tel protocol support.

library/HTMLPurifier/ConfigSchema/schema/URI.AllowedSchemes.txt

@@ -8,6 +8,7 @@ array (
   'ftp' => true,
   'nntp' => true,
   'news' => true,
+  'tel' => true,
 )
 --DESCRIPTION--
 Whitelist that defines the schemes that a URI is allowed to have.  This

library/HTMLPurifier/URIScheme/tel.php

@@ -0,0 +1,46 @@
+<?php
+
+/**
+ * Validates tel (for phone numbers).
+ *
+ * The relevant specifications for this protocol are RFC 3966 and RFC 5341,
+ * but this class takes a much simpler approach: we normalize phone
+ * numbers so that they only include (possibly) a leading plus,
+ * and then any number of digits and x'es.
+ */
+
+class HTMLPurifier_URIScheme_tel extends HTMLPurifier_URIScheme
+{
+    /**
+     * @type bool
+     */
+    public $browsable = false;
+
+    /**
+     * @type bool
+     */
+    public $may_omit_host = true;
+
+    /**
+     * @param HTMLPurifier_URI $uri
+     * @param HTMLPurifier_Config $config
+     * @param HTMLPurifier_Context $context
+     * @return bool
+     */
+    public function doValidate(&$uri, $config, $context)
+    {
+        $uri->userinfo = null;
+        $uri->host     = null;
+        $uri->port     = null;
+
+        // Delete all non-numeric characters, non-x characters
+        // from phone number, EXCEPT for a leading plus sign.
+        $uri->path = preg_replace('/(?!^\+)[^\dx]/', '',
+                     // Normalize e(x)tension to lower-case
+                     str_replace('X', 'x', $uri->path));
+
+        return true;
+    }
+}
+
+// vim: et sw=4 sts=4