研究laravel收穫的收穫之一

laravel框架可以說是一款代碼非常優雅的框架，懷着邊學習怎麼使用邊去研究源碼的心態去學習這個框架還是很有必要的。在今天我學習了laravel框架自帶的登錄認證，說實話中文的文檔寫的確實不怎麼好。我發現帶着研究源碼的方法去學習框架，不僅學習的更加透徹，同時還能學習大牛優秀的編碼思想和風格。

laravel框架的登陸認證主要包含兩個組件guards和providers，guards負責定義每個用戶請求（登錄、註冊啥的）的認證邏輯，providers負責從持久層獲取用戶數據，Laravel 底層支持通過 Eloquent 和數據庫查詢構建器兩種方式來獲取用戶，如果需要的話，你還可以定義額外的 Provider。下面就來說說這兩個組件。

guards

這裏拿laravel框架自己實習的SessionGuard來說

class SessionGuard implements StatefulGuard, SupportsBasicAuth
{
    use GuardHelpers, Macroable;

可以看到SessionGuard實習了StatefulGuard和SupportsBasicAuth這兩個接口，還使用了GuardHelpers和Macroable這兩個trait。

下面我們就來分別看一下這些個東西

首先是StatefulGuard這個接口

<?php

namespace Illuminate\Contracts\Auth;

interface StatefulGuard extends Guard
{
    /**
     * Attempt to authenticate a user using the given credentials.
     *
     * @param  array  $credentials
     * @param  bool   $remember
     * @return bool
     */
    public function attempt(array $credentials = [], $remember = false);

    /**
     * Log a user into the application without sessions or cookies.
     *
     * @param  array  $credentials
     * @return bool
     */
    public function once(array $credentials = []);

    /**
     * Log a user into the application.
     *
     * @param  \Illuminate\Contracts\Auth\Authenticatable  $user
     * @param  bool  $remember
     * @return void
     */
    public function login(Authenticatable $user, $remember = false);

    /**
     * Log the given user ID into the application.
     *
     * @param  mixed  $id
     * @param  bool   $remember
     * @return \Illuminate\Contracts\Auth\Authenticatable
     */
    public function loginUsingId($id, $remember = false);

    /**
     * Log the given user ID into the application without sessions or cookies.
     *
     * @param  mixed  $id
     * @return bool
     */
    public function onceUsingId($id);

    /**
     * Determine if the user was authenticated via "remember me" cookie.
     *
     * @return bool
     */
    public function viaRemember();

    /**
     * Log the user out of the application.
     *
     * @return void
     */
    public function logout();
}

可以看到這個接口繼承成了一個Guard接口，Guard這個接口還定義了一些其他的方法，當然我這裏就不放出來了。

然後是SupportsBasicAuth接口

interface SupportsBasicAuth
{
    /**
     * Attempt to authenticate using HTTP Basic Auth.
     *
     * @param  string  $field
     * @param  array  $extraConditions
     * @return \Symfony\Component\HttpFoundation\Response|null
     */
    public function basic($field = 'email', $extraConditions = []);

    /**
     * Perform a stateless HTTP Basic login attempt.
     *
     * @param  string  $field
     * @param  array  $extraConditions
     * @return \Symfony\Component\HttpFoundation\Response|null
     */
    public function onceBasic($field = 'email', $extraConditions = []);
}

可以這樣理解，這兩個接口實際上是一種協議，它規定了作爲guards的這個類必須要實現什麼方法。實際上面向接口編程是很有必要的，這對代碼解耦很有幫助，有利於寫出擴展性高的代碼。客戶端可以在多種實現了規定接口的類之間進行切換，不需要關注類方法是怎麼實現的，方法的修改了實現代碼也不影響客戶端的代碼。所以laravel框架才支持你使用多種框架實現的guards以及你自己定義的guards（前提是你要實現上面兩個接口）。

GuardHelpers這個trait就不多說了，其實包含也是實現上面兩個接口的方法，可能還有一些擴展方法吧。可能laravel框架作者覺得把實現都寫在一個類裏面太臃腫了，或者是兩個trait就裏面的代碼不同的guards可以進行復用。

<?php

namespace Illuminate\Auth;

use Illuminate\Contracts\Auth\UserProvider;
use Illuminate\Contracts\Auth\Authenticatable as AuthenticatableContract;

