Header-based versioning in Rest API - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is header-based versioning in REST APIs?

Header-based versioning is a way to specify the API version by including a custom header in the HTTP request, such as Accept-Version or X-API-Version, instead of using the URL or query parameters.

beginner

Why use header-based versioning instead of URL versioning?

Header-based versioning keeps URLs clean and stable, separating version info from resource paths. It allows clients to request different versions without changing the URL, making APIs more flexible and easier to maintain.

beginner

Which HTTP header is commonly used for header-based versioning?

Common headers include Accept with media type parameters (e.g., application/vnd.example.v1+json) or custom headers like X-API-Version or Accept-Version.

intermediate

How does the server handle header-based versioning?

The server reads the version information from the request headers and routes the request to the appropriate version of the API logic or controller to respond accordingly.

intermediate

What is a potential downside of header-based versioning?

It can be harder to test and debug because the version is hidden in headers, not visible in the URL. Also, some caching systems or proxies may not handle custom headers well, affecting performance.

Which header is often used to specify API version in header-based versioning?

A Authorization

B Content-Type

C X-API-Version

D User-Agent

The X-API-Version header is commonly used to specify the API version in header-based versioning.

What is a main advantage of header-based versioning over URL versioning?

A It requires no headers

B It keeps URLs clean and stable

C It uses query parameters

D It changes the resource path

Header-based versioning keeps URLs clean and stable by moving version info to headers.

How does the server know which API version to use in header-based versioning?

A By reading the version from the request header

B By checking the URL path

C By looking at the query string

D By inspecting the request body

The server reads the version information from the request headers to route the request.

Which of these is a downside of header-based versioning?

A Version info is hidden in headers, making debugging harder

B It makes URLs longer

C It requires changing resource paths

D It cannot support multiple versions

Because version info is in headers, it can be harder to debug and test.

Which media type format is used in Accept header for versioning?

A application/xml

B text/html

C multipart/form-data

D application/vnd.example.v1+json

Custom media types like application/vnd.example.v1+json are used in the Accept header for versioning.

Explain how header-based versioning works in REST APIs and why it might be chosen over URL versioning.

Think about where the version info lives and how the server uses it.

Describe common headers used for API versioning and how a server processes them.

Focus on headers and server behavior.

Practice

1. What is the main purpose of header-based versioning in REST APIs?

easy

A. To change the API URL structure for each version

B. To specify the API version using HTTP headers instead of URLs

C. To embed version info inside the request body

D. To use query parameters for version control

Solution

1. Step 1: Understand header-based versioning concept

   Header-based versioning uses HTTP headers to indicate which API version the client wants.

2. Step 2: Compare with other versioning methods

   Unlike URL or query parameter versioning, header-based keeps URLs clean and uses headers instead.

3. Final Answer:

   To specify the API version using HTTP headers instead of URLs -> Option B

4. Quick Check:

   Header versioning = version in HTTP headers [OK]

Hint: Remember: header versioning hides version in HTTP headers [OK]

Common Mistakes:

• Confusing header versioning with URL versioning
• Thinking version is in request body
• Assuming query parameters are used

2. Which HTTP header is commonly used to specify API version in header-based versioning?

easy

A. Content-Type

B. User-Agent

C. Accept

D. Authorization

Solution

1. Step 1: Identify common headers for versioning

   The Accept header is often used to specify the desired API version by content negotiation.

2. Step 2: Exclude unrelated headers

   Content-Type specifies data format sent, Authorization is for credentials, and User-Agent identifies client software.

3. Final Answer:

   Accept -> Option C

4. Quick Check:

   Version in Accept header = D [OK]

Hint: Version info usually goes in the Accept header [OK]

Common Mistakes:

• Using Content-Type instead of Accept for versioning
• Confusing Authorization with version header
• Thinking User-Agent controls version

3. Given this HTTP request header:
Accept: application/vnd.example.v2+json
Which API version is the client requesting?

medium

A. Version 2

B. Version 1

C. Version 3

D. No version specified

Solution

1. Step 1: Parse the Accept header value

   The value application/vnd.example.v2+json includes v2, indicating version 2.

2. Step 2: Confirm version number meaning

   The v2 part is a common pattern to specify version 2 of the API.

3. Final Answer:

   Version 2 -> Option A

4. Quick Check:

   v2 in Accept header means version 2 [OK]

Hint: Look for 'v' followed by number in Accept header [OK]

Common Mistakes:

• Ignoring the 'v2' part and guessing version 1
• Assuming no version if not in URL
• Confusing +json suffix with version

4. A developer wrote this code snippet to check API version from headers:

version = request.headers.get('Content-Type')
if version == 'application/vnd.example.v1+json':
    return 'Version 1'
else:
    return 'Unknown version'

What is the main issue here?

medium

A. Using request.headers.get instead of request.get_header

B. Comparing version string incorrectly

C. Missing else condition

D. Using Content-Type header instead of Accept header for versioning

Solution

1. Step 1: Identify header used for versioning

   Header-based versioning typically uses the Accept header, not Content-Type.

2. Step 2: Explain why Content-Type is wrong here

   Content-Type describes the data format sent by the client, not the requested API version.

3. Final Answer:

   Using Content-Type header instead of Accept header for versioning -> Option D

4. Quick Check:

   Version header should be Accept, not Content-Type [OK]

Hint: Version info is in Accept header, not Content-Type [OK]

Common Mistakes:

• Checking Content-Type for version info
• Assuming request.headers.get is invalid
• Ignoring else branch

5. You want to support two API versions (v1 and v2) simultaneously using header-based versioning. Which approach correctly handles this in your server code?

hard

A. Check the Accept header for 'application/vnd.example.v1+json' or 'application/vnd.example.v2+json' and route accordingly

B. Use URL paths like /v1/resource and /v2/resource to separate versions

C. Ignore headers and always serve the latest version

D. Use query parameters like ?version=1 or ?version=2 to select version

Solution

1. Step 1: Understand header-based versioning goal

   It requires checking the HTTP headers to determine which API version to serve.

2. Step 2: Identify correct version detection method

   Checking the Accept header for specific version strings and routing requests accordingly is the right approach.

3. Final Answer:

   Check the Accept header for 'application/vnd.example.v1+json' or 'application/vnd.example.v2+json' and route accordingly -> Option A

4. Quick Check:

   Route by Accept header version strings [OK]

Hint: Route requests by Accept header version values [OK]

Common Mistakes:

• Mixing header versioning with URL or query parameter versioning
• Ignoring version headers and serving one version only
• Using wrong headers for version detection