fix: Ensure \r\n for line breaks and properly encode subject for umlauts.

assets/php/contact_form.php

@@ -13,8 +13,23 @@ function sanitize_text(string $name, string $type) {
     return $text;
 }
 
+function prepare_message_body($message) {
+    // Replace HTML-Entities with actual carriage returns and line feeds
+    $message = str_replace("
", "\r", $message);
+    $message = str_replace("
", "\r", $message);
+
+    // Ensure line breaks via carriage return + line feed
+    $message = str_replace("\r\n", "\n", $message);
+    $message = str_replace("\n", "\r\n", $message);
+
+    $message = "Nachricht von: $name\r\n\r\n" . $message;
+    $message = base64_encode($message);
+
+    return $message;
+}
+
 /**
- *  Sending email (Platzhalter)
+ *  Sending email
  *
  *  mail(): Braucht auf dem Server einen korrekt konfigurierten Mailserver
  *  phpmailer: Bibliothek, der per Composer installiert wird. Tut ganz gut mit SMTP.
@@ -22,12 +37,14 @@ function sanitize_text(string $name, string $type) {
 function send_message_to_office($subject, $message, $name, $email) {
     return mail(
         getenv('WTF_CONTACT_TO'),
-        $subject,
-        $name . "\r\n" . $message,
+        "=?UTF-8?B?" . base64_encode($subject) . "?=",
+        prepare_message_body($message),
         $additional_headers = array(
             "From" => getenv('WTF_CONTACT_FROM'),
             "Reply-To" => $email,
             "Return-Path" => getenv('WTF_RETURN_PATH'),
+            "Content-Type" => "text/plain; charset=utf-8",
+            "Content-Transfer-Encoding" => "base64",
         ),
     );
 }