Add an example for Fauna using cookie based auth (round 2)

examples/with-cookie-auth-fauna/.env

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+FAUNA_SERVER_KEY="<ENTER YOUR FAUNA SERVER KEY>"

examples/with-cookie-auth-fauna/README.md

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+# With Cookie Auth and Fauna
+
+## How to use
+
+### Using `create-next-app`
+
+Download [`create-next-app`](https://github.com/zeit/next.js/tree/canary/packages/create-next-app) to bootstrap the example:
+
+```bash
+npm i -g create-next-app
+create-next-app --example with-cookie-auth-fauna with-cookie-auth-fauna-app
+```
+
+### Download manually
+
+Download the example [or clone the repo](https://github.com/zeit/next.js):
+
+```bash
+curl https://codeload.github.com/zeit/next.js/tar.gz/canary | tar -xz --strip=2 next.js-canary/examples/with-cookie-auth-fauna
+cd with-cookie-auth-fauna
+```
+
+### Run locally
+
+First, you'll need to create an account on [Fauna](https://fauna.com/), then follow these steps:
+
+1. In the [FaunaDB Console](https://dashboard.fauna.com/), click "New Database". Name it whatever you like and click "Save".
+2. Click "New Collection", name it `User`, leave "Create collection index" checked, and click "Save".
+3. Now go to "Indexes" in the left sidebar, and click "New Index". Select the `User` collection, call it `users_by_email`, and in the "terms" field type `data.email`. Select the "Unique" checkbox and click "Save". This will create an index that allows looking up users by their email, which we will use to log a user in.
+4. Next, go to "Security" in the sidebar, then click "New Key". Create a new key with the `Server` role, call it `server-key`, and click "Save". Your key's secret will be displayed, copy that value and paste it as the value for `FAUNA_SERVER_KEY` in the `.env` file at the project root. Keep this key safely as it has privileged access to your database.
+
+> For more information, read the [User Authentication Tutorial in Fauna](https://app.fauna.com/tutorials/authentication).
+
+> **Add `.env` to `.gitignore`**, files with secrets should never be in the cloud, we have it here for the sake of the example.
+
+Now, install it and run:
+
+```bash
+npm install
+npm run dev
+# or
+yarn
+yarn dev
+```
+
+### Deploy
+
+We'll use [now](https://zeit.co/now) to deploy our app, first we need to add the server key as a secret using [now secrets](https://zeit.co/docs/v2/serverless-functions/env-and-secrets/?query=secrets#adding-secrets), like so:
+
+```bash
+now secrets add fauna-secret-key "ENTER YOUR FAUNA SERVER KEY"
+```
+
+Then deploy it to the cloud:
+
+```bash
+now
+```
+
+## The idea behind the example
+
+In this example, we authenticate users and store a token in a secure (non-JS) cookie. The example only shows how the user session works, keeping a user logged in between pages.
+
+This example uses [Fauna](https://fauna.com/) as the auth service and DB.
+
+The repo includes a minimal auth backend built with the new [API Routes support](https://github.com/zeit/next.js/pull/7296) (`pages/api`), [Micro](https://www.npmjs.com/package/micro), [Fauna for Auth](https://app.fauna.com/tutorials/authentication) and [dotenv](https://github.com/zeit/next.js/tree/canary/examples/with-dotenv) for environment variables. The backend allows the user to create an account (a User document), login, and see their user id (User ref id).
+
+Session is synchronized across tabs. If you logout your session gets removed on all the windows as well. We use the HOC `withAuthSync` for this.
+
+The helper function `auth` helps to retrieve the token across pages and redirects the user if not token was found.

