<?php

interface Logger
{
    public function info($message);
}

abstract class Service
{
    protected $logger;

    public function __construct(Logger $logger)
    {
        $this->logger = $logger;
    }

    abstract public function handle();
}

<?php

class UserService
{
    public function UserService()
    {
        // 老式构造函数，不建议继续使用
    }
}

<?php

$pdo = new PDO(
    'mysql:host=127.0.0.1;dbname=demo;charset=utf8mb4',
    'root',
    'secret'
);

$stmt = $pdo->prepare('select id, name from users where id = ?');
$stmt->execute([1]);

echo json_encode($stmt->fetch(PDO::FETCH_ASSOC), JSON_UNESCAPED_UNICODE);

<?php

$email = filter_input(INPUT_POST, 'email', FILTER_VALIDATE_EMAIL);

if ($email === false || $email === null) {
    exit('邮箱格式不正确');
}

<?php

namespace App\Service;

class OrderService
{
    public function paidOrders(array $orders)
    {
        return array_filter($orders, function (array $order) {
            return $order['status'] === 'paid';
        });
    }
}

<?php

class Model
{
    public static function table()
    {
        return get_called_class();
    }
}

class User extends Model
{
}

echo User::table();

<?php

$config = [
    'debug' => true,
    'timezone' => 'Asia/Shanghai',
];

<?php

trait HasTimestamps
{
    public function now()
    {
        return date('Y-m-d H:i:s');
    }
}

class Article
{
    use HasTimestamps;
}

<?php

function readLines($file)
{
    $handle = fopen($file, 'r');

    try {
        while (($line = fgets($handle)) !== false) {
            yield trim($line);
        }
    } finally {
        fclose($handle);
    }
}

foreach (readLines(__DIR__ . '/access.log') as $line) {
    echo $line . PHP_EOL;
}

<?php

$hash = password_hash('123456', PASSWORD_DEFAULT);

if (password_verify('123456', $hash)) {
    echo '登录成功';
}

<?php

function sum(...$numbers)
{
    return array_sum($numbers);
}

echo sum(1, 2, 3);

<?php

function makeUrl($scheme, $host, $path)
{
    return $scheme . '://' . $host . '/' . ltrim($path, '/');
}

$args = ['https', 'example.com', 'api/users'];

echo makeUrl(...$args);

<?php

$expected = hash_hmac('sha256', $payload, $secret);

if (!hash_equals($expected, $signature)) {
    exit('签名错误');
}

<?php

declare(strict_types=1);

function total(int $price, int $count): int
{
    return $price * $count;
}

echo total(20, 3);

<?php

$page = $_GET['page'] ?? 1;
$keyword = trim($_GET['keyword'] ?? '');

<?php

usort($users, function (array $a, array $b) {
    return $a['created_at'] <=> $b['created_at'];
});

<?php

// 旧写法：PHP 7 不再支持
// mysql_query('select * from users');

// 新写法：改用 PDO 或 MySQLi
$stmt = $pdo->query('select id, name from users');

<?php

function findUser(int $id): ?array
{
    return $id > 0 ? ['id' => $id, 'name' => 'Leroi'] : null;
}

function writeLog(string $message): void
{
    error_log($message);
}

<?php

try {
    $service->handle();
} catch (InvalidArgumentException | RuntimeException $e) {
    report($e);
}

<?php

function touchModel(object $model): object
{
    $model->updated_at = date('Y-m-d H:i:s');

    return $model;
}

<?php

if (is_countable($items) && count($items) > 0) {
    $firstKey = array_key_first($items);
    $lastKey = array_key_last($items);
}

<?php

class UserData
{
    public int $id;
    public string $name;
    public ?string $mobile = null;
}

<?php

$names = array_map(
    fn (array $user) => $user['name'],
    $users
);

<?php

$config['timeout'] ??= 5;
$config['retry'] ??= 3;

<?php

class Task
{
    public string $name;
}

$task = new Task();

// Fatal error: Typed property Task::$name must not be accessed before initialization
// echo $task->name;

