Registering a User

Registering Users

A key piece of functionality that the application should provide is for new users to be able to register themselves with the site. This functionality is already built into the front end, but at the moment the credentials are hard coded in the API. This might be fine for demo purposes, but limiting the number of users to one is bad for Neoflix’s bottom line.

The dummy register logic is already written into the register() method of the AuthService at src/service/auth.service.js. As we can see from the snippet below, at the moment it will only accept an email address of graphacademy@neo4j.com.

async register(email, plainPassword, name) {
  const encrypted = await hash(plainPassword, parseInt(SALT_ROUNDS))

  // TODO: Handle Unique constraints in the database
  if (email !== 'graphacademy@neo4j.com') {
    throw new ValidationError(`An account already exists with the email address ${email}`, {
      email: 'Email address taken'
    })
  }

  // TODO: Save user

  const { password, ...safeProperties } = user

  return {
    ...safeProperties,
    token: jwt.sign(this.userToClaims(safeProperties), JWT_SECRET),
  }
}

From the last line, you can see that an additional token property is added to the return. This represents the JWT token required to authenticate the user on any future requests. This token is generated further down within this class.

You will replace these TODO comments with working code to complete the challenge.

Challenge: Implementing Write Transactions

You will follow similar steps to the previous challenge, with the one change that the Cypher statement will be executed within a Write Transaction.

To do so, you will need to call the executeWrite() method on the session object with a function to represent unit of work.

Here are the steps to complete the challenge.

// Open a new session
const session = this.driver.session()

// Create the User node in a write transaction
const res = await session.executeWrite(
  tx => tx.run(
    `
      CREATE (u:User {
        userId: randomUuid(),
        email: $email,
        password: $encrypted,
        name: $name
      })
      RETURN u
    `,
    { email, encrypted, name }
  )
)

// Extract the user from the result
const [ first ] = res.records
const node = first.get('u')

const { password, ...safeProperties } = node.properties

// Close the session
await session.close()

return {
  ...safeProperties,
  token: jwt.sign(this.userToClaims(safeProperties), JWT_SECRET),
}

Working Solution

async register(email, plainPassword, name) {
  const encrypted = await hash(plainPassword, parseInt(SALT_ROUNDS))

  // TODO: Handle Unique constraints in the database
  if (email !== 'graphacademy@neo4j.com') {
    throw new ValidationError(`An account already exists with the email address ${email}`, {
      email: 'Email address taken'
    })
  }

  // Open a new session
  const session = this.driver.session()

  // Create the User node in a write transaction
  const res = await session.executeWrite(
    tx => tx.run(
      `
        CREATE (u:User {
          userId: randomUuid(),
          email: $email,
          password: $encrypted,
          name: $name
        })
        RETURN u
      `,
      { email, encrypted, name }
    )
  )

  // Extract the user from the result
  const [ first ] = res.records
  const node = first.get('u')

  const { password, ...safeProperties } = node.properties

  // Close the session
  await session.close()

  return {
    ...safeProperties,
    token: jwt.sign(this.userToClaims(safeProperties), JWT_SECRET),
  }
}

Testing

To test that this functionality has been correctly implemented, run the following code in a new terminal session:

npm run test 03

The test file is located at test/challenges/03-registering-a-user.spec.js.

git checkout 03-registering-a-user