Initial commit to support page mapping
Signed-off-by: Roberto Rosario <roberto.rosario@mayan-edms.com>
This commit is contained in:
Roberto Rosario
284
mayan/apps/documents/models/document_version_page_models.py
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284
mayan/apps/documents/models/document_version_page_models.py
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from __future__ import absolute_import, unicode_literals
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import logging
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from furl import furl
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from django.db import models
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from django.urls import reverse
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from django.utils.encoding import force_text, python_2_unicode_compatible
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from django.utils.functional import cached_property
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from django.utils.translation import ugettext_lazy as _
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from mayan.apps.converter.literals import DEFAULT_ZOOM_LEVEL, DEFAULT_ROTATION
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from mayan.apps.converter.models import LayerTransformation
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from mayan.apps.converter.transformations import (
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BaseTransformation, TransformationResize, TransformationRotate,
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TransformationZoom
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)
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from mayan.apps.converter.utils import get_converter_class
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from ..managers import DocumentVersionPageManager
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from ..settings import (
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setting_disable_base_image_cache, setting_disable_transformed_image_cache,
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setting_display_width, setting_display_height, setting_zoom_max_level,
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setting_zoom_min_level
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)
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from .document_version_models import DocumentVersion
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__all__ = ('DocumentVersionPage', 'DocumentVersionPageResult')
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logger = logging.getLogger(__name__)
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@python_2_unicode_compatible
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class DocumentVersionPage(models.Model):
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"""
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Model that describes a document version page
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"""
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document_version = models.ForeignKey(
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on_delete=models.CASCADE, related_name='pages', to=DocumentVersion,
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verbose_name=_('Document version')
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)
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enabled = models.BooleanField(default=True, verbose_name=_('Enabled'))
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page_number = models.PositiveIntegerField(
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db_index=True, default=1, editable=False,
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verbose_name=_('Page number')
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)
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objects = DocumentVersionPageManager()
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#passthrough = models.Manager()
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class Meta:
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ordering = ('page_number',)
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verbose_name = _('Document version page')
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verbose_name_plural = _('Document version pages')
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def __str__(self):
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return self.get_label()
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@cached_property
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def cache_partition(self):
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partition, created = self.document_version.cache.partitions.get_or_create(
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name=self.uuid
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)
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return partition
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def delete(self, *args, **kwargs):
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self.cache_partition.delete()
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super(DocumentVersionPage, self).delete(*args, **kwargs)
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#def detect_orientation(self):
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# with self.document_version.open() as file_object:
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# converter = get_converter_class()(
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# file_object=file_object,
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# mime_type=self.document_version.mimetype
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# )
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# return converter.detect_orientation(
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# page_number=self.page_number
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# )
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@property
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def document(self):
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return self.document_version.document
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def generate_image(self, user=None, **kwargs):
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transformation_list = self.get_combined_transformation_list(user=user, **kwargs)
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combined_cache_filename = BaseTransformation.combine(transformation_list)
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# Check is transformed image is available
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logger.debug('transformations cache filename: %s', combined_cache_filename)
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if self.cache_partition.get_file(filename=combined_cache_filename):
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logger.debug(
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'transformations cache file "%s" found', combined_cache_filename
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)
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else:
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logger.debug(
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'transformations cache file "%s" not found', combined_cache_filename
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)
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image = self.get_image(transformations=transformation_list)
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with self.cache_partition.create_file(filename=combined_cache_filename) as file_object:
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file_object.write(image.getvalue())
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return combined_cache_filename
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#def get_absolute_url(self):
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# return reverse(
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# viewname='documents:document_version_page_view', kwargs={
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# 'pk': self.pk
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# }
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# )
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def get_api_image_url(self, *args, **kwargs):
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"""
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Create an unique URL combining:
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- the page's image URL
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- the interactive argument
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- a hash from the server side and interactive transformations
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The purpose of this unique URL is to allow client side caching
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if document page images.
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"""
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transformations_hash = BaseTransformation.combine(
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self.get_combined_transformation_list(*args, **kwargs)
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)
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kwargs.pop('transformations', None)
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final_url = furl()
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final_url.args = kwargs
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final_url.path = reverse(
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viewname='rest_api:documentversionpage-image', kwargs={
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'pk': self.document.pk, 'version_pk': self.document_version.pk,
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'page_pk': self.pk
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}
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)
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final_url.args['_hash'] = transformations_hash
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return final_url.tostr()
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def get_combined_transformation_list(self, user=None, *args, **kwargs):
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"""
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Return a list of transformation containing the server side
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document page transformation as well as tranformations created
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from the arguments as transient interactive transformation.
