Code Explainers

Code explainers tagged #caching

ruby 
class SearchIndexReconciler
  DEBOUNCE_WINDOW = 5.seconds
 
  def self.schedule(record)

Debouncing search reindex jobs in Rails

debouncing background-jobs caching
Advanced 7 steps
typescript 
type AsyncFn<A extends unknown[], R> = (...args: A) => Promise<R>;
 
interface MemoizeOptions<A extends unknown[]> {
  keyFn?: (...args: A) => string;

Memoizing async functions with TTL in TypeScript

memoization generics promises
Advanced 8 steps
javascript 
const cache = new Map();
const inflight = new Map();
 
async function fetchResults(query) {

Building a typeahead with an LRU cache

caching lru-eviction request-deduplication
Intermediate 9 steps
python 
from functools import lru_cache
import math
 
 

Memoizing number theory with lru_cache

memoization number-theory caching
Intermediate 8 steps
ruby 
class ReportGenerator
  def initialize(account, period)
    @account = account
    @period = period

Memoized report metrics in Ruby in Rails

memoization query-composition service-object
Intermediate 7 steps
php 
<?php
 
namespace App\Services;
 

Caching tenant dashboard metrics in Laravel

caching multi-tenancy aggregation
Intermediate 7 steps
java 
@Service
public class ProductCatalogService {
 
    private final ProductRepository productRepository;

How Spring cache annotations keep data fresh

caching cache-invalidation dependency-injection
Intermediate 7 steps
python 
from django.core.cache import cache
from rest_framework.throttling import SimpleRateThrottle
 
 

A login rate throttle in Django REST Framework

rate-limiting caching throttling
Intermediate 8 steps
php 
function memoize(callable $fn): callable
{
    $cache = [];
 

How memoization works in PHP closures

memoization closures higher-order-functions
Intermediate 8 steps
rust 
use std::collections::HashMap;
 
pub struct Memoizer<K, V, F> {
    cache: HashMap<K, V>,

A generic memoizer in Rust

memoization generics caching
Intermediate 6 steps
ruby 
class SessionsController < ApplicationController
  MAX_ATTEMPTS = 5
  THROTTLE_WINDOW = 15.minutes
 

Throttling failed logins in Rails

rate-limiting authentication caching
Intermediate 7 steps
java 
import java.util.Map;
import java.util.concurrent.ConcurrentHashMap;
import java.math.BigInteger;
 

A thread-safe memoized factorial cache

memoization thread-safety caching
Intermediate 6 steps
php 
<?php
 
namespace App\Security;
 

A fixed-window rate limiter on APCu

rate-limiting fixed-window caching
Intermediate 8 steps
python 
from functools import wraps
 
 
def memoize(func):

Building a memoize decorator in Python

decorators closures memoization
Intermediate 5 steps
typescript 
import { Injectable } from '@angular/core';
import { HttpClient } from '@angular/common/http';
import { Observable, shareReplay } from 'rxjs';
 

Caching HTTP config in an Angular service

caching observables dependency-injection
Intermediate 6 steps
typescript 
import {
  CACHE_MANAGER,
  CacheInterceptor,
} from '@nestjs/cache-manager';

A tenant-aware HTTP cache in NestJS

caching interceptors multi-tenancy
Intermediate 7 steps
ruby 
class ProductCatalog
  def featured_products
    Rails.cache.fetch("catalog/featured_products", expires_in: 12.hours) do
      Product.where(featured: true)

Caching patterns with Rails.cache.fetch

caching cache-keys expiry
Intermediate 5 steps
typescript 
class LRUCache<K, V> {
  private readonly capacity: number;
  private readonly map: Map<K, V>;
 

Building an LRU cache on a JS Map

caching data-structures generics
Intermediate 8 steps