examples/with-cookie-auth-fauna/components/header.js

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+import Link from 'next/link'
+import { logout } from '../utils/auth'
+
+const Header = props => (
+  <header>
+    <nav>
+      <ul>
+        <li>
+          <Link href="/">
+            <a>Home</a>
+          </Link>
+        </li>
+        <li>
+          <Link href="/login">
+            <a>Login</a>
+          </Link>
+        </li>
+        <li>
+          <Link href="/signup">
+            <a>Signup</a>
+          </Link>
+        </li>
+        <li>
+          <Link href="/profile">
+            <a>Profile</a>
+          </Link>
+        </li>
+        <li>
+          <button onClick={logout}>Logout</button>
+        </li>
+      </ul>
+    </nav>
+    <style jsx>{`
+      ul {
+        display: flex;
+        list-style: none;
+        margin-left: 0;
+        padding-left: 0;
+      }
+
+      li {
+        margin-right: 1rem;
+      }
+
+      li:first-child {
+        margin-left: auto;
+      }
+
+      a {
+        color: #fff;
+        text-decoration: none;
+      }
+
+      header {
+        padding: 0.2rem;
+        color: #fff;
+        background-color: #333;
+      }
+    `}</style>
+  </header>
+)
+
+export default Header

examples/with-cookie-auth-fauna/components/layout.js

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+import Head from 'next/head'
+import Header from './header'
+
+const Layout = props => (
+  <>
+    <Head>
+      <title>With Cookies</title>
+    </Head>
+    <style jsx global>{`
+      *,
+      *::before,
+      *::after {
+        box-sizing: border-box;
+      }
+
+      body {
+        margin: 0;
+        color: #333;
+        font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto,
+          'Helvetica Neue', Arial, Noto Sans, sans-serif, 'Apple Color Emoji',
+          'Segoe UI Emoji', 'Segoe UI Symbol', 'Noto Color Emoji';
+      }
+
+      .container {
+        max-width: 65rem;
+        margin: 1.5rem auto;
+        padding-left: 1rem;
+        padding-right: 1rem;
+      }
+    `}</style>
+    <Header />
+
+    <main>
+      <div className="container">{props.children}</div>
+    </main>
+  </>
+)
+
+export default Layout

examples/with-cookie-auth-fauna/next.config.js

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+require('dotenv').config()
+
+module.exports = {
+  env: {
+    // Set the fauna server key in the .env file and make it available at Build Time.
+    FAUNA_SERVER_KEY: process.env.FAUNA_SERVER_KEY,
+  },
+}

examples/with-cookie-auth-fauna/now.json

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+{
+  "build": {
+    "env": {
+      "FAUNA_SERVER_KEY": "@fauna-secret-key"
+    }
+  }
+}

examples/with-cookie-auth-fauna/package.json

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+{
+  "name": "with-cookie-auth",
+  "scripts": {
+    "dev": "next",
+    "build": "next build",
+    "start": "next start"
+  },
+  "dependencies": {
+    "cookie": "^0.4.0",
+    "dotenv": "8.2.0",
+    "faunadb": "2.10.0",
+    "js-cookie": "^2.2.0",
+    "next": "^9.0.1",
+    "react": "^16.8.6",
+    "react-dom": "^16.8.6"
+  }
+}

examples/with-cookie-auth-fauna/pages/api/login.js

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+import { query as q } from 'faunadb'
+import { serverClient, serializeFaunaCookie } from '../../utils/fauna-auth'
+
+export default async (req, res) => {
+  const { email, password } = await req.body
+
+  try {
+    if (!email || !password) {
+      throw new Error('Email and password must be provided.')
+    }
+
+    const loginRes = await serverClient.query(
+      q.Login(q.Match(q.Index('users_by_email'), email), {
+        password,
+      })
+    )
+
+    if (!loginRes.secret) {
+      throw new Error('No secret present in login query response.')
+    }
+
+    const cookieSerialized = serializeFaunaCookie(loginRes.secret)
+
+    res.setHeader('Set-Cookie', cookieSerialized)
+    res.status(200).end()
+  } catch (error) {
+    res.status(400).send(error.message)
+  }
+}

