Esther-Lita for Hanko.io

Posted on Sep 13, 2023 • Updated on Oct 11, 2023 • Originally published at docs.hanko.io

💥 Building a Next.js 13 Todo app with Prisma and passkey login 🤯

In this tutorial, you’ll learn how to build a Todo app with the Next.js 13 popular “App Router” structure and understand some of the most important changes that come with it.

We will build a fully functional Todo app:

Create todo
Check and delete a single item
Delete all todos

We will use Hanko for:

Login and registration
User management
Logout

Prisma will handle the storage.

Where should we start? 👷🏻‍♂️

Dealing with complicated frameworks can steal the joy from the beautiful process of creating something from scratch, that’s why finding the right stack for our project is a big step. In this guide, I’ve decided to bring Next.js as the main character of this project because of the amazing opportunity to test the crazy twist they brought with all these “use server” vs “use client” implementations. Also when you are creating the new app, Next.js makes it very simple by giving you the option to integrate everything you’ll probably need like Typescript, ESLint and Tailwind CSS, and yes, we’ll use them all!

Tailwind CSS

For most of the project, I will use Tailwind CSS to style, because I just find it super easy to implement and to bring life into the app, when it comes to code maintenance it’s easy to read and immediately know what is going on in the exact element and Tailwind just makes working with CSS enjoyable.

Prisma

In this app, we don’t need a lot when it comes to where we will store the data, and Prisma is just perfect for what we need for the “todos” to be properly created, updated, and/or deleted.

Hanko

When it comes to securing an app the first thing that comes into play is the combination of building, configuring and styling the login and sign-up on the frontend, and then the complexity of the backend with the functionality, authentication, handling errors, and all the details needed to have a successful and secure “user session”. Here is where Hanko enters the game, taking care of the login, registration, user management and logout, giving us the freedom to be able to spend more time and focus on the other parts of the project.

“Build the best login you have ever seen”

Hanko is an open-source authentication solution focused on taking the development experience to a new level. You can decide what type of information your app will require for the login like email & password, passkeys, email passcodes, and 3rd-party identity providers. Then you can be as creative as you like by styling Hanko's Web Components.

We are ready to set it 🆙

Here I'll walk you through creating the project setup for the application. Make sure to have the latest version of Node.js installed.

Create a new Next.js app

To create a new Next.js app, we can use the create-next-app or create-next-app@latest command-line tool followed by the name of your choice for the app. Open your terminal in Visual Studio Code and run the following command:

 npx  create-next-app@latest todo-nextjs-hanko

This will start the process of creating the project, you will then be asked some prompts on what you will use for the app. The project configuration options should look something like:

The above choices will create a new Next.js app with the chosen name, all the required dependencies for this project will also be installed.

Understanding the project structure

When using version 13 of Next.js, we have the option to work with the App Router directory instead of the Pages Router, for a quick summary we could say that:

The new directory named “app” is replacing “pages”
“page.tsx|page.jsx” is the new “index.tsx|index.jsx”
“layout.tsx” is the new “_app.tsx”
Everything is a Server Component unless you make it a Client Component using the “use client” directive at the top of the file.
API Routes are now Server Components or Route Handlers

Remove unnecessary files, such as logos, icons, etc. If you are going to use Tailwind CSS make sure to bring your desired configuration to the tailwind.config.ts file, defining your color palette, fonts, breakpoints, etc.

ℹ️ For more information about the App Router of Next.js click here.

Get Prisma started

Install the Prisma CLI as a development dependency in the project:

 npm install prisma --save-dev

Set up Prisma with the init command of the Prisma CLI:

 npx prisma init --datasource-provider sqlite

This creates a new prisma directory with your Prisma schema file and configures SQLite as your database. Once we also create the "Todo" model, the Prisma schema file should look like this:

// This is your Prisma schema file,
// learn more about it in the docs: https://pris.ly/d/prisma-schema

generator client {
  provider = "prisma-client-js"
}

datasource db {
  provider = "sqlite"
  url      = env("DATABASE_URL")
}

model Todo {

 id String @id @default(uuid())
  title String
  complete Boolean
  createdAt DateTime @default(now())
  updatedAt DateTime @updatedAt
}

At this point, you have a Prisma schema but no database yet. Run the following command in your terminal to create the SQLite database and the Todo table:

 $ npx prisma migrate dev --name init

This command did two things:

It creates a new SQL migration file for this migration in the prisma/migrations directory.
It runs the SQL migration file against the database.

