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-rw-r--r--Zotlabs/Lib/MarkdownSoap.php86
1 files changed, 86 insertions, 0 deletions
diff --git a/Zotlabs/Lib/MarkdownSoap.php b/Zotlabs/Lib/MarkdownSoap.php
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+++ b/Zotlabs/Lib/MarkdownSoap.php
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+<?php
+
+namespace Zotlabs\Lib;
+
+/**
+ * MarkdownSoap
+ * Purify Markdown for storage
+ * $x = newMarkdownSoap($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);
+ }
+}