Fix type bug + update to PHP 7.4+

Related to FreshRSS/Extensions#185
fix FreshRSS/FreshRSS#5989 (comment)

README.md

@@ -1,4 +1,5 @@
 # xExtension-WhiteList
+
 A FreshRSS extension to validate that new feeds are allowed according to a white-list.
 The comparison with the white-list uses regex to find matches. If the format used has
 to be recognized by the PHP `preg_match` function.

configure.phtml

@@ -1,3 +1,7 @@
+<?php
+	declare(strict_types=1);
+	/** @var WhiteListExtension $this */
+?>
 <form action="<?= _url('extension', 'configure', 'e', urlencode($this->getName())); ?>" method="post">
 	<input type="hidden" name="_csrf" value="<?= FreshRSS_Auth::csrfToken(); ?>" />
 

extension.php

@@ -1,34 +1,41 @@
 <?php
 
 class WhiteListExtension extends Minz_Extension {
-    public function init() {
+    public function init(): void {
         $this->registerTranslates();
 
         $this->registerHook('check_url_before_add', [$this, 'checkWhiteList']);
     }
-    
-    public function handleConfigureAction() {
+
+    public function handleConfigureAction(): void {
         $this->registerTranslates();
 
         if (Minz_Request::isPost()) {
             $configuration = [
-                'patterns' => Minz_Request::paramTextToArray('patterns', ''),
+                'patterns' => Minz_Request::paramTextToArray('patterns', []),
             ];
             $this->setSystemConfiguration($configuration);
         }
     }
 
-    public function checkWhiteList($url) {
-        foreach ($this->getSystemConfigurationValue('patterns') as $pattern) {
-            if (1 === preg_match("/{$pattern}/i", $url)) {
-                return $url;
+    public function checkWhiteList(string $url): string {
+        $patterns = $this->getSystemConfigurationValue('patterns') ?? [];
+        if (is_array($patterns)) {
+            foreach ($patterns as $pattern) {
+                if (1 === preg_match("/{$pattern}/i", $url)) {
+                    return $url;
+                }
             }
         }
         Minz_Log::warning(_t('ext.white_list.warning.not_white_listed', $url));
         throw new FreshRSS_FeedNotAdded_Exception($url);
     }
 
-    public function getPatterns() {
-        return implode(PHP_EOL, $this->getSystemConfigurationValue('patterns') ?? []);
+    public function getPatterns(): string {
+        $patterns = $this->getSystemConfigurationValue('patterns') ?? [];
+        if (is_array($patterns)) {
+            return implode(PHP_EOL, $patterns);
+        }
+        return '';
     }
 }