Because the SQLite database file didn't exist before, the command also created it inside the prisma directory with the name dev.db as defined via the environment variable in the .env file.

To prevent problems when instantiating PrismaClient, on the Prisma Docs there’s a section dedicated to the best practice to do it. Let’s try it by creating a db.ts file in the root of the app and add the following code inside:

import { PrismaClient } from "@prisma/client";

const globalForPrisma = globalThis as unknown as {
  prisma: PrismaClient | undefined;
};

export const prisma = globalForPrisma.prisma ?? new PrismaClient();

if (process.env.NODE_ENV !== "production") globalForPrisma.prisma = prisma;

ℹ️ For more information about Prisma integration click here.

Building the user interface 🛠️

Keeping in mind that we want to build a simple "todo app" with a nice login to protect the todos, we will only need two pages:

The login page where the Hanko-auth component will play its part in handling authentication.
The todo page where all the todos will be displayed.

App structure

In the App Router directory, the page.tsx is like the new index.tsx, which means that this name will play an important role when creating a new route. You can define a page by exporting a component from a page.tsx file.

Now you can update the page.tsx file to display "Hello World" as done below.

export default function Home() {
  return (
    <div>
      <p>Hello World</p>
    </div>
  );
}

We will get back to it later to add a nice login with Hanko.

The Todo page

We will style this page using Tailwind CSS classes to simply create a centered container to display the todos. We need a form with an input to create the new todos, and every todo element will have a checkbox and a delete button. Inside the app directory, create a new todo folder with a page.tsx file inside of it. Use the code below as the todo/page.tsx contents:

export default function Todo() {
  return (
    <main className=" flex min-h-screen justify-center items-center bg-slate-50 ">
      <div className="bg-slate-300 rounded-3xl py-6  h-[400px] w-[450px] flex flex-col text-slate-800">
        <h1 className="text-3xl text-center">My to dos</h1>
        <div className="mx-8 mt-4 mb-6">
          <form className="flex gap-3 items-center">
            <input
              type="text"
              name="title"
              placeholder="New todo"
              className=" border border-slate-400 rounded-full flex-1  py-1 px-2 outline-none focus-within:border-slate-100 bg-slate-50 focus-within:bg-slate-100 placeholder:text-slate-300"
              required
            />
            <button className="  bg-slate-50 rounded-full p-1 border border-slate-400 text-slate-400 hover:text-slate-500 text-base hover:ring-0 hover:ring-slate-100 hover:border-slate-500">
              <p className=" text-center">
             +
              </p>
            </button>
          </form>
        </div>
        <ul className="px-6">
          <li className="flex px-4">
            <span className="flex gap-2 flex-1">
              <input
                type="checkbox"
                name="check"
                className="peer cursor-pointer accent-slate-300 "
              />
              <label
                htmlFor=""
                className="peer-checked:line-through peer-checked:text-slate-500 cursor-pointer"
              >
                Todo 1
              </label>
            </span>
            <button className="text-slate-500  hover:text-slate-800 mr-3">
              X
            </button>
          </li>
        </ul>
      </div>
    </main>
  );
}

🚨 For a better UI use SVGs or icons inside the buttons.

ℹ️ For a better understanding of the Tailwind CSS classes click here.

Todos in the making 🚧

To make our app functional, we need to be able to create a new todo, then check the todo once it’s completed and finally be able to remove a single todo from the list.

API Routes in Next.js 13

When using the App Router of Next.js 13, the API Routes are replaced by Route Handlers and they are defined in a route.ts|js file inside the app directory. There cannot be a route file at the same route segment level as a page.tsx. Read more about the Route Handlers in the Next.js Docs.

