1 files changed, 86 insertions, 0 deletions
diff --git a/Zotlabs/Lib/MarkdownSoap.php b/Zotlabs/Lib/MarkdownSoap.php
new file mode 100644
index 000000000..2dcaaec9a
--- /dev/null
+++ b/Zotlabs/Lib/MarkdownSoap.php
@@ -0,0 +1,86 @@
+<?php
+
+namespace Zotlabs\Lib;
+
+/**
+ * MarkdownSoap
+ * Purify Markdown for storage
+ *   $x = new MarkdownSoap($string_to_be_cleansed);
+ *   $text = $x->clean();
+ *
+ * What this does:
+ * 1. extracts code blocks and privately escapes them from processing
+ * 2. Run html purifier on the content
+ * 3. put back the code blocks
+ * 4. run htmlspecialchars on the entire content for safe storage
+ *
+ * At render time: 
+ *    $markdown = \Zotlabs\Lib\MarkdownSoap::unescape($text);
+ *    $html = \Michelf\MarkdownExtra::DefaultTransform($markdown);
+ */
+
+
+
+class MarkdownSoap {
+
+	private $token;
+
+	private $str;
+
+	function __construct($s) {
+		$this->str  = $s;
+		$this->token = random_string(20);
+	}
+
+
+	function clean() {
+		$x = $this->extract_code($this->str);
+		$x = $this->purify($x);
+		$x = $this->putback_code($x);		
+		$x = $this->escape($x);
+		
+		return $x;
+	}
+
+	function extract_code($s) {
+			
+		$text = preg_replace_callback('{
+					(?:\n\n|\A\n?)
+					(	            # $1 = the code block -- one or more lines, starting with a space/tab
+					  (?>
+						[ ]{'.'4'.'}  # Lines must start with a tab or a tab-width of spaces
+						.*\n+
+					  )+
+					)
+					((?=^[ ]{0,'.'4'.'}\S)|\Z)	# Lookahead for non-space at line-start, or end of doc
+				}xm',
+				[ $this , 'encode_code' ], $s);
+
+		return $text;
+	}
+	
+	function encode_code($matches) {
+		return $this->token . ';' . base64_encode($matches[1]) . ';' ;
+	}
+
+	function decode_code($matches) {
+		return base64_decode($matches[1]);
+	}
+
+	function putback_code($s) {
+		$text = preg_replace_callback('{' . $this->token . '\;(.*?)\;}xm',[ $this, 'decode_code' ], $s);
+		return $text;
+	}
+
+	function purify($s) {
+		return purify_html($s);
+	}
+
+	function escape($s) {
+		return htmlspecialchars($s,ENT_QUOTES);
+	}
+
+	static public function unescape($s) {
+		return htmlspecialchars_decode($s,ENT_QUOTES);
+	}
+}