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"""
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# Convert arguments into transformations
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transformations = kwargs.get('transformations', [])
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# Set sensible defaults if the argument is not specified or if the
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# argument is None
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width = kwargs.get('width', setting_display_width.value) or setting_display_width.value
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height = kwargs.get('height', setting_display_height.value) or setting_display_height.value
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rotation = kwargs.get('rotation', DEFAULT_ROTATION) or DEFAULT_ROTATION
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zoom_level = kwargs.get('zoom', DEFAULT_ZOOM_LEVEL) or DEFAULT_ZOOM_LEVEL
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if zoom_level < setting_zoom_min_level.value:
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zoom_level = setting_zoom_min_level.value
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if zoom_level > setting_zoom_max_level.value:
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zoom_level = setting_zoom_max_level.value
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# Generate transformation hash
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transformation_list = []
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maximum_layer_order = kwargs.get('maximum_layer_order', None)
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# Stored transformations first
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for stored_transformation in LayerTransformation.objects.get_for_object(
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self, maximum_layer_order=maximum_layer_order, as_classes=True,
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user=user
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):
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transformation_list.append(stored_transformation)
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# Interactive transformations second
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for transformation in transformations:
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transformation_list.append(transformation)
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if rotation:
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transformation_list.append(
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TransformationRotate(degrees=rotation)
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)
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if width:
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transformation_list.append(
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TransformationResize(width=width, height=height)
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)
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if zoom_level:
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transformation_list.append(TransformationZoom(percent=zoom_level))
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return transformation_list
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def get_image(self, transformations=None):
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cache_filename = 'base_image'
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logger.debug('Page cache filename: %s', cache_filename)
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cache_file = self.cache_partition.get_file(filename=cache_filename)
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if cache_file:
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logger.debug('Page cache file "%s" found', cache_filename)
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with cache_file.open() as file_object:
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converter = get_converter_class()(
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file_object=file_object
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)
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converter.seek_page(page_number=0)
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# This code is also repeated below to allow using a context
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# manager with cache_file.open and close it automatically.
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# Apply runtime transformations
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for transformation in transformations or []:
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converter.transform(transformation=transformation)
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return converter.get_page()
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else:
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logger.debug('Page cache file "%s" not found', cache_filename)
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try:
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with self.document_version.get_intermediate_file() as file_object:
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converter = get_converter_class()(
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file_object=file_object
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)
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converter.seek_page(page_number=self.page_number - 1)
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page_image = converter.get_page()
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# Since open "wb+" doesn't create files, create it explicitly
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with self.cache_partition.create_file(filename=cache_filename) as file_object:
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file_object.write(page_image.getvalue())
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# Apply runtime transformations
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for transformation in transformations or []:
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converter.transform(transformation=transformation)
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return converter.get_page()
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except Exception as exception:
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# Cleanup in case of error
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logger.error(
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'Error creating page cache file "%s"; %s',
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cache_filename, exception
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)
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raise
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#@property
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#def is_in_trash(self):
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# return self.document.is_in_trash
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def get_label(self):
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return _(
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'Version page %(page_number)d out of %(total_pages)d of %(document)s'
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) % {
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'document': force_text(self.document),
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'page_number': self.page_number,
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'total_pages': self.document_version.pages.count()
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}
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get_label.short_description = _('Label')
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def natural_key(self):
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return (self.page_number, self.document_version.natural_key())
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natural_key.dependencies = ['documents.DocumentVersion']
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#@property
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#def siblings(self):
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# return DocumentVersionPage.objects.filter(
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# document_version=self.document_version
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# )
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@property
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def uuid(self):
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"""
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Make cache UUID a mix of version ID and page ID to avoid using stale
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images
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"""
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return '{}-{}'.format(self.document_version.uuid, self.pk)
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class DocumentVersionPageResult(DocumentVersionPage):
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class Meta:
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ordering = ('document_version__document', 'page_number')
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proxy = True
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verbose_name = _('Document version page')
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verbose_name_plural = _('Document version pages')
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