent this in the UI, but the real thing you need to do is protect the data that powers those pages. There are also considerations for different user roles and permissions. This section will teach you how to:

- Ensure users only access data they own
- Restrict private pages to logged in users
- Implement smart redirects for login and logout
- Specify and enforce permissions with Role-Based Access Control (RBAC)

## Managed Sessions

Imagine a user logging in on a public computer, who then forgets to log out. This security risk can be mitigated by implementing a session management feature:

- Add a session model to the database
- Update auth utils, login, and logout routes to query sessions
- Refactor for session expiration support
- Create a page for displaying & managing active sessions

## Email Verification & Password Resets

Email is one of the most common ways to verify a user's identity. If a user loses access to their account, needs to reset their password, or wants to change their email address, you'll need to send them an email. While the actual sending of the email is best handled by a third-party service, the process flow behind the scenes is what you'll need to implement:

- Integrate a third-party email API
- Share session data between routes for multi-step flows
- Style HTML emails
- Generate time-based one time passwords (TOTP) for password resets
- Force verification of email address change

## Two-Factor Authentication

Two-factor authentication (2FA) is a great way to add an extra layer of security to your application. It requires the user to enter a code from a second device along with their username and password. Even if an attacker determines a password, they won't be able to access the account without the second factor. In this section, you'll add 2FA to the Epic Notes application:

- Handle the 2FA enable flow
- Provide the user with a QR code
- Implement a 2FA code input form
- Verify the code and log the user in
- Require re-verification
- Provide option to disable 2FA

## Third-Party Authentication

There are several reasons to use third-party authentication providers. It can be a great way to reduce friction for users, or allow easier access to other data. The most common way to do this is with OAuth 2. Once you’re finished with this section, you’ll be geared up to implement third party auth with any provider. Including Single-Sign On (SSO) flows. We’ll be following these steps:

- Add an authentication strategy to enable GitHub login
- Create a connections model to associate users with providers
- Prevent duplicate account connections & hijack attempts
- Pre-fill user account data based on third-party login
- Mocking third party APIs for testing
- Gracefully handle login errors
- Implement smart redirection to return to original page after login

Authentication Strategies & Implementation

We all know the drill. The code works on your machine but you didn’t realize the impact of the change you made and it breaks in production. This problem grows exponentially as your application’s size and usefulness grows. Unpredictability can be a developer's worst nightmare.

However, many developers find it difficult to effectively test their code. Manual testing gets tedious fast. Complex logic and async code can be tricky to test effectively.

The Full Stack Testing Workshop will equip you with the tools you need to ensure your app works now and in the future. You'll learn how to write modular, maintainable tests that cover all of your code, from the backend to the frontend.

As the author of the de-facto standard testing library for web development (called eh… Testing Library), I have some solid opinions that have led many teams to much more confidence shipping their code. Let’s get you some of that confidence.

## End-to-End Testing with Playwright

With end-to-end (E2E) testing, you can validate a web app from the user's perspective. This is the closest you can get to a real user interacting with your app. In this section, you'll learn the ins and outs of writing a test with Playwright:

- Best practices for setup before running tests
- Simulating user actions like interacting with the UI to perform a search
- Creating a new user in the database
- Cleaning up after tests have run
- Using playwright fixtures for reliable setup/teardown

## Mocking & Authentication for E2E Tests

When your application relies on external services, you need to have a way to test them without actually using them. Similarly, you don't want to fully onboard a new account every time you test an authenticated user flow. In this section, you'll learn how to re-use the same mocks we’ve been using for development to mock third-party services and simulate logging in:

- Use Mock Service Worker to intercept network requests
- Replace email verification with a local file solution
- Attach cookies to Playwright
- Reusing 2FA logic for local testing
- Testing behavior with different HTTP responses

## Unit Testing

Sometimes you’ve got some really complicated business logic in your app. Business logic that is critical to your application. For this stuff, it’s nice to package it up in its own function or module to keep all that logic in one place. This is the perfect situation where lower level unit testing comes in handy. Here, we'll dive into unit testing with the Vitest framework to ensure that each function and module behaves as expected:

- Organizational best practices
- Asserting outcomes with `expect`
- Recording function calls with spies
- Specifying test behavior with Vitest hooks
- Keeping test output clean to avoid cluttering up the terminal

## Component and Hook Testing

When building React components, you should focus on two users: the user who interacts with a component, and the developer who renders it. By using Testing Library, we can avoid mocking React and its hooks and instead test components as they would be used in a real app:

- Render components with Testing Library
- Simulate the DOM environment on a per-test basis
- Querying for missing elements
- Testing hooks in isolation from React
- Stubbing React context
- Cleanup after testing

## Authenticated Integration

Similar to higher-level E2E tests, it is often necessary to simulate an authenticated user. However, we don't want to test the entire user flow every time we make a change. In this section, you'll learn how to test authenticated operations without the overhead of a full E2E test:

- Generating random session IDs
- Associating sessions with users
- Testing authenticated routes
- Asserting user state in responses

## Custom Assertions

Writing tests is good; writing readable and maintainable tests is better. Custom assertions can make your test code easier to understand and modify. Here you'll learn to encapsulate complex checks into simple, understandable assertions:

- Create matchers for specific states
- Share assertions across tests
- Add custom assertions to TypeScript definitions
- Format test output with colors for readability

## Test Database

There are some decisions to make when writing tests that interact with the database. Testing with the development database has benefits, but requires us to remember to delete data after each test. By using a test database, we can avoid accidents while still being able to run our test suites:

- Set up a test-specific database instance
- Seeding a minimal amount of data
- Defining a global setup for Vitest
- Understanding the importance of module import order

Web Application Testing

Kent C. Dodds is joined by expert developers, library creators, and tech industry leaders who share their insights and experience working within the ever-evolving world of web development.

These conversations cover a wide range of topics ranging from the intricacies of database efficiency, the future of authorization, the role of leadership in tech, and everything in between.

No matter your level of experience in web development, these conversations offer a wealth of knowledge and ideas that will inspire you to refine your craft, push boundaries, and become an Epic Web dev!

## Content Management Systems with Alexandra Spalato

Alexandra Spalato, a Developer Relations Engineer at Storyblok, discusses the future of content management systems. She emphasizes the significance of a CMS in simplifying complex processes into user-friendly interfaces and making content creation more accessible to non-developers.

## Leadership in Tech with Ankita Kulkarni

Developer and leadership educator Ankita Kulkarni discusses the intersection of leadership and development. The conversation explores the acquisition of leadership skills, and how to find the balance between coding and leadership roles. Ankita provides strategies for advancing into leadership positions, emphasizing the importance of proactive career management.

## API Mocking with Artem Zakharchenko

Artem Zakharchenko, the creator of Mock Service Worker (MSW), joins Kent to discuss the evolution of MSW from a weekend project into to a powerful open-source tool for API mocking and debugging.

## Enhancing SQLite with Ben Johnson

Ben Johnson is a developer with a 20-year coding career spanning roles from Oracle to creating BoltDB. In this conversation, Ben discusses LiteFS and Litestream, both tools aimed at expanding SQLite's utility. Topics include a dive into SQLite's architectural elements, and how LiteFS enhances scalability on a single node.

## The Evolution of Type Safety with Colin McDonnell

Colin McDonnell, a Developer Relations representative at Bun and the creator of Zod, discusses how Zod has grown from its original usage in medical software into a prominent tool in the TypeScript ecosystem. Colin also touches on TRPC, an end-to-end type safety library, and the challenges it addresses.

## Navigating the Testing Terrain with Debbie O'Brien

Debbie O'Brien, a community advocate for Playwright at Microsoft, discusses the adaptability and versatility of Playwright as a testing tool. She emphasizes its value in various testing scenarios and its role in Microsoft's application testing, including VSCode, Bing, and Teams.

## Simplifying Web Form Management with Edmund Hung

Edmund Hung, web developer at Delivery Hero, discusses how Conform has become a crucial component of the Epic Stack. He highlights Conform's unique approach to form management, which bypasses native browser validation in favor of its own system.

