Authentication errors in context in GraphQL - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to check if the user is authenticated in the context.

GraphQL

if (!context.[1]) {
  throw new Error('Not authenticated');
}

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Atoken

Bauth

Cuser

Dsession

Attempts:

3 left

💡 Hint

Common Mistakes

Checking context.auth instead of context.user

Checking context.token which may not be set

Using context.session which might not exist

The context.user property usually holds the authenticated user information. Checking if it exists helps determine if the user is authenticated.

2fill in blank

medium

Complete the code to throw an authentication error with a specific message.

GraphQL

throw new [1]('Authentication failed');

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ATypeError

BReferenceError

CError

DAuthenticationError

Attempts:

3 left

💡 Hint

Common Mistakes

Using generic Error which is less descriptive

Using TypeError or ReferenceError which are unrelated

Not throwing an error at all

AuthenticationError is a common custom error type used to indicate authentication failures in GraphQL APIs.

3fill in blank

hard

Fix the error in the code to correctly access the authentication token from context headers.

GraphQL

const token = context.req.headers.[1];

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AAuthorization

Bauthorization

Ctoken

Dauth

Attempts:

3 left

💡 Hint

Common Mistakes

Using uppercase 'Authorization' which may be undefined

Using 'auth' or 'token' which are not standard header names

The HTTP header for authentication tokens is usually authorization in lowercase when accessed in Node.js request headers.

4fill in blank

hard

Fill both blanks to extract the token from the authorization header string.

GraphQL

const token = context.req.headers.authorization?.[1](' ')[[2]];

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Asplit

B1

C0

Djoin

Attempts:

3 left

💡 Hint

Common Mistakes

Using index 0 which returns 'Bearer' instead of the token

Using join instead of split

Not handling the case when authorization is undefined

The authorization header usually has the format 'Bearer TOKEN'. Splitting by space and taking the second part (index 1) extracts the token.

5fill in blank

hard

Fill all three blanks to verify the token and attach the user to context.

GraphQL

const user = await verifyToken([1]);
if (!user) {
  throw new AuthenticationError('Invalid token');
}
context.[2] = user;
return [3];

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Atoken

Buser

Ccontext.user

Attempts:

3 left

💡 Hint

Common Mistakes

Passing the wrong variable to verifyToken

Not attaching the user to context

Returning context.user instead of user

The token is passed to verifyToken. If valid, the user is attached to context.user. Finally, the user object is returned.