gistfile1.diff

diff --git a/community/shortcodes/adapters/__init__.py b/community/shortcodes/adapters/__init__.py
index a2a25cb..ca1dbe9 100644
--- a/community/shortcodes/adapters/__init__.py
+++ b/community/shortcodes/adapters/__init__.py
@@ -473,8 +473,28 @@ class IframeAdapter(BaseAdapter):
     brief_text = 'iframe'
     html_param_prefix = ''
 
+    def _get_url(self):
+        parts = urlparse(self.iden)
+        if bool(parts.scheme and parts.netloc):
+            return self.iden
+
+        match = re.search(r'href=[\'"]?([^\'" >]+)', self.iden)
+        if match:
+            try:
+                parts = urlparse(match.group(1))
+            except IndexError:
+                return None
+            if bool(parts.scheme and parts.netloc):
+                return match.group(1)
+
+        return None
+
     def decode_description(self):
+        url = self._get_url()
+        if not url:
+            raise DecodeError
+
         return u'<iframe src="{}" {}></iframe>'.format(
-            self.iden,
+            url,
             self._add_extra_html_params(self.params)
         )