## Scalable Databases and Authentication with Iheanyi Ekechukwu

Iheanyi Ekechukwu, a software engineer at PlanetScale, explore database and hosting options, highlights PlanetScale's scalability and the role of Vitess in the technology. The conversation also covers authentication solutions, and cautions against over-reliance on external services.

## Understanding Web Development with Jacob Paris

Jacob Paris joins Kent to discuss his work on Remix. He highlights some of the challenges of server rendering, including handling user preferences and time zones. One the client side, Jacob emphasizes the importance of server output for correct client rendering, especially when users disable JavaScript.

## The Depth of Software Testing with Jessica Sachs

Jessica Sachs, software engineer at Ionic and a testing & QA expert, joins Kent in a conversation about various testing paradigms. They discuss topics ranging from Test-Driven Development to End-to-End testing, emphasizing the importance of a balanced approach.

## Platform Engineering with Jocelyn Harper

Jocelyn "Josie" Harper, tech lead at The New York Times, discusses her tech journey into roles including platform engineering and system design. Additional topics include backend optimization and the significance of documentation.

## Exploring the Front-End Ecosystem with Mark Dalgleish

Mark Dalgleish, co-creator of CSS Modules and contributor at Shopify, discusses the evolution of CSS, React, and design systems. Touching on CSS Modules and CSS-in-JS, the conversation also goes into the challenges of managing design systems, particularly when it comes to balancing flexibility with standardization.

## Navigating Changing Web Technologies with Mark Thompson

Mark Thompson from Google's Angular team joins Kent to share his career journey, the web's evolution, and AI's role in software development. Additional topics include the transformational role of APIs and Angular's transition from the View Engine to Ivy.

## The Magic of TypeScript with Matt Pocock

Matt Pocock, internet-renowned as the "TypeScript guy", discusses the merits and challenges of the TypeScript ecosystem. Highlighting its benefits in IDE capabilities and bug reduction, Matt also touches upon complexities in managing types and creating libraries.

## Building Deep Skills with Michael Chan

Educator and enthusiast Michael Chan shares his thoughts on the changing React landscape, emphasizing the significance of TypeScript and libraries like React Query. He advocates for building a deep understanding over surface-level knowledge. Both Michael and Kent stress the joy of creating meaningful projects and the importance of a comprehensive web development understanding.

## Examining MDX with Monica Powell

Monica Powell, a senior software engineer at Newsela, dives into MDX, which allows for developers to combine JSX with Markdown for creating rich content. She highlights MDX's role in the Unify ecosystem, as well as its challenges when getting started with CMS integration.

## Efficient Form Management with Sandrina Pereira

Sandrina Pereira, a staff front-end engineer at remote.com, emphasizes the significance of web accessibility using the POUR principles. Additional topics include the complexities of managing large-scale forms dynamically for users across the world. 

## Transitioning from Rails to Remix with Sergio Xalambrí

Sergio Xalambrí shares his experience transitioning from a Rails and Next.js setup to Remix at fintech startup Duffy. Some of the challenges include highlighting challenges in internationalization and adding middleware. The conversation also into remix-auth's authentication strategies and contrasting Remix's modular approach with Rails' cohesive framework.

## The Capabilities and Ecosystem of Tailwind CSS with Simon Vrachliotis

Simon Vrachliotis, a Tailwind expert at Thinkmill, praises the benefits and adaptability of Tailwind CSS, emphasizing its alignment with React's component-level concerns. Simon discusses solving for type safety in addition to recommending tools for enhancing the Tailwind workflow.

## The Crucial Role of Database Optimization with Tyler Benfield

Tyler Benfield, a software engineer at Prisma, dives into the intricacies of database efficiency, emphasizing backend optimization for enhanced frontend performance. Tyler also explores the advantages and limitations of ORM tools like Prisma, the potential of SQLite in production, and the universal importance of SQL knowledge across platforms.

