Service for adding, removing and listing votes

settings/common.py

@@ -183,6 +183,7 @@ INSTALLED_APPS = [
     "taiga.projects.history",
     "taiga.projects.notifications",
     "taiga.projects.stars",
+    "taiga.projects.votes",
 
     "south",
     "reversion",

taiga/projects/votes/admin.py

@@ -0,0 +1,3 @@
+from django.contrib import admin
+
+# Register your models here.

taiga/projects/votes/models.py

@@ -0,0 +1,35 @@
+from django.conf import settings
+from django.db import models
+from django.utils.translation import ugettext_lazy as _
+from django.contrib.contenttypes import generic
+
+
+class Votes(models.Model):
+    content_type = models.ForeignKey("contenttypes.ContentType")
+    object_id = models.PositiveIntegerField()
+    content_object = generic.GenericForeignKey("content_type", "object_id")
+    count = models.PositiveIntegerField(default=0)
+
+    class Meta:
+        verbose_name = _("Votes")
+        verbose_name_plural = _("Votes")
+        unique_together = ("content_type", "object_id")
+
+    def __str__(self):
+        return self.count
+
+
+class Vote(models.Model):
+    content_type = models.ForeignKey("contenttypes.ContentType")
+    object_id = models.PositiveIntegerField(null=False)
+    content_object = generic.GenericForeignKey("content_type", "object_id")
+    user = models.ForeignKey(settings.AUTH_USER_MODEL, null=False, blank=False,
+                             related_name="votes", verbose_name=_("votes"))
+
+    class Meta:
+        verbose_name = _("Vote")
+        verbose_name_plural = _("Votes")
+        unique_together = ("content_type", "object_id", "user")
+
+    def __str__(self):
+        return self.user

taiga/projects/votes/services.py

@@ -0,0 +1,92 @@
+from django.db.models import F
+from django.db.transaction import atomic
+from django.db.models.loading import get_model
+from django.contrib.auth import get_user_model
+
+from .models import Votes, Vote
+
+
+def add_vote(obj, user):
+    """Add a vote to an object.
+
+    If the user has already voted the object nothing happends, so this function can be considered
+    idempotent.
+
+    :param obj: Any Django model instance.
+    :param user: User adding the vote. :class:`~taiga.users.models.User` instance.
+    """
+    obj_type = get_model("contenttypes", "ContentType").objects.get_for_model(obj)
+    with atomic():
+        _, created = Vote.objects.get_or_create(content_type=obj_type, object_id=obj.id, user=user)
+
+        if not created:
+            return
+
+        votes, _ = Votes.objects.get_or_create(content_type=obj_type, object_id=obj.id)
+        votes.count = F('count') + 1
+        votes.save()
+
+
+def remove_vote(obj, user):
+    """Remove an user vote from an object.
+
+    If the user has not voted the object nothing happens so this function can be considered
+    idempotent.
+
+    :param obj: Any Django model instance.
+    :param user: User removing her vote. :class:`~taiga.users.models.User` instance.
+    """
+    obj_type = get_model("contenttypes", "ContentType").objects.get_for_model(obj)
+    with atomic():
+        qs = Vote.objects.filter(content_type=obj_type, object_id=obj.id, user=user)
+        if not qs.exists():
+            return
+
+        qs.delete()
+
+        votes, _ = Votes.objects.get_or_create(content_type=obj_type, object_id=obj.id)
+        votes.count = F('count') - 1
+        votes.save()
+
+
+def get_voters(obj):
+    """Get the voters of an object.
+
+    :param obj: Any Django model instance.
+
+    :return: User queryset object representing the users that voted the object.
+    """
+    obj_type = get_model("contenttypes", "ContentType").objects.get_for_model(obj)
+
+    return get_user_model().objects.filter(votes__content_type=obj_type, votes__object_id=obj.id)
+
+
+def get_votes(obj):
+    """Get the number of votes an object has.
+
+    :param obj: Any Django model instance.
+
+    :return: Number of votes or `0` if the object has no votes at all.
+    """
+    obj_type = get_model("contenttypes", "ContentType").objects.get_for_model(obj)
+
+    try:
+        return Votes.objects.get(content_type=obj_type, object_id=obj.id).count
+    except Votes.DoesNotExist:
+        return 0
+
+
+def get_voted(user, obj_class):
+    """Get the objects voted by an user.
+
+    :param user: :class:`~taiga.users.models.User` instance.
+    :param obj_class: Show only objects of this kind. Can be any Django model class.
+
+    :return:
+    """
+    obj_type = get_model("contenttypes", "ContentType").objects.get_for_model(obj_class)
+    conditions = ('votes_vote.content_type_id = %s',
+                  '%s.id = votes_vote.object_id' % obj_class._meta.db_table,
+                  'votes_vote.user_id = %s')
+    return obj_class.objects.extra(where=conditions, tables=('votes_vote',),
+                                   params=(obj_type.id, user.id))

