Link headers for navigation in Rest API - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to add a Link header for the next page URL.

Rest API

response.headers['Link'] = '<[1]>; rel="next"'

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

A/items?page=3

Bitems?page=2

Chttps://api.example.com/items?page=1

Dhttps://api.example.com/items?page=2

Attempts:

3 left

💡 Hint

Common Mistakes

Using a relative URL instead of a full absolute URL.

Forgetting to enclose the URL in angle brackets.

The Link header must contain the full URL for the next page, enclosed in <>.

2fill in blank

medium

Complete the code to add Link headers for both previous and next pages.

Rest API

response.headers['Link'] = '<[1]>; rel="prev", <https://api.example.com/items?page=3>; rel="next"'

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

Ahttps://api.example.com/items?page=4

Bhttps://api.example.com/items?page=2

Chttps://api.example.com/items?page=1

D/items?page=1

Attempts:

3 left

💡 Hint

Common Mistakes

Using a relative URL for the previous page.

Mixing up the page numbers for prev and next.

The Link header for the previous page must be the full URL for page 1.

3fill in blank

hard

Fix the error in the Link header format to correctly separate multiple links.

Rest API

response.headers['Link'] = '<https://api.example.com/items?page=1>; rel="prev"[1]<https://api.example.com/items?page=3>; rel="next"'

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

A;

B,

C &

D |

Attempts:

3 left

💡 Hint

Common Mistakes

Using semicolon or other characters instead of a comma.

Not adding a space after the comma.

Multiple links in the Link header must be separated by a comma and a space.

4fill in blank

hard

Fill both blanks to create a Link header with first and last page URLs.

Rest API

response.headers['Link'] = '<[1]>; rel="first", <[2]>; rel="last"'

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

Ahttps://api.example.com/items?page=1

Bhttps://api.example.com/items?page=2

Chttps://api.example.com/items?page=10

D/items?page=10

Attempts:

3 left

💡 Hint

Common Mistakes

Using relative URLs instead of full URLs.

Mixing up first and last page numbers.

The first page URL is page 1, and the last page URL is page 10, both as full URLs.

5fill in blank

hard

Fill all three blanks to build a Link header with prev, next, and last page URLs.

Rest API

response.headers['Link'] = '<[1]>; rel="prev", <[2]>; rel="next", <[3]>; rel="last"'

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

Ahttps://api.example.com/items?page=2

Bhttps://api.example.com/items?page=4

Chttps://api.example.com/items?page=10

Dhttps://api.example.com/items?page=3

Attempts:

3 left

💡 Hint

Common Mistakes

Swapping prev and next URLs.

Using relative URLs instead of full URLs.

The previous page is page 3, next page is page 4, and last page is page 10, all full URLs.

Practice

1. What is the main purpose of using Link headers in REST APIs?

easy

A. To provide URLs for navigating between related API pages or resources

B. To send authentication tokens securely

C. To specify the content type of the response

D. To compress the API response data

Solution

1. Step 1: Understand the role of Link headers

   Link headers are used to provide URLs that help clients navigate between related pages or resources in an API.

2. Step 2: Compare with other header uses

   Authentication tokens, content types, and compression are handled by other headers, not Link headers.

3. Final Answer:

   To provide URLs for navigating between related API pages or resources -> Option A

4. Quick Check:

   Link headers = navigation URLs [OK]

Hint: Link headers always give navigation URLs, not data or tokens [OK]

Common Mistakes:

• Confusing Link headers with authentication headers
• Thinking Link headers specify content type
• Assuming Link headers compress data

2. Which of the following is the correct syntax for a Link header indicating the next page URL?

easy

A. Link: next=

B. Link: ; rel="next"

C. Link: rel="next"

D. Link: next

Solution

1. Step 1: Recall Link header format

   The correct format is: Link: <URL>; rel="relation" where URL is in angle brackets and rel specifies the link role.

2. Step 2: Check each option

   Link: ; rel="next" matches the correct syntax with URL in <> and rel="next". Others have incorrect order or missing punctuation.

3. Final Answer:

   Link: <https://api.example.com/items?page=2>; rel="next" -> Option B

4. Quick Check:

   Link header syntax = <URL>; rel="next" [OK]

Hint: Link header always uses angle brackets for URLs and rel="next" [OK]

Common Mistakes:

• Placing rel before the URL
• Omitting angle brackets around URL
• Using incorrect separators or missing semicolons

3. Given the following HTTP response header:

Link: ; rel="next", ; rel="prev"

What URL should the client use to get the previous page?

medium

A. https://api.example.com/items?page=3

B. https://api.example.com/items?page=4

C. https://api.example.com/items?page=1

D. https://api.example.com/items?page=2

Solution

1. Step 1: Identify the rel attribute for previous page

   The Link header with rel="prev" indicates the URL for the previous page, which is https://api.example.com/items?page=1.

2. Step 2: Match the URL to the correct option

   https://api.example.com/items?page=1 matches the URL with rel="prev" exactly.

3. Final Answer:

   https://api.example.com/items?page=1 -> Option C

4. Quick Check:

   rel="prev" URL = page=1 [OK]

Hint: Look for rel="prev" to find previous page URL [OK]

Common Mistakes:

• Confusing rel="next" with rel="prev"
• Choosing a page number not in the Link header
• Ignoring the rel attribute

4. You receive this Link header:

Link: https://api.example.com/items?page=2; rel="next"

What is wrong with this header?

medium

A. The URL should not contain query parameters

B. The rel attribute should be capitalized

C. The semicolon should be a comma

D. The URL is missing angle brackets <>

Solution

1. Step 1: Check URL formatting in Link header

   URLs in Link headers must be enclosed in angle brackets <> to be valid.

2. Step 2: Verify other parts

   rel attribute is case-insensitive and semicolon is correct separator; query parameters are allowed.

3. Final Answer:

   The URL is missing angle brackets <> -> Option D

4. Quick Check:

   URL must be inside <> in Link header [OK]

Hint: Always put URLs in angle brackets in Link headers [OK]

Common Mistakes:

• Omitting angle brackets around URLs
• Changing semicolon to comma incorrectly
• Thinking rel attribute is case sensitive

5. You want to provide navigation links for first, previous, next, and last pages in your API response. Which of the following Link header values correctly includes all these relations?

hard

A. Link: ; rel="first", ; rel="prev", ; rel="next", ; rel="last"

B. Link: ; rel first, ; rel=prev, ; rel=next, ; rel=last

C. Link: first, prev, next, last

D. Link: rel="first" , rel="prev" , rel="next" , rel="last"

Solution

1. Step 1: Confirm correct Link header syntax

   The correct format is Link: <URL>; rel="relation", <URL>; rel="relation" etc., with URL in <>, semicolon, rel= with value in quotes.

2. Step 2: Evaluate each option

   Link: <https://api.example.com/items?page=1>; rel="first", <https://api.example.com/items?page=2>; rel="prev" etc. matches exactly. The similar one has 'rel first' (missing = after rel). Others miss semicolons, have rel before URL, or wrong separators.

3. Final Answer:

   Link: <https://api.example.com/items?page=1>; rel="first", <https://api.example.com/items?page=2>; rel="prev", <https://api.example.com/items?page=4>; rel="next", <https://api.example.com/items?page=10>; rel="last" -> Option A

4. Quick Check:

   All links with <> and rel="relation" separated by commas [OK]

Hint: Use <URL>; rel="relation" for each link, separated by commas [OK]

Common Mistakes:

• Placing rel before URL
• Missing semicolons between URL and rel
• Not separating links with commas