Merge pull request #2074 from ResearchHub/new-follow

feat: Add new follow model

src/user/migrations/0130_follow.py

@@ -0,0 +1,52 @@
+# Generated by Django 5.1.4 on 2025-01-17 11:41
+
+import django.db.models.deletion
+from django.conf import settings
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ("contenttypes", "0002_remove_content_type_name"),
+        ("user", "0129_delete_follow"),
+    ]
+
+    operations = [
+        migrations.CreateModel(
+            name="Follow",
+            fields=[
+                (
+                    "id",
+                    models.AutoField(
+                        auto_created=True,
+                        primary_key=True,
+                        serialize=False,
+                        verbose_name="ID",
+                    ),
+                ),
+                ("created_date", models.DateTimeField(auto_now_add=True)),
+                ("updated_date", models.DateTimeField(auto_now=True)),
+                ("object_id", models.PositiveIntegerField()),
+                (
+                    "content_type",
+                    models.ForeignKey(
+                        limit_choices_to={"model__in": ["hub", "paper", "user"]},
+                        on_delete=django.db.models.deletion.CASCADE,
+                        to="contenttypes.contenttype",
+                    ),
+                ),
+                (
+                    "user",
+                    models.ForeignKey(
+                        on_delete=django.db.models.deletion.CASCADE,
+                        related_name="following",
+                        to=settings.AUTH_USER_MODEL,
+                    ),
+                ),
+            ],
+            options={
+                "unique_together": {("user", "content_type", "object_id")},
+            },
+        ),
+    ]

src/user/models.py

@@ -1,5 +1,6 @@
 from .related_models.action_model import Action
 from .related_models.author_model import Author
+from .related_models.follow_model import Follow
 from .related_models.gatekeeper_model import Gatekeeper
 from .related_models.organization_model import Organization
 from .related_models.profile_image_storage import ProfileImageStorage
@@ -12,6 +13,7 @@
 migratables = (
     Action,
     Author,
+    Follow,
     Major,
     ProfileImageStorage,
     University,

src/user/related_models/follow_model.py

@@ -0,0 +1,35 @@
+from django.contrib.contenttypes.fields import GenericForeignKey
+from django.contrib.contenttypes.models import ContentType
+from django.core.exceptions import ValidationError
+from django.db import models
+
+from utils.models import DefaultModel
+
+
+class Follow(DefaultModel):
+    ALLOWED_FOLLOW_MODELS = ["hub", "paper", "user"]
+
+    user = models.ForeignKey(
+        "user.User",
+        on_delete=models.CASCADE,
+        related_name="following",
+    )
+    content_type = models.ForeignKey(
+        ContentType,
+        on_delete=models.CASCADE,
+        limit_choices_to={"model__in": ALLOWED_FOLLOW_MODELS},
+    )
+    object_id = models.PositiveIntegerField()
+    followed_object = GenericForeignKey("content_type", "object_id")
+
+    class Meta:
+        unique_together = ("user", "content_type", "object_id")
+
+    def clean(self):
+        if self.content_type.model not in self.ALLOWED_FOLLOW_MODELS:
+            raise ValidationError(f"Invalid follow model: {self.content_type.model}")
+        super().clean()
+
+    def save(self, *args, **kwargs):
+        self.clean()
+        super().save(*args, **kwargs)

src/user/tests/test_models.py

@@ -1,7 +1,11 @@
+from django.contrib.contenttypes.models import ContentType
+from django.core.exceptions import ValidationError
 from django.test import TestCase
 
 from paper.related_models.authorship_model import Authorship
 from paper.related_models.paper_model import Paper
+from user.related_models.follow_model import Follow
+from user.related_models.user_model import User
 from user.tests.helpers import create_user
 
 
@@ -39,3 +43,50 @@ def test_open_access_pct_property(self):
 
     def test_achievements(self):
         self.assertIn("CITED_AUTHOR", self.user.author_profile.achievements)
+
+
+class FollowModelTests(TestCase):
+    def setUp(self):
+        self.user = create_user(
+            email="[email protected]",
+            first_name="random",
+            last_name="user",
+        )
+
+    def test_follow_user(self):
+        # Arrange & Act
+        follow = Follow.objects.create(
+            user=self.user,
+            content_type=ContentType.objects.get_for_model(User),
+            object_id=self.user.id,
+        )
+
+        # Assert
+        self.assertEqual(follow.user, self.user)
+        self.assertEqual(follow.content_type, ContentType.objects.get_for_model(User))
+        self.assertEqual(follow.object_id, self.user.id)
+
+    def test_follow_paper(self):
+        # Arrange
+        paper = Paper.objects.create(title="title1", citations=10, is_open_access=True)
+
+        # Act
+        follow = Follow.objects.create(
+            user=self.user,
+            content_type=ContentType.objects.get_for_model(Paper),
+            object_id=paper.id,
+        )
+
+        # Assert
+        self.assertEqual(follow.user, self.user)
+        self.assertEqual(follow.content_type, ContentType.objects.get_for_model(Paper))
+        self.assertEqual(follow.object_id, paper.id)
+
+    def test_follow_unsupported_model(self):
+        # Arrange
+        with self.assertRaises(ValidationError):
+            Follow.objects.create(
+                user=self.user,
+                content_type=ContentType.objects.get_for_model(Authorship),
+                object_id=1,
+            )