Serialization considerations in Redis - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to serialize a Python dictionary to a JSON string before storing it in Redis.

Redis

import json
import redis
r = redis.Redis()
data = {'name': 'Alice', 'age': 30}
r.set('user:1', [1])

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

Astr(data)

Bjson.loads(data)

Cjson.dumps(data)

Ddata.encode()

Attempts:

3 left

💡 Hint

Common Mistakes

Using json.loads which deserializes JSON instead of serializing.

Trying to encode the dictionary directly without converting to string.

We use json.dumps() to convert the Python dictionary into a JSON string before storing it in Redis.

2fill in blank

medium

Complete the code to deserialize a JSON string retrieved from Redis back into a Python dictionary.

Redis

import json
import redis
r = redis.Redis()
json_data = r.get('user:1')
data = [1]

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

Ajson.loads(json_data.decode('utf-8'))

Bjson.loads(json_data)

Cjson.dumps(json_data)

Djson.dumps(json_data.decode('utf-8'))

Attempts:

3 left

💡 Hint

Common Mistakes

Trying to load JSON directly from bytes without decoding.

Using json.dumps instead of json.loads for deserialization.

Redis returns bytes, so we decode to a string first, then use json.loads() to convert JSON string to a Python dictionary.

3fill in blank

hard

Fix the error in the code that tries to store a Python set in Redis by serializing it.

Redis

import json
import redis
r = redis.Redis()
my_set = {1, 2, 3}
r.set('myset', [1])

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

Astr(my_set)

Bjson.dumps(list(my_set))

Cjson.dumps(my_set)

Dmy_set.encode()

Attempts:

3 left

💡 Hint

Common Mistakes

Trying to serialize the set directly causing an error.

Using str() which is not JSON format.

Python sets are not JSON serializable directly. Convert the set to a list first, then serialize.

4fill in blank

hard

Fill both blanks to correctly serialize a nested Python object with a datetime before storing it in Redis.

Redis

import json
import redis
from datetime import datetime
r = redis.Redis()
data = {'event': 'login', 'time': datetime.now()}

class DateTimeEncoder(json.JSONEncoder):
    def default(self, obj):
        if isinstance(obj, datetime):
            return obj.[1]()
        return super().default(obj)
r.set('event', json.dumps(data, cls=[2]))

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

Aisoformat

Btimestamp

CDateTimeEncoder

DDateEncoder

Attempts:

3 left

💡 Hint

Common Mistakes

Using timestamp instead of isoformat which is more readable.

Passing wrong class name to json.dumps.

Use isoformat() to convert datetime to string, and pass the custom encoder class DateTimeEncoder to json.dumps().

5fill in blank

hard

Fill all three blanks to deserialize JSON from Redis and convert the datetime string back to a datetime object.

Redis

import json
import redis
from datetime import datetime
r = redis.Redis()
json_str = r.get('event').decode('utf-8')

def datetime_parser(dct):
    for k, v in dct.items():
        if k == '[1]':
            dct[k] = datetime.[2](v)
    return dct

data = json.loads(json_str, object_hook=[3])

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

Atime

Bfromisoformat

Cdatetime_parser

Disoformat

Attempts:

3 left

💡 Hint

Common Mistakes

Using wrong key name in the parser function.

Not passing the parser function to json.loads.

Using isoformat instead of fromisoformat for parsing.

The key holding the datetime string is 'time'. Use datetime.fromisoformat() to convert the string back to datetime. Pass the datetime_parser function as the object_hook to json.loads().