Inside the app directory create an api folder. We will group our Route Handlers as follows: one directory todo with a route.ts which will contain the POST HTTP method handler for creating a new todo, and in that same directory we will use a dynamic route to GET and DELETE todos. Should look like the following example:

api
└── todo
    ├── [id]
    │   └── route.ts
    └── route.ts

New Todo

Let’s start by creating a todo. This is a good moment to start breaking it down into components, let’s first create a components folder at the root directory, then create a components/todos/NewTodo.tsx file and use the following as its contents:

"use client";
import { useState } from "react";
import { useRouter } from "next/navigation";

export const NewTodo = () => {
  const [newItem, setNewItem] = useState("");

  const router = useRouter();
  const create = async (e: React.SyntheticEvent) => {
    e.preventDefault();
    await fetch(`/api/todo`, {
      method: "POST",
      credentials: "include",
      headers: {
        "Content-Type": "application/json",
      },
      body: JSON.stringify({
        title: newItem,
      }),
    });

    router.refresh();
    setNewItem("");
  };
  return (
    <div className="mx-8 mt-4 mb-6">
      <form onSubmit={create} className="flex gap-3 items-center">
        <input
          type="text"
          name="title"
          value={newItem}
          onChange={(e) => setNewItem(e.target.value)}
          placeholder="New todo"
          className=" border border-slate-400 rounded-full flex-1  py-1 px-2 outline-none focus-within:border-slate-100 bg-slate-50 focus-within:bg-slate-100 placeholder:text-slate-300"
          required
        />
        <button
          type="submit"
          className="  bg-slate-50 rounded-full p-1 border border-slate-400 text-slate-400 hover:text-slate-500 text-base hover:ring-0 hover:ring-slate-100 hover:border-slate-500"
        >
          <p className=" text-center">+</p>
        </button>
      </form>
    </div>
  );
}

This is a good example of where to bring the "use client" directive to the game, since we are using useState() and subscribing to interactive events.

This is how we call Prisma to create the todo inside the api/todo/route.ts Route Handler:

import { NextResponse } from "next/server";
import { prisma } from "@/db";

export async function POST(req: Request) {
  const { title } = await req.json();

  await prisma.todo.create({
    data: { title, complete: false },
  });

  return NextResponse.json({ message: "Created Todo" }, { status: 200 });
}

You can decide how to check for the right values to be passed and how to handle the errors in the Route Handlers.

Let’s test the "all server components" until we say the opposite from Next.js 13 by calling Prisma from the todo/page.tsx file to get all our todos, then we pass them to our components/todos/TodoItem.tsx file to be displayed. This is how the todo/page.tsx should look after our changes:

import { NewTodo } from "@/components/todos/NewTodo";
import { TodoItem } from "@/components/todos/TodoItem";
import { prisma } from "@/db";

export default async function Todo() {
  const todos = await prisma.todo.findMany();

  return (
    <main className=" flex min-h-screen justify-center items-center bg-slate-50 ">
      <div className="bg-slate-300 rounded-3xl py-6  h-[400px] w-[450px] flex flex-col text-slate-800">
        <h1 className="text-3xl text-center">My to dos</h1>
        <NewTodo />
        <ul className="px-6">
        <TodoItem  todos={todos} />
        </ul>
      </div>
    </main>
  );
}

🚨 Client Components themselves cannot be async functions (official FAQ). And Prisma will break the app if you try to call it inside a Client Component.

Update and Delete todo by ID ✅

Now we already have a way to create a new todo and to display the list of all the todos, in the next step we need a way to handle marking a todo as completed and to handle the deletion of a todo. Accordingly, we create update and delete functions that fetch our dynamic route. This would be the components/todos/TodoItem.tsx file:

"use client";
import { useRouter } from "next/navigation";
import { Todo } from "@prisma/client";

export const TodoItem = ({ todos }: { todos: Todo[] }) => {
  const router = useRouter();
  const update = async (todo: Todo) => {
    await fetch(`/api/todo/${todo.id}`, {
      method: "PATCH",
      headers: {
        "Content-Type": "application/json",
      },
      body: JSON.stringify({
        completed: !todo.complete,
      }),
    });
    router.refresh();
  };

  const deleteTodo = async (todo: Todo) => {
    await fetch(`/api/todo/${todo.id}`, {
      method: "DELETE",
      headers: {
        "Content-Type": "application/json",
      },
      body: JSON.stringify({
        id: todo.id,
      }),
    });

