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System design patterns

Sharding, load balancing, CAP tradeoffs, and scaling patterns — interview and production ready.

3 matches

Create a Data Helper Class in Python

A reusable DataHelper class that saves and loads JSON and CSV files from a configurable base directory, with automatic header detection for CSV.

data-helper json csv

Python

import json
import csv
from pathlib import Path

class DataHelper:
    def __init__(self, base_path="."):
        self.base_path = Path(base_path)
        self.base_path.mkdir(exist_ok=True)

    def save_json(self, data, filename):
        path = self.base_path / filename
        with open(path, "w") as f:
          …

16 0 Open

System design patterns easy

How to Implement a Simple Event Bus in Python

Create a publish-subscribe event bus using dataclasses and defaultdict to decouple event producers from consumers.

event-bus publish-subscribe design-patterns

Python

from collections import defaultdict
from dataclasses import dataclass, field
from typing import Callable, Dict, List, Set


@dataclass
class EventBus:
    _subscribers: Dict[str, List[Callable]] = field(
        default_factory=lambda: defaultdict(list)
    )

    def subscribe(self, event_type: str, handler: Callable…

15 0 Open

System design patterns easy

How to Implement the Repository Pattern in Python with an In-Memory Dict

Stores, retrieves, updates, and deletes user records in memory using a Repository abstraction over a plain dict, isolating data access from business logic.

repository-pattern design-patterns in-memory

Python

class UserRepository:
    def __init__(self):
        self._storage = {}
        self._next_id = 1

    def create(self, name, email):
        user_id = self._next_id
        self._next_id += 1
        self._storage[user_id] = {"id": user_id, "name": name, "email": email}
        return self._storage[user_id]

    def…

11 0 Open

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