add "falsey" test

1 files changed, 11 insertions, 1 deletions

diff --git a/Zotlabs/Lib/MessageFilter.php b/Zotlabs/Lib/MessageFilter.php
index 70b0188c4..13ec78072 100644
--- a/Zotlabs/Lib/MessageFilter.php
+++ b/Zotlabs/Lib/MessageFilter.php
@@ -123,7 +123,8 @@ class MessageFilter {
 	 * - ?foo {} baz which will check if 'baz' is an array element in item.foo
 	 * - ?foo {*} baz which will check if 'baz' is an array key in item.foo
 	 * - ?foo which will check for a return of a true condition for item.foo;
-	 *
+     * - ?!foo which will check for a return of a false condition for item.foo;
+     *
 	 * The values 0, '', an empty array, and an unset value will all evaluate to false.
 	 *
 	 * @param string $s
@@ -205,6 +206,15 @@ class MessageFilter {
 			return false;
 		}
 
+		// Ordering of this check (for falsiness) with relation to the following one (check for truthiness) is important.
+		if (preg_match('/\!(.*?)$/', $s, $matches)) {
+			$x = ((array_key_exists(trim($matches[1]),$item)) ? $item[trim($matches[1])] : EMPTY_STR);
+			if (!$x) {
+				return true;
+			}
+			return false;
+		}
+
 		if (preg_match('/(.*?)$/', $s, $matches)) {
 			$x = ((array_key_exists(trim($matches[1]),$item)) ? $item[trim($matches[1])] : EMPTY_STR);
 			if ($x) {