    router.refresh();
  };
  return (
    <>
      {todos.map((todo) => {
        return (
          <li key={todo.id} className="flex px-4">
            <span className="flex gap-2 flex-1">
              <input
                type="checkbox"
                name="check"
                checked={todo.complete}
                onChange={() => update(todo)}
                className="peer cursor-pointer accent-slate-300 "
              />
              <label
                htmlFor={todo.id}
                className="peer-checked:line-through peer-checked:text-slate-500 cursor-pointer"
              >
                {todo.title}
              </label>
            </span>
            <button
              onClick={() => deleteTodo(todo)}
              className="text-slate-500  hover:text-slate-800 mr-3"
            >
              X
            </button>
          </li>
        );
      })}
    </>
  );
};

Add the following code inside the api/todo/[id]/route.ts Route Handler:

import { NextResponse } from "next/server";
import { prisma } from "@/db";

export async function PATCH(
  req: Request,
  { params: { id } }: { params: { id: string } }
) {
  const { completed } = await req.json();

  await prisma.todo.update({
    where: {
      id: id,
    },
    data: {
      complete: completed,
    },
  });
  return NextResponse.json({ message: "Updated" }, { status: 200 });
}

export async function DELETE(req: Request) {
  const { id } = await req.json();

  await prisma.todo.delete({
    where: {
      id: id,
    },
  });
  return NextResponse.json({ message: "Deleted Item" }, { status: 200 });
}

ℹ️ For more information on the Prisma Client Api click here.

Authentication by Hanko

By now you should have a fully functional todo app running. We should start working on the security.

If you’re familiar with Hanko you can skip the next step, otherwise keep on reading to get started with Hanko Cloud to get your Hanko API running.

Hanko Cloud setup ☁️

Visit Hanko Cloud and create an account. Then create an organization for your Hanko project.

Then create a new project and set the App URL to your development URL (example: http://localhost:3000):

And that’s all! Now you can always return to your Hanko Cloud dashboard to see your API URL and other insights about your project, you can also change the app URL in the settings, so that once you want to move from "development" to "production", you can change it to a proper domain/URL. Take the time to discover all the features.

Adding Hanko to the Next.js app

Hanko is a lightweight and easy to implement user authentication solution that makes the transition to passkeys a lot simpler. Let’s bring Hanko to the game by installing the package running the code below:

npm install @teamhanko/hanko-elements

First, let’s update our "Home" page and rename the function to "Login". Import the register function from @teamhanko/hanko-elements, and call the function with the Hanko API URL as an argument to register the <hanko-auth>. Now include it in your JSX:

"use client";
import { useEffect} from "react";
import { register } from "@teamhanko/hanko-elements";

const hankoApi = "YOUR_HANKO_API_URL";
export default function Login() {
  useEffect(() => {
    //
    register(hankoApi ?? "").catch((error) => {
      console.log(error);
    });
  }, []);

  return (
    <div className="flex min-h-screen justify-center items-center ">
      <hanko-auth />
    </div>
  );
}

The code snippet above should display the Hanko authentication component:

The <hanko-profile> component offers a page for managing email addresses and passkeys, and we want to get access to it. Let's create a profile button component by creating a file components/Profile.tsx and use the following code as its content:

"use client";
import { useEffect, useState } from "react";
import { register } from "@teamhanko/hanko-elements";

const hankoApi = "YOUR_HANKO_API_URL";

export const Profile = () => {
  const [openState, setOpenState] = useState(false);

  useEffect(() => {
    register(hankoApi ?? "").catch((error) => {
      console.log(error);
    });
  }, []);

  const openProfile = () => {
    setOpenState(!openState);
  };

  return (
    <>
      <button type="button" onClick={openProfile}>
        Profile
      </button>
      {openState && (
        <div className=" absolute top-14 ">
          <section className=" w-[450px] h-auto rounded-2xl bg-white p-5">
            <hanko-profile />
          </section>
        </div>
      )}
    </>
  );
};

It should look like this:

Now let’s use @teamhanko/hanko-elements to manage user logouts by creating a logout button component. Create a file components/Logout.tsx and use the following as its content:

"use client";
import { useState, useEffect, useCallback } from "react";
import { useRouter } from "next/navigation";
import { Hanko } from "@teamhanko/hanko-elements";

const hankoApi = "YOUR_HANKO_API_URL";

export const Logout = () => {
  const router = useRouter();
  const [hanko, setHanko] = useState<Hanko>();

  useEffect(() => {
    import("@teamhanko/hanko-elements").then(({ Hanko }) =>
      setHanko(new Hanko(hankoApi ?? ""))
    );
  }, []);

  const logout = () => {
    hanko?.user
      .logout()
      .then(() => {
        router.push("/");
        router.refresh();
        return;
      })
      .catch((error) => {
        console.log(error);
      });
  };
  return (
    <>
      <button type="button" onClick={logout}>Logout</button>
    </>
  );
};

When a user logs out, a specific event is triggered that you can subscribe to, like redirecting to an specific page after logout:

  const renewSession = useCallback(() => {
    router.replace("/");
  }, [router]);

  useEffect(
    () =>
      hanko?.onSessionExpired(() => {
        renewSession();
      }),

    [hanko, renewSession]
  );

We will use both buttons at the top left of our Todo page.

ℹ️For more information about all the events that you can "listen" from the Hanko client click here.

Customizing Hanko Components

Hanko components are very easy to customize! To change the <hanko-auth > component, inside our globals.css file we can change the default values of the preconfigured CSS variables listed here to change the default color for the primary button and the border-radius for example:

:root {
  --border-radius: 20px;
  --brand-color: #ff2e4c;
  --brand-color-shade-1: #d52845;
  --brand-color-shade-2: #d62a4c;
}

ℹ️ For more information on how to customize Hanko Components click here.

Verifying JWT with jose library

The JWT is signed by Hanko and to secure our app we still need to verify the JWT.

What are JWTs?
A JSON Web Token (JWT) is a compact and self-contained way for transmitting information between parties as a JSON object in a secure way. The purpose of a JWT is to ensure the authenticity of the data.

Hanko handles the authentication and signing of the JWT. On successful authentication with Hanko a cookie, which contains said JWT as its value, is set. We don’t really need to know a lot about them but it’s worth getting familiar with the parts of a JWT (header, payload and signature), and what a JWKS is. For more information you can also visit JWT.io.

To verify the JWT we need to install the jose-jwt package:

npm i jose

Jose is a JavaScript module that supports JWT and provides functionality for signing and verifying tokens.

ℹ️ For more information about Jose click here.

Middleware

Create a new file middleware.tsx in the root of your project and use the following code:

import * as jose from "jose";
import { NextRequest, NextResponse } from "next/server";

const hankoApi = "YOUR_HANKO_API_URL";

export default async function middleware(req: NextRequest) {
  const token = req.cookies.get("hanko")?.value;

  const JWKS = jose.createRemoteJWKSet(
    new URL(`${hankoApi}/.well-known/jwks.json`)
  );

  try {
    const verifiedJWT = await jose.jwtVerify(token, JWKS);
    console.log(verifiedJWT);
  } catch {
return NextResponse.redirect(new URL("/", req.url));
}
}

To verify the JWT we need the token and the JWKS. We get the token from the "hanko" cookie, and then we obtain the JSON Web Key Set (JWKS) by calling the createRemoteJWKSet function from jose. Then we call await jose.jwtVerify(token, JWKS). If the token can be verified, then the promise returned from the function resolves to a decoded token. If it cannot be verified, then the promise rejects and we can catch the error and handle it appropriately, e.g. by redirecting the user to the login/home page. If you console.log the const verifiedJWT you should see the decoded token showing the payload, the protectedHeader and the key. Inside the key, you should be able to see a "true" if it’s verified.

ℹ️ For more information about Next.js Middleware click here.

