Cache management in GraphQL - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

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

GraphQL

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

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

A60

Bnull

C"max-age"

Dtrue

Attempts:

3 left

💡 Hint

Common Mistakes

Using boolean values instead of a number for maxAge.

Putting maxAge value in quotes.

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

2fill in blank

medium

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

GraphQL

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

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

Acache

Bttl

Cduration

DmaxAge

Attempts:

3 left

💡 Hint

Common Mistakes

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

Passing a string instead of a number for maxAge.

The setCacheHint method expects an object with maxAge to set cache duration.

3fill in blank

hard

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

GraphQL

type Query { books: [Book] @cacheControl(maxAge: [1]) }

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

Atrue

B"300"

C300

Dnull

Attempts:

3 left

💡 Hint

Common Mistakes

Putting the number in quotes making it a string.

Using boolean values instead of a number.

The maxAge value 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

info.cacheControl.setCacheHint({ [1]: 180, [2]: '[3]' });

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

AmaxAge

Bscope

CPUBLIC

DPRIVATE

Attempts:

3 left

💡 Hint

Common Mistakes

Using incorrect keys like 'cache' or 'duration'.

Using lowercase or misspelled scope values.

Use maxAge for duration and scope with values like PUBLIC or PRIVATE.

5fill in blank

hard

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

GraphQL

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

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

A120

BPUBLIC

Ctrue

Dfalse

Attempts:

3 left

💡 Hint

Common Mistakes

Using quotes around numeric values.

Using lowercase for scope values.

Using strings instead of booleans for inheritMaxAge.

The @cacheControl directive accepts maxAge as a number, scope as 'PUBLIC' or 'PRIVATE', and inheritMaxAge as a boolean.

Practice

1. What is the main purpose of cache management in GraphQL?

easy

A. To temporarily store data for faster repeated requests

B. To permanently save all data in the database

C. To delete all data after each request

D. To encrypt data for security

Solution

1. Step 1: Understand cache management purpose

   Cache management is used to store data temporarily to speed up access.

2. Step 2: Compare options with cache purpose

   Only To temporarily store data for faster repeated requests matches the temporary storage for faster repeated requests.

3. Final Answer:

   To temporarily store data for faster repeated requests -> Option A

4. Quick Check:

   Cache speeds up repeated requests = A [OK]

Hint: Cache means temporary storage for speed [OK]

Common Mistakes:

• Thinking cache stores data permanently
• Confusing cache with encryption
• Assuming cache deletes data immediately

2. Which of the following is the correct way to specify a cache key argument in a GraphQL query?

easy

A. query { user(id: 1) @cacheKey(key: "id") { name }

B. query { user(id: 1) @cache(key: "id") { name }

C. query { user(id: 1) @cacheKey(id) { name }

D. query { user(id: 1) @cacheKey(key: id) { name }

Solution

1. Step 1: Identify correct syntax for cache key argument

   The cache key argument uses @cacheKey with a key string in quotes.

2. Step 2: Check each option's syntax

   query { user(id: 1) @cacheKey(key: "id") { name } correctly uses @cacheKey(key: "id") with quotes around key name.

3. Final Answer:

   query { user(id: 1) @cacheKey(key: "id") { name } -> Option A

4. Quick Check:

   Cache key argument needs quotes = A [OK]

Hint: Cache keys need quotes around key name [OK]

Common Mistakes:

• Omitting quotes around key name
• Using wrong directive name like @cache
• Passing key without key: label

3. Given the following GraphQL query with cache expiry set to 60 seconds:

query { product(id: 5) @cacheControl(maxAge: 60) { name price } }

What happens if you request the same product again within 30 seconds?

medium

A. An error occurs due to cache expiry mismatch

B. The server fetches fresh data ignoring the cache

C. The cache is cleared and data is refetched

D. The cached data is returned without fetching from the server

Solution

1. Step 1: Understand maxAge cache expiry

   maxAge: 60 means cache is valid for 60 seconds after storing data.

2. Step 2: Check request timing

   Request within 30 seconds is before expiry, so cached data is used.

3. Final Answer:

   The cached data is returned without fetching from the server -> Option D

4. Quick Check:

   Request before maxAge returns cache = C [OK]

Hint: Cache valid until maxAge seconds pass [OK]

Common Mistakes:

• Assuming cache expires immediately
• Thinking server always refetches
• Confusing maxAge with minimum age

4. Identify the error in this GraphQL cache directive usage:

query { user(id: 10) @cacheControl(maxAge: "thirty") { name email } }

medium

A. The directive name should be @cacheKey, not @cacheControl

B. The user id must be a string, not a number

C. maxAge value must be a number, not a string

D. The query is missing a required fragment

Solution

1. Step 1: Check maxAge argument type

   maxAge expects a numeric value representing seconds, not a string.

2. Step 2: Analyze the given value

   "thirty" is a string, causing a type error in cacheControl directive.

3. Final Answer:

   maxAge value must be a number, not a string -> Option C

4. Quick Check:

   maxAge needs number, not string = B [OK]

Hint: maxAge must be numeric, no quotes [OK]

Common Mistakes:

• Using string instead of number for maxAge
• Confusing directive names
• Assuming id type causes cache error

5. You want to cache a list of posts but ensure that each post is cached separately by its unique ID. Which cache management strategy should you use in your GraphQL schema?

hard

A. Cache the entire posts list as one entry without keys

B. Use a cache key argument with the post ID to store each post individually

C. Disable caching for posts to always fetch fresh data

D. Set a global cache expiry time for all posts together

Solution

1. Step 1: Understand caching by unique keys

   Caching each post separately requires using a cache key based on post ID.

2. Step 2: Evaluate options for separate caching

   Only Use a cache key argument with the post ID to store each post individually uses cache key argument to store posts individually by ID.

3. Final Answer:

   Use a cache key argument with the post ID to store each post individually -> Option B

4. Quick Check:

   Cache by unique ID key = D [OK]

Hint: Cache items individually using unique keys [OK]

Common Mistakes:

• Caching entire list as one entry
• Relying only on global expiry without keys
• Disabling cache unnecessarily