LOOP-1158: Handled relative urls in mail body

Author: rimi-itk

web/profiles/custom/os2loop/modules/os2loop_mail_notifications/src/Plugin/Mail/PhpMail.php

@@ -4,6 +4,7 @@
 
 use Drupal\Core\Mail\MailInterface;
 use Drupal\Core\Mail\Plugin\Mail\PhpMail as PhpMailBase;
+use Drupal\Core\Url;
 
 /**
  * Copy of the default Drupal mail backend, using PHP's native mail() function.
@@ -28,6 +29,8 @@ class PhpMail extends PhpMailBase implements MailInterface {
   public function format(array $message) {
     $message['body'] = implode("\n\n", $message['body']);
 
+    $message['body'] = $this->makeUrlsAbsolute($message['body']);
+
     return $message;
   }
 
@@ -48,4 +51,29 @@ public function mail(array $message) {
     return parent::mail($message);
   }
 
+  /**
+   * Convert relative urls (paths) in html to absolute urls.
+   */
+  private function makeUrlsAbsolute(string $html) {
+    return preg_replace_callback(
+      '/\s(href|src)\s*=\s*(?:\'([^\']+)\'|"([^"]+)")/',
+      static function ($matches) {
+        $name = $matches[1];
+        $value = $matches[2] ?: $matches[3];
+        $scheme = parse_url($value, PHP_URL_SCHEME);
+        if (NULL === $scheme) {
+          // We have a local path.
+          try {
+            $value = Url::fromUri('internal:/' . ltrim($value, '/'), ['absolute' => TRUE])->toString();
+          }
+          catch (\InvalidArgumentException $exception) {
+          }
+        }
+
+        return sprintf(' %s="%s"', $name, htmlspecialchars($value));
+      },
+      $html
+    );
+  }
+
 }