Securing the application and redirecting 🔐

We want to prevent unauthorized users from getting access to private user data. A simple way to do this is by adding the paths to be protected in the Middleware configuration. Copy the following code at the bottom of your middleware.tsx file:

export const config = {
  matcher: ["/todo"],
};

Update the Login page to subscribe to the events of the Hanko client and redirect to the Todo page after a successful login:

"use client";
import { useEffect, useState, useCallback } from "react";
import { useRouter } from "next/navigation";
import { register, Hanko } from "@teamhanko/hanko-elements";

const hankoApi = "YOUR_HANKO_API_URL";
export default function Login() {
  const router = useRouter();
  const [hanko, setHanko] = useState<Hanko>();

  useEffect(() => {
    import("@teamhanko/hanko-elements").then(({ Hanko }) =>
      setHanko(new Hanko(hankoApi ?? ""))
    );
  }, []);

  const redirectAfterLogin = useCallback(() => {
    router.replace("/todo");
  }, [router]);

  useEffect(
    () =>
      hanko?.onAuthFlowCompleted(() => {
        redirectAfterLogin();
      }),
    [hanko, redirectAfterLogin]
  );

  useEffect(() => {
    //
    register(hankoApi ?? "").catch((error) => {
      console.log(error);
    });
  }, []);

  return (
    <div className="flex min-h-screen justify-center items-center bg-slate-50">
      <div className="bg-white p-5 rounded-2xl shadow-md">
        <hanko-auth />
      </div>
    </div>
  );
}

Time to display the right Todos 🪄✨

Lastly, we should only display the todos for the user that is logged in. To do so, we need to link the todos to the correct "user ID". The first step is to update the Todo model in the prisma schema:

model Todo {
  userId String
  id String @id @default(uuid())
  title String
  complete Boolean
  createdAt DateTime @default(now())
  updatedAt DateTime @updatedAt
}

Then run the following command to create a migration:

npx prisma migrate

Or the following to push the schema changes directly to the database:

npx prisma db push

Next step is to update the api/todo/route.ts file to get the user ID from the token, then create a new todo if there is a user ID:

import { NextResponse } from "next/server";
import { cookies } from "next/headers";
import * as jose from "jose";
import { prisma } from "@/db";

export async function userId() {
  const token = cookies().get("hanko")?.value;
  const payload = jose.decodeJwt(token ?? "");

  return payload.sub;
}

export async function POST(req: Request) {
  const userID = await userId();
  const { title } = await req.json();

  if (userID) {
    if (typeof title !== "string" || title.length === 0) {
      throw new Error("That can't be a title");
    }
    await prisma.todo.create({
      data: { title, complete: false, userId: userID ?? "" },
    });

    return NextResponse.json({ message: "Created Todo" }, { status: 200 });
  } else {
    return NextResponse.json({ error: "Not Found" }, { status: 404 });
  }
}

The final step is to update the Prisma call to fetch all the todos from the todo/page.tsx:

import { Logout } from "@/components/Logout";
import { Profile } from "@/components/Profile";
import { NewTodo } from "@/components/todos/NewTodo";
import { TodoItem } from "@/components/todos/TodoItem";
import { prisma } from "@/db";
import { userId } from "../api/todo/route";

export default async function Todo() {
  const userID = await userId();

  const todos = await prisma.todo.findMany({
    where: {
      userId: { equals: userID },
    },
  });

  return (
    <main className=" flex flex-col min-h-screen justify-center items-center bg-slate-50 relative ">
      <div className="absolute top-4 left-16">
        <div className=" relative py-4 space-x-6">
          <Profile />
          <Logout />
        </div>
      </div>
      <div className="bg-slate-300 rounded-3xl py-6  h-[400px] w-[450px] flex flex-col text-slate-800">
        <h1 className="text-3xl text-center">My to dos</h1>
        <NewTodo />
        <ul className="px-6">
          <TodoItem todos={todos} />
        </ul>
      </div>
    </main>
  );
}

🤩 App demonstration

You made it! 🎉

Congratulations, You now have a fully functional "Todo App"!

Thanks for staying all the way to the end, today you’ve learnt how to implement some of the Next.js new features, how to authenticate users with Hanko, and a little bit about databases with Prisma.

Next.js App Router has surely been a challenge for me, the transition to learn when and how to use some of the new features can take time but from my perspective it’s totally worth the try.

In times of constant changes, being able to count on authentication easy to integrate is almost a dream come true, Hanko aims to change the way developers and users experience both sides of the login.

Thank you for reading, auf wiedersehen! 👋