Laravel5.5源码详解 -- Laravel-debugbar及使用elementUI-ajax的注意事项

小灰灰 2022-06-02 00:23 202阅读 0赞

# Laravel5.5源码详解 – Laravel-debugbar 及使用elementUI - ajax的注意事项 #

关于laravel对中间件的处理，请参中间件考另文，  
[Laravel5.5源码详解 – 中间件MiddleWare分析][Laravel5.5_ _ _MiddleWare]  
这里只是快速把debugbar的事务处理流程记录一遍。

我在Illuminate\\Pipeline\\Pipeline的then函数中进行中间件捕获，发现有下面这些中间件，

array:6 [▼
      0 => "Illuminate\Foundation\Http\Middleware\CheckForMaintenanceMode"
      1 => "Illuminate\Foundation\Http\Middleware\ValidatePostSize"
      2 => "App\Http\Middleware\TrimStrings"
      3 => "Illuminate\Foundation\Http\Middleware\ConvertEmptyStringsToNull"
      4 => "App\Http\Middleware\TrustProxies"
      5 => "Barryvdh\Debugbar\Middleware\InjectDebugbar"
    ]
    array:6 [▼
      0 => "App\Http\Middleware\EncryptCookies"
      1 => "Illuminate\Cookie\Middleware\AddQueuedCookiesToResponse"
      2 => "Illuminate\Session\Middleware\StartSession"
      3 => "Illuminate\View\Middleware\ShareErrorsFromSession"
      4 => "App\Http\Middleware\VerifyCsrfToken"
      5 => "Illuminate\Routing\Middleware\SubstituteBindings"
    ]

其中就包括这个`Barryvdh\Debugbar\Middleware\InjectDebugbar`，它是在larave启动时，在`vendor\composer\installed.json`发现并引入，

laravel-debugbar的配置在`Barryvdh\laravel-debugbar\config\debugbar`，里面解释比较详尽，这里也不再重复。顺便说一下，这个类是在`Barryvdh\Debugbar\ServiceProvider`中注册的，

<?php namespace Barryvdh\Debugbar; use Barryvdh\Debugbar\Middleware\DebugbarEnabled; use Barryvdh\Debugbar\Middleware\InjectDebugbar; use DebugBar\DataFormatter\DataFormatter; use DebugBar\DataFormatter\DataFormatterInterface; use Illuminate\Contracts\Http\Kernel; use Illuminate\Routing\Router; use Illuminate\Session\SessionManager; class ServiceProvider extends \Illuminate\Support\ServiceProvider { protected $defer = false; public function register() { $configPath = __DIR__ . '/../config/debugbar.php'; $this->mergeConfigFrom($configPath, 'debugbar'); $this->app->alias( DataFormatter::class, DataFormatterInterface::class ); $this->app->singleton(LaravelDebugbar::class, function () { $debugbar = new LaravelDebugbar($this->app); if ($this->app->bound(SessionManager::class)) { $sessionManager = $this->app->make(SessionManager::class); $httpDriver = new SymfonyHttpDriver($sessionManager); $debugbar->setHttpDriver($httpDriver); } return $debugbar; } ); $this->app->alias(LaravelDebugbar::class, 'debugbar'); $this->app->singleton('command.debugbar.clear', function ($app) { return new Console\ClearCommand($app['debugbar']); } ); $this->commands(['command.debugbar.clear']); } // 这里注册了很多事件处理功能，都是后面在处理request的时候可能会用到的 public function boot() { $configPath = __DIR__ . '/../config/debugbar.php'; $this->publishes([$configPath => $this->getConfigPath()], 'config'); $routeConfig = [ 'namespace' => 'Barryvdh\Debugbar\Controllers', 'prefix' => $this->app['config']->get('debugbar.route_prefix'), 'domain' => $this->app['config']->get('debugbar.route_domain'), 'middleware' => [DebugbarEnabled::class], ]; $this->getRouter()->group($routeConfig, function($router) { $router->get('open', [ 'uses' => 'OpenHandlerController@handle', 'as' => 'debugbar.openhandler', ]); $router->get('clockwork/{id}', [ 'uses' => 'OpenHandlerController@clockwork', 'as' => 'debugbar.clockwork', ]); $router->get('assets/stylesheets', [ 'uses' => 'AssetController@css', 'as' => 'debugbar.assets.css', ]); $router->get('assets/javascript', [ 'uses' => 'AssetController@js', 'as' => 'debugbar.assets.js', ]); }); $this->registerMiddleware(InjectDebugbar::class); } protected function getRouter() { return $this->app['router']; } protected function getConfigPath() { return config_path('debugbar.php'); } protected function publishConfig($configPath) { $this->publishes([$configPath => config_path('debugbar.php')], 'config'); } protected function registerMiddleware($middleware) { $kernel = $this->app[Kernel::class]; $kernel->pushMiddleware($middleware); } public function provides() { return ['debugbar', 'command.debugbar.clear', DataFormatterInterface::class, LaravelDebugbar::class]; } }

