145 lines
4.8 KiB
Python
145 lines
4.8 KiB
Python
from __future__ import unicode_literals
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from django.db import models
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from django.db.models import Q
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from django.template import Context, Template
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from django.utils.encoding import force_text, python_2_unicode_compatible
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from django.utils.translation import ugettext_lazy as _
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from documents.models import Document, DocumentType
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from .literals import (
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INCLUSION_AND, INCLUSION_CHOICES, INCLUSION_OR, OPERATOR_CHOICES
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)
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from .managers import SmartLinkManager
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@python_2_unicode_compatible
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class SmartLink(models.Model):
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label = models.CharField(
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db_index=True, max_length=96, verbose_name=_('Label')
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)
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dynamic_label = models.CharField(
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blank=True, max_length=96, help_text=_(
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'Enter a template to render. '
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'Use Django\'s default templating language '
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'(https://docs.djangoproject.com/en/1.7/ref/templates/builtins/). '
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'The {{ document }} context variable is available.'
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), verbose_name=_('Dynamic label')
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)
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enabled = models.BooleanField(default=True, verbose_name=_('Enabled'))
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document_types = models.ManyToManyField(
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DocumentType, verbose_name=_('Document types')
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)
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objects = SmartLinkManager()
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class Meta:
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ordering = ('label',)
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verbose_name = _('Smart link')
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verbose_name_plural = _('Smart links')
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def __str__(self):
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return self.label
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def get_dynamic_label(self, document):
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if self.dynamic_label:
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context = Context({'document': document})
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try:
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template = Template(self.dynamic_label)
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return template.render(context=context)
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except Exception as exception:
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return _(
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'Error generating dynamic label; %s' % force_text(
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exception
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)
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)
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else:
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return None
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def get_linked_document_for(self, document):
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if document.document_type.pk not in self.document_types.values_list('pk', flat=True):
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raise Exception(
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_(
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'This smart link is not allowed for the selected '
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'document\'s type.'
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)
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)
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smart_link_query = Q()
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context = Context({'document': document})
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for condition in self.conditions.filter(enabled=True):
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template = Template(condition.expression)
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condition_query = Q(**{
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'%s__%s' % (
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condition.foreign_document_data, condition.operator
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): template.render(context=context)
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})
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if condition.negated:
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condition_query = ~condition_query
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if condition.inclusion == INCLUSION_AND:
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smart_link_query &= condition_query
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elif condition.inclusion == INCLUSION_OR:
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smart_link_query |= condition_query
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if smart_link_query:
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return Document.objects.filter(smart_link_query)
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else:
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return Document.objects.none()
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def resolve_for(self, document):
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return ResolvedSmartLink(
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smart_link=self, queryset=self.get_linked_document_for(document)
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)
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class ResolvedSmartLink(SmartLink):
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class Meta:
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proxy = True
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@python_2_unicode_compatible
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class SmartLinkCondition(models.Model):
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smart_link = models.ForeignKey(
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SmartLink, on_delete=models.CASCADE, related_name='conditions',
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verbose_name=_('Smart link')
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)
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inclusion = models.CharField(
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choices=INCLUSION_CHOICES, default=INCLUSION_AND,
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help_text=_('The inclusion is ignored for the first item.'),
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max_length=16
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)
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foreign_document_data = models.CharField(
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help_text=_('This represents the metadata of all other documents.'),
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max_length=128, verbose_name=_('Foreign document attribute')
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)
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operator = models.CharField(choices=OPERATOR_CHOICES, max_length=16)
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expression = models.TextField(
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help_text=_(
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'Enter a template to render. '
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'Use Django\'s default templating language '
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'(https://docs.djangoproject.com/en/1.7/ref/templates/builtins/). '
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'The {{ document }} context variable is available.'
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), verbose_name=_('Expression')
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)
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negated = models.BooleanField(
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default=False, help_text=_('Inverts the logic of the operator.'),
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verbose_name=_('Negated')
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)
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enabled = models.BooleanField(default=True, verbose_name=_('Enabled'))
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class Meta:
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verbose_name = _('Link condition')
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verbose_name_plural = _('Link conditions')
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def __str__(self):
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return '%s foreign %s %s %s %s' % (
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self.get_inclusion_display(),
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self.foreign_document_data, _('not') if self.negated else '',
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self.get_operator_display(), self.expression
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)
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