入门篇 - Task API 服务

Slim 4 入门教程：Task API 服务

1. 背景

Slim 是构建轻量 API 的最佳 PHP 框架。本教程将构建完整的 Task CRUD API，掌握路由分组、中间件模式和 PSR-7 消息处理。

2. 前置概念

概念	说明
PSR-7 Request/Response	HTTP 消息抽象
PSR-15 Middleware	请求-响应处理链
Route Groups	路由分组共享中间件
Closure vs Class Handler	闭包处理器 vs 类处理器

3. 分步操作

步骤一：项目初始化

mkdir task-api &;& cd task-api
composer require slim/slim:"4.*"
composer require slim/psr7
mkdir -p public src/Handlers

步骤二：数据库初始化

CREATE TABLE tasks (
    id INTEGER PRIMARY KEY AUTOINCREMENT,
    title TEXT NOT NULL,
    description TEXT,
    status TEXT DEFAULT 'pending',
    created_at DATETIME DEFAULT CURRENT_TIMESTAMP,
    updated_at DATETIME DEFAULT CURRENT_TIMESTAMP
);

步骤三: 入口文件 public/index.php

<?php

require __DIR__ . '/../vendor/autoload.php';

use Slim\Factory\AppFactory;

$app = AppFactory::create();
$app->addErrorMiddleware(true, true, true);

// 加载路由
(require __DIR__ . '/../config/routes.php')($app);

$app->run();

步骤四：路由 config/routes.php

<?php

use Psr\Http\Message\ResponseInterface as Response;
use Psr\Http\Message\ServerRequestInterface as Request;
use Slim\App;

return function (App $app) {
    $pdo = new PDO('sqlite:../data/tasks.db');
    $pdo->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);

    $app->group('/api/tasks', function ($group) use ($pdo) {

        $group->get('', function (Request $req, Response $res) use ($pdo): Response {
            $stmt = $pdo->query('SELECT * FROM tasks ORDER BY id DESC');
            $payload = json_encode($stmt->fetchAll(PDO::FETCH_ASSOC));
            $res->getBody()->write($payload);
            return $res->withHeader('Content-Type', 'application/json');
        });

        $group->post('', function (Request $req, Response $res) use ($pdo): Response {
            $data = json_decode($req->getBody()->__toString(), true);

            $stmt = $pdo->prepare('INSERT INTO tasks (title, description) VALUES (:title, :description)');
            $stmt->execute([
                ':title' => $data['title'],
                ':description' => $data['description'] ?? '',
            ]);

            $id = $pdo->lastInsertId();
            $payload = json_encode(['id' => $id, 'message' => 'Task created']);

            $res->getBody()->write($payload);
            return $res->withHeader('Content-Type', 'application/json')->withStatus(201);
        });

        $group->put('/{id}', function (Request $req, Response $res, array $args) use ($pdo): Response {
            $data = json_decode($req->getBody()->__toString(), true);

            $stmt = $pdo->prepare('UPDATE tasks SET title = :title, status = :status, updated_at = CURRENT_TIMESTAMP WHERE id = :id');
            $stmt->execute([
                ':title' => $data['title'] ?? '',
                ':status' => $data['status'] ?? 'pending',
                ':id' => $args['id'],
            ]);

            $payload = json_encode(['message' => 'Task updated']);
            $res->getBody()->write($payload);
            return $res->withHeader('Content-Type', 'application/json');
        });

        $group->delete('/{id}', function (Request $req, Response $res, array $args) use ($pdo): Response {
            $stmt = $pdo->prepare('DELETE FROM tasks WHERE id = :id');
            $stmt->execute([':id' => $args['id']]);

            return $res->withStatus(204);
        });
    });
};

4. 验证

php -S localhost:8080 -t public/

curl -X POST http://localhost:8080/api/tasks \
  -H "Content-Type: application/json" \
  -d '{"title":"Learn Slim 4"}'

curl http://localhost:8080/api/tasks

5. 思考题

1. 如何将闭包路由重构为独立的 Action 类？
2. 如何添加 JSON 校验中间件？
3. 如何集成 Eloquent ORM 替代原生 PDO？