/**
 * These methods are typically the same across all guards.
 */
trait GuardHelpers
{
    /**
     * The currently authenticated user.
     *
     * @var \Illuminate\Contracts\Auth\Authenticatable
     */
    protected $user;

    /**
     * The user provider implementation.
     *
     * @var \Illuminate\Contracts\Auth\UserProvider
     */
    protected $provider;

    /**
     * Determine if current user is authenticated. If not, throw an exception.
     *
     * @return \Illuminate\Contracts\Auth\Authenticatable
     *
     * @throws \Illuminate\Auth\AuthenticationException
     */
    public function authenticate()
    {
        if (! is_null($user = $this->user())) {
            return $user;
        }

        throw new AuthenticationException;
    }

    /**
     * Determine if the guard has a user instance.
     *
     * @return bool
     */
    public function hasUser()
    {
        return ! is_null($this->user);
    }

    /**
     * Determine if the current user is authenticated.
     *
     * @return bool
     */
    public function check()
    {
        return ! is_null($this->user());
    }

    /**
     * Determine if the current user is a guest.
     *
     * @return bool
     */
    public function guest()
    {
        return ! $this->check();
    }

    /**
     * Get the ID for the currently authenticated user.
     *
     * @return int|null
     */
    public function id()
    {
        if ($this->user()) {
            return $this->user()->getAuthIdentifier();
        }
    }

    /**
     * Set the current user.
     *
     * @param  \Illuminate\Contracts\Auth\Authenticatable  $user
     * @return $this
     */
    public function setUser(AuthenticatableContract $user)
    {
        $this->user = $user;

        return $this;
    }

    /**
     * Get the user provider used by the guard.
     *
     * @return \Illuminate\Contracts\Auth\UserProvider
     */
    public function getProvider()
    {
        return $this->provider;
    }

    /**
     * Set the user provider used by the guard.
     *
     * @param  \Illuminate\Contracts\Auth\UserProvider  $provider
     * @return void
     */
    public function setProvider(UserProvider $provider)
    {
        $this->provider = $provider;
    }
}

好吧，看了裏面的代碼我更多覺得是爲了複用，畢竟這裏面的代碼通用性比較大。所以說大牛的代碼還是很優雅的，能複用的地方就複用。

Macroable這個trait還是有點東西的，我看到很多框架的類也使用了這個trait。這個Macroable有啥用呢，看下代碼就知道了。

trait Macroable
{
    /**
     * The registered string macros.
     *
     * @var array
     */
    protected static $macros = [];

    /**
     * Register a custom macro.
     *
     * @param  string $name
     * @param  object|callable  $macro
     *
     * @return void
     */
    public static function macro($name, $macro)
    {
        static::$macros[$name] = $macro;
    }

    /**
     * Mix another object into the class.
     *
     * @param  object  $mixin
     * @param  bool  $replace
     * @return void
     *
     * @throws \ReflectionException
     */
    public static function mixin($mixin, $replace = true)
    {
        $methods = (new ReflectionClass($mixin))->getMethods(
            ReflectionMethod::IS_PUBLIC | ReflectionMethod::IS_PROTECTED
        );

        foreach ($methods as $method) {
            if ($replace || ! static::hasMacro($method->name)) {
                $method->setAccessible(true);
                static::macro($method->name, $method->invoke($mixin));
            }
        }
    }

    /**
     * Checks if macro is registered.
     *
     * @param  string  $name
     * @return bool
     */
    public static function hasMacro($name)
    {
        return isset(static::$macros[$name]);
    }

    /**
     * Dynamically handle calls to the class.
     *
     * @param  string  $method
     * @param  array   $parameters
     * @return mixed
     *
     * @throws \BadMethodCallException
     */
    public static function __callStatic($method, $parameters)
    {
        if (! static::hasMacro($method)) {
            throw new BadMethodCallException(sprintf(
                'Method %s::%s does not exist.', static::class, $method
            ));
        }

        if (static::$macros[$method] instanceof Closure) {
            return call_user_func_array(Closure::bind(static::$macros[$method], null, static::class), $parameters);
        }

        return call_user_func_array(static::$macros[$method], $parameters);
    }

    /**
     * Dynamically handle calls to the class.
     *
     * @param  string  $method
     * @param  array   $parameters
     * @return mixed
     *
     * @throws \BadMethodCallException
     */
    public function __call($method, $parameters)
    {
        if (! static::hasMacro($method)) {
            throw new BadMethodCallException(sprintf(
                'Method %s::%s does not exist.', static::class, $method
            ));
        }

