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Python Code Samples

Medium snippets you can copy, study, and run in the browser editor.

5 matches
System design patterns medium

Build a BFF (Backend for Frontend) Mock Aggregator in Python

A minimal HTTP server implementing the BFF pattern that aggregates user data and orders from two mock backends into a single JSON response.

bff http-server aggregation
Python
import json
from http.server import BaseHTTPRequestHandler, HTTPServer
from urllib.parse import urlparse


class MockBackendA:
    def get_user(self, user_id):
        return {"id": user_id, "name": "Alice", "service": "backend-a"}


class MockBackendB:
    def get_orders(self, user_id):
        return [
            {…
18 0 Open
System design patterns medium

Domain Driven Design Aggregate Root Example in Python

Model an Order as an aggregate root with invariants enforced through methods, demonstrating DDD principles in Python.

ddd aggregate-root object-oriented
Python
from __future__ import annotations
from dataclasses import dataclass
from typing import List, Optional
from uuid import uuid4


class Money:
    def __init__(self, amount: float, currency: str = "USD"):
        self.amount = amount
        self.currency = currency

    def __add__(self, other: Money) -> Money:
       …
12 0 Open
Streaming & messaging medium

How to Aggregate Periodic Snapshot Data in Python

Generates mock snapshot data and groups values into periods to compute average aggregates with Python's standard library.

aggregation snapshots streaming
Python
import random
from collections import defaultdict

def snapshot_aggregate(n=10, period=3):
    data = defaultdict(list)
    for i in range(n):
        key = f"item_{i % period}"
        data[key].append(random.randint(1, 100))
    return dict(data)

def aggregate_periodic(snapshots, period=3):
    result = {}
    for …
14 0 Open
Big data & Spark medium

How to Mock a UDAF Aggregate Function in Python

This code provides a minimal mock of a User-Defined Aggregate Function (UDAF), simulating the initialize-update-merge-finalize lifecycle with a defaultdict counter.

udaf aggregate mock
Python
from collections import defaultdict

class MockUDAF:
    """A minimal mock of a User-Defined Aggregate Function.

    Simulates aggregate lifecycle: initialize, update per row,
    and finalize the result.
    """

    def __init__(self):
        self._buffer = defaultdict(int)

    def initialize(self):
        """Re…
13 0 Open
Big data & Spark medium

How to Simulate a MapReduce Mock with Combine Phase in Python

Simulates a MapReduce pipeline with a combiner that aggregates local counts per reducer to reduce network and compute overhead.

mapreduce combiner hadoop
Python
from collections import defaultdict

def map_phase(lines):
    intermediate = defaultdict(list)
    for line in lines:
        for word in line.strip().lower().split():
            intermediate[word].append(1)
    return dict(intermediate)

def combine_phase(intermediate, num_reducers=3):
    combined = defaultdict(li…
14 0 Open

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