Intermediate code explainers

rust

use axum::{
    extract::State,
    routing::{get, post, MethodRouter},
    Json, Router,

Self-documenting routes in Axum

builder-pattern closures shared-state

Intermediate 8 steps

python

import time
 
from flask import Flask, g, request

Timing requests with Flask hooks

middleware request-lifecycle instrumentation

Intermediate 5 steps

typescript

import { Injectable, Logger, OnApplicationShutdown } from '@nestjs/common';
import { InjectRedis } from '@nestjs-modules/ioredis';
import Redis from 'ioredis';
import { DataSource } from 'typeorm';

Graceful shutdown hooks in NestJS

graceful-shutdown lifecycle-hooks dependency-injection

Intermediate 7 steps

ruby

require "csv"
 
def parse_transaction_row(line)
  fields = CSV.parse_line(line, headers: false, skip_blanks: true)

Parsing one CSV transaction row in Ruby

parsing type-coercion error-handling

Intermediate 6 steps

go

func ServeVideo(c *gin.Context) {
	id := c.Param("id")
	video, err := videoRepo.FindByID(c.Request.Context(), id)
	if err != nil {

Streaming video files with Gin

http streaming range requests file serving

Intermediate 6 steps

php

<?php
 
namespace App\Cache;

A content-hashed fragment cache in PHP

caching content-hashing atomic-writes

Intermediate 10 steps

javascript

export function diffIds(current, desired) {
  const currentSet = new Set(current);
  const desiredSet = new Set(desired);

Diffing sets to sync group membership

set-operations diffing transactions

Intermediate 8 steps

rust

use std::collections::HashMap;
use std::fs::File;
use std::io::{self, BufRead, BufReader};
use std::path::Path;

Parsing INI files in Rust

parsing file-io hashmap

Intermediate 9 steps

python

from pathlib import Path
 
from PIL import Image, ImageOps

Batch image resizing with Pillow

image-processing batch-jobs error-handling

Intermediate 8 steps

typescript

import { Injectable, OnModuleInit, Logger } from '@nestjs/common';
import { ConfigService } from '@nestjs/config';
import { Cron, CronExpression } from '@nestjs/schedule';

A self-refreshing feature flags provider in NestJS

caching scheduled-tasks dependency-injection

Intermediate 8 steps

ruby

class NewCommentNotifier < ApplicationNotifier
  deliver_by :database
 
  deliver_by :email do |config|

Multi-channel notifications with Noticed in Rails

notifications delivery-methods fan-out

Intermediate 6 steps

go

package handler
 
type LineItem struct {
	SKU      string  `json:"sku" binding:"required,alphanum"`

Structured validation errors in Gin

validation json-binding error-handling

Intermediate 8 steps

javascript

class HistoryStack {
  constructor(initial = '', limit = 100) {
    this.past = [];
    this.present = initial;

Building an undo/redo history stack

undo-redo state-management debouncing

Intermediate 7 steps

java

@Controller
public class BookController {
 
    private final BookService bookService;

Solving GraphQL N+1 with batch mapping in Spring

graphql n+1-problem batching

Intermediate 8 steps

python

import base64
import hashlib
import hmac
import json

Building signed expiring tokens with HMAC

hmac authentication base64

Intermediate 7 steps

rust

use axum::{
    extract::{Path, Query},
    http::Uri,
    response::{IntoResponse, Redirect},

Building HTTP redirect handlers in Axum

redirects extractors url-handling

Intermediate 7 steps

php

<?php
 
namespace App\View\Composers;

How a Laravel view composer feeds the navigation

view-composer caching dependency-injection

Intermediate 5 steps

typescript

import { Test, TestingModule } from '@nestjs/testing';
import { getRepositoryToken } from '@nestjs/typeorm';
import { Repository } from 'typeorm';

Unit testing a NestJS service with mocked providers

dependency injection mocking unit testing

Intermediate 7 steps