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Python Code Samples

Copy-ready Python snippets by topic and difficulty — short, focused, and runnable in the browser editor.

124 matches
Auth & security at scale easy

How to Salt Passwords per User in Python

Hash each user's password with a unique random salt using hashlib, and verify logins with timing-safe comparison.

password-hashing security authentication
Python 
import hashlib
import secrets

def hash_password(password: str, salt: str | None = None) -> tuple[str, str]:
    """Hash a password with a random salt (or provided salt).

    Returns:
        (salt_hex, password_hash_hex)
    """
    if salt is None:
        salt = secrets.token_hex(16)
    salted = (salt + password)…
14 0 Open
Auth & security at scale easy

How to Verify Passwords in Constant Time in Python

Use hmac.compare_digest to verify passwords in constant time, preventing timing attacks that could reveal password length or character positions.

security authentication timing-attacks
Python 
import hmac
import time

# Mock of a constant-time password comparison (prevents timing attacks)
def verify_password(stored_password: str, supplied_password: str) -> bool:
    # hmac.compare_digest runs in constant time (for a given length)
    return hmac.compare_digest(stored_password.encode(), supplied_password.enc…
17 0 Open
Auth & security at scale medium

How to mock DNS CAA record lookups in Python

Parse and filter DNS CAA records with a mock lookup function, demonstrating how certificate authorities validate domain authorization.

dns security caa
Python 
import dnslib

def parse_caa_record(record_string):
    """Parse a DNS CAA record string into its components."""
    parts = record_string.split()
    flags = int(parts[0])
    tag = parts[1]
    value = parts[2]
    return flags, tag, value

def mock_caa_lookup(domain, caa_records):
    """Mock DNS CAA lookup that re…
18 0 Open
Production deployment patterns easy

How to Build a Simple Data Helper Class in Python

A beginner-friendly DataHelper class that stores Python dataclass objects as JSON records to disk, with load, add, and save methods.

dataclass json file-io
Python 
import json
from dataclasses import dataclass, asdict
from pathlib import Path

@dataclass
class User:
    name: str
    age: int
    email: str

class DataHelper:
    def __init__(self, filepath: str = "data.json"):
        self.filepath = Path(filepath)
        self._data = self._load()
    
    def _load(self) -> l…
12 0 Open

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