## Product Management with Nevi Shah

Nevi Shah, a product manager at Cloudflare, combined her technical and business skills to  transition from academia and consulting into product management. She highlights the role of a product manager in understanding user needs and introduces Cloudflare Pages as a solution for serverless architecture, while also discussing alternative hosting options like Fly.io.

## Remix Behind the Scenes with Ryan Florence

Ryan Florence, co-founder of Remix and React Training, discusses the innovations behind Remix and its transition from React Router. The framework's compatibility with the web's fetch API broadens its server architecture reach, and its recent acquisition by Shopify promises a bright future for Remix.

## From Tech Sales to Engineering with Shaundai Person

Shaundai Person, a senior software engineer at Netflix, joins Kent to discuss transitioning from tech sales to software engineering. She highlights the importance of recognizing and building individual strengths, especially communication, in large corporate settings.

## Art, Code, and Data Visualization with Shirley Wu

Shirley Wu, an award-winning creator specializing in data-driven art, transitioned from the business sector to web development. She shares how her work offers artistic fulfillment and financial stability, but she emphasizes the importance of ethical considerations.

## Understanding the Future of Authentication with Will Johnson

Will Johnson from Auth0 highlights the limitations of password-based authentication and discusses the potential of alternatives like the Web Authentication API (WebAuthn). Will shares his anticipation for a future where biometrics or digital verification replace traditional passwords, as well as a need for more nuanced access controls in growing organizations.


Interviews with Experts

Full Stack Vol 1

Intro to Professional Web Forms Workshop

Introduction to Workshop

Intro to Form Validation 

Discover the importance of validation in web apps. Learn to implement required field validation for data integrity and UX enhancement.

Leverage HTML attributes for form validation, enhancing UX and accessibility. Explore browser validation and screen reader integration for user guidance.

Form Validation for Accessibility

Required Field Validation for User Input

Prevent incorrect form submissions pre-JavaScript with novalidate attribute using useHydrated hook. Elevate UX, maintain data integrity.

Optimize form validation with 'useHydrated' hook for client-side hydration. Enhance UX with browser-built and server-side validation synergy.

Form Validation with Client-Side Hydration

Dynamic Error Validation with Hooks

Dad Joke Break From Validation

Form Validation

Intro to Accessibility

Learn how to troubleshoot and fix issues with a non-functioning reset button and accessibility problems in a web form.

Learn how to properly associate buttons and form elements, such as the reset button, with their respective forms for improved functionality and accessibility.

Improving Accessibility and Form Associations

Fixing Form Reset Button and Accessibility Issues

Associate error messages with input fields via ARIA attributes for precise screen reader notifications. Learn about semantic HTML and ARIA for accessibility.

Use ARIA attributes like ARIA invalid & describedby. Link error messages to inputs for improved screen reader support, aiding assistive tech users.

Accessible Forms with ARIA Attributes

Error Messages and Accessibility with ARIA Attributes

Enhance app accessibility & UX with focus management: auto-focus error fields, programmable forms, & better editing. Create an inclusive, user-friendly app.

Enhance React app accessibility and UX: auto-focus form inputs and navigate to error messages for improved handling of form errors.

Managing Focus for Form Errors

Focus Management for Better User Experience

Dad Break Joke Accessibility

Accessibility

Intro to Schema Validation

Optimize development with Zod schema validation. Boost efficiency and code robustness, replacing custom logic for an enhanced developer experience. 

Learn how to implement schema validation using Zod in a note editor application. Discover how to define and enforce data

Schema Validation with Zod 

Schema Validation 

Data parsing with Conform's Conform utility. Apply server-side logic and streamline development with additional UI utilities for efficient form handling.

Improve UX & enable progressive enhancement: Replace form validation & error handling with powerful Zod utility in your app

 Form Submission and Error Handling with Conform & Zod

Form Data Parsing with Conform

Enhance UI with Conform's React utilities for end-to-end type safety. Leverage progressive enhancement for a fabulous development experience.

Eliminate custom code for better UX. Seamlessly manage form submission and client-side validation with Conform, ensuring robust server-side validation

Simplifying Form Handling with Conform and Schema Validation

Type Safety with Conform

Dad Joke Break Schema Validation

Schema Validation

Intro to File Upload

Add file upload to edit page for user-friendly image & file attachments. Handle uploads in Remix, enforcing size limits. 