        $macro = static::$macros[$method];

        if ($macro instanceof Closure) {
            return call_user_func_array($macro->bindTo($this, static::class), $parameters);
        }

        return call_user_func_array($macro, $parameters);
    }
}

Macroable這個trait其實就是對使用他的類進行擴充，它的作用很強大。可以將一個方法、其他類的所有方法注入到、一個類到注入到使用它的類的作用域裏面。方法的注入主要就是通過這個方法Closure::bind（靜態方法）和Closure::bindTo（非靜態方法）。

 

providers

這裏拿DatabaseUserProvider來說，就是數據庫查詢構建器的方式

class DatabaseUserProvider implements UserProvider
{

可以看到這個Provider也是通過實現接口的方式，所以框架可以在不同的Provider實現之間切換，這裏就不多說了。

 

AuthManager

<?php

namespace Illuminate\Auth;

use Closure;
use InvalidArgumentException;
use Illuminate\Contracts\Auth\Factory as FactoryContract;

class AuthManager implements FactoryContract
{
    use CreatesUserProviders;

    /**
     * The application instance.
     *
     * @var \Illuminate\Contracts\Foundation\Application
     */
    protected $app;

    /**
     * The registered custom driver creators.
     *
     * @var array
     */
    protected $customCreators = [];

    /**
     * The array of created "drivers".
     *
     * @var array
     */
    protected $guards = [];

    /**
     * The user resolver shared by various services.
     *
     * Determines the default user for Gate, Request, and the Authenticatable contract.
     *
     * @var \Closure
     */
    protected $userResolver;

    /**
     * Create a new Auth manager instance.
     *
     * @param  \Illuminate\Contracts\Foundation\Application  $app
     * @return void
     */
    public function __construct($app)
    {
        $this->app = $app;

        $this->userResolver = function ($guard = null) {
            return $this->guard($guard)->user();
        };
    }

    /**
     * Attempt to get the guard from the local cache.
     *
     * @param  string  $name
     * @return \Illuminate\Contracts\Auth\Guard|\Illuminate\Contracts\Auth\StatefulGuard
     */
    public function guard($name = null)
    {
        $name = $name ?: $this->getDefaultDriver();

        return $this->guards[$name] ?? $this->guards[$name] = $this->resolve($name);
    }

    /**
     * Resolve the given guard.
     *
     * @param  string  $name
     * @return \Illuminate\Contracts\Auth\Guard|\Illuminate\Contracts\Auth\StatefulGuard
     *
     * @throws \InvalidArgumentException
     */
    protected function resolve($name)
    {
        $config = $this->getConfig($name);

        if (is_null($config)) {
            throw new InvalidArgumentException("Auth guard [{$name}] is not defined.");
        }

        if (isset($this->customCreators[$config['driver']])) {
            return $this->callCustomCreator($name, $config);
        }

        $driverMethod = 'create'.ucfirst($config['driver']).'Driver';

        if (method_exists($this, $driverMethod)) {
            return $this->{$driverMethod}($name, $config);
        }

        throw new InvalidArgumentException(
            "Auth driver [{$config['driver']}] for guard [{$name}] is not defined."
        );
    }

    /**
     * Call a custom driver creator.
     *
     * @param  string  $name
     * @param  array  $config
     * @return mixed
     */
    protected function callCustomCreator($name, array $config)
    {
        return $this->customCreators[$config['driver']]($this->app, $name, $config);
    }

    /**
     * Create a session based authentication guard.
     *
     * @param  string  $name
     * @param  array  $config
     * @return \Illuminate\Auth\SessionGuard
     */
    public function createSessionDriver($name, $config)
    {
        $provider = $this->createUserProvider($config['provider'] ?? null);

        $guard = new SessionGuard($name, $provider, $this->app['session.store']);

