Notify Slack on Exceptions (issue #97)

Squashed commit of the following:

commit 104a106d735f586f893dffb57e07f15b2e20d901
Author: Jonny Barnes <jonny@jonnybarnes.uk>
Date:   Fri Feb 1 21:54:06 2019 +0000

    Remove unused class use statement, add array trailing comma

commit 8fbc46e816789d26447a01cbd0d542c62a287671
Author: Jonny Barnes <jonny@jonnybarnes.uk>
Date:   Fri Feb 1 21:27:42 2019 +0000

    Set default values for slack message

commit b54650d85d73702dfb836436a964dd882844fff5
Author: Jonny Barnes <jonny@jonnybarnes.uk>
Date:   Fri Feb 1 21:26:06 2019 +0000

    Post exceptions to Slack

commit 74f394ab2b5e66eac8c3f75ccf13aae0a7bc8e11
Author: Jonny Barnes <jonny@jonnybarnes.uk>
Date:   Fri Feb 1 21:25:47 2019 +0000

    Slack Webhook env variable

.env.example

@@ -60,3 +60,5 @@ APP_TIMEZONE=UTC
 APP_LANG=en
 APP_LOG=daily
 SECURE_SESSION_COOKIE=true
+
+SLACK_WEBHOOK_URL=

app/Exceptions/Handler.php

@@ -2,6 +2,7 @@
 
 namespace App\Exceptions;
 
+use App;
 use Exception;
 use Illuminate\Support\Facades\Route;
 use Illuminate\Session\TokenMismatchException;
@@ -18,7 +19,7 @@ class Handler extends ExceptionHandler
      * @var array
      */
     protected $dontReport = [
-        //
+        \Symfony\Component\HttpKernel\Exception\HttpException::class,
     ];
 
     /**
@@ -41,6 +42,32 @@ class Handler extends ExceptionHandler
      */
     public function report(Exception $exception)
     {
+        $guzzle = new \GuzzleHttp\Client([
+            'headers' => [
+                'Content-Type' => 'application/json',
+            ],
+        ]);
+
+        $guzzle->post(
+            env('SLACK_WEBHOOK_URL'),
+            [
+                'body' => json_encode([
+                    'attachments' => [[
+                        'fallback' => 'There was an exception.',
+                        'pretext' => 'There was an exception.',
+                        'color' => '#d00000',
+                        'author_name' => App::environment(),
+                        'author_link' => config('app.url'),
+                        'fields' => [[
+                            'title' => get_class($exception) ?? 'Unkown Exception',
+                            'value' => $exception->getMessage() ?? '',
+                        ]],
+                        'ts' => time(),
+                    ]],
+                ]),
+            ]
+        );
+
         parent::report($exception);
     }