Content negotiation in Rest API - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to set the response content type to JSON.

Rest API

response.headers['Content-Type'] = '[1]'

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

Atext/html

Btext/plain

Capplication/json

Dapplication/xml

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'text/html' instead of 'application/json' for JSON responses.

Forgetting to set the Content-Type header.

The Content-Type header tells the client the format of the response. For JSON, it should be application/json.

2fill in blank

medium

Complete the code to check if the client accepts JSON responses.

Rest API

if 'application/json' in request.headers.get('[1]', ''):

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

AContent-Type

BAccept

CAuthorization

DUser-Agent

Attempts:

3 left

💡 Hint

Common Mistakes

Checking 'Content-Type' header instead of 'Accept'.

Not handling the case when the header is missing.

The Accept header tells the server what content types the client can handle. Checking it for 'application/json' helps decide the response format.

3fill in blank

hard

Fix the error in the code to correctly parse the client's preferred content type.

Rest API

preferred = request.headers.get('Accept', '').split(',')[[1]].strip()

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

A2

B1

C-1

D0

Attempts:

3 left

💡 Hint

Common Mistakes

Using index 1 instead of 0, causing an error if only one type is present.

Using negative index which may not be intended here.

The first item in the 'Accept' header list is at index 0. Using 0 gets the primary preferred content type.

4fill in blank

hard

Fill both blanks to create a dictionary comprehension that maps content types to their quality values from the Accept header.

Rest API

qualities = {ctype: float(q.split('=')[1]) if 'q=' in q else 1.0 for ctype, q in (item.split(';')[1] for item in request.headers.get('Accept', '').split(',')) if ctype [2] ''}

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

A if len(item.split(';')) > 1 else ''

B!=

C==

D else None

Attempts:

3 left

💡 Hint

Common Mistakes

Using '==' instead of '!=' in the filter condition.

Not handling items without quality values properly.

The first blank checks if the split has a quality value part; if not, it uses an empty string. The second blank filters out empty content types.

5fill in blank

hard

Fill all three blanks to return the best matching content type from the server's supported types based on client's Accept header.

Rest API

def best_match(supported_types):
    qualities = {ctype: float(q.split('=')[1]) if 'q=' in q else 1.0 for ctype, q in (item.split(';')[1] for item in request.headers.get('Accept', '').split(',')) if ctype [2] ''}
    best = max(supported_types, key=lambda t: qualities.get(t, [3]))
    return best

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

A if len(item.split(';')) > 1 else ''

B!=

C0

D==

Attempts:

3 left

💡 Hint

Common Mistakes

Using '==' instead of '!=' in the filter.

Using None or other values instead of 0 as default quality.

The first blank handles quality parsing, the second filters out empty types, and the third provides a default quality of 0 for unsupported types.

Practice

1. What is the main purpose of content negotiation in REST APIs?

easy

A. To allow clients to specify the data format they want using the Accept header

B. To encrypt data between client and server

C. To authenticate users before sending data

D. To compress data for faster transfer

Solution

1. Step 1: Understand content negotiation role

   Content negotiation lets clients tell servers what data format they prefer.

2. Step 2: Identify how clients specify format

   Clients use the Accept header to communicate their preferred format.

3. Final Answer:

   To allow clients to specify the data format they want using the Accept header -> Option A

4. Quick Check:

   Content negotiation = Accept header usage [OK]

Hint: Remember: Accept header tells server your preferred format [OK]

Common Mistakes:

• Confusing content negotiation with authentication
• Thinking it compresses data
• Believing it encrypts data

2. Which of the following is the correct way to specify JSON format in the Accept header?

easy

A. Accept: application/xml

B. Accept: text/html

C. Accept: image/png

D. Accept: application/json

Solution

1. Step 1: Recall MIME types for common formats

   JSON format uses the MIME type 'application/json'.

2. Step 2: Match Accept header to JSON

   The correct Accept header for JSON is 'Accept: application/json'.

3. Final Answer:

   Accept: application/json -> Option D

4. Quick Check:

   JSON MIME type = application/json [OK]

Hint: JSON MIME type always is application/json in Accept header [OK]

Common Mistakes:

• Using text/html for JSON
• Confusing image/png with data formats
• Using application/xml instead of JSON

3. Given this HTTP request header:
Accept: application/xml, application/json;q=0.8
Which content type will the server most likely respond with?

medium

A. application/xml

B. application/pdf

C. text/html

D. application/json

Solution

1. Step 1: Understand quality values (q) in Accept header

   The q value shows preference; higher q means higher priority.

2. Step 2: Compare q values for application/xml and application/json

   application/xml has no q value, so defaults to 1. application/json has q=0.8, lower priority.

3. Final Answer:

   application/xml -> Option A

4. Quick Check:

   Higher q or default 1 wins = application/xml [OK]

Hint: No q means 1.0, highest priority wins [OK]

Common Mistakes:

• Ignoring q values and picking lower priority
• Choosing JSON because it appears second
• Selecting unrelated content types

4. A server returns a 406 Not Acceptable error. What is the most likely cause related to content negotiation?

medium

A. Server failed to authenticate the client

B. Client requested a format the server cannot provide

C. Client sent an invalid HTTP method

D. Server ran out of memory

Solution

1. Step 1: Understand HTTP 406 status meaning

   406 means server cannot provide a response matching the Accept header.

2. Step 2: Link 406 to content negotiation failure

   If client requests unsupported format, server responds 406 Not Acceptable.

3. Final Answer:

   Client requested a format the server cannot provide -> Option B

4. Quick Check:

   406 = unsupported requested format [OK]

Hint: 406 means no matching format found for Accept header [OK]

Common Mistakes:

• Confusing 406 with authentication errors
• Thinking 406 means server error
• Assuming 406 is about HTTP methods

5. You want your REST API to support both JSON and XML responses. Which server-side approach correctly implements content negotiation?

hard

A. Ignore the Accept header and always send JSON

B. Send both JSON and XML in the same response body

C. Check the Accept header and respond with JSON or XML accordingly

D. Respond with XML only if the client sends a custom header

Solution

1. Step 1: Understand content negotiation best practice

   The server should read the Accept header to decide response format.

2. Step 2: Choose approach matching client preference

   Responding with JSON or XML based on Accept header is correct behavior.

3. Final Answer:

   Check the Accept header and respond with JSON or XML accordingly -> Option C

4. Quick Check:

   Content negotiation = respond per Accept header [OK]

Hint: Always respect Accept header to choose response format [OK]

Common Mistakes:

• Ignoring Accept header and hardcoding response
• Sending multiple formats in one response
• Using unrelated custom headers for format choice