From 76b0964c940ceeb79e8f73fea0f2d03e97ef3735 Mon Sep 17 00:00:00 2001
From: Matt Westcott <matt@west.co.tt>
Date: Wed, 11 Feb 2015 12:20:32 +0000
Subject: [PATCH] add DocumentChooserBlock

---
 wagtail/wagtaildocs/blocks.py  | 23 +++++++++++++++++++++++
 wagtail/wagtaildocs/widgets.py |  3 +--
 2 files changed, 24 insertions(+), 2 deletions(-)
 create mode 100644 wagtail/wagtaildocs/blocks.py

diff --git a/wagtail/wagtaildocs/blocks.py b/wagtail/wagtaildocs/blocks.py
new file mode 100644
index 000000000..07e893d74
--- /dev/null
+++ b/wagtail/wagtaildocs/blocks.py
@@ -0,0 +1,23 @@
+from __future__ import unicode_literals
+
+from django.utils.functional import cached_property
+from django.utils.html import format_html
+
+from wagtail.wagtailadmin.blocks import ChooserBlock
+
+class DocumentChooserBlock(ChooserBlock):
+    @cached_property
+    def target_model(self):
+        from wagtail.wagtaildocs.models import Document
+        return Document
+
+    @cached_property
+    def widget(self):
+        from wagtail.wagtaildocs.widgets import AdminDocumentChooser
+        return AdminDocumentChooser
+
+    def render_basic(self, value):
+        if value:
+            return format_html('<a href="{0}">{1}</a>', value.url, value.title)
+        else:
+            return ''
diff --git a/wagtail/wagtaildocs/widgets.py b/wagtail/wagtaildocs/widgets.py
index 73267b539..75225ef0c 100644
--- a/wagtail/wagtaildocs/widgets.py
+++ b/wagtail/wagtaildocs/widgets.py
@@ -14,10 +14,9 @@ class AdminDocumentChooser(AdminChooser):
     choose_another_text = _('Choose another document')
 
     def render_html(self, name, value, attrs):
+        instance, value = self.get_instance_and_id(Document, value)
         original_field_html = super(AdminDocumentChooser, self).render_html(name, value, attrs)
 
-        instance = self.get_instance(Document, value)
-
         return render_to_string("wagtaildocs/widgets/document_chooser.html", {
             'widget': self,
             'original_field_html': original_field_html,