JSON as standard format in Rest API - Mini Project: Build & Apply

Using JSON as Standard Format in REST API

📖 Scenario: You are building a simple REST API that sends and receives data in JSON format. JSON is a common way to share data between computers because it is easy to read and write.

🎯 Goal: Learn how to create a Python dictionary with data, convert it to JSON format, and print the JSON string. This simulates sending data in a REST API response.

📋 What You'll Learn

Create a Python dictionary with specific data

Create a variable to hold the JSON string

Convert the dictionary to a JSON string using the json module

Print the JSON string

💡 Why This Matters

🌍 Real World

APIs use JSON to send data between servers and apps because JSON is easy to read and write for both humans and machines.

💼 Career

Understanding JSON is essential for backend and frontend developers working with REST APIs, which are common in web and mobile app development.

1

Create the data dictionary

Create a dictionary called user_data with these exact entries: 'name': 'Alice', 'age': 30, 'city': 'New York'

Rest API

# Create the dictionary user_data with name, age, and city
# Your code here

Hint

Use curly braces {} to create a dictionary. Separate keys and values with a colon.

2

Import json module and prepare JSON string variable

Import the json module and create a variable called json_string to hold the JSON data (leave it empty for now).

Rest API

user_data = {'name': 'Alice', 'age': 30, 'city': 'New York'}
# Import json module and create json_string variable
# Your code here

Hint

Use import json to bring in the JSON tools. Create json_string and set it to an empty string.

3

Convert dictionary to JSON string

Use json.dumps() to convert user_data to a JSON string and store it in json_string.

Rest API

import json
user_data = {'name': 'Alice', 'age': 30, 'city': 'New York'}
json_string = ''
# Convert user_data to JSON string and store in json_string
# Your code here

Hint

Use json.dumps() to turn a dictionary into a JSON string.

4

Print the JSON string

Print the variable json_string to display the JSON formatted data.

Rest API

import json
user_data = {'name': 'Alice', 'age': 30, 'city': 'New York'}
json_string = json.dumps(user_data)
# Print the JSON string
# Your code here

Hint

Use print(json_string) to show the JSON data.

Practice

1. What is the main reason REST APIs use JSON as their standard format?

easy

A. Because JSON is easy to read and write for both humans and machines

B. Because JSON requires special software to understand

C. Because JSON is a binary format

D. Because JSON only supports numbers

Solution

1. Step 1: Understand JSON format

   JSON is a text-based format that uses simple syntax with objects and arrays.

2. Step 2: Identify why REST APIs prefer JSON

   REST APIs use JSON because it is easy for humans to read and easy for machines to parse.

3. Final Answer:

   Because JSON is easy to read and write for both humans and machines -> Option A

4. Quick Check:

   JSON is text-based and readable [OK]

Hint: JSON is popular because it's simple and readable [OK]

Common Mistakes:

• Thinking JSON is binary
• Believing JSON needs special software
• Assuming JSON only supports numbers

2. Which of the following is the correct JSON syntax for an object with a key "name" and value "Alice"?

easy

A. {"name" = "Alice"}

B. {name: "Alice"}

C. ["name": "Alice"]

D. {"name": "Alice"}

Solution

1. Step 1: Recall JSON object syntax

   JSON objects use curly braces with keys and values as strings, keys must be in double quotes.

2. Step 2: Check each option

   {"name": "Alice"} uses double quotes correctly around key and value, with colon separator.

3. Final Answer:

   {"name": "Alice"} -> Option D

4. Quick Check:

   Keys and strings in double quotes [OK]

Hint: Keys and string values must be in double quotes [OK]

Common Mistakes:

• Omitting quotes around keys
• Using square brackets for objects
• Using equals sign instead of colon

3. Given this JSON response from a REST API:

{"status": "success", "data": [10, 20, 30]}

What is the value of the key "data"?

medium

A. "success"

B. [10, 20, 30]

C. 10

D. {"status": "success"}

Solution

1. Step 1: Identify the key "data" in JSON

   The key "data" holds an array with values 10, 20, and 30.

2. Step 2: Match the value to the options

   [10, 20, 30] correctly shows the array [10, 20, 30].

3. Final Answer:

   [10, 20, 30] -> Option B

4. Quick Check:

   Key "data" = array [10, 20, 30] [OK]

Hint: Look for the key and read its value exactly as shown [OK]

Common Mistakes:

• Confusing key "status" value with "data"
• Picking a single number instead of the array
• Choosing the whole JSON object as value

4. You receive this JSON string from an API:

{"user": "Bob", "age": 25,}

What is wrong with this JSON?

medium

A. Trailing comma after the last item is invalid

B. Keys must be numbers, not strings

C. Values cannot be numbers

D. Missing square brackets around the object

Solution

1. Step 1: Check JSON syntax rules

   JSON objects cannot have a comma after the last key-value pair.

2. Step 2: Identify the error in the string

   The comma after "age": 25 is invalid and causes a syntax error.

3. Final Answer:

   Trailing comma after the last item is invalid -> Option A

4. Quick Check:

   No trailing commas allowed in JSON objects [OK]

Hint: No commas after last item in JSON objects [OK]

Common Mistakes:

• Thinking keys must be numbers
• Believing numbers are invalid values
• Adding brackets incorrectly

5. You want to send a JSON payload to a REST API with user info: name "Eve", age 28, and hobbies as an array of "reading" and "swimming". Which JSON is correct?

hard

A. {"name": "Eve", "age": 28, "hobbies": "reading, swimming"}

B. {"name": Eve, "age": "28", "hobbies": ("reading", "swimming")}

C. {"name": "Eve", "age": 28, "hobbies": ["reading", "swimming"]}

D. {"name": "Eve", "age": 28, "hobbies": {"reading", "swimming"}}

Solution

1. Step 1: Check correct JSON types for each field

   Name is a string, age is a number, hobbies is an array of strings.

2. Step 2: Validate each option's syntax

   {"name": "Eve", "age": 28, "hobbies": ["reading", "swimming"]} correctly uses double quotes for strings, numbers without quotes, and square brackets for array.

3. Final Answer:

   {"name": "Eve", "age": 28, "hobbies": ["reading", "swimming"]} -> Option C

4. Quick Check:

   Strings in quotes, numbers plain, arrays in brackets [OK]

Hint: Use quotes for strings, brackets for arrays, no quotes for numbers [OK]

Common Mistakes:

• Using parentheses instead of brackets for arrays
• Not quoting string values
• Putting numbers in quotes unnecessarily