11-authenticate-a-user-with-a-graphql-mutation.md

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Summary

In this lesson we learn how to authenticate a user using mutations.

Notes

Mutations let you invoke backend functions from the client. Here we will use the logIn mutation to log in a user.

mutation {
  logIn(username: "ep123", password: "pass")
}

A type LogInPayload is returned from the logIn mutation. This is a custom object that returns both a customer and user token. We can use the token to validate that the user is authorized.

When we send the logIn mutation, we have access to the customer details and token.

mutation {
  logIn(username: "ep123", password: "pass") {
    customer {
      name
    }
    token
  }
}

Once we provide the token in the HTTP headers, we are able to send queries that are only for authorized users.

Now we are able to make the query me, and get back data for the logged in user.

query me {
  me {
    name
  }
}

Resources

• Mutations (official website)