forms: show uploaded images as thumbnails in form and validation pages (#8675)

debian/control

@@ -9,7 +9,7 @@ X-Python-Version: 2.7
 
 Package: wcs
 Architecture: all
-Depends: ${python:Depends}, python-quixote, python-scgi, graphviz, python-feedparser
+Depends: ${python:Depends}, python-quixote, python-scgi, graphviz, python-feedparser, python-imaging
 Recommends: python-dns, python-m2crypto, python-xlwt, python-qrcode, libjs-leaflet
 Suggests: libapache2-mod-scgi | libapache-mod-scgi, python-libxml2, python-lasso, python-psycopg2
 Description: web application to design and set up online forms

wcs/forms/root.py

@@ -20,6 +20,11 @@ from StringIO import StringIO
 import sys
 import urllib2
 
+try:
+    from PIL import Image
+except ImportError:
+    Image = None
+
 try:
     import qrcode
 except ImportError:
@@ -908,7 +913,15 @@ class FormPage(Directory):
         if tempfile['charset']:
             response.set_charset(tempfile['charset'])
 
-        return get_session().get_tempfile_content(t).get_file_pointer().read()
+        file_pointer = get_session().get_tempfile_content(t).get_file_pointer()
+        if Image is not None and get_request().form.get('thumbnail') == '1':
+            image = Image.open(file_pointer)
+            image.thumbnail((500, 300))
+            image_thumb_fp = StringIO()
+            image.save(image_thumb_fp, "PNG")
+            return image_thumb_fp.getvalue()
+        else:
+            return file_pointer.read()
 
     def validating(self, data):
         self.html_top(self.formdef.name)

wcs/qommon/form.py

@@ -599,9 +599,8 @@ class FileWithPreviewWidget(CompositeWidget):
         elif temp:
             filetype = mimetypes.guess_type(temp.get('orig_filename', ''))
             if filetype and filetype[0] and filetype[0].startswith('image'):
-                r += htmltext('<img alt="%s" src="tempfile?t=%s" />' % \
-                                            (temp.get('orig_filename', ''),
-                                             self.get('token')))
+                r += htmltext('<img alt="" src="tempfile?t=%s&thumbnail=1" />' % \
+                                             self.get('token'))
 
         r += htmltext('</div>')
         return r.getvalue()