[Zope] External Method limits

[Lee Harr]

>From: Dieter Maurer <dieter@handshake.de>
>
>Lee Harr writes:
>  > I am working through the section of the Zope Book on External Methods
>  > (chapter 8: Advanced Zope Scripting --
>  > http://www.zope.org/Members/michel/ZB/ScriptingZope.dtml -- Secton: 
>Using
>  > External Methods)
>  >
>  > There is an example there which uses PIL that I am having some trouble 
>with.
>  > Whenever I try to use makeThumbnail on a file which is more than about 
>60K I
>  > get the following error:
>  >
>  >
>  > Error Type: TypeError
>  > Error Value: expected string, ImplicitAcquirerWrapper found
>  > ...
>  > File /usr/local/www/Zope/Extensions/Thumbnail.py, line 18, in 
>makeThumbnail
>  > (Object: Traversable)
>  > TypeError: (see above)
>Seems you use "file.data".
>
>This is a string for small file sizes but an object for large ones.
>Use "str(file.data)", instead.
>
>
>Dieter


Dieter:

Thank you so much. Works like a charm now. Here is the corrected code:


def makeThumbnail(self, original_id, size=128):
          """
          Makes a thumbnail image given an image Id when called on a Zope
          folder.

          The thumbnail is a Zope image object that is a small JPG
          representation of the original image. The thumbnail has a
          'original_id' property set to the id of the full size image
          object.
          """

          from PIL import Image
          from cStringIO import StringIO
          import os.path

          # create a thumbnail image file
          original_image=getattr(self, original_id)
          original_file=StringIO(str(original_image.data)) # bug fix here
          image=Image.open(original_file)
          image=image.convert('RGB')
          image.thumbnail((size,size))
          thumbnail_file=StringIO()
          image.save(thumbnail_file, "JPEG")
          thumbnail_file.seek(0)

          # create an id for the thumbnail
          path, ext=os.path.splitext(original_id)
          thumbnail_id=path + '.thumb.jpg'

          # if there's and old thumbnail, delete it
          if thumbnail_id in self.objectIds():
              self.manage_delObjects(thumbnail_id)

          # create the Zope image object
          self.manage_addProduct['OFSP'].manage_addImage(thumbnail_id, 
thumbnail_file, 'thumbnail image')

          thumbnail_image=getattr(self, thumbnail_id)

          # set the 'originial_id' property
          thumbnail_image.manage_addProperty('original_id', original_id, 
'string')


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