taiga/projects/votes/tests.py

@@ -0,0 +1,3 @@
+from django.test import TestCase
+
+# Create your tests here.

taiga/projects/votes/views.py

@@ -0,0 +1,3 @@
+from django.shortcuts import render
+
+# Create your views here.

tests/factories.py

@@ -173,3 +173,22 @@ class StarsFactory(Factory):
 
     project = factory.SubFactory("tests.factories.ProjectFactory")
     count = 0
+
+
+class VoteFactory(Factory):
+    FACTORY_FOR = get_model("votes", "Vote")
+
+    content_type = factory.SubFactory("tests.factories.ContentTypeFactory")
+    object_id = factory.Sequence(lambda n: n)
+    user = factory.SubFactory("tests.factories.UserFactory")
+
+
+class VotesFactory(Factory):
+    FACTORY_FOR = get_model("votes", "Votes")
+
+    content_type = factory.SubFactory("tests.factories.ContentTypeFactory")
+    object_id = factory.Sequence(lambda n: n)
+
+
+class ContentTypeFactory(Factory):
+    FACTORY_FOR = get_model("contenttypes", "ContentType")

tests/integration/test_votes.py

@@ -0,0 +1,69 @@
+import pytest
+
+from django.contrib.contenttypes.models import ContentType
+
+from taiga.projects.votes import services as votes, models
+
+from .. import factories as f
+
+pytestmark = pytest.mark.django_db
+
+
+def test_add_vote():
+    project = f.ProjectFactory()
+    project_type = ContentType.objects.get_for_model(project)
+    user = f.UserFactory()
+    votes_qs = models.Votes.objects.filter(content_type=project_type, object_id=project.id)
+
+    votes.add_vote(project, user)
+
+    assert votes_qs.get().count == 1
+
+    votes.add_vote(project, user)  # add_vote must be idempotent
+
+    assert votes_qs.get().count == 1
+
+
+def test_remove_vote():
+    user = f.UserFactory()
+    project = f.ProjectFactory()
+    project_type = ContentType.objects.get_for_model(project)
+    votes_qs = models.Votes.objects.filter(content_type=project_type, object_id=project.id)
+    f.VotesFactory(content_type=project_type, object_id=project.id, count=1)
+    f.VoteFactory(content_type=project_type, object_id=project.id, user=user)
+
+    assert votes_qs.get().count == 1
+
+    votes.remove_vote(project, user)
+
+    assert votes_qs.get().count == 0
+
+    votes.remove_vote(project, user)  # remove_vote must be idempotent
+
+    assert votes_qs.get().count == 0
+
+
+def test_get_votes():
+    project = f.ProjectFactory()
+    project_type = ContentType.objects.get_for_model(project)
+    f.VotesFactory(content_type=project_type, object_id=project.id, count=4)
+
+    assert votes.get_votes(project) == 4
+
+
+def test_get_voters():
+    f.UserFactory()
+    project = f.ProjectFactory()
+    project_type = ContentType.objects.get_for_model(project)
+    vote = f.VoteFactory(content_type=project_type, object_id=project.id)
+
+    assert list(votes.get_voters(project)) == [vote.user]
+
+
+def test_get_voted():
+    f.ProjectFactory()
+    project = f.ProjectFactory()
+    project_type = ContentType.objects.get_for_model(project)
+    vote = f.VoteFactory(content_type=project_type, object_id=project.id)
+
+    assert list(votes.get_voted(vote.user, type(project))) == [project]