Code Explainers

Code explainers tagged #validation

php 
class OrderReceiptController extends Controller
{
    public function store(Request $request, Order $order)
    {

Handling receipt uploads in a Laravel controller

file-upload validation authorization
Intermediate 5 steps
javascript 
function parseHexColor(hex) {
  const cleaned = hex.trim().replace(/^#/, '');
 
  const expand = (short) =>

Parsing hex colors into RGBA channels

parsing bitwise regex
Intermediate 7 steps
java 
public record AppConfig(
        String host,
        int port,
        String databaseUrl,

Loading typed config from env vars in Java

records configuration environment-variables
Intermediate 6 steps
php 
<?php
 
namespace App\Validation;
 

Building a reusable address form validator in PHP

validation error-accumulation regex
Intermediate 9 steps
php 
<?php
 
namespace App\Http\Controllers;
 

A cached autocomplete endpoint in Laravel

caching validation query-ranking
Intermediate 8 steps
go 
type CreateUserInput struct {
	Name     string `json:"name" binding:"required,min=2,max=64"`
	Email    string `json:"email" binding:"required,email"`
	Password string `json:"password" binding:"required,min=8"`

Turning Gin validation errors into JSON

validation request-binding error-handling
Intermediate 9 steps
javascript 
import { useCallback, useRef, useState } from 'react';
 
export function ColorPicker({ initialColor = '#3b82f6', onCommit }) {
  const [committed, setCommitted] = useState(initialColor);

A validated color picker in React

uncontrolled-inputs refs validation
Intermediate 7 steps
go 
package middleware
 
import (
	"net/http"

A content-type guard middleware in Gin

middleware closures http
Intermediate 7 steps
go 
package api
 
import (
	"errors"

Turning Gin validation errors into JSON

validation error-handling http-handlers
Intermediate 9 steps
java 
public final class EmailNormalizer {
 
    private static final Pattern EMAIL_PATTERN = Pattern.compile(
        "^[A-Za-z0-9._%+-]+@[A-Za-z0-9.-]+\\.[A-Za-z]{2,}$"

Normalizing email addresses in Java

validation regex normalization
Intermediate 8 steps
python 
from datetime import date, timedelta
from typing import Annotated
 
from fastapi import APIRouter, Depends, Query

Validating date ranges with FastAPI dependencies

dependency-injection validation pydantic
Intermediate 6 steps
php 
<?php
 
namespace App\Http\Requests\DataObjects;
 

Typed request DTOs in Laravel

data-transfer-object validation immutability
Intermediate 6 steps
python 
from fastapi import FastAPI, Request, status
from fastapi.encoders import jsonable_encoder
from fastapi.exceptions import RequestValidationError
from fastapi.responses import JSONResponse

Redacting sensitive fields in FastAPI errors

validation error-handling security
Intermediate 7 steps
java 
@Component
@Order(Ordered.HIGHEST_PRECEDENCE)
public class TenantResolutionFilter extends OncePerRequestFilter {
 

How a tenant-resolution filter works in Spring

multi-tenancy servlet-filter thread-local
Intermediate 8 steps
php 
<?php
 
namespace App\Experiments;
 

Weighted random selection in PHP

weighted-random cumulative-sum sampling
Intermediate 8 steps
go 
package events
 
import (
	"net/http"

Two-pass JSON dispatch in Gin

polymorphic-json request-binding validation
Intermediate 8 steps
typescript 
import {
  Injectable,
  PipeTransform,
  ArgumentMetadata,

A custom validation pipe in NestJS

validation dto recursion
Intermediate 10 steps
ruby 
module CreditCard
  module_function
 
  def valid?(number)

Validating credit card numbers with Luhn

checksum luhn-algorithm validation
Intermediate 6 steps