[Zope-CMF] CMF-HOWTO: automatically make thumbnails on image upload

[Brad Clements]

A mini-howto

I have a custom portal type derived from a Zclass and Portal Folder. Users will be able 
to upload multiple images as child objects of this type.

I want to automatically make a thumbnail when the image is uploaded.

To do this, I customized image_edit (here it is)

import PIL.Image
import StringIO

file=REQUEST.file # work around hang "bug" in CMF-1.1 because file doesn't get passed if custom image_edit used

context.edit(
     precondition=precondition,
     file=file)

qst='?portal_status_message=Image+changed.'
   
parentFolder=context.REQUEST.PARENTS[1]

if parentFolder.meta_type == 'CompanyProduct' and \
    context.getId()[-10:] != '_Thumbnail':
    thumbName = context.getId()+'_Thumbnail'
    newthumb=getattr(parentFolder,thumbName,None)
    if not newthumb:
        newthumb = parentFolder.invokeFactory('Image',thumbName,RESPONSE=None)
    file.seek(0)
    im = PIL.Image.open(file) 
    im.thumbnail((200,200))
    outFile = StringIO.StringIO() 
    im.save(outFile,'jpeg')
    outFile.seek(0)
    newthumb.manage_upload(outFile) 
 
context.REQUEST.RESPONSE.redirect( context.absolute_url() + '/image_edit_form' + qst )

--

Then I had to create a PILProduct that has this __init__.py ( to allow Python scripts to 
get access  to PIL)

from Products.PythonScripts.Utility import allow_module, allow_class
from StringIO import StringIO

import PIL.Image

allow_class(PIL.Image.Image)
allow_module('PIL.Image')


allow_class(StringIO)
allow_module('StringIO')


--

Unfortunately I had to use StringIO instead of cStringIO, because you can't pass 
cStringIO.StringIO to allow_class() 


Brad Clements,                bkc@murkworks.com   (315)268-1000
http://www.murkworks.com                          (315)268-9812 Fax
netmeeting: ils://ils.murkworks.com               AOL-IM: BKClements