Schema visibility control in GraphQL - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to define a GraphQL schema with a visible Query type.

GraphQL

type [1] { hello: String }

Drag options to blanks, or click blank then click option'

AMutation

BQuery

CSubscription

DVisible

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'Mutation' or 'Subscription' as the root query type.

Naming the type something unrelated like 'Visible'.

The root query type in GraphQL schema is named Query. This makes the schema visible for queries.

2fill in blank

medium

Complete the directive to hide a field from the schema.

GraphQL

type Query { secretField: String [1] }

Drag options to blanks, or click blank then click option'

A@deprecated

B@skip

C@hidden

D@include

Attempts:

3 left

💡 Hint

Common Mistakes

Using '@deprecated' which only marks a field as deprecated but does not hide it.

Using '@skip' or '@include' which control query execution, not schema visibility.

The @hidden directive is used to hide fields from the schema visibility.

3fill in blank

hard

Fix the error in the schema to properly hide the Mutation type.

GraphQL

schema { query: Query mutation: [1] }

Drag options to blanks, or click blank then click option'

AMutation

BHiddenMutation

CMutation @deprecated

DMutation @hidden

Attempts:

3 left

💡 Hint

Common Mistakes

Just renaming the type without hiding it.

Using '@deprecated' which does not hide the type.

To hide the Mutation type, you must add the @hidden directive after its name in the schema definition.

4fill in blank

hard

Fill both blanks to define a schema with a visible Query and a hidden Mutation.

GraphQL

schema { query: [1] mutation: [2] }

Drag options to blanks, or click blank then click option'

AQuery

BMutation

CMutation @hidden

DSubscription

Attempts:

3 left

💡 Hint

Common Mistakes

Not adding '@hidden' to Mutation.

Using 'Subscription' instead of 'Mutation' for mutation root.

The query root is set to Query to be visible, and the mutation root is set to Mutation @hidden to hide it.

5fill in blank

hard

Fill all three blanks to define a schema with a visible Query, a hidden Mutation, and a visible Subscription.

GraphQL

schema { query: [1] mutation: [2] subscription: [3] }

Drag options to blanks, or click blank then click option'

AQuery

BMutation @hidden

CSubscription

DMutation

Attempts:

3 left

💡 Hint

Common Mistakes

Not hiding Mutation with '@hidden'.

Mixing up Subscription and Mutation roots.

The schema has a visible Query, a hidden Mutation @hidden, and a visible Subscription root.

Practice

1. What is the main purpose of schema visibility control in GraphQL?

easy

A. To limit what parts of the schema users can see or access

B. To speed up query execution by caching results

C. To automatically generate schema documentation

D. To convert GraphQL queries into SQL queries

Solution

1. Step 1: Understand schema visibility control concept

   Schema visibility control is about restricting access to parts of the GraphQL schema based on user roles or permissions.

2. Step 2: Identify the main goal

   The goal is to protect sensitive data and tailor the API by limiting what users can see or use.

3. Final Answer:

   To limit what parts of the schema users can see or access -> Option A

4. Quick Check:

   Schema visibility control = limit schema access [OK]

Hint: Focus on access limits, not performance or docs [OK]

Common Mistakes:

• Confusing visibility control with caching
• Thinking it auto-generates docs
• Assuming it converts queries to SQL

2. Which of the following is a correct way to hide a field in a GraphQL schema using a directive?

easy

A. @deprecated(reason: "hidden") on the field

B. @private on the query operation

C. @skip(if: false) on the schema type

D. @hide(if: true) on the field definition

Solution

1. Step 1: Understand directive usage for visibility

   Directives like @hide(if: true) can be used on fields to conditionally hide them based on logic.

2. Step 2: Evaluate options

   @private is not a standard directive; @skip(if: false) means do not skip (show field); @deprecated marks fields as deprecated but does not hide them.

3. Final Answer:

   @hide(if: true) on the field definition -> Option D

4. Quick Check:

   Use conditional directives like @hide to control visibility [OK]

Hint: Look for conditional directive on field, not operation [OK]

Common Mistakes:

• Using @deprecated to hide fields
• Applying directives on queries instead of fields
• Misunderstanding @skip logic

3. Given this schema snippet with a visibility directive:

type User {
  id: ID!
  email: String @hide(if: $isGuest)
  name: String
}

What fields will a guest user see if $isGuest is true?

medium

A. id and name only

B. id, email, and name

C. email and name only

D. id and email only

Solution

1. Step 1: Analyze the directive condition

   The @hide(if: $isGuest) directive hides the email field when $isGuest is true.

2. Step 2: Determine visible fields for guest

   Since $isGuest is true, email is hidden. The visible fields are id and name.

3. Final Answer:

   id and name only -> Option A

4. Quick Check:

   @hide(if: true) hides field = id and name visible [OK]

Hint: True condition hides field, so exclude it [OK]

Common Mistakes:

• Including hidden fields in output
• Confusing @hide with @skip
• Ignoring variable values in directives

4. You wrote this directive to hide a field:

email: String @hide(if: isGuest)

But the field is always visible. What is the likely error?

medium

A. Using @hide on a field is not supported

B. Missing $ before variable name in directive condition

C. The field type String cannot have directives

D. The directive should be @skip, not @hide

Solution

1. Step 1: Check variable usage in directive

   GraphQL variables in directives must be prefixed with $. Here, isGuest is missing $.

2. Step 2: Understand impact of missing $

   Without $, the directive condition is invalid or always false, so the field is never hidden.

3. Final Answer:

   Missing $ before variable name in directive condition -> Option B

4. Quick Check:

   Variables need $ prefix in directives [OK]

Hint: Always prefix variables with $ in directives [OK]

Common Mistakes:

• Forgetting $ before variable in directive
• Assuming @hide is unsupported
• Thinking directives can't be on scalar fields

5. You want to create a GraphQL API that shows users' email only to admins and hides it from regular users. Which approach best implements this schema visibility control?

hard

A. Return null for email in resolver for regular users without schema changes

B. Remove the email field from the schema entirely

C. Use @hide(if: $isNotAdmin) on the email field and pass $isNotAdmin from server context

D. Use @deprecated directive on email field for regular users

Solution

1. Step 1: Identify requirement for conditional visibility

   The email field should be visible only to admins, so visibility depends on user role.

2. Step 2: Evaluate options for controlling visibility

   Use a directive like @hide(if: $isNotAdmin) on the email field and pass $isNotAdmin from server context. This uses a directive with a variable from server context to hide email for non-admins, which is the correct schema visibility control method.

3. Step 3: Understand why other options fail

   Removing the field removes it for all users; @deprecated only marks as outdated; returning null hides data but not schema field.

4. Final Answer:

   Use @hide(if: $isNotAdmin) on the email field and pass $isNotAdmin from server context -> Option C

5. Quick Check:

   Use conditional directives with server variables for visibility [OK]

Hint: Use directives with server variables for role-based hiding [OK]

Common Mistakes:

• Removing fields instead of hiding conditionally
• Using @deprecated to hide fields
• Returning null but not hiding schema field