ETag for conditional requests in Rest API - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to set the ETag header in the HTTP response.

Rest API

response.headers['ETag'] = [1]

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

A"12345abcde"

Betag_value

Crequest.headers['ETag']

DNone

Attempts:

3 left

💡 Hint

Common Mistakes

Using the request header value instead of setting a new ETag.

Assigning None instead of a string.

The ETag header must be set to a string value representing the resource version, such as a hash or unique identifier.

2fill in blank

medium

Complete the code to check if the client's ETag matches the server's ETag.

Rest API

if request.headers.get('If-None-Match') == [1]:

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

Aresponse.headers['ETag']

BNone

C"12345abcde"

Drequest.headers['ETag']

Attempts:

3 left

💡 Hint

Common Mistakes

Comparing with the request's own ETag header.

Using None instead of the ETag string.

The server compares the client's 'If-None-Match' header to the current ETag string to decide if the resource has changed.

3fill in blank

hard

Fix the error in the code to return 304 Not Modified when ETags match.

Rest API

if request.headers.get('If-None-Match') == [1]:
    return '', 304

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

A"12345abcde"

Bresponse.headers['ETag']

Crequest.headers['ETag']

DNone

Attempts:

3 left

💡 Hint

Common Mistakes

Using request or response header objects instead of string.

Using None which causes errors.

The comparison must be done with the exact ETag string value, not headers from request or response objects.

4fill in blank

hard

Fill both blanks to generate an ETag from the content and check the client's ETag.

Rest API

import hashlib

content = b"Hello World"
etag = [1](content).hexdigest()
if request.headers.get('If-None-Match') == [2]:
    return '', 304

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

Ahashlib.md5

Betag

C"etag"

Dhashlib.sha256

Attempts:

3 left

💡 Hint

Common Mistakes

Using a string literal instead of the variable for comparison.

Using the wrong hash function or variable names.

We use hashlib.md5 to create a hash of the content as the ETag, then compare it to the client's 'If-None-Match' header stored in the variable etag.

5fill in blank

hard

Fill all three blanks to set the ETag header, check the client's ETag, and return 304 if they match.

Rest API

import hashlib

content = b"Data to cache"
etag = [1](content).hexdigest()
response.headers['ETag'] = [2]
if request.headers.get('If-None-Match') == [3]:
    return '', 304

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

Ahashlib.sha1

Betag

C"etag"

Dhashlib.md5

Attempts:

3 left

💡 Hint

Common Mistakes

Using string literals instead of variables for headers.

Mixing different hash functions.

We generate the ETag using hashlib.md5, assign the etag variable to the response header, and compare the same etag variable to the client's 'If-None-Match' header.