Implement first version for automated link checks (#20)

app/Console/CheckLinksCommand.php

@@ -0,0 +1,189 @@
+<?php
+
+namespace App\Console\Commands;
+
+use App\Models\Link;
+use GuzzleHttp\Client;
+use Illuminate\Console\Command;
+use Illuminate\Support\Facades\Cache;
+
+/**
+ * Class CheckLinksCommand
+ *
+ * @package App\Console\Commands
+ */
+class CheckLinksCommand extends Command
+{
+    /**
+     * The name and signature of the console command.
+     *
+     * @var string
+     */
+    protected $signature = 'links:check';
+
+    /**
+     * The console command description.
+     *
+     * @var string
+     */
+    protected $description = 'Checks links for availablility';
+
+    /**
+     * Check a maximum of 100 links at once
+     *
+     * @var int
+     */
+    protected $limit = 100;
+
+    /** @var int */
+    protected $offset;
+
+    /** @var int */
+    protected $total;
+
+    /** @var int */
+    protected $checked_link_count;
+
+    /** @var Client */
+    protected $client;
+
+    /** @var string */
+    protected $cache_key_offset = 'command_links:check_offset';
+
+    /** @var string */
+    protected $cache_key_skip_timestamp = 'command_links:check_skip_timestamp';
+
+    /** @var string */
+    protected $cache_key_checked_count = 'command_links:check_checked_count';
+
+    /**
+     * RegisterUser constructor.
+     */
+    public function __construct()
+    {
+        $this->client = new Client();
+
+        parent::__construct();
+    }
+
+    /**
+     * Execute the console command.
+     *
+     * @return void
+     */
+    public function handle(): void
+    {
+        // Check if the command should skip the execution
+        $skip_timestamp = Cache::get($this->cache_key_skip_timestamp);
+        $this->offset = Cache::get($this->cache_key_offset, 0);
+        $this->checked_link_count = Cache::get($this->cache_key_checked_count, 0);
+
+        if (now()->timestamp < $skip_timestamp) {
+            return;
+        }
+
+        $links = $this->getLinks();
+
+        // Cancel if there are no links to check
+        if ($links->isEmpty()) {
+            Cache::forget($this->cache_key_offset);
+            Cache::forget($this->cache_key_skip_timestamp);
+
+            $this->comment('No links found, aborting...');
+            return;
+        }
+
+        // Check all provided links
+        $this->comment('Checking ' . $links->count() . ' links now.');
+
+        $links->each(function ($link) {
+            $this->checkLink($link);
+
+            // Prevent spam-ish behaviour by limiting outgoing HTTP requests
+            sleep(1);
+        });
+
+        // Check if there are more links to check
+        $checked_count = $this->checked_link_count + $links->count();
+        Cache::forever($this->cache_key_checked_count, $checked_count);
+
+        if ($this->total > $checked_count) {
+
+            // If yes, simply save the offset to the cache.
+            // The next link check will pick it up and continue the check
+            $next_offset = $this->offset + $this->limit;
+            Cache::forever($this->cache_key_offset, $next_offset);
+
+            $this->comment('Saving offset for next link check.');
+
+        } else {
+
+            // If not, all links have been successfully checked.
+            // Save a cache flag that prevents link checks for the next days.
+            $next_check = now()->addDays(5)->timestamp;
+            Cache::forever($this->cache_key_skip_timestamp, $next_check);
+
+            $this->comment('All existing links checked, next link check scheduled for ' . now()->addDays(5)->toDateTimeString());
+
+        }
+    }
+
+    /**
+     * Get links but limit the results to a fixed number of links
+     * If there is an offset saved, use this instead of beginning from the first entry
+     *
+     * @return mixed
+     */
+    protected function getLinks()
+    {
+        // Get the total amount of remaining links
+        $this->total = Link::count();
+
+        // Get a porton of the remaining links based on the limit
+        return Link::orderBy('id', 'ASC')->offset($this->offset)->limit($this->limit)->get();
+    }
+
+    /**
+     * Check the URL of an link and set the status accordingly
+     *
+     * @param Link $link
+     * @return void
+     * @throws \GuzzleHttp\Exception\GuzzleException
+     */
+    protected function checkLink(Link $link): void
+    {
+        $this->comment('Checking link ' . $link->url);
+
+        $options = [
+            'http_errors' => false, // Do not throw exceptions for 4xx and 5xx errors
+            'timeout' => 5, // wait a maximum of 5 seconds for the request to finish
+        ];
+
+        try {
+            $res = $this->client->request('GET', $link->url, $options);
+            $status_code = $res->getStatusCode();
+        } catch (\Exception $e) {
+            // Just abort now, may be a temporary issue
+            $this->warn('› Unknown error while trying to check the URL, trying again later.');
+            return;
+        }
+
+        // Check if the status code is not 200
+        if ($status_code !== 200) {
+            // If the link target is a redirect, set the status 2 (moved)
+            // else set the status to 3 (broken)
+            if ($status_code === 301 || $status_code === 302) {
+                $link->status = 2;
+                $this->warn('› Link moved to another URL!');
+            } else {
+                $link->status = 3;
+                $this->error('› Link seems to be broken!');
+            }
+
+            $link->save();
+
+        } else {
+            $this->info('› Link looks okay.');
+        }
+    }
+}

app/Console/Kernel.php

@@ -2,10 +2,16 @@
 
 namespace App\Console;
 
+use App\Console\Commands\CheckLinksCommand;
 use App\Console\Commands\RegisterUserCommand;
 use Illuminate\Console\Scheduling\Schedule;
 use Illuminate\Foundation\Console\Kernel as ConsoleKernel;
 
+/**
+ * Class Kernel
+ *
+ * @package App\Console
+ */
 class Kernel extends ConsoleKernel
 {
     /**
@@ -14,7 +20,8 @@ class Kernel extends ConsoleKernel
      * @var array
      */
     protected $commands = [
-        RegisterUserCommand::class
+        RegisterUserCommand::class,
+        CheckLinksCommand::class,
     ];
 
     /**
@@ -25,8 +32,7 @@ class Kernel extends ConsoleKernel
      */
     protected function schedule(Schedule $schedule)
     {
-        // $schedule->command('inspire')
-        //          ->hourly();
+         $schedule->command('links:check')->hourly();
     }
 
     /**

app/Http/Controllers/API/CronController.php

@@ -4,6 +4,7 @@ namespace App\Http\Controllers\API;
 
 use App\Http\Controllers\Controller;
 use Illuminate\Http\Request;
+use Illuminate\Support\Facades\Artisan;
 
 /**
  * Class CronController
@@ -13,11 +14,18 @@ use Illuminate\Http\Request;
 class CronController extends Controller
 {
     /**
-     * @param Request $request
+     * @param Request     $request
+     * @param null|string $cron_token
      * @return void
      */
-    public function run(Request $request)
+    public function run(Request $request, $cron_token)
     {
-        //
+        // Verify the cron token
+        if (!$cron_token || $cron_token !== systemsettings('cron_token')) {
+            abort(403);
+        }
+
+        // Run all cron tasks
+        Artisan::call('schedule:run');
     }
 }