source: main/waeup.kofa/branches/uli-diazo-themed/src/waeup/kofa/image/schema.py @ 11089

Last change on this file since 11089 was 7819, checked in by Henrik Bettermann, 13 years ago

KOFA -> Kofa

  • Property svn:keywords set to Id
File size: 2.9 KB
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1## $Id: schema.py 7819 2012-03-08 22:28:46Z henrik $
2##
3## Copyright (C) 2011 Uli Fouquet & Henrik Bettermann
4## This program is free software; you can redistribute it and/or modify
5## it under the terms of the GNU General Public License as published by
6## the Free Software Foundation; either version 2 of the License, or
7## (at your option) any later version.
8##
9## This program is distributed in the hope that it will be useful,
10## but WITHOUT ANY WARRANTY; without even the implied warranty of
11## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
12## GNU General Public License for more details.
13##
14## You should have received a copy of the GNU General Public License
15## along with this program; if not, write to the Free Software
16## Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
17##
18"""Image file schemas.
19"""
20from zope.interface import implements
21from zope.schema import MinMaxLen
22from zope.schema.interfaces import TooBig, TooSmall
23from hurry.file.schema import File
24from waeup.kofa.image.interfaces import IImageFile
25from waeup.kofa.image.image import KofaImageFile
26
27class MinMaxSize(object):
28    """Expresses constraints on the size of an object.
29
30    The 'size' of an object is determined by its `size` method or
31    attribute. If an object has no such 'size' then it cannot be
32    validated by this mixin.
33
34    Please do not confuse `MinMaxSize` with `MinMaxLen`, for instance
35    supported by ordinary text fields. These test on ``len(obj)``
36    which is not necessary possible for file-like objects.
37
38    Therefore we distinguish 'size' from 'len' here.
39    """
40    min_size = None
41    max_size = None
42
43    def __init__(self, min_size=None, max_size=None, **kw):
44        self.min_size = min_size
45        self.max_size = max_size
46        super(MinMaxSize, self).__init__(**kw)
47
48    def _validate(self, value):
49        super(MinMaxSize, self)._validate(value)
50        if self.max_size is not None and value.size > self.max_size:
51            raise TooBig(
52                value.filename,
53                "%s bytes (max: %s bytes)" % (value.size, self.max_size))
54
55        if self.min_size is not None and value.size < self.min_size:
56            raise TooSmall(
57                value.filename,
58                "%s bytes (min: %s bytes)" % (value.size, self.min_size))
59
60   
61class ImageFile(MinMaxSize, File):
62    """An image file field.
63
64    Suitable for interfaces that wish to store image files in an
65    attribute.
66
67    This field type supports `MinMaxSize` so that you can set
68    `min_size` or `max_size` for all `ImageFile` fields in your
69    interfaces like this:
70
71      class MyInterface(Interface):
72         image = ImageFile(
73             title = u'The image',
74             description = u'The nice image',
75             max_size = 1024 * 10,
76             )
77
78    to restrict the file size of stored images to 10 KBytes.
79
80    By default no such restriction is set.
81    """
82    implements(IImageFile)
83
84    _type = KofaImageFile
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