Intermediate code explainers

ruby

class DigestMailer < ApplicationMailer
  default from: "notifications@example.com"
 
  def weekly_digest(user)

Building a weekly digest email in Rails

mailers active-record query-scopes

Intermediate 6 steps

python

from pathlib import Path
 
import chardet

Reading text files of unknown encoding in Python

encoding byte-order-mark fallback

Intermediate 8 steps

rust

use std::time::Duration;
 
use axum::{
    extract::State,

Rate-limiting an expensive Axum route with tower

middleware concurrency-limiting shared-state

Intermediate 9 steps

go

package archive
 
import (
	"bytes"

Gzip round-trip compression in Go

compression io error-handling

Intermediate 5 steps

typescript

import { Injectable } from '@angular/core';
import { HttpClient, HttpParams } from '@angular/common/http';
import {
  Observable,

A city autocomplete service in Angular

rxjs observables debouncing

Intermediate 7 steps

rust

use axum::{
    extract::State,
    http::{header, HeaderMap, StatusCode},
    response::{IntoResponse, Response},

Conditional GET caching in Axum

http-caching conditional-requests extractors

Intermediate 7 steps

go

package handlers
 
import (
	"encoding/json"

Hardening JSON decoding in Go HTTP handlers

json error-handling http

Intermediate 8 steps

php

<?php
 
namespace App\Http\Middleware;

ETag caching and gzip in Laravel middleware

middleware http-caching etag

Intermediate 8 steps

ruby

class OrdersController < ApplicationController
  rescue_from ActiveRecord::RecordNotUnique, with: :handle_duplicate_submission
 
  def create

Idempotent order creation in Rails

idempotency database-constraints error-handling

Intermediate 8 steps

java

import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.util.zip.GZIPInputStream;

Compressing byte arrays with GZIP in Java

compression streams try-with-resources

Intermediate 6 steps

python

from flask import Blueprint, jsonify, request, abort
from flask_caching import Cache
 
cache = Cache(config={"CACHE_TYPE": "RedisCache", "CACHE_REDIS_URL": "redis://localhost:6379/0"})

Custom cache keys for Flask endpoints

caching redis cache-invalidation

Intermediate 7 steps

typescript

import { Controller, Get, Param, Post, Body, Version, VERSION_NEUTRAL } from '@nestjs/common';
import { UsersService } from './users.service';
import { CreateUserDto } from './dto/create-user.dto';

How API versioning works in NestJS

api-versioning routing dependency-injection

Intermediate 9 steps

rust

use std::io::{BufRead, BufReader};
use std::process::{Command, Stdio};
 
#[derive(Debug)]

Parsing ps output into structs in Rust

subprocess parsing iterators

Intermediate 8 steps

go

package handlers
 
import (
	"net/http"

Validating query params with Gin binding tags

validation struct-tags pagination

Intermediate 8 steps

php

<?php
 
namespace App\Http\Resources;

Shaping API JSON with a Laravel Resource

api serialization data transformation

Intermediate 7 steps

java

package com.example.inventory;
 
import org.apache.commons.csv.CSVFormat;
import org.apache.commons.csv.CSVParser;

Reading and writing CSV with Commons CSV

csv-parsing file-io try-with-resources

Intermediate 7 steps

python

from fastapi import APIRouter, FastAPI, HTTPException
from pydantic import BaseModel

Versioning a FastAPI API with mounted sub-apps

api-versioning response-models sub-applications

Intermediate 6 steps

javascript

import { useState } from "react";
 
const EMAIL_RE = /^[^\s@]+@[^\s@]+\.[^\s@]+$/;

Building a validated signup form in React

form-validation controlled-components state-management

Intermediate 10 steps