CDN caching rules in Azure - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to set the default caching behavior in Azure CDN.

Azure

cdnEndpoint.DefaultCacheBehavior = new CacheBehavior { CacheDuration = TimeSpan.FromSeconds([1]) };

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

A60

B3600

C86400

D0

Attempts:

3 left

💡 Hint

Common Mistakes

Using 0 disables caching, which is not default.

Using very large values may cause stale content.

The default cache duration is set in seconds. 60 seconds is a common default for short caching.

2fill in blank

medium

Complete the code to add a caching rule that bypasses caching for query strings.

Azure

cdnEndpoint.CachingRules.Add(new CachingRule { QueryStringCachingBehavior = [1] });

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

ABypassCache

BIgnoreQueryString

CUseQueryString

DCacheEveryQueryString

Attempts:

3 left

💡 Hint

Common Mistakes

Using IgnoreQueryString caches ignoring query strings, not bypassing.

UseQueryString caches based on query strings.

BypassCache means the CDN will not cache responses when query strings are present.

3fill in blank

hard

Fix the error in setting the cache duration to 2 hours in Azure CDN caching rule.

Azure

cachingRule.CacheDuration = TimeSpan.FromSeconds([1]);

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

A3600

B7200

C120

D14400

Attempts:

3 left

💡 Hint

Common Mistakes

Using 120 seconds equals 2 minutes, not 2 hours.

Using 3600 seconds equals 1 hour.

2 hours equals 7200 seconds, so the cache duration must be set to 7200.

4fill in blank

hard

Fill both blanks to configure a caching rule that caches only if the request method is GET and the response status code is 200.

Azure

cachingRule.MatchConditions.Add(new RequestMethodCondition { Method = "[1]" });
cachingRule.MatchConditions.Add(new ResponseStatusCodeCondition { StatusCode = [2] });

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

AGET

BPOST

C200

D404

Attempts:

3 left

💡 Hint

Common Mistakes

Using POST method is not cacheable by default.

Using 404 status code caches error pages.

GET requests with 200 status code are typically cached to serve valid content.

5fill in blank

hard

Fill all three blanks to create a caching rule that caches content for 30 minutes, ignores query strings, and caches only for GET requests.

Azure

var cachingRule = new CachingRule {
  CacheDuration = TimeSpan.FromSeconds([1]),
  QueryStringCachingBehavior = "[2]",
  MatchConditions = { new RequestMethodCondition { Method = "[3]" } }
};

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

A1800

BIgnoreQueryString

CGET

DBypassCache

Attempts:

3 left

💡 Hint

Common Mistakes

Using BypassCache disables caching for query strings.

Using POST method is not cacheable by default.

30 minutes is 1800 seconds, ignoring query strings means caching regardless of them, and caching GET requests is standard.

Practice

1. What is the primary purpose of CDN caching rules in Azure CDN?

easy

A. To monitor server CPU usage

B. To encrypt data between client and server

C. To control how content is stored and served from CDN servers

D. To manage user authentication

Solution

1. Step 1: Understand CDN caching rules

   CDN caching rules define how content is cached and delivered by CDN servers.

2. Step 2: Identify the main goal

   The main goal is to improve speed and reduce load by controlling content storage and delivery.

3. Final Answer:

   To control how content is stored and served from CDN servers -> Option C

4. Quick Check:

   CDN caching rules = control content caching [OK]

Hint: Caching rules control content storage and delivery [OK]

Common Mistakes:

• Confusing caching with encryption
• Thinking caching manages authentication
• Assuming caching monitors server CPU

2. Which Azure CDN caching rule syntax correctly sets a cache duration of 3600 seconds for all images?

easy

A. cache-duration: 3600; match: *.jpg, *.png

B. cache-control: max-age=3600; match: *.jpg, *.png

C. cache-control: max-age=3600; match: images/*

D. cache-duration: max-age=3600; match: images/*

Solution

1. Step 1: Identify correct cache-control syntax

   Azure CDN uses 'cache-control: max-age=seconds' to set cache duration.

