Code Explainers

Code explainers tagged #concurrency

php 
<?php
 
function fetchAll(array $urls, int $concurrency = 10, int $timeout = 15): array
{

Bounded-concurrency HTTP fetching with curl_multi

concurrency http curl
Advanced 8 steps
rust 
use axum::{
    async_trait,
    extract::{FromRequestParts, State},
    http::{request::Parts, StatusCode},

Idempotent payments with an Axum extractor

idempotency extractors shared-state
Intermediate 8 steps
go 
package middleware
 
import (
	"bytes"

Building a response cache middleware in Gin

middleware caching concurrency
Intermediate 8 steps
java 
@RestController
@RequestMapping("/api/notifications")
public class NotificationStreamController {
 

Server-Sent Events per user in Spring

server-sent-events concurrency event-driven
Advanced 8 steps
ruby 
class InventoryItem < ApplicationRecord
  belongs_to :warehouse
 
  validates :quantity, numericality: { greater_than_or_equal_to: 0 }

Safe inventory updates in Rails

concurrency pessimistic-locking optimistic-locking
Advanced 7 steps
typescript 
type Task<T> = () => Promise<T>;
 
export class Mutex {
  private queue: Array<() => void> = [];

Building an async mutex in TypeScript

concurrency promises locking
Advanced 7 steps
go 
package middleware
 
import (
	"net/http"

Per-IP rate limiting middleware in Gin

rate-limiting token-bucket concurrency
Intermediate 7 steps
rust 
use axum::{extract::State, http::StatusCode, response::IntoResponse, Json};
use chrono::{Duration, Utc};
use serde::{Deserialize, Serialize};
use std::{collections::HashMap, sync::Arc};

Refresh token rotation in Axum

authentication token-rotation reuse-detection
Advanced 9 steps
php 
<?php
 
namespace App\Jobs;
 

Serializing balance reconciliation in Laravel

queues concurrency idempotency
Intermediate 7 steps
rust 
use axum::{extract::{Path, State}, http::StatusCode, Json};
use serde::Serialize;
use std::sync::Arc;
 

Concurrent dashboard aggregation in Axum

concurrency error-handling graceful-degradation
Intermediate 7 steps
java 
public final class TokenBucketRateLimiter {
 
    private final long capacity;
    private final double refillTokensPerNano;

How a token bucket rate limiter works

rate-limiting concurrency token-bucket
Intermediate 8 steps
python 
from decimal import Decimal
 
from django.db import transaction
from django.core.exceptions import ValidationError

Placing an order atomically in Django

transactions row-locking concurrency
Advanced 9 steps
go 
package fetcher
 
import (
	"context"

Bounded-concurrency HTTP fetching in Go

concurrency semaphore context-cancellation
Advanced 9 steps
php 
<?php
 
namespace App\Services;
 

Placing an order atomically in Laravel

transactions pessimistic-locking concurrency
Advanced 8 steps
java 
@Aspect
@Component
public class IdempotencyAspect {
 

How an idempotency aspect works in Spring

aop idempotency caching
Advanced 9 steps
typescript 
import { Injectable } from '@angular/core';
import {
  HttpInterceptor,
  HttpHandler,

Refreshing tokens with an Angular HttpInterceptor

http-interceptor token-refresh rxjs
Advanced 8 steps
go 
package ratelimit
 
import (
	"context"

A token bucket rate limiter in Go

rate-limiting concurrency goroutines
Intermediate 7 steps
typescript 
type Fetcher<T> = (key: string) => Promise<T>;
 
export class RequestDeduplicator<T> {
  private inFlight = new Map<string, Promise<T>>();

Deduplicating in-flight requests in TypeScript

deduplication promises caching
Intermediate 7 steps