Lumen开发：Lumen的异常处理机制

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Lumen的核心类Application引用了专门用于异常处理的RegistersExceptionHandlers，

class Application extends Container
{
    use Concerns\RoutesRequests,
        Concerns\RegistersExceptionHandlers;

直接来看一下这个引用里的方法RegistersExceptionHandlers.php

<?php

namespace Laravel\Lumen\Concerns;

use Error;
use ErrorException;
use Symfony\Component\Console\Output\ConsoleOutput;
use Symfony\Component\HttpKernel\Exception\HttpException;
use Symfony\Component\Debug\Exception\FatalErrorException;
use Symfony\Component\Debug\Exception\FatalThrowableError;
use Symfony\Component\HttpKernel\Exception\NotFoundHttpException;

trait RegistersExceptionHandlers
{
    /**
     * Throw an HttpException with the given data.（通过给定的数据HttpException。）
     *
     * @param  int     $code
     * @param  string  $message
     * @param  array   $headers
     * @return void
     *
     * @throws \Symfony\Component\HttpKernel\Exception\HttpException
     */
    public function abort($code, $message = '', array $headers = [])
    {
        if ($code == 404) {
            throw new NotFoundHttpException($message);
        }

        throw new HttpException($code, $message, null, $headers);
    }

    /**
     * Set the error handling for the application.（设置应用程序的错误处理。）
     *
     * @return void
     */
    protected function registerErrorHandling()
    {
        error_reporting(-1);

        set_error_handler(function ($level, $message, $file = '', $line = 0) {
            if (error_reporting() & $level) {
                throw new ErrorException($message, 0, $level, $file, $line);
            }
        });

        set_exception_handler(function ($e) {
            $this->handleUncaughtException($e);
        });

        register_shutdown_function(function () {
            $this->handleShutdown();
        });
    }

    /**
     * Handle the application shutdown routine.（处理关闭应用程序。）
     *
     * @return void
     */
    protected function handleShutdown()
    {
        if (! is_null($error = error_get_last()) && $this->isFatalError($error['type'])) {
            $this->handleUncaughtException(new FatalErrorException(
                $error['message'], $error['type'], 0, $error['file'], $error['line']
            ));
        }
    }

    /**
     * Determine if the error type is fatal.（如果确定的错误类型是致命的。）
     *
     * @param  int  $type
     * @return bool
     */
    protected function isFatalError($type)
    {
        $errorCodes = [E_ERROR, E_CORE_ERROR, E_COMPILE_ERROR, E_PARSE];

        if (defined('FATAL_ERROR')) {
            $errorCodes[] = FATAL_ERROR;
        }

        return in_array($type, $errorCodes);
    }

    /**
     * Send the exception to the handler and return the response.（将异常发送给处理程序并返回响应。）
     *
     * @param  \Throwable  $e
     * @return Response
     */
    protected function sendExceptionToHandler($e)
    {
        $handler = $this->resolveExceptionHandler();

        if ($e instanceof Error) {
            $e = new FatalThrowableError($e);
        }

        $handler->report($e);

        return $handler->render($this->make('request'), $e);
    }

    /**
     * Handle an uncaught exception instance.（处理未捕获的异常情况。）
     *
     * @param  \Throwable  $e
     * @return void
     */
    protected function handleUncaughtException($e)
    {
        $handler = $this->resolveExceptionHandler();

        if ($e instanceof Error) {
            $e = new FatalThrowableError($e);
        }

        $handler->report($e);

        if ($this->runningInConsole()) {
            $handler->renderForConsole(new ConsoleOutput, $e);
        } else {
            $handler->render($this->make('request'), $e)->send();
        }
    }

    /**
     * Get the exception handler from the container.（从容器中获取异常处理程序。）
     *
     * @return mixed
     */
    protected function resolveExceptionHandler()
    {
        if ($this->bound('Illuminate\Contracts\Debug\ExceptionHandler')) {
            return $this->make('Illuminate\Contracts\Debug\ExceptionHandler');
        } else {
            return $this->make('Laravel\Lumen\Exceptions\Handler');
        }
    }
}

以上就是封装用于$app的几个异常处理方法了，接下来看一下Lumen对异常处理做的默认绑定，这里的单例绑定是接口绑定类的类型

$app->singleton(
    Illuminate\Contracts\Debug\ExceptionHandler::class,
    App\Exceptions\Handler::class
);

app/Exceptions/Handler.php

<?php

namespace App\Exceptions;

use Exception;
use Illuminate\Validation\ValidationException;
use Illuminate\Auth\Access\AuthorizationException;
use Illuminate\Database\Eloquent\ModelNotFoundException;
use Laravel\Lumen\Exceptions\Handler as ExceptionHandler;
use Symfony\Component\HttpKernel\Exception\HttpException;

class Handler extends ExceptionHandler
{
    /**
     * A list of the exception types that should not be reported.（不应该报告的异常类型的列表。）
     *
     * @var array
     */
    protected $dontReport = [
        AuthorizationException::class,
        HttpException::class,
        ModelNotFoundException::class,
        ValidationException::class,
    ];

    /**
     * Report or log an exception.（报告或记录异常。）
     *
     * This is a great spot to send exceptions to Sentry, Bugsnag, etc.
     *
     * @param  \Exception  $e
     * @return void
     */
    public function report(Exception $e)
    {
        parent::report($e);
    }

    /**
     * Render an exception into an HTTP response.（在HTTP响应中呈现异常。）
     *
     * @param  \Illuminate\Http\Request  $request
     * @param  \Exception  $e
     * @return \Illuminate\Http\Response
     */
    public function render($request, Exception $e)
    {
        return parent::render($request, $e);
    }
}

这个类继承了一个实现Illuminate\Contracts\Debug\ExceptionHandler::class接口的异常处理基类Laravel\Lumen\Exceptions\Handler，这样，我们就可以很方便的做异常拦截和处理了！比如，

public function render($request, Exception $e)
    {
        //数据验证异常拦截
        if ($e instanceof \Illuminate\Validation\ValidationException) {
            var_dump($e->validator->errors()->toArray());
        }
    
        return parent::render($request, $e);
    }

这样我们就监听拦截到了Validation的ValidationException的异常，其实这部分往深扒的话，还有很多东西，如symfony下的debug和http-kernel两个模块的包，可以研究下

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版权声明：本文为博主原创文章，未经博主允许不得转载。