异常处理

app/Exceptions/Handler.php

@@ -13,7 +13,7 @@ class Handler extends ExceptionHandler
      * @var array
      */
     protected $dontReport = [
-        //
+        InvalidRequestException::class,
     ];
 
     /**

app/Exceptions/InternalException.php

@@ -0,0 +1,26 @@
+<?php
+
+namespace App\Exceptions;
+
+use Exception;
+use Illuminate\Http\Request;
+
+class InternalException extends Exception
+{
+    protected $msgForUser;
+
+    public function __construct(string $message, string $msgForUser = '系统内部错误', int $code = 500)
+    {
+        parent::__construct($message, $code);
+        $this->msgForUser = $msgForUser;
+    }
+
+    public function render(Request $request)
+    {
+        if ($request->expectsJson()) {
+            return response()->json(['msg' => $this->msgForUser], $this->code);
+        }
+
+        return view('pages.error', ['msg' => $this->msgForUser]);
+    }
+}

app/Exceptions/InvalidRequestException.php

@@ -0,0 +1,24 @@
+<?php
+
+namespace App\Exceptions;
+
+use Exception;
+use Illuminate\Http\Request;
+
+class InvalidRequestException extends Exception
+{
+    public function __construct(string $message = "", int $code = 400)
+    {
+        parent::__construct($message, $code);
+    }
+
+    public function render(Request $request)
+    {
+        if ($request->expectsJson()) {
+            // json() 方法第二个参数就是 Http 返回码
+            return response()->json(['msg' => $this->message], $this->code);
+        }
+
+        return view('pages.error', ['msg' => $this->message]);
+    }
+}

app/Http/Controllers/ProductsController.php

@@ -2,6 +2,7 @@
 
 namespace App\Http\Controllers;
 
+use App\Exceptions\InvalidRequestException;
 use App\Models\Product;
 use Illuminate\Http\Request;
 
@@ -54,7 +55,7 @@ public function show(Product $product, Request $request)
     {
         // 判断商品是否已经上架，如果没有上架则抛出异常。
         if (!$product->on_sale) {
-            throw new \Exception('商品未上架');
+            throw new InvalidRequestException('商品未上架');
         }
 
         return view('products.show', ['product' => $product]);

resources/views/pages/error.blade.php

@@ -0,0 +1,12 @@
+@extends('layouts.app')
+@section('title', '错误')
+
+@section('content')
+  <div class="card">
+    <div class="card-header">错误</div>
+    <div class="card-body text-center">
+      <h1>{{ $msg }}</h1>
+      <a class="btn btn-primary" href="{{ route('root') }}">返回首页</a>
+    </div>
+  </div>
+@endsection