Intermediate code explainers

ruby

module Api
  module V1
    class BaseController < ActionController::API
      rescue_from StandardError, with: :render_internal_error

Centralized API error handling in Rails

error-handling rescue-from json-api

Intermediate 7 steps

ruby

require "openssl"
require "base64"
 
module WebhookSignature

Signing and verifying webhooks in Ruby

hmac cryptography webhooks

Intermediate 7 steps

go

package httpx
 
import (
	"net/http"

A retrying HTTP transport in Go

http middleware retry

Intermediate 8 steps

php

<?php
 
namespace App\Notifications;

How a queued weekly digest email works in Laravel

notifications queues email

Intermediate 7 steps

javascript

import { parsePhoneNumberFromString } from 'libphonenumber-js';
 
export class PhoneValidationError extends Error {
  constructor(message, code) {

Normalizing phone numbers with typed errors

validation error-handling custom-errors

Intermediate 6 steps

typescript

import { Injectable, computed, inject, signal } from '@angular/core';
import { HttpClient } from '@angular/common/http';
import { firstValueFrom } from 'rxjs';

Optimistic updates with Angular signals

signals optimistic-updates state-management

Intermediate 9 steps

java

@RestControllerAdvice
public class GlobalExceptionHandler {
 
    private static final Logger log = LoggerFactory.getLogger(GlobalExceptionHandler.class);

Centralized error handling in Spring

exception-handling problemdetail rest-api

Intermediate 7 steps

python

import os
from datetime import datetime, timezone
 
import jwt

JWT bearer auth as a FastAPI dependency

authentication jwt dependency-injection

Intermediate 7 steps

rust

use std::error::Error;
use std::path::Path;
 
use serde::Deserialize;

Custom CSV deserialization with serde in Rust

serde csv deserialization

Intermediate 7 steps

ruby

class CartMergeService
  def initialize(guest_cart:, user_cart:)
    @guest_cart = guest_cart
    @user_cart = user_cart

Merging a guest cart into a user cart in Rails

service object transactions idempotency

Intermediate 7 steps

php

public function importCustomers(UploadedFile $file): array
{
    $errors = [];
    $imported = 0;

Validating a CSV import in Laravel

csv-parsing validation error-accumulation

Intermediate 8 steps

javascript

const express = require('express');
const { z } = require('zod');
const router = express.Router();

Validating query params with Zod in Express

validation schema-parsing query-building

Intermediate 9 steps

java

public List<String> collectTagsFromArticles(List<Article> articles) {
    return articles.stream()
        .flatMap(article -> article.getTags().stream())
        .map(String::trim)

Flattening nested data with Java streams

streams flatmap collectors

Intermediate 7 steps

python

import logging
import traceback
 
from flask import Blueprint, jsonify, request

Centralized JSON error handling in Flask

error-handling blueprints json-api

Intermediate 5 steps

rust

use std::time::Duration;
 
use axum::{extract::State, http::StatusCode, response::IntoResponse, Json};
use serde::Serialize;

A timeout-guarded health check in Axum

health-check timeout error-handling

Intermediate 6 steps

ruby

require 'monitor'
 
class TokenBucket
  include MonitorMixin

A thread-safe token bucket rate limiter in Ruby

rate-limiting concurrency thread-safety

Intermediate 8 steps

go

package middleware
 
import (
	"crypto/subtle"

Building an API-key middleware in Gin

middleware authentication dependency-injection

Intermediate 5 steps

php

<?php
 
final class OrderRepository
{

Atomic order placement with PDO transactions

transactions prepared-statements atomicity

Intermediate 8 steps