examples/with-cookie-auth-fauna/pages/api/logout.js

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+import { query as q } from 'faunadb'
+import cookie from 'cookie'
+import { faunaClient, FAUNA_SECRET_COOKIE } from '../../utils/fauna-auth'
+
+export default async (req, res) => {
+  const cookies = cookie.parse(req.headers.cookie ?? '')
+  const faunaSecret = cookies[FAUNA_SECRET_COOKIE]
+  if (!faunaSecret) {
+    // Already logged out.
+    return res.status(200).end()
+  }
+  // Invalidate secret (ie. logout from Fauna).
+  await faunaClient(faunaSecret).query(q.Logout(false))
+  // Clear cookie.
+  const cookieSerialized = cookie.serialize(FAUNA_SECRET_COOKIE, '', {
+    sameSite: 'lax',
+    secure: process.env.NODE_ENV === 'production',
+    maxAge: -1,
+    httpOnly: true,
+    path: '/',
+  })
+  res.setHeader('Set-Cookie', cookieSerialized)
+  res.status(200).end()
+}

examples/with-cookie-auth-fauna/pages/api/profile.js

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+import { query as q } from 'faunadb'
+import cookie from 'cookie'
+import { faunaClient, FAUNA_SECRET_COOKIE } from '../../utils/fauna-auth'
+
+export const profileApi = async faunaSecret => {
+  const ref = await faunaClient(faunaSecret).query(q.Identity())
+  return ref.id
+}
+
+export default async (req, res) => {
+  const cookies = cookie.parse(req.headers.cookie ?? '')
+  const faunaSecret = cookies[FAUNA_SECRET_COOKIE]
+
+  if (!faunaSecret) {
+    return res.status(401).send('Auth cookie missing.')
+  }
+
+  res.status(200).json({ userId: await profileApi(faunaSecret) })
+}

examples/with-cookie-auth-fauna/pages/api/signup.js

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+import { query as q } from 'faunadb'
+import { serverClient, serializeFaunaCookie } from '../../utils/fauna-auth'
+
+export default async (req, res) => {
+  const { email, password } = await req.body
+
+  try {
+    if (!email || !password) {
+      throw new Error('Email and password must be provided.')
+    }
+    console.log(`email: ${email} trying to create user.`)
+
+    let user
+
+    try {
+      user = await serverClient.query(
+        q.Create(q.Collection('User'), {
+          credentials: { password },
+          data: { email },
+        })
+      )
+    } catch (error) {
+      console.error('Fauna create user error:', error)
+      throw new Error('User already exists.')
+    }
+
+    if (!user.ref) {
+      throw new Error('No ref present in create query response.')
+    }
+
+    const loginRes = await serverClient.query(
+      q.Login(user.ref, {
+        password,
+      })
+    )
+
+    if (!loginRes.secret) {
+      throw new Error('No secret present in login query response.')
+    }
+
+    const cookieSerialized = serializeFaunaCookie(loginRes.secret)
+
+    res.setHeader('Set-Cookie', cookieSerialized)
+    res.status(200).end()
+  } catch (error) {
+    res.status(400).send(error.message)
+  }
+}

examples/with-cookie-auth-fauna/pages/index.js

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+import React from 'react'
+import Layout from '../components/layout'
+
+const Home = () => (
+  <Layout>
+    <h1>Cookie-based authentication example</h1>
+
+    <p>Steps to test the functionality:</p>
+
+    <ol>
+      <li>Click signup and create an account, this will also log you in.</li>
+      <li>
+        Click home and click profile again, notice how your session is being
+        used through a token stored in a cookie.
+      </li>
+      <li>
+        Click logout and try to go to profile again. You'll get redirected to
+        the `/login` route.
+      </li>
+    </ol>
+    <style jsx>{`
+      li {
+        margin-bottom: 0.5rem;
+      }
+    `}</style>
+  </Layout>
+)
+
+export default Home