HEAD and OPTIONS methods in Rest API - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to define a HEAD method handler that returns headers without a body.

Rest API

def handle_request(request):
    if request.method == '[1]':
        return get_headers_only()
    else:
        return get_full_response()

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

APOST

BGET

COPTIONS

DHEAD

Attempts:

3 left

💡 Hint

Common Mistakes

Using GET instead of HEAD for header-only requests.

The HEAD method requests headers only, without the response body.

2fill in blank

medium

Complete the code to respond to an OPTIONS request with allowed methods.

Rest API

def handle_request(request):
    if request.method == 'OPTIONS':
        return {'Allow': '[1]'}
    else:
        return process_request(request)

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

A'GET, POST, OPTIONS'

B'GET, POST'

C'HEAD, OPTIONS'

D'POST, PUT'

Attempts:

3 left

💡 Hint

Common Mistakes

Omitting OPTIONS from the Allow header.

The OPTIONS method response includes all allowed methods, including OPTIONS itself.

3fill in blank

hard

Fix the error in the code to correctly handle HEAD requests by removing the response body.

Rest API

def handle_head(request):
    response = get_full_response()
    if request.method == '[1]':
        response.body = None
    return response

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

AHEAD

BPOST

CGET

DPUT

Attempts:

3 left

💡 Hint

Common Mistakes

Using GET instead of HEAD in the condition.

HEAD requests require the body to be empty but headers to be present.

4fill in blank

hard

Fill both blanks to create a dictionary comprehension that maps HTTP methods to their descriptions for OPTIONS response.

Rest API

methods_info = {method: '[1]' for method in ['GET', 'POST', 'HEAD', 'OPTIONS'] if method [2] 'OPTIONS'}

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

Asupported

B!=

C==

Dallowed

Attempts:

3 left

💡 Hint

Common Mistakes

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

This comprehension maps methods except OPTIONS to the string 'supported'.

5fill in blank

hard

Fill all three blanks to build a response dictionary for OPTIONS method with method names, descriptions, and a flag.

Rest API

response = {
    '[1]': [method for method in allowed_methods],
    '[2]': {method: '[3]' for method in allowed_methods}
}

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

Amethods

Bdescriptions

Cactive

Dsupported

Attempts:

3 left

💡 Hint

Common Mistakes

Using incorrect keys that don't match the response structure.

The response includes a list of methods and a dictionary of descriptions labeled 'supported'.

Practice

1. What is the primary purpose of the HEAD method in REST APIs?

easy

A. To create a new resource on the server

B. To delete a resource from the server

C. To update a resource partially

D. To retrieve only the headers of a resource without the body

Solution

1. Step 1: Understand the HEAD method role

   The HEAD method requests headers only, not the full content.

2. Step 2: Compare with other methods

   Unlike GET, it does not return the body, only metadata.

3. Final Answer:

   To retrieve only the headers of a resource without the body -> Option D

4. Quick Check:

   HEAD returns headers only [OK]

Hint: HEAD fetches headers only, no content body [OK]

Common Mistakes:

• Confusing HEAD with GET which returns full content
• Thinking HEAD modifies data on server
• Assuming HEAD returns body content

2. Which of the following is the correct syntax to send an OPTIONS request using curl?

easy

A. curl -X POST https://api.example.com/resource

B. curl -X HEAD https://api.example.com/resource

C. curl -X OPTIONS https://api.example.com/resource

D. curl --get https://api.example.com/resource

Solution

1. Step 1: Identify the method flag in curl

   The -X option specifies the HTTP method to use.

2. Step 2: Match the method to the question

   To send an OPTIONS request, use -X OPTIONS.

3. Final Answer:

   curl -X OPTIONS https://api.example.com/resource -> Option C

4. Quick Check:

   curl -X OPTIONS sends OPTIONS request [OK]

Hint: Use curl -X OPTIONS to send OPTIONS request [OK]

Common Mistakes:

• Using -X HEAD instead of OPTIONS
• Using --get which sends GET request
• Using POST method incorrectly

3. Given the following HTTP response headers from an OPTIONS request:

Allow: GET, POST, OPTIONS, HEAD

What does this header tell the client?

medium

A. The server supports only GET and POST methods

B. The server supports GET, POST, OPTIONS, and HEAD methods on this resource

C. The server denies all methods except OPTIONS

D. The server supports DELETE and PUT methods

Solution

1. Step 1: Read the Allow header

   The Allow header lists HTTP methods the server supports for the resource.

2. Step 2: Interpret the methods listed

   It shows GET, POST, OPTIONS, and HEAD are allowed methods.

3. Final Answer:

   The server supports GET, POST, OPTIONS, and HEAD methods on this resource -> Option B

4. Quick Check:

   Allow header lists supported methods [OK]

Hint: Allow header shows all supported methods [OK]

Common Mistakes:

• Ignoring OPTIONS and HEAD in the list
• Assuming only GET and POST are allowed
• Confusing Allow header with authentication

4. You wrote this code to handle HEAD requests in your REST API server:

if request.method == 'HEAD':
    return get_resource()

But clients receive the full content body. What is the problem?

medium

A. The code returns full content instead of headers only

B. The method name should be lowercase 'head'

C. HEAD requests must be redirected to GET method

D. The server must respond with status 201 for HEAD

Solution

1. Step 1: Analyze the code behavior

   The code calls get_resource() which returns full content including body.

2. Step 2: Understand HEAD response requirements

   HEAD must return headers only, no body content.

3. Final Answer:

   The code returns full content instead of headers only -> Option A

4. Quick Check:

   HEAD returns headers only, not full body [OK]

Hint: HEAD must not return body, only headers [OK]

Common Mistakes:

• Returning full content for HEAD requests
• Using wrong method name case
• Confusing HEAD with GET behavior

5. You want to optimize your REST API by using HEAD and OPTIONS methods. Which approach best improves client efficiency?

hard

A. Use HEAD to check resource existence and OPTIONS to discover allowed methods before sending requests

B. Use OPTIONS to fetch full resource data and HEAD to update resources

C. Use HEAD to delete resources and OPTIONS to create new ones

D. Ignore HEAD and OPTIONS and always use GET and POST

Solution

1. Step 1: Understand HEAD usage

   HEAD checks if a resource exists by fetching headers without body, saving bandwidth.

2. Step 2: Understand OPTIONS usage

   OPTIONS tells clients which HTTP methods are allowed, helping avoid invalid requests.

3. Step 3: Combine for efficiency

   Using both before heavy requests reduces unnecessary data transfer and errors.

4. Final Answer:

   Use HEAD to check resource existence and OPTIONS to discover allowed methods before sending requests -> Option A

5. Quick Check:

   HEAD checks headers, OPTIONS lists methods [OK]

Hint: HEAD checks existence, OPTIONS lists allowed methods [OK]

Common Mistakes:

• Using OPTIONS to fetch full data (wrong)
• Using HEAD to modify resources (wrong)
• Ignoring these methods and wasting bandwidth