Code Explainers

Code explainers tagged #dependency injection

php 
<?php
 
namespace App\Services\Checkout;
 

Validating coupons with Laravel's Pipeline

pipeline chain of responsibility transactions
Intermediate 7 steps
ruby 
class WeeklySignupsReport
  DEFAULT_WEEKS = 12
 
  def initialize(weeks: DEFAULT_WEEKS, source: User.all)

Building a weekly signups report in Rails

service object aggregation group by
Intermediate 7 steps
python 
from fastapi import Depends, FastAPI, Header, HTTPException, status
from sqlalchemy import select
from sqlalchemy.ext.asyncio import AsyncSession
 

Chaining tenant dependencies in FastAPI

dependency injection multi-tenancy authentication
Intermediate 7 steps
php 
<?php
 
namespace App\Http\Controllers;
 

Processing refunds safely in Laravel

dependency injection validation database transactions
Intermediate 8 steps
rust 
use axum::{
    extract::{Path, State},
    routing::{get, post},
    Json, Router,

Composing Axum apps from feature modules

trait objects modular routing shared state
Intermediate 8 steps
java 
@RestController
@RequestMapping("/api/reports")
public class ReportController {
 

Header-driven endpoints in a Spring controller

rest api request headers dependency injection
Intermediate 7 steps
java 
@Configuration
public class UserImportJobConfig {
 
    @Bean

How a Spring Batch CSV import job is wired

batch processing chunk oriented fault tolerance
Intermediate 10 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
python 
from flask import Flask, g, jsonify, request, abort
from sqlalchemy import create_engine
from sqlalchemy.orm import scoped_session, sessionmaker
 

Per-request SQLAlchemy sessions in Flask

database sessions request lifecycle connection management
Intermediate 7 steps
python 
from fastapi import APIRouter, Depends, Response, status
from sqlalchemy.orm import Session
 
from .database import get_db

Building a REST article resource in FastAPI

dependency injection rest api orm
Intermediate 8 steps
java 
package com.example.web.convert;
 
import java.time.LocalDate;
import java.time.format.DateTimeFormatter;

A custom ISO-week Converter in Spring

type conversion value object immutability
Intermediate 5 steps