Introspection control in GraphQL - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is GraphQL introspection?

GraphQL introspection is a feature that lets clients ask a GraphQL server about its schema, types, and queries it supports. It helps tools and developers explore the API.

intermediate

Why might you want to control or disable introspection in GraphQL?

To improve security by hiding schema details from unauthorized users, reducing attack surface, and preventing exposure of sensitive API structure.

intermediate

How can you disable introspection in a GraphQL server?

You can disable introspection by intercepting introspection queries and returning errors or empty results, or by configuring server settings to block introspection queries.

beginner

What is a common introspection query in GraphQL?

A common introspection query is one that asks for __schema or __type fields to get details about the schema, types, fields, and directives supported by the server.

advanced

What is a safe way to allow introspection only for authorized users?

Implement authentication and authorization checks in the server to allow introspection queries only if the user has proper permissions, otherwise block or deny introspection.

What does GraphQL introspection allow you to do?

A Ask the server about its schema and types

B Modify the database directly

C Encrypt the API data

D Automatically generate client code

Introspection lets clients query the server for schema details, not modify data or encrypt it.

Why might disabling introspection improve security?

A It hides schema details from unauthorized users

B It speeds up query execution

C It encrypts all data sent to clients

D It prevents all queries from running

Disabling introspection hides schema info, reducing what attackers can learn about the API.

Which GraphQL field is commonly used in introspection queries?

A mutation

B query

C subscription

D __schema

__schema is a special field used to get schema details in introspection.

How can you restrict introspection to authorized users?

A Disable all queries except introspection

B Allow introspection only on weekends

C Check user permissions before allowing introspection queries

D Use introspection to authenticate users

Authorization checks ensure only permitted users can run introspection queries.

What happens if introspection is disabled on a GraphQL server?

A Clients get full schema details

B Introspection queries return errors or no data

C The server crashes

D All queries fail

Disabling introspection causes introspection queries to fail or return empty results.

Explain what GraphQL introspection is and why controlling it matters.

Think about how introspection helps and what risks it might bring.

Describe methods to control or disable introspection in a GraphQL server.

Consider both technical and security approaches.

Practice

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

easy

A. To speed up database queries by caching results

B. To allow or block schema queries for security and performance

C. To automatically generate API documentation

D. To encrypt data sent between client and server

Solution

1. Step 1: Understand what introspection means in GraphQL

   Introspection allows clients to query the schema itself to learn about types and fields.

2. Step 2: Identify the purpose of controlling introspection

   Controlling introspection lets you block or allow these schema queries to protect your API and improve performance.

3. Final Answer:

   To allow or block schema queries for security and performance -> Option B

4. Quick Check:

   Introspection control = Allow/block schema queries [OK]

Hint: Introspection controls schema query access, not data fetching [OK]

Common Mistakes:

• Confusing introspection with data query optimization
• Thinking introspection encrypts data
• Assuming introspection auto-generates docs

2. Which of the following is the correct way to disable introspection in a GraphQL server setup?

easy

A. introspection: 'off'

B. introspection = false

C. disableIntrospection: true

D. introspection: false

Solution

1. Step 1: Recall the syntax for toggling introspection in GraphQL server config

   The option is usually set as introspection: true or introspection: false.

2. Step 2: Identify the correct syntax to disable introspection

   Setting introspection: false disables introspection queries.

3. Final Answer:

   introspection: false -> Option D

4. Quick Check:

   Disable introspection = introspection: false [OK]

Hint: Use boolean false, not strings or other keys [OK]

Common Mistakes:

• Using assignment (=) instead of colon (:)
• Using string values instead of boolean
• Using incorrect option names like disableIntrospection

3. Given this GraphQL server config snippet:

const server = new ApolloServer({
  typeDefs,
  resolvers,
  introspection: false
});

What will happen if a client sends an introspection query?

medium

A. The server will return an error or empty response

B. The server will respond with the full schema details

C. The server will ignore the introspection query and respond normally

D. The server will crash due to unsupported query

Solution

1. Step 1: Understand the effect of introspection: false

   This setting disables introspection queries, so the server blocks schema queries.

2. Step 2: Predict server response to introspection query

   The server will reject the introspection query, usually returning an error or empty result.

3. Final Answer:

   The server will return an error or empty response -> Option A

4. Quick Check:

   introspection: false blocks schema queries [OK]

Hint: introspection false means introspection queries fail [OK]

Common Mistakes:

• Thinking server still returns schema data
• Assuming server crashes on introspection query
• Believing server ignores introspection queries silently

4. You wrote this server setup:

const server = new ApolloServer({
  typeDefs,
  resolvers,
  introspection: 'false'
});

Why does introspection control not work as expected?

medium

A. Because ApolloServer does not support introspection control

B. Because introspection must be set to true to disable it

C. Because introspection expects a boolean, not a string

D. Because typeDefs is missing introspection schema

Solution

1. Step 1: Check the data type of the introspection option

   The option should be a boolean (true or false), not a string.

2. Step 2: Identify why using a string causes failure

   Using 'false' as a string is truthy in JavaScript, so introspection remains enabled.

3. Final Answer:

   Because introspection expects a boolean, not a string -> Option C

4. Quick Check:

   introspection must be boolean, not string [OK]

Hint: Use true/false without quotes for boolean options [OK]

Common Mistakes:

• Using string 'false' instead of boolean false
• Thinking introspection must be true to disable
• Assuming ApolloServer lacks introspection control

5. You want to improve API security by disabling introspection only in production but keep it enabled in development. Which code snippet correctly implements this?

hard

A. const server = new ApolloServer({ typeDefs, resolvers, introspection: process.env.NODE_ENV !== 'production' });

B. const server = new ApolloServer({ typeDefs, resolvers, introspection: process.env.NODE_ENV === 'production' });

C. const server = new ApolloServer({ typeDefs, resolvers, introspection: false });

D. const server = new ApolloServer({ typeDefs, resolvers, introspection: true });

Solution

1. Step 1: Understand the goal

   Disable introspection in production, enable in development.

2. Step 2: Analyze each option's logic

   const server = new ApolloServer({ typeDefs, resolvers, introspection: process.env.NODE_ENV !== 'production' }); sets introspection to true when not in production, false in production, matching the goal.

3. Final Answer:

   const server = new ApolloServer({ typeDefs, resolvers, introspection: process.env.NODE_ENV !== 'production' }); -> Option A

4. Quick Check:

   introspection enabled only if not production [OK]

Hint: Use environment check with !== 'production' for introspection [OK]

Common Mistakes:

• Using === 'production' enables introspection in production
• Always setting introspection true or false ignores environment
• Confusing production and development environment logic