PHP Class Examples

1<?php
2declare(strict_types=1);
3
4namespace App\Auth;
5
6class UserAuthenticator
7{
8    private PDO $db;
9    
10    public function __construct(PDO $database)
11    {
12        $this->db = $database;
13    }
14    
15    public function register(string $email, string $password): bool
16    {
17        $hash = password_hash($password, PASSWORD_ARGON2ID);
18        
19        $stmt = $this->db->prepare(
20            "INSERT INTO users (email, password) VALUES (?, ?)"
21        );
22        
23        return $stmt->execute([$email, $hash]);
24    }
25    
26    public function authenticate(string $email, string $password): bool
27    {
28        $stmt = $this->db->prepare(
29            "SELECT password FROM users WHERE email = ?"
30        );
31        $stmt->execute([$email]);
32        $user = $stmt->fetch();
33        
34        return $user && password_verify($password, $user['password']);
35    }
36}

1<?php
2declare(strict_types=1);
3
4namespace App\Database;
5
6class QueryBuilder
7{
8    private PDO $pdo;
9    private string $table = '';
10    private array $wheres = [];
11    private array $bindings = [];
12    
13    public function __construct(PDO $pdo)
14    {
15        $this->pdo = $pdo;
16    }
17    
18    public function table(string $table): self
19    {
20        $this->table = $table;
21        return $this;
22    }
23    
24    public function where(string $column, string $operator, mixed $value): self
25    {
26        $this->wheres[] = "$column $operator ?";
27        $this->bindings[] = $value;
28        return $this;
29    }
30    
31    public function get(): array
32    {
33        $sql = "SELECT * FROM {$this->table}";
34        
35        if (!empty($this->wheres)) {
36            $sql .= " WHERE " . implode(' AND ', $this->wheres);
37        }
38        
39        $stmt = $this->pdo->prepare($sql);
40        $stmt->execute($this->bindings);
41        
42        return $stmt->fetchAll(PDO::FETCH_ASSOC);
43    }
44}

1<?php
2declare(strict_types=1);
3
4namespace App\Validation;
5
6class Validator
7{
8    private array $errors = [];
9    
10    public function validate(array $data, array $rules): bool
11    {
12        foreach ($rules as $field => $ruleSet) {
13            $value = $data[$field] ?? null;
14            
15            foreach (explode('|', $ruleSet) as $rule) {
16                $this->applyRule($field, $value, $rule);
17            }
18        }
19        
20        return empty($this->errors);
21    }
22    
23    private function applyRule(string $field, mixed $value, string $rule): void
24    {
25        if ($rule === 'required' && empty($value)) {
26            $this->errors[$field][] = "The $field field is required.";
27        }
28        
29        if ($rule === 'email' && !filter_var($value, FILTER_VALIDATE_EMAIL)) {
30            $this->errors[$field][] = "The $field must be a valid email.";
31        }
32        
33        if (str_starts_with($rule, 'min:')) {
34            $min = (int) substr($rule, 4);
35            if (strlen((string)$value) < $min) {
36                $this->errors[$field][] = "The $field must be at least $min characters.";
37            }
38        }
39    }
40    
41    public function errors(): array
42    {
43        return $this->errors;
44    }
45}

1<?php
2declare(strict_types=1);
3
4namespace App\Http;
5
6class JsonResponse
7{
8    public static function success(mixed $data, int $status = 200): void
9    {
10        http_response_code($status);
11        header('Content-Type: application/json');
12        
13        echo json_encode([
14            'success' => true,
15            'data' => $data,
16        ], JSON_THROW_ON_ERROR);
17        
18        exit;
19    }
20    
21    public static function error(string $message, int $status = 400): void
22    {
23        http_response_code($status);
24        header('Content-Type: application/json');
25        
26        echo json_encode([
27            'success' => false,
28            'error' => $message,
29        ], JSON_THROW_ON_ERROR);
30        
31        exit;
32    }
33    
34    public static function validationError(array $errors): void
35    {
36        self::error('Validation failed', 422);
37    }
38}