Chapter 14: JSON, XML & HTTP Requests

Objectives

• Load and dump JSON with the json module.
• Parse XML using xml.etree.ElementTree.
• Make HTTP GET and POST requests with requests.
• Handle query parameters, headers and JSON bodies.
• Process API responses and error handling.

1. JSON Handling

Convert between JSON text and Python objects:

import json

data = {"user": "alice", "active": True, "roles": ["admin","user"]}
# serialize
text = json.dumps(data, indent=2)
# deserialize
obj = json.loads(text)
print(obj["roles"])  # ['admin', 'user']

2. XML Parsing

Use xml.etree.ElementTree to read and navigate XML:

import xml.etree.ElementTree as ET

xml = "<root><item id='1'>Foo</item></root>"
root = ET.fromstring(xml)
for item in root.findall("item"):
    print(item.get("id"), item.text)  # 1 Foo

3. HTTP with requests

Install via pip install requests. Make GET and POST:

import requests

# GET with params
resp = requests.get("https://api.example.com/data", params={"q":"python"})
print(resp.status_code, resp.json())

# POST JSON body
payload = {"name":"bob","age":30}
resp = requests.post("https://api.example.com/users", json=payload)
print(resp.status_code, resp.text)

Set headers and timeout:

headers = {"Authorization":"Bearer TOKEN"}
resp = requests.get("https://api.example.com/secure", headers=headers, timeout=5)

Exercises

1. Read a JSON file, modify it and write it back.
2. Parse an XML file of books and print titles published after 2000.
3. Use requests to fetch GitHub user data (https://api.github.com/users/<username>).
4. POST a JSON payload to a mock API (e.g., https://httpbin.org/post) and display the response.