        // When using the remember me functionality of the authentication services we
        // will need to be set the encryption instance of the guard, which allows
        // secure, encrypted cookie values to get generated for those cookies.
        if (method_exists($guard, 'setCookieJar')) {
            $guard->setCookieJar($this->app['cookie']);
        }

        if (method_exists($guard, 'setDispatcher')) {
            $guard->setDispatcher($this->app['events']);
        }

        if (method_exists($guard, 'setRequest')) {
            $guard->setRequest($this->app->refresh('request', $guard, 'setRequest'));
        }

        return $guard;
    }

    /**
     * Create a token based authentication guard.
     *
     * @param  string  $name
     * @param  array  $config
     * @return \Illuminate\Auth\TokenGuard
     */
    public function createTokenDriver($name, $config)
    {
        // The token guard implements a basic API token based guard implementation
        // that takes an API token field from the request and matches it to the
        // user in the database or another persistence layer where users are.
        $guard = new TokenGuard(
            $this->createUserProvider($config['provider'] ?? null),
            $this->app['request'],
            $config['input_key'] ?? 'api_token',
            $config['storage_key'] ?? 'api_token',
            $config['hash'] ?? false
        );

        $this->app->refresh('request', $guard, 'setRequest');

        return $guard;
    }

    /**
     * Get the guard configuration.
     *
     * @param  string  $name
     * @return array
     */
    protected function getConfig($name)
    {
        return $this->app['config']["auth.guards.{$name}"];
    }

    /**
     * Get the default authentication driver name.
     *
     * @return string
     */
    public function getDefaultDriver()
    {
        return $this->app['config']['auth.defaults.guard'];
    }

    /**
     * Set the default guard driver the factory should serve.
     *
     * @param  string  $name
     * @return void
     */
    public function shouldUse($name)
    {
        $name = $name ?: $this->getDefaultDriver();

        $this->setDefaultDriver($name);

        $this->userResolver = function ($name = null) {
            return $this->guard($name)->user();
        };
    }

    /**
     * Set the default authentication driver name.
     *
     * @param  string  $name
     * @return void
     */
    public function setDefaultDriver($name)
    {
        $this->app['config']['auth.defaults.guard'] = $name;
    }

    /**
     * Register a new callback based request guard.
     *
     * @param  string  $driver
     * @param  callable  $callback
     * @return $this
     */
    public function viaRequest($driver, callable $callback)
    {
        return $this->extend($driver, function () use ($callback) {
            $guard = new RequestGuard($callback, $this->app['request'], $this->createUserProvider());

            $this->app->refresh('request', $guard, 'setRequest');

            return $guard;
        });
    }

    /**
     * Get the user resolver callback.
     *
     * @return \Closure
     */
    public function userResolver()
    {
        return $this->userResolver;
    }

    /**
     * Set the callback to be used to resolve users.
     *
     * @param  \Closure  $userResolver
     * @return $this
     */
    public function resolveUsersUsing(Closure $userResolver)
    {
        $this->userResolver = $userResolver;

        return $this;
    }

    /**
     * Register a custom driver creator Closure.
     *
     * @param  string  $driver
     * @param  \Closure  $callback
     * @return $this
     */
    public function extend($driver, Closure $callback)
    {
        $this->customCreators[$driver] = $callback;

        return $this;
    }

    /**
     * Register a custom provider creator Closure.
     *
     * @param  string  $name
     * @param  \Closure  $callback
     * @return $this
     */
    public function provider($name, Closure $callback)
    {
        $this->customProviderCreators[$name] = $callback;

        return $this;
    }

    /**
     * Dynamically call the default driver instance.
     *
     * @param  string  $method
     * @param  array  $parameters
     * @return mixed
     */
    public function __call($method, $parameters)
    {
        return $this->guard()->{$method}(...$parameters);
    }
}

 

對guards進行調用的類就是這個類，調用的方式就是

 public function __call($method, $parameters)
    {
        return $this->guard()->{$method}(...$parameters);
    }

可以看到這個類負責管理guards和provider，包括通過讀取配置文件設置、創建、切換guards和provider。

最後

可以看的出laravel框架的代碼設計真的是無可挑剔，不管怎麼進行guards和provider的切換，包括自定義的guards和provider。你只需要修改配置文件，將實現規定接口的guards和provider引入即可，可以說是插口式的，你可以對接口進行擴展。