forked from plone/plone.namedfile
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scaling.py
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scaling.py
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from logging import exception
from xml.sax.saxutils import quoteattr
from Acquisition import aq_base
from AccessControl.ZopeGuards import guarded_getattr
from ZODB.POSException import ConflictError
from zope.component import queryUtility
from zope.interface import implements
from zope.traversing.interfaces import ITraversable, TraversalError
from zope.publisher.interfaces import IPublishTraverse, NotFound
from plone.rfc822.interfaces import IPrimaryFieldInfo
from plone.scale.storage import AnnotationStorage
from plone.scale.scale import scaleImage
from Products.Five import BrowserView
from plone.namedfile.interfaces import IAvailableSizes
from plone.namedfile.utils import set_headers, stream_data
_marker = object()
class ImageScale(BrowserView):
""" view used for rendering image scales """
# Grant full access to this view even if the object being viewed is protected
# (it's okay because we explicitly validate access to the image attribute
# when we retrieve it)
__roles__ = ('Anonymous',)
__allow_access_to_unprotected_subobjects__ = 1
def __init__(self, context, request, **info):
self.context = context
self.request = request
self.__dict__.update(**info)
if self.data is None:
self.data = getattr(self.context, self.fieldname)
url = self.context.absolute_url()
extension = self.data.contentType.split('/')[-1].lower()
if 'uid' in info:
name = info['uid']
else:
name = info['fieldname']
self.__name__ = '%s.%s' % (name, extension)
self.url = '%s/@@images/%s' % (url, self.__name__)
def absolute_url(self):
return self.url
def tag(self, height=_marker, width=_marker, alt=_marker,
css_class=None, title=_marker, **kwargs):
"""Create a tag including scale
"""
if height is _marker:
height = getattr(self, 'height', self.data._height)
if width is _marker:
width = getattr(self, 'width', self.data._width)
if alt is _marker:
alt = self.context.Title()
if title is _marker:
title = self.context.Title()
values = [
('src', self.url),
('alt', alt),
('title', title),
('height', height),
('width', width),
('class', css_class),
]
values.extend(kwargs.items())
parts = ['<img']
parts.extend("%s=%s" % (k, quoteattr(unicode(v))) for k, v in values if v is not None)
parts.append('/>')
return u' '.join(parts)
def index_html(self):
""" download the image """
# validate access
fieldname = getattr(self.data, 'fieldname', getattr(self, 'fieldname', None))
guarded_getattr(self.context, fieldname)
set_headers(self.data, self.request.response)
return stream_data(self.data)
def __call__(self):
# avoid the need to prefix with nocall: in TAL
return self
class ImageScaling(BrowserView):
""" view used for generating (and storing) image scales """
implements(ITraversable, IPublishTraverse)
def publishTraverse(self, request, name):
""" used for traversal via publisher, i.e. when using as a url """
stack = request.get('TraversalRequestNameStack')
image = None
if stack:
# field and scale name were given...
scale = stack.pop()
image = self.scale(name, scale) # this is aq-wrapped
elif '-' in name:
# we got a uid...
if '.' in name:
name, ext = name.rsplit('.', 1)
storage = AnnotationStorage(self.context)
info = storage.get(name)
if info is not None:
scale_view = ImageScale(self.context, self.request, **info)
return scale_view.__of__(self.context)
else:
# otherwise `name` must refer to a field...
if '.' in name:
name, ext = name.rsplit('.', 1)
value = getattr(self.context, name)
scale_view = ImageScale(self.context, self.request, data=value, fieldname=name)
return scale_view.__of__(self.context)
if image is not None:
return image
raise NotFound(self, name, self.request)
def traverse(self, name, furtherPath):
""" used for path traversal, i.e. in zope page templates """
# validate access
value = self.guarded_orig_image(name)
if not furtherPath:
image = ImageScale(self.context, self.request, data=value, fieldname=name)
else:
image = self.scale(name, furtherPath.pop())
if image is not None:
return image.tag()
raise TraversalError(self, name)
_sizes = {}
def getAvailableSizes(self, fieldname=None):
# fieldname is ignored by default
getAvailableSizes = queryUtility(IAvailableSizes)
if getAvailableSizes is None:
return self._sizes
sizes = getAvailableSizes()
if sizes is None:
return {}
return sizes
def _set_sizes(self, value):
self._sizes = value
available_sizes = property(getAvailableSizes, _set_sizes)
def getImageSize(self, fieldname=None):
if fieldname is not None:
value = self.guarded_orig_image(fieldname)
return value.getImageSize()
value = IPrimaryFieldInfo(self.context).value
return value.getImageSize()
def guarded_orig_image(self, fieldname):
return guarded_getattr(self.context, fieldname)
def create(self, fieldname, direction='thumbnail', height=None, width=None, **parameters):
""" factory for image scales, see `IImageScaleStorage.scale` """
orig_value = getattr(self.context, fieldname)
if orig_value is None:
return
if height is None and width is None:
_, format = orig_value.contentType.split('/', 1)
return None, format, (orig_value._width, orig_value._height)
if hasattr(aq_base(orig_value), 'open'):
orig_data = orig_value.open()
else:
orig_data = getattr(aq_base(orig_value), 'data', orig_value)
if not orig_data:
return
try:
result = scaleImage(orig_data, direction=direction, height=height, width=width, **parameters)
except (ConflictError, KeyboardInterrupt):
raise
except Exception:
exception('could not scale "%r" of %r',
orig_value, self.context.absolute_url())
return
if result is not None:
data, format, dimensions = result
mimetype = 'image/%s' % format.lower()
value = orig_value.__class__(data, contentType=mimetype, filename=orig_value.filename)
value.fieldname = fieldname
return value, format, dimensions
def modified(self):
""" provide a callable to return the modification time of content
items, so stored image scales can be invalidated """
return self.context.modified().millis()
def scale(self, fieldname=None, scale=None, height=None, width=None, **parameters):
if fieldname is None:
fieldname = IPrimaryFieldInfo(self.context).fieldname
if scale is not None:
available = self.getAvailableSizes(fieldname)
if not scale in available:
return None
width, height = available[scale]
storage = AnnotationStorage(self.context, self.modified)
info = storage.scale(factory=self.create,
fieldname=fieldname, height=height, width=width, **parameters)
if info is not None:
info['fieldname'] = fieldname
scale_view = ImageScale(self.context, self.request, **info)
return scale_view.__of__(self.context)
def tag(self, fieldname=None, scale=None, height=None, width=None, **kwargs):
scale = self.scale(fieldname, scale, height, width)
return scale.tag(**kwargs)