Integrate image upload with form data and memory handling. Use image chooser, manage existing images, set encoding, size limit, and specify alt text. 

Image Upload with Form Data and Memory Upload Handling

File Upload Functionality 

Improve code quality and address TypeScript errors for a robust application, making Lily the life jacket (and yourself) happy.

Update schema for image ID, alt text, and file uploads. Master file validation with Zod for size restrictions and error handling on client & server sides. 

Validating File Uploads with Zod Schema in a Web Application

TypeScript Integration

Dad Joke Break File Upload

File Upload

Intro to Complex Structures 

Address challenges in grouping properties into sub-objects in forms, especially for multiple image uploads. Satisfy Zod's requirements for seamless integration.

Learn to add image field set schema to Zod schema, update HTML elements, and integrate with Conform for type safety and form functionality. 

Implementing Image Field Set with Conform and TypeScript

Grouping and Managing Related Fields in Form Objects

Update your app's schema for multiple images, adapt actions/components, and enable seamless addition/removal of multiple images for an enhanced user experience.

Master dynamic image lists with Qualifax: add and remove images effortlessly. Update schema, implement field sets, and iterate through image choosers with ease.

Dynamic Image Lists with Field Sets 

Multiple Image Uploading 

Dynamic image addition and deletion with alt text functionality, progressive enhancements, and input submission using Conform utilities in web development

Master dynamic button generation for form accessibility using Conform utilities. Modify field sets with list functions, explore progressive enhancement.

Dynamically Delete and Add Buttons

 Interactive Image Management

Dad Joke Break Complex Structures 

Complex Structures

Intro to Honeypot

Add a hidden input field honeypot to deter spam bots, enhance deliverability, and prevent spam issues. Explore additional tips for form security.

Boost sign-up form security with invisible honeypot fields to catch spam bots. Discover effective techniques for handling bot submissions in your app.

Honeypot Fields in Sign Up Forms

Adding a Honeypot to Protect Against Spam Bots

Protect your website from spam bots with automatic updates to Honeypot configurations.

Enhance security with Remix Utils Honeypot fields. Customize divs, ARIA, and server-side validation to deter spam. Best practices for errors and HTTP codes.

Honeypot Fields for Form Security

Honeypot Protection with `remix-utils`

Efficiently implement Honeypot security on forms: Transfer server data to client for reliable bot protection.

Implement honeypot protection: Create provider, configure props, render components, prevent quick form submission, thwart automated bots.

Honeypot Protection

Honeypots for Form Security 

Ensure consistent Honeypot encryption secret across servers and regions for form data integrity and conflict avoidance

Securely add honeypot secret to server validation, configure in local .env for data protection.

Setting Up Honeypot Security for Server Environment Variables

Consistent Encryption with Honeypot Server

Dad Joke Break Honeypot

Honeypot

Intro to CSRF

Implement CSRF protection: Generate tokens, set secure cookies, associate with clients, and use environment variables.

Implement Node.js CSRF utility: Generate tokens, secure cookies, prevent cross-site request forgery attacks.  

Creating and Managing CSRF Tokens With Node.js

CSRF Protection with Cookies 

Protect user data with authenticity tokens: Render, verify, and enhance user experience.

Secure forms with Authenticity Token input and CSRF validation for protection against tampering. Improve security and error responses.

Security with Authenticity Token and CSRF Validation

Authenticity With Token Protection 

Dad Joke Break CSRF

Cross-Site Request Forgery

Intro to Rate Limit 

Learn how to implement rate limiting middleware in Express for efficient resource management in your server.

Safeguarding Your Server: Adding Rate Limit Configuration

Optimizing Your Express Server with Rate Limiting Middleware

Implement tiered rate limiting: Strong for sign-up/login, moderate for posts, and general defense. Custom middleware assigns tiers.

Professional Web Forms

Professional Web Forms

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Server-side Validation and Custom Error Messages

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