Files
mayan-edms/mayan/apps/linking/models.py
2019-04-29 01:08:52 -04:00

216 lines
7.3 KiB
Python

from __future__ import unicode_literals
from django.db import models, transaction
from django.db.models import Q
from django.template import Context, Template
from django.utils.encoding import force_text, python_2_unicode_compatible
from django.utils.translation import ugettext_lazy as _
from mayan.apps.documents.events import event_document_type_edited
from mayan.apps.documents.models import Document, DocumentType
from .events import event_smart_link_created, event_smart_link_edited
from .literals import (
INCLUSION_AND, INCLUSION_CHOICES, INCLUSION_OR, OPERATOR_CHOICES
)
from .managers import SmartLinkManager
@python_2_unicode_compatible
class SmartLink(models.Model):
"""
This model stores the basic fields for a smart link. Smart links allow
linking documents using a programmatic method of conditions that mirror
Django's database filter operations.
"""
label = models.CharField(
db_index=True, max_length=96, verbose_name=_('Label')
)
dynamic_label = models.CharField(
blank=True, max_length=96, help_text=_(
'Enter a template to render. '
'Use Django\'s default templating language '
'(https://docs.djangoproject.com/en/1.11/ref/templates/builtins/). '
'The {{ document }} context variable is available.'
), verbose_name=_('Dynamic label')
)
enabled = models.BooleanField(default=True, verbose_name=_('Enabled'))
document_types = models.ManyToManyField(
related_name='smart_links', to=DocumentType,
verbose_name=_('Document types')
)
objects = SmartLinkManager()
class Meta:
ordering = ('label',)
verbose_name = _('Smart link')
verbose_name_plural = _('Smart links')
def __str__(self):
return self.label
def document_types_add(self, queryset, _user=None):
with transaction.atomic():
event_smart_link_edited.commit(
actor=_user, target=self
)
for obj in queryset:
self.document_types.add(obj)
event_document_type_edited.commit(
actor=_user, action_object=self, target=obj
)
def document_types_remove(self, queryset, _user=None):
with transaction.atomic():
event_smart_link_edited.commit(
actor=_user, target=self
)
for obj in queryset:
self.document_types.remove(obj)
event_document_type_edited.commit(
actor=_user, action_object=self, target=obj
)
def get_dynamic_label(self, document):
"""
If the smart links was created using a template label instead of a
static label, resolve the template and return the result.
"""
if self.dynamic_label:
context = Context({'document': document})
try:
template = Template(self.dynamic_label)
return template.render(context=context)
except Exception as exception:
return _(
'Error generating dynamic label; %s' % force_text(
exception
)
)
else:
return None
def get_linked_document_for(self, document):
"""
Execute the corresponding smart links conditions for the document
provided and return the resulting document queryset.
"""
if document.document_type.pk not in self.document_types.values_list('pk', flat=True):
raise Exception(
_(
'This smart link is not allowed for the selected '
'document\'s type.'
)
)
smart_link_query = Q()
context = Context({'document': document})
for condition in self.conditions.filter(enabled=True):
template = Template(condition.expression)
condition_query = Q(**{
'%s__%s' % (
condition.foreign_document_data, condition.operator
): template.render(context=context)
})
if condition.negated:
condition_query = ~condition_query
if condition.inclusion == INCLUSION_AND:
smart_link_query &= condition_query
elif condition.inclusion == INCLUSION_OR:
smart_link_query |= condition_query
if smart_link_query:
return Document.objects.filter(smart_link_query)
else:
return Document.objects.none()
def resolve_for(self, document):
return ResolvedSmartLink(
smart_link=self, queryset=self.get_linked_document_for(
document=document
)
)
def save(self, *args, **kwargs):
_user = kwargs.pop('_user', None)
with transaction.atomic():
is_new = not self.pk
super(SmartLink, self).save(*args, **kwargs)
if is_new:
event_smart_link_created.commit(
actor=_user, target=self
)
else:
event_smart_link_edited.commit(
actor=_user, target=self
)
class ResolvedSmartLink(SmartLink):
"""
Proxy model to represent an already resolved smart link. Used for easier
colums registration.
"""
class Meta:
proxy = True
def get_label_for(self, document):
return self.get_dynamic_label(document=document) or self.label
@python_2_unicode_compatible
class SmartLinkCondition(models.Model):
"""
This model stores a single smart link condition. A smart link is a
collection of one of more smart link conditions.
"""
smart_link = models.ForeignKey(
on_delete=models.CASCADE, related_name='conditions', to=SmartLink,
verbose_name=_('Smart link')
)
inclusion = models.CharField(
choices=INCLUSION_CHOICES, default=INCLUSION_AND,
help_text=_('The inclusion is ignored for the first item.'),
max_length=16
)
foreign_document_data = models.CharField(
help_text=_('This represents the metadata of all other documents.'),
max_length=128, verbose_name=_('Foreign document attribute')
)
operator = models.CharField(choices=OPERATOR_CHOICES, max_length=16)
expression = models.TextField(
help_text=_(
'Enter a template to render. '
'Use Django\'s default templating language '
'(https://docs.djangoproject.com/en/1.11/ref/templates/builtins/). '
'The {{ document }} context variable is available.'
), verbose_name=_('Expression')
)
negated = models.BooleanField(
default=False, help_text=_('Inverts the logic of the operator.'),
verbose_name=_('Negated')
)
enabled = models.BooleanField(default=True, verbose_name=_('Enabled'))
class Meta:
verbose_name = _('Link condition')
verbose_name_plural = _('Link conditions')
def __str__(self):
return self.get_full_label()
def get_full_label(self):
return '%s foreign %s %s %s %s' % (
self.get_inclusion_display(),
self.foreign_document_data, _('not') if self.negated else '',
self.get_operator_display(), self.expression
)
get_full_label.short_description = _('Full label')