Code Explainers

Code explainers tagged #validation

rust 
use axum::{
    extract::{Path, State},
    http::StatusCode,
    response::{IntoResponse, Response},

Typed error handling in an Axum handler

error-handling extractors validation
Intermediate 9 steps
typescript 
import { Module, Injectable } from '@nestjs/common';
import { ConfigModule, ConfigService } from '@nestjs/config';
import * as Joi from 'joi';
 

Validated, typed config in NestJS

configuration validation dependency-injection
Intermediate 6 steps
java 
public record ServerConfig(String host, int port, boolean tls, List<String> allowedOrigins) {
 
    public ServerConfig {
        Objects.requireNonNull(host, "host is required");

Validating config with a Java record

records validation immutability
Intermediate 9 steps
go 
func UploadFiles(c *gin.Context) {
	form, err := c.MultipartForm()
	if err != nil {
		c.JSON(http.StatusBadRequest, gin.H{"error": "invalid multipart form"})

Handling multi-file uploads in Gin

file-upload multipart validation
Intermediate 8 steps
php 
<?php
 
namespace App\Http\Controllers\Auth;
 

Rate-limited login in Laravel

authentication rate-limiting validation
Intermediate 9 steps
javascript 
function validateSignup({ email, password, confirmPassword, username, age }) {
  const errors = {};
 
  if (!email) {

Building a signup validator in JavaScript

validation regex guard-clauses
Beginner 7 steps
ruby 
class EmailValidator < ActiveModel::EachValidator
  EMAIL_FORMAT = /\A[a-z0-9._%+-]+@[a-z0-9.-]+\.[a-z]{2,}\z/i
 
  def validate_each(record, attribute, value)

Writing a custom email validator in Rails

validation regex custom validators
Intermediate 7 steps
javascript 
const { validationResult, matchedData } = require('express-validator');
 
function validate(schema) {
  const runners = schema.map((rule) => rule.run.bind(rule));

A reusable validation middleware in Express

middleware validation higher-order-functions
Intermediate 8 steps
python 
import re
 
_UNIT_SECONDS = {
    "w": 604800,

Parsing duration strings like 1h30m in Python

regex parsing validation
Intermediate 8 steps
java 
@RestController
@RequestMapping("/api/users")
public class UserController {
 

Bean Validation in a Spring REST controller

validation rest-api exception-handling
Intermediate 9 steps
php 
<?php
 
namespace App\Http\Controllers;
 

Building a filtered product index in Laravel

query-builder validation conditional-queries
Intermediate 9 steps
php 
<?php
 
declare(strict_types=1);
 

Validating registration input with filter_var

validation sanitization filter_var
Intermediate 8 steps
go 
package main
 
import (
	"errors"

Parsing and validating CLI flags in Go

cli-parsing validation error-handling
Intermediate 8 steps
javascript 
'use server'
 
import { revalidatePath } from 'next/cache'
import { redirect } from 'next/navigation'

How a Next.js Server Action updates a post

server-actions authorization validation
Intermediate 7 steps
php 
<?php
 
namespace App\Support;
 

Merging query params onto a URL in PHP

url-parsing query-strings immutability
Intermediate 8 steps
javascript 
const transitions = {
  cart: { checkout: 'shipping' },
  shipping: { submitAddress: 'payment', back: 'cart' },
  payment: { submitPayment: 'review', back: 'shipping' },

A finite state machine for checkout flow

state-machine event-driven data-driven-design
Intermediate 7 steps
php 
<?php
 
namespace App\Rules;
 

How a custom phone validation rule works in Laravel

validation custom-rules dependency
Intermediate 6 steps
php 
<?php
 
namespace App\Http\Controllers\Auth;
 

How a Laravel registration endpoint works

validation database-transactions events
Intermediate 8 steps