Response caching strategies in GraphQL - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to set a cache control directive for a GraphQL query response.

GraphQL

query GetUser { user(id: 1) @cacheControl(maxAge: [1]) { id name } }

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

Atrue

Bnull

C"max-age"

D60

Attempts:

3 left

💡 Hint

Common Mistakes

Using a boolean value instead of a number for maxAge.

Using a string instead of a number for maxAge.

The @cacheControl directive uses maxAge to specify how many seconds the response should be cached.

2fill in blank

medium

Complete the code to add a cache hint to a GraphQL resolver.

GraphQL

const resolvers = { Query: { user: (parent, args, context) => { context.cacheControl.setCacheHint({ [1]: 120 }); return getUser(args.id); } } };

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

AmaxAge

Bcache

Cttl

Dduration

Attempts:

3 left

💡 Hint

Common Mistakes

Using incorrect property names like 'ttl' or 'duration'.

Omitting the property name and passing only a number.

The setCacheHint method expects a maxAge property to define cache duration in seconds.

3fill in blank

hard

Fix the error in the cache control directive usage in this GraphQL schema snippet.

GraphQL

type Query { user(id: ID!): User @cacheControl(maxAge: [1]) }

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

A60

Btrue

C"60"

Dnull

Attempts:

3 left

💡 Hint

Common Mistakes

Using a string instead of a number for maxAge.

Using a boolean value instead of a number.

The maxAge argument must be a number, not a string or boolean.

4fill in blank

hard

Fill both blanks to set cache hints with maxAge and scope in a resolver.

GraphQL

context.cacheControl.setCacheHint({ [1]: 300, scope: '[2]' });

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

AmaxAge

Bscope

CPUBLIC

DPRIVATE

Attempts:

3 left

💡 Hint

Common Mistakes

Using incorrect property names.

Using scope values without quotes.

The maxAge sets cache duration, and scope defines if cache is public or private.

5fill in blank

hard

Fill all three blanks to define a cache control directive with maxAge, scope, and inheritMaxAge.

GraphQL

type Query { posts: [Post] @cacheControl(maxAge: [1], scope: [2], inheritMaxAge: [3]) }

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

A120

BPUBLIC

Ctrue

DPRIVATE

Attempts:

3 left

💡 Hint

Common Mistakes

Putting quotes around maxAge number.

Using unquoted scope values.

Using string instead of boolean for inheritMaxAge.

maxAge is a number, scope is a string ('PUBLIC' or 'PRIVATE'), and inheritMaxAge is a boolean.

Practice

1. What is the main purpose of response caching in GraphQL?

easy

A. To store query results and speed up repeated requests

B. To encrypt data sent between client and server

C. To validate user permissions for queries

D. To log all queries for debugging

Solution

1. Step 1: Understand response caching concept

   Response caching saves the answers of queries so that if the same query is asked again, the server can quickly return the saved answer instead of recalculating it.

2. Step 2: Identify the main benefit

   This speeds up repeated requests and reduces server load.

3. Final Answer:

   To store query results and speed up repeated requests -> Option A

4. Quick Check:

   Response caching = store and speed up [OK]

Hint: Caching saves answers to reuse later, speeding up requests [OK]

Common Mistakes:

• Confusing caching with encryption
• Thinking caching controls permissions
• Believing caching logs queries

2. Which of the following is the correct way to set a cache duration using the @cacheControl directive in GraphQL SDL?

easy

A. @cacheControl(duration: 60)

B. @cacheControl(maxAge: 60)

C. @cacheControl(cacheTime: 60)

D. @cacheControl(time: 60)

Solution

1. Step 1: Recall the correct directive syntax

   The @cacheControl directive uses the argument maxAge to specify cache duration in seconds.

2. Step 2: Match the correct argument name

   Only maxAge is valid; other argument names like duration, cacheTime, or time are incorrect.

3. Final Answer:

   @cacheControl(maxAge: 60) -> Option B

4. Quick Check:

   @cacheControl uses maxAge [OK]

Hint: Use maxAge to set cache seconds in @cacheControl [OK]

Common Mistakes:

• Using wrong argument names like duration or time
• Omitting the argument name
• Using invalid directive syntax

3. Given this GraphQL query with caching set to @cacheControl(maxAge: 120), what happens if the same query is requested twice within 2 minutes?

medium

A. The server returns the cached response on the second request

B. The server returns an error on the second request

C. The server recalculates the response both times

D. The cache is ignored and data is fetched fresh every time

Solution

1. Step 1: Understand maxAge meaning

   The maxAge: 120 means the response is cached for 120 seconds (2 minutes).

2. Step 2: Analyze repeated request timing

   If the second request happens within 2 minutes, the cached response is still valid and returned immediately.

3. Final Answer:

   The server returns the cached response on the second request -> Option A

4. Quick Check:

   maxAge 120 means cache valid 2 minutes [OK]

Hint: Within maxAge, cached response is reused [OK]

Common Mistakes:

• Thinking cache expires immediately
• Assuming server errors on repeated queries
• Believing cache is ignored always

4. You set @cacheControl(maxAge: -10) on a field. What is the likely problem?

medium

A. Negative maxAge causes a syntax error

B. Negative maxAge disables caching for that field

C. Negative maxAge is treated as zero, caching forever

D. Negative maxAge causes cache to expire immediately

Solution

1. Step 1: Understand maxAge value meaning

   maxAge defines how long the response is cached in seconds. Negative values are invalid for duration.

2. Step 2: Interpret negative maxAge effect

   Negative maxAge is treated as cache expired immediately, so no caching occurs effectively.

3. Final Answer:

   Negative maxAge causes cache to expire immediately -> Option D

4. Quick Check:

   Negative maxAge means cache expires instantly [OK]

Hint: Negative maxAge means cache expires right away [OK]

Common Mistakes:

• Expecting syntax error from negative value
• Thinking negative disables caching explicitly
• Assuming negative means cache forever

5. You want to cache a GraphQL query response for a user profile that updates frequently but not every second. Which caching strategy is best?

hard

A. Set @cacheControl(maxAge: 5) to cache for 5 seconds

B. Set @cacheControl(maxAge: 3600) to cache for 1 hour

C. Set @cacheControl(maxAge: 300) to cache for 5 minutes

D. Do not use caching to always get fresh data

Solution

1. Step 1: Consider data freshness needs

   User profiles update frequently but not every second, so caching too long risks stale data.

2. Step 2: Choose a balanced cache duration

   5 seconds is too short to gain caching benefits; 1 hour is too long risking stale data. 5 minutes (300 seconds) balances freshness and performance.

3. Final Answer:

   Set @cacheControl(maxAge: 300) to cache for 5 minutes -> Option C

4. Quick Check:

   Moderate maxAge balances freshness and speed [OK]

Hint: Pick cache time balancing freshness and speed [OK]

Common Mistakes:

• Choosing too short cache time losing benefits
• Choosing too long cache time causing stale data
• Avoiding caching when moderate caching helps