重点在这里，实际处理response和request的handle函数在Barryvdh\\Debugbar\\Middleware\\InjectDebugbar中，

<?php namespace Barryvdh\Debugbar\Middleware; use Error; use Closure; use Exception; use Illuminate\Http\Request; use Barryvdh\Debugbar\LaravelDebugbar; use Illuminate\Contracts\Container\Container; use Illuminate\Contracts\Debug\ExceptionHandler; use Symfony\Component\Debug\Exception\FatalThrowableError; class InjectDebugbar { protected $container; protected $debugbar; protected $except = []; public function __construct(Container $container, LaravelDebugbar $debugbar) { $this->container = $container; $this->debugbar = $debugbar; $this->except = config('debugbar.except') ?: []; } public function handle($request, Closure $next) { // 如果debugbar没有使能，或传入的request是空的，则直接返回。 if (!$this->debugbar->isEnabled() || $this->inExceptArray($request)) { return $next($request); } // 注册事务处理功能 $this->debugbar->boot(); try { /** @var \Illuminate\Http\Response $response */ // 可以看到，handle是处理后置的，也就是在（来回两次经过handle）回途中处理函数， // 所以这里先$next() $response = $next($request); } catch (Exception $e) { $response = $this->handleException($request, $e); } catch (Error $error) { $e = new FatalThrowableError($error); $response = $this->handleException($request, $e); } // 处理后置，接上面的next()之后才是debugbar干活的时间 // Modify the response to add the Debugbar $this->debugbar->modifyResponse($request, $response); // 处理完毕，返回结果 return $response; }

上面这段，真正起作用的就是这句：`$this->debugbar->modifyResponse($request, $response);` ，它是debugbar 修改response的地方所在，具体请看在Barryvdh\\Debugbar\\LaravelDebugbar，请注意其中的注释，

public function modifyResponse(Request $request, Response $response) { // 如果没有使能，就直接返回response $app = $this->app; if (!$this->isEnabled() || $this->isDebugbarRequest()) { return $response; } // Show the Http Response Exception in the Debugbar, when available // 如果有Http异常，则打印显示出来 if (isset($response->exception)) { $this->addThrowable($response->exception); } // 要不要调试设置信息，默认是不需要的 if ($this->shouldCollect('config', false)) { try { $configCollector = new ConfigCollector(); $configCollector->setData($app['config']->all()); $this->addCollector($configCollector); } catch (\Exception $e) { $this->addThrowable( new Exception( 'Cannot add ConfigCollector to Laravel Debugbar: ' . $e->getMessage(), $e->getCode(), $e ) ); } } // 如果绑定session调试 if ($this->app->bound(SessionManager::class)){ /** @var \Illuminate\Session\SessionManager $sessionManager */ $sessionManager = $app->make(SessionManager::class); $httpDriver = new SymfonyHttpDriver($sessionManager, $response); $this->setHttpDriver($httpDriver); if ($this->shouldCollect('session') && ! $this->hasCollector('session')) { try { $this->addCollector(new SessionCollector($sessionManager)); } catch (\Exception $e) { $this->addThrowable( new Exception( 'Cannot add SessionCollector to Laravel Debugbar: ' . $e->getMessage(), $e->getCode(), $e ) ); } } } else { $sessionManager = null; } // 貌似这句的意思是，如果只调试一个session? 还没进入源码深究。 if ($this->shouldCollect('symfony_request', true) && !$this->hasCollector('request')) { try { $this->addCollector(new RequestCollector($request, $response, $sessionManager)); } catch (\Exception $e) { $this->addThrowable( new Exception( 'Cannot add SymfonyRequestCollector to Laravel Debugbar: ' . $e->getMessage(), $e->getCode(), $e ) ); } } // 如果要支持Clockwork调试，（比如支持Chrome插件Clockwork调试） if ($app['config']->get('debugbar.clockwork') && ! $this->hasCollector('clockwork')) { try { $this->addCollector(new ClockworkCollector($request, $response, $sessionManager)); } catch (\Exception $e) { $this->addThrowable( new Exception( 'Cannot add ClockworkCollector to Laravel Debugbar: ' . $e->getMessage(), $e->getCode(), $e ) ); } $this->addClockworkHeaders($response); } // 首先判断一下，这是不是一个redirect()的请求（刷新页面） // 这个判断的语句原型是$this->statusCode >= 300 && $this->statusCode < 400; // 函数原型在vendor\symfony\http-foundation\Response.php中， if ($response->isRedirection()) { try { $this->stackData(); } catch (\Exception $e) { $app['log']->error('Debugbar exception: ' . $e->getMessage()); } } elseif ( // 如果是ajax请求，并且已经设置了对ajax进行调试，则这在里处理 $this->isJsonRequest($request) && $app['config']->get('debugbar.capture_ajax', true) ) { try { $this->sendDataInHeaders(true); if ($app['config']->get('debugbar.add_ajax_timing', false)) { $this->addServerTimingHeaders($response); } } catch (\Exception $e) { $app['log']->error('Debugbar exception: ' . $e->getMessage()); } } elseif ( // 如果headers有Content-Type这个标签，并且不是html，那么就应该是JSON数据 // 很明显，这里只对Content-Type=JSON的数据进行操作， // 对其他类型的数据，如图片，MSWORD等，则直接抛出异常 ($response->headers->has('Content-Type') && strpos($response->headers->get('Content-Type'), 'html') === false) || $request->getRequestFormat() !== 'html' || $response->getContent() === false ) { try { // Just collect + store data, don't inject it. $this->collect(); } catch (\Exception $e) { $app['log']->error('Debugbar exception: ' . $e->getMessage()); } } elseif ($app['config']->get('debugbar.inject', true)) { // 对普通的情况，debugbar会在这里修改的response，并注入渲染 try { $this->injectDebugbar($response); } catch (\Exception $e) { $app['log']->error('Debugbar exception: ' . $e->getMessage()); } } return $response; }