<?php

echo htmlspecialchars(
    string: $content,
    flags: ENT_QUOTES,
    encoding: 'UTF-8',
    double_encode: false
);

<?php

class UserController
{
    #[Route('/api/users/{id}', methods: ['GET'])]
    public function show(int $id): array
    {
        return $this->userService->find($id);
    }
}

<?php

class Point
{
    public function __construct(
        public float $x,
        public float $y,
        public float $z = 0.0,
    ) {
    }
}

<?php

$label = match ($status) {
    0 => '待支付',
    1 => '已支付',
    2 => '已取消',
    default => '未知状态',
};

<?php

$city = $order->user?->profile?->city ?? '未知';

<?php

enum OrderStatus: string
{
    case Pending = 'pending';
    case Paid = 'paid';
    case Closed = 'closed';
}

function canRefund(OrderStatus $status): bool
{
    return $status === OrderStatus::Paid;
}

<?php

class Config
{
    public function __construct(
        public readonly string $appName,
        public readonly string $env,
    ) {
    }
}

<?php

readonly class UserSnapshot
{
    public function __construct(
        public int $id,
        public string $name,
    ) {
    }
}

<?php

class User
{
    public string $name = '';
}

$user = new User();

// Deprecated: Creation of dynamic property User::$age is deprecated
$user->age = 18;

<?php

class User
{
    public string $name = '';
    public int $age = 0;
}

<?php

interface ApiVersion
{
    public const string VERSION = 'v1';
}

<?php

class BaseController
{
    public function boot(): void
    {
    }
}

class UserController extends BaseController
{
    #[Override]
    public function boot(): void
    {
        parent::boot();
    }
}

<?php

if (!json_validate($rawBody)) {
    http_response_code(400);
    exit('JSON 格式错误');
}

<?php

class UserName
{
    public string $name {
        set => trim($value);
    }
}

$user = new UserName();
$user->name = ' Leroi ';

echo $user->name;

<?php

class Article
{
    public private(set) string $title;

    public function __construct(string $title)
    {
        $this->title = $title;
    }
}

<?php

$date = new DateTimeImmutable('now')->format('Y-m-d');

<?php

use Uri\Rfc3986\Uri;

$uri = new Uri('https://example.com/docs/php?page=1');

echo $uri->getHost();

<?php

$slug = ' PHP 8.5 Released '
    |> trim(...)
    |> (fn (string $value) => str_replace(' ', '-', $value))
    |> strtolower(...);

echo $slug;

<?php

readonly class Color
{
    public function __construct(
        public int $red,
        public int $green,
        public int $blue,
        public int $alpha = 255,
    ) {
    }

    public function withAlpha(int $alpha): self
    {
        return clone($this, [
            'alpha' => $alpha,
        ]);
    }
}

<?php

#[\NoDiscard]
function createToken(int $userId): string
{
    return bin2hex(random_bytes(16));
}

createToken(1);

<?php

$id = intval($_GET['id']);
$sql = "select * from users where id = {$id}";
$result = mysql_query($sql);
$user = mysql_fetch_assoc($result);

echo json_encode($user);

<?php

$id = (int) ($_GET['id'] ?? 0);

$stmt = $pdo->prepare('select id, name, mobile from users where id = ? limit 1');
$stmt->execute([$id]);

$user = $stmt->fetch(PDO::FETCH_ASSOC);

header('Content-Type: application/json; charset=utf-8');
echo json_encode($user ?: [], JSON_UNESCAPED_UNICODE);

<?php

function findUser(PDO $pdo, int $id): ?array
{
    $stmt = $pdo->prepare('select id, name, mobile from users where id = ? limit 1');
    $stmt->execute([$id]);

    $user = $stmt->fetch(PDO::FETCH_ASSOC);

    return $user === false ? null : $user;
}

$id = filter_input(INPUT_GET, 'id', FILTER_VALIDATE_INT);
$user = $id ? findUser($pdo, $id) : null;

header('Content-Type: application/json; charset=utf-8');
echo json_encode($user ?? [], JSON_UNESCAPED_UNICODE);

<?php

class User
{
    public int $age = 0;
}

<?php

class User
{
    public string $name = '';
}