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Correlation ID HTTP header mock in Python
A lightweight HTTP server that echoes or generates correlation IDs to help test distributed systems.
import json
import uuid
from http.server import BaseHTTPRequestHandler, HTTPServer
class CorrelationHandler(BaseHTTPRequestHandler):
CORRELATION_HEADER = "X-Correlation-ID"
def do_GET(self):
correlation_id = self.headers.get(self.CORRELATION_HEADER) or str(uuid.uuid4())
response = {
…How to Load CSV Training Data in Python Without Pandas
Load CSV training data using Python's standard library and mock it with io.StringIO for testing, returning headers and rows as dictionaries.
import csv
from pathlib import Path
def load_csv_training_data(file_path: str | Path) -> tuple[list[str], list[dict[str, str]]]:
"""Load CSV training data and return headers plus rows as dictionaries."""
with open(file_path, mode="r", newline="", encoding="utf-8") as csv_file:
reader = csv.DictReader…How to Enforce a Strict Referrer Policy in Python
Validate HTTP headers to enforce a strict same-origin Referrer policy, accepting only origin-only URLs or absent Referer values.
import re
from unittest.mock import patch
def strict_referrer_policy(headers):
"""Return True if Referer header is absent or strictly same-origin."""
referer = headers.get("Referer")
if referer is None:
return True
# Strict-Origin-When-Cross-Origin allows same-origin full URL
# but here we…How to Mock a Content Security Policy Header in Python
Mock a Content-Security-Policy header locally and verify it's served correctly using Python's built-in HTTP server.
import json
from http.server import BaseHTTPRequestHandler, HTTPServer
CSP_HEADER = "default-src 'self'; script-src 'self'; style-src 'self' 'unsafe-inline'"
class MockServer(BaseHTTPRequestHandler):
def do_GET(self):
if self.path == "/":
self.send_response(200)
self.send_header("…How to Mock a Permissions Policy in Python
A lightweight Python class that simulates a browser Permissions-Policy header by tracking allowed/ denied feature permissions with get, set, reset, and bulk operations.
class PermissionsPolicy:
def __init__(self):
self._features = {
"geolocation": "self",
"camera": "self",
"microphone": "self",
"payment": "self",
"usb": "self",
}
def get_feature_policy(self, feature):
return self._features.ge…How to Set X-Frame-Options DENY in Flask with a Mock Response
Set the X-Frame-Options header to DENY in a Flask response to prevent clickjacking, and verify it with Flask's test client.
from flask import Flask, Response
app = Flask(__name__)
@app.route("/")
def index():
response = Response("Hello, World!")
response.headers["X-Frame-Options"] = "DENY"
return response
if __name__ == "__main__":
with app.test_client() as client:
resp = client.get("/")
print(resp.get_da…Browse by section
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Guide: free Python code samples library
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PythonSkillset code samples are short, focused examples organised by topic and difficulty. Every snippet is server-rendered HTML — readable by search engines and easy to copy. Open any sample, read the notes, copy the code, then press Try in editor to run it in the browser with Pyodide.
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- Pick a topic section — strings, lists, files, functions, and more
- Open a sample, read How it works, and copy the code block
- Run it in the IDE, tweak values, then take a related quiz or tutorial lesson
Samples vs tutorials and challenges
Samples are quick reference — one concept per page. For step-by-step teaching, use our Python tutorials. To test yourself, try quizzes or coding challenges. Clean up style with the Python formatter.