1 files changed, 43 insertions, 0 deletions
diff --git a/lib/htmlpurifier/library/HTMLPurifier/AttrTransform/ImgRequired.php b/lib/htmlpurifier/library/HTMLPurifier/AttrTransform/ImgRequired.php
new file mode 100644
index 000000000..7f0e4b7a5
--- /dev/null
+++ b/lib/htmlpurifier/library/HTMLPurifier/AttrTransform/ImgRequired.php
@@ -0,0 +1,43 @@
+<?php
+
+// must be called POST validation
+
+/**
+ * Transform that supplies default values for the src and alt attributes
+ * in img tags, as well as prevents the img tag from being removed
+ * because of a missing alt tag. This needs to be registered as both
+ * a pre and post attribute transform.
+ */
+class HTMLPurifier_AttrTransform_ImgRequired extends HTMLPurifier_AttrTransform
+{
+
+    public function transform($attr, $config, $context) {
+
+        $src = true;
+        if (!isset($attr['src'])) {
+            if ($config->get('Core.RemoveInvalidImg')) return $attr;
+            $attr['src'] = $config->get('Attr.DefaultInvalidImage');
+            $src = false;
+        }
+
+        if (!isset($attr['alt'])) {
+            if ($src) {
+                $alt = $config->get('Attr.DefaultImageAlt');
+                if ($alt === null) {
+                    // truncate if the alt is too long
+                    $attr['alt'] = substr(basename($attr['src']),0,40);
+                } else {
+                    $attr['alt'] = $alt;
+                }
+            } else {
+                $attr['alt'] = $config->get('Attr.DefaultInvalidImageAlt');
+            }
+        }
+
+        return $attr;
+
+    }
+
+}
+
+// vim: et sw=4 sts=4