1 files changed, 46 insertions, 0 deletions
diff --git a/library/HTMLPurifier/Filter.php b/library/HTMLPurifier/Filter.php
new file mode 100644
index 000000000..9a0e7b09f
--- /dev/null
+++ b/library/HTMLPurifier/Filter.php
@@ -0,0 +1,46 @@
+<?php
+
+/**
+ * Represents a pre or post processing filter on HTML Purifier's output
+ *
+ * Sometimes, a little ad-hoc fixing of HTML has to be done before
+ * it gets sent through HTML Purifier: you can use filters to acheive
+ * this effect. For instance, YouTube videos can be preserved using
+ * this manner. You could have used a decorator for this task, but
+ * PHP's support for them is not terribly robust, so we're going
+ * to just loop through the filters.
+ *
+ * Filters should be exited first in, last out. If there are three filters,
+ * named 1, 2 and 3, the order of execution should go 1->preFilter,
+ * 2->preFilter, 3->preFilter, purify, 3->postFilter, 2->postFilter,
+ * 1->postFilter.
+ *
+ * @note Methods are not declared abstract as it is perfectly legitimate
+ *       for an implementation not to want anything to happen on a step
+ */
+
+class HTMLPurifier_Filter
+{
+
+    /**
+     * Name of the filter for identification purposes
+     */
+    public $name;
+
+    /**
+     * Pre-processor function, handles HTML before HTML Purifier
+     */
+    public function preFilter($html, $config, $context) {
+        return $html;
+    }
+
+    /**
+     * Post-processor function, handles HTML after HTML Purifier
+     */
+    public function postFilter($html, $config, $context) {
+        return $html;
+    }
+
+}
+
+// vim: et sw=4 sts=4