Lumen開發：Lumen的異常處理機制

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Lumen的核心類Application引用了專門用於異常處理的RegistersExceptionHandlers，

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

直接來看一下這個引用里的方法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.（通過給定的數據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.（設置應用程序的錯誤處理。）
     *
     * @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.（處理關閉應用程序。）
     *
     * @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.（如果確定的錯誤類型是致命的。）
     *
     * @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.（將異常發送給處理程序並返回響應。）
     *
     * @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.（處理未捕獲的異常情況。）
     *
     * @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.（從容器中獲取異常處理程序。）
     *
     * @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');
        }
    }
}

以上就是封裝用於$app的幾個異常處理方法了，接下來看一下Lumen對異常處理做的默認綁定，這里的單例綁定是接口綁定類的類型

$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.（不應該報告的異常類型的列表。）
     *
     * @var array
     */
    protected $dontReport = [
        AuthorizationException::class,
        HttpException::class,
        ModelNotFoundException::class,
        ValidationException::class,
    ];

    /**
     * Report or log an exception.（報告或記錄異常。）
     *
     * 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響應中呈現異常。）
     *
     * @param  \Illuminate\Http\Request  $request
     * @param  \Exception  $e
     * @return \Illuminate\Http\Response
     */
    public function render($request, Exception $e)
    {
        return parent::render($request, $e);
    }
}

這個類繼承了一個實現Illuminate\Contracts\Debug\ExceptionHandler::class接口的異常處理基類Laravel\Lumen\Exceptions\Handler，這樣，我們就可以很方便的做異常攔截和處理了！比如，

public function render($request, Exception $e)
    {
        //數據驗證異常攔截
        if ($e instanceof \Illuminate\Validation\ValidationException) {
            var_dump($e->validator->errors()->toArray());
        }
    
        return parent::render($request, $e);
    }

這樣我們就監聽攔截到了Validation的ValidationException的異常，其實這部分往深扒的話，還有很多東西，如symfony下的debug和http-kernel兩個模塊的包，可以研究下

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版權聲明：本文為博主原創文章，未經博主允許不得轉載。