2. Step 2: Match correct file patterns

   Images are matched by extensions like '*.jpg, *.png' not 'images/*'.

3. Final Answer:

   cache-control: max-age=3600; match: *.jpg, *.png -> Option B

4. Quick Check:

   cache-control max-age + correct pattern = cache-control: max-age=3600; match: *.jpg, *.png [OK]

Hint: Use 'cache-control: max-age' with file extensions for images [OK]

Common Mistakes:

• Using 'cache-duration' instead of 'cache-control'
• Using folder pattern 'images/*' instead of file extensions
• Mixing syntax keywords incorrectly

3. Given this Azure CDN caching rule:
cache-control: max-age=0; match: /api/*
What will happen when a user requests /api/data?

medium

A. Content will be blocked by CDN

B. Content will be cached indefinitely

C. Content will be cached for 3600 seconds

D. Content will be cached for 0 seconds, forcing CDN to fetch fresh data every time

Solution

1. Step 1: Interpret max-age=0 meaning

   max-age=0 means no caching; content is always fresh.

2. Step 2: Apply rule to /api/* path

   Requests to /api/data match /api/*, so caching is disabled.

3. Final Answer:

   Content will be cached for 0 seconds, forcing CDN to fetch fresh data every time -> Option D

4. Quick Check:

   max-age=0 disables caching = Content will be cached for 0 seconds, forcing CDN to fetch fresh data every time [OK]

Hint: max-age=0 means no caching, always fresh content [OK]

Common Mistakes:

• Assuming max-age=0 caches content indefinitely
• Confusing path matching syntax
• Thinking content is blocked

4. You wrote this Azure CDN caching rule:
cache-control max-age=600; match: *.css
But it does not work as expected. What is the error?

medium

A. Missing colon after 'cache-control'

B. Incorrect file extension pattern

C. max-age value too low

D. Match pattern should be a full URL

Solution

1. Step 1: Check syntax for cache-control

   The correct syntax requires a colon after 'cache-control', like 'cache-control: max-age=600'.

2. Step 2: Validate other parts

   File extension '*.css' is correct; max-age=600 is valid; match pattern does not require full URL.

3. Final Answer:

   Missing colon after 'cache-control' -> Option A

4. Quick Check:

   Syntax error: missing colon = Missing colon after 'cache-control' [OK]

Hint: Remember colon after 'cache-control:' in rules [OK]

Common Mistakes:

• Omitting colon after 'cache-control'
• Using wrong file patterns
• Thinking max-age value causes failure

5. You want to optimize caching for a website with static images and dynamic API data. Which Azure CDN caching rules setup is best?

hard

A. Set cache-control: max-age=86400 for images (*.jpg, *.png) and cache-control: max-age=0 for API (/api/*)

B. Set cache-control: max-age=0 for all content

C. Set cache-control: max-age=3600 for all content

D. Set cache-control: max-age=86400 for API and cache-control: max-age=0 for images

Solution

1. Step 1: Understand content types and caching needs

   Static images benefit from long caching (86400 seconds = 1 day). Dynamic API data needs fresh content, so max-age=0.

2. Step 2: Match rules to content paths

   Apply long cache to image extensions (*.jpg, *.png) and no cache to API paths (/api/*).

3. Final Answer:

   Set cache-control: max-age=86400 for images (*.jpg, *.png) and cache-control: max-age=0 for API (/api/*) -> Option A

4. Quick Check:

   Static long cache + dynamic no cache = Set cache-control: max-age=86400 for images (*.jpg, *.png) and cache-control: max-age=0 for API (/api/*) [OK]

Hint: Long cache for static, no cache for dynamic content [OK]

Common Mistakes:

• Caching dynamic API data too long
• Not differentiating static and dynamic content
• Reversing cache durations for content types