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system/Helpers/security_helper.php

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+<?php
+
+/**
+ * This file is part of the CodeIgniter 4 framework.
+ *
+ * (c) CodeIgniter Foundation <admin@codeigniter.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+use Config\Services;
+
+/**
+ * CodeIgniter Security Helpers
+ */
+
+if (! function_exists('sanitize_filename'))
+{
+	/**
+	 * Sanitize a filename to use in a URI.
+	 *
+	 * @param string $filename
+	 *
+	 * @return string
+	 */
+	function sanitize_filename(string $filename): string
+	{
+		return Services::security()->sanitizeFilename($filename);
+	}
+}
+
+//--------------------------------------------------------------------
+
+if (! function_exists('strip_image_tags'))
+{
+	/**
+	 * Strip Image Tags
+	 *
+	 * @param string $str
+	 *
+	 * @return string
+	 */
+	function strip_image_tags(string $str): string
+	{
+		return preg_replace([
+			'#<img[\s/]+.*?src\s*=\s*(["\'])([^\\1]+?)\\1.*?\>#i',
+			'#<img[\s/]+.*?src\s*=\s*?(([^\s"\'=<>`]+)).*?\>#i',
+		], '\\2', $str
+		);
+	}
+}
+
+//--------------------------------------------------------------------
+
+if (! function_exists('encode_php_tags'))
+{
+	/**
+	 * Convert PHP tags to entities
+	 *
+	 * @param string $str
+	 *
+	 * @return string
+	 */
+	function encode_php_tags(string $str): string
+	{
+		return str_replace(['<?', '?>'], ['&lt;?', '?&gt;'], $str);
+	}
+}
+
+//--------------------------------------------------------------------