MVP of the weblinks app

Signed-off-by: Roberto Rosario <roberto.rosario@mayan-edms.com>

mayan/apps/weblinks/models.py

@@ -0,0 +1,90 @@
+from __future__ import unicode_literals
+
+from django.db import models, transaction
+from django.template import Context, Template
+from django.utils.encoding import 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 DocumentType
+
+from .events import event_web_link_created, event_web_link_edited
+from .managers import WebLinkManager
+
+
+@python_2_unicode_compatible
+class WebLink(models.Model):
+    """
+    This model stores the basic fields for a web link. Web links allow
+    generating links from documents to external resources.
+    """
+    label = models.CharField(
+        db_index=True, max_length=96, verbose_name=_('Label')
+    )
+    template = models.TextField(verbose_name=_('Template'))
+    enabled = models.BooleanField(default=True, verbose_name=_('Enabled'))
+    document_types = models.ManyToManyField(
+        related_name='web_links', to=DocumentType,
+        verbose_name=_('Document types')
+    )
+
+    objects = WebLinkManager()
+
+    class Meta:
+        ordering = ('label',)
+        verbose_name = _('Web link')
+        verbose_name_plural = _('Web links')
+
+    def __str__(self):
+        return self.label
+
+    def document_types_add(self, queryset, _user=None):
+        with transaction.atomic():
+            event_web_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_web_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 save(self, *args, **kwargs):
+        _user = kwargs.pop('_user', None)
+
+        with transaction.atomic():
+            is_new = not self.pk
+            super(WebLink, self).save(*args, **kwargs)
+            if is_new:
+                event_web_link_created.commit(
+                    actor=_user, target=self
+                )
+            else:
+                event_web_link_edited.commit(
+                    actor=_user, target=self
+                )
+
+
+class ResolvedWebLink(WebLink):
+    """
+    Proxy model to represent an already resolved web link. Used for easier
+    colums registration.
+    """
+    class Meta:
+        proxy = True
+
+    def get_url_for(self, document):
+        context = Context({'document': document})
+
+        return Template(self.template).render(context=context)