摘要：的話，是一個遵循規范微型的框架，作者這樣說大致意思的核心工作分發了請求，然后調用回調函數，返回一個對象。執行的方法時，我們從中取出的依賴，這時候，注冊的回調函數被調用，返回實例。

Slim的話，是一個遵循PSR (PSR-7)規范微型的框架，作者這樣說：

Slim is a PHP micro framework that helps you quickly write simple yet powerful web applications and APIs. At its core, Slim is a dispatcher that receives an HTTP request, invokes an appropriate callback routine, and returns an HTTP response. That’s it.

大致意思：slim的核心工作：分發了Http請求，然后調用回調函數，返回一個Http response對象。

Slim其實就幫我們做了兩件事

路由的分發

依賴的注入

框架很小，所以別的部分（如db操作、模板引擎）可能需要自己實現，但slim通過依賴注入，讓你可以很輕松的組裝其他功能到slim中。

 [
    "addContentLengthHeader" => false,
]];
$app = new SlimApp($config);

// Define app routes
$app->get("/hello/{name}", function ($request, $response, $args) {
    return $response->write("Hello " . $args["name"]);
});

// Run app
$app->run();

request代表了當前請求對象，response代表了當前響應對象，$args是占位符的鍵值對數組。
訪問/hello/salamander就會輸出Hello salamander

DB是我自己封裝的一個PDO的操作類。

$config = ["settings" => [
    "addContentLengthHeader" => false,
]];
$app = new SlimApp($config);
$container = $app->getContainer();

$container["db"] = function($c) {
    $dbHost = "localhost";
    $dbName = "test";

    $dbConf = [
        "dsn" => "mysql:dbname={$dbName};host={$dbHost}",
        "username" => "root",
        "password" => "******",
        "charset" => "utf8"
    ];
    $db = new AppLibraryDB();
    $db->__setup($dbConf);
    return $db;
};

// Define app routes
$app->get("/user/{uid}", "AppControllerIndexController:index");

namespace AppController;

class IndexController 
{
    protected $container;
    
    public function __construct(ContainerInterface $container) {
        $this->container = $container;
    }
    
    public function index($request, $response, $args) {
        $info = $this->container["db"]->fetch("SELECT name FROM user WHERE uid = :uid", [
            "uid" => $args["uid"]
        ]);
        echo "user name is " . $info["name"];
    }
}

IndexController類的是通過composer自動載入的（代碼中沒寫）：

"autoload": {
    "psr-4": {
        "App": "app/"
    }
},

代碼中可以發現，依賴容器的注入是在類實例化的時候發生的。執行IndexController的index方法時，我們從$container中取出的db依賴，這時候，注冊的回調函數被調用，返回實例。因為是用到時才實例化，這個叫做延遲實例化。

Swoole讓PHP可以常駐內存，而且它提供了Http Server的功能，所以Slim和Swoole沒什么沖突。

Slim是通過當前路由(譬如/user/2，不帶查詢字符串)和http方法來找到正確的回調函數的。這些量Slim是從哪里取的呢？肯定是$_SERVER。查看slim源碼：
run()方法：

public function run($silent = false)
{
    $response = $this->container->get("response");

    try {
        ob_start();
        $response = $this->process($this->container->get("request"), $response);
    } catch (InvalidMethodException $e) {
        $response = $this->processInvalidMethod($e->getRequest(), $response);
    } finally {
        $output = ob_get_clean();
    }

    if (!empty($output) && $response->getBody()->isWritable()) {
        $outputBuffering = $this->container->get("settings")["outputBuffering"];
        if ($outputBuffering === "prepend") {
            // prepend output buffer content
            $body = new HttpBody(fopen("php://temp", "r+"));
            $body->write($output . $response->getBody());
            $response = $response->withBody($body);
        } elseif ($outputBuffering === "append") {
            // append output buffer content
            $response->getBody()->write($output);
        }
    }

    $response = $this->finalize($response);

    if (!$silent) {
        $this->respond($response);
    }

    return $response;
}

發現$request對象是從容器取出來的，那$request是怎么注冊的呢？？，那就看App類的構造函數了，最后發現Container類的構造函數中有registerDefaultServices()方法：

private function registerDefaultServices($userSettings)
{
    $defaultSettings = $this->defaultSettings;

    /**
     * This service MUST return an array or an
     * instance of ArrayAccess.
     *
     * @return array|ArrayAccess
     */
    $this["settings"] = function () use ($userSettings, $defaultSettings) {
        return new Collection(array_merge($defaultSettings, $userSettings));
    };

    $defaultProvider = new DefaultServicesProvider();
    $defaultProvider->register($this);
}

查看$defaultProvider->register()方法：

public function register($container)
{
    if (!isset($container["environment"])) {
        /**
         * This service MUST return a shared instance
         * of SlimInterfacesHttpEnvironmentInterface.
         *
         * @return EnvironmentInterface
         */
        $container["environment"] = function () {
            return new Environment($_SERVER);
        };
    }

    if (!isset($container["request"])) {
        /**
         * PSR-7 Request object
         *
         * @param Container $container
         *
         * @return ServerRequestInterface
         */
        $container["request"] = function ($container) {
            return Request::createFromEnvironment($container->get("environment"));
        };
    }
    
    //...

可以看到$request對象是通過Request::createFromEnvironment方法構造的，它需要從容器中取出environment依賴，而environment依賴是通過構造一個Environment對象得來的，它正好放入了$_SERVER
查看Environment類源碼，可以發現它繼承了Collection類，Collection的構造函數如下：

public function __construct(array $items = [])
{
    $this->replace($items);
}

從上面我們可以得出，我們主要注冊一個自定義的environment依賴就行，原來$_SERVER的信息可以從swoole的$request->server中取。

server.php

on("start", function ($server) {
    echo "Swoole http server is started at http://0.0.0.0:8888
";
});

$http->on("request", function ($request, $response) {
    // Instantiate the app
    $config = [
        "settings" => [
            "addContentLengthHeader" => false,
        ]
    ];
    $config["environment"] = function () use($request) {
        $server = [];
        foreach ($request->server as $key => $value) {
            $server[strtoupper($key)] = $value;
        }
        return new Environment($server);
    };
    $app = new SlimApp($config);
    // Register routes
    require APP . "/routes.php";

    // Run app
    $slimResponse = $app->run(true);
    $headers = $slimResponse->getHeaders();
    foreach ($headers as $name => $values) {
        $response->header($name, implode(", ", $values));
    }
    $response->header("X-Powered-By", "Salamander");
    $response->end($slimResponse->getBody());
});

$http->start();

注意$request->server中key都是小寫的，所以這里轉化了一下。

routes.php（在App目錄中）

get("/", function (Request $request, Response $response) {
    $response->getBody()->write("Hello Salamander");
    return $response;
});


$app->get("/user/{uid}", function (Request $request, Response $response, $args) {
    $response->getBody()->write("Hello User:" . $args["uid"]);
    return $response;
});

訪問/

訪問/user/45

百度云盤
tip：環境基于docker的，運行docker-compose up即可

Issue