用到的 `$app['config']` 的原貌是这样的，

Repository {#24 ▼
      #items: array:13 [▼
        "app" => array:13 [▶]
        "auth" => array:4 [▶]
        "broadcasting" => array:2 [▶]
        "cache" => array:3 [▶]
        "database" => array:4 [▶]
        "filesystems" => array:3 [▶]
        "mail" => array:9 [▶]
        "queue" => array:3 [▶]
        "services" => array:4 [▶]
        "session" => array:15 [▶]
        "view" => array:2 [▶]
        "debugbar" => array:13 [▼
          "enabled" => null
          "except" => []
          "storage" => array:5 [▶]
          "include_vendors" => true
          "capture_ajax" => true
          "add_ajax_timing" => false
          "error_handler" => false
          "clockwork" => false
          "collectors" => array:21 [▶]
          "options" => array:7 [▶]
          "inject" => true
          "route_prefix" => "_debugbar"
          "route_domain" => null
        ]
        "trustedproxy" => array:2 [▶]
      ]
    }

比如，这个inject是true，就对应了上面的普通调试情况，现在来到下一步的重点，

public function injectDebugbar(Response $response)
        {
            $content = $response->getContent();
    
            $renderer = $this->getJavascriptRenderer();
            if ($this->getStorage()) {
                $openHandlerUrl = route('debugbar.openhandler');
                $renderer->setOpenHandlerUrl($openHandlerUrl);
            }
    
            $renderedContent = $renderer->renderHead() . $renderer->render();
    
            $pos = strripos($content, '</body>');
            if (false !== $pos) {
                $content = substr($content, 0, $pos) . $renderedContent . substr($content, $pos);
            } else {
                $content = $content . $renderedContent;
            }
    
            // Update the new content and reset the content length
            // 在这里注入页面渲染与调试信息
            $response->setContent($content);        
            $response->headers->remove('Content-Length');
        }

整个大致流程就是这样子的。

我使用的laravel+vuejs+elementUI做练习，发现在使用elementUI时，el-upload默认并没有支持ajax，虽然它采用了XMLHttpRequest()来处理上传，但头文件并没有XHR处理，所以laravel收到其发出的只是一个普通的post请求，这种情况下，laravel-debugbar会把所有的调试信息和相关渲染，全部加入到response中返回（对axios也是同样如此），而这恰恰不是我们所需要的，所以有必要特别细说一下。

如果是ajax请求，debugbar会在这里判断

protected function isJsonRequest(Request $request) { 
            // If XmlHttpRequest, return true
            if ($request->isXmlHttpRequest()) {
                return true;
            }
    
            // Check if the request wants Json
            $acceptable = $request->getAcceptableContentTypes();
            return (isset($acceptable[0]) && $acceptable[0] == 'application/json');
        }

其中有对request是否为ajax的判断 `$request->isXmlHttpRequest()` ，它实际是在`vendor\symfony\http-foundation\Request.php`里面，

public function isXmlHttpRequest() { 
        return 'XMLHttpRequest' == $this->headers->get('X-Requested-With');
    }

所以不难明白，为什么在headers里面，必须加入`'X-Requested-With': 'XMLHttpRequest'` 这一行，或者是这样，

options.headers['X-Requested-With'] = 'XMLHttpRequest';

其目的就是让laravel-debugger知道，发送的是ajax请求，不要再把调试信息和页面渲染再注入response了。

如果不加这一行的话，laravel会默认这是一个普通的Post请求，此时，larave-debugbar这样的插件，就会对response进行注入渲染，最后这些注入的代码会返回给页面，造成混乱和难以处理。

[Laravel5.5_ _ _MiddleWare]: http://blog.csdn.net/tanmx219/article/details/78903521