Log DB modifications

apps/api/urls.py

@@ -1,3 +1,4 @@
+from django.conf import settings
 from django.conf.urls import url, include
 from rest_framework import routers
 
@@ -8,6 +9,10 @@ from .viewsets import UserViewSet
 router = routers.DefaultRouter()
 router.register('user', UserViewSet)
 
+if "logs" in settings.INSTALLED_APPS:
+    from logs.api.views import ChangelogViewSet
+    router.register('logs', ChangelogViewSet)
+
 app_name = 'api'
 
 # Wire up our API using automatic URL routing.

apps/logs/__init__.py

@@ -0,0 +1,4 @@
+# Copyright (C) 2018-2020 by BDE ENS Paris-Saclay
+# SPDX-License-Identifier: GPL-3.0-or-later
+
+default_app_config = 'logs.apps.LogsConfig'

apps/logs/api/serializers.py

@@ -0,0 +1,19 @@
+# Copyright (C) 2018-2020 by BDE ENS Paris-Saclay
+# SPDX-License-Identifier: GPL-3.0-or-later
+
+from rest_framework import serializers
+
+from ..models import Changelog
+
+
+class ChangelogSerializer(serializers.ModelSerializer):
+    """
+    REST API Serializer for Changelog types.
+    The djangorestframework plugin will analyse the model `Changelog` and parse all fields in the API.
+    """
+
+    class Meta:
+        model = Changelog
+        fields = '__all__'
+        # noinspection PyProtectedMember
+        read_only_fields = [f.name for f in model._meta.get_fields()]  # Changelogs are read-only protected

apps/logs/api/urls.py

@@ -0,0 +1,11 @@
+# Copyright (C) 2018-2020 by BDE ENS Paris-Saclay
+# SPDX-License-Identifier: GPL-3.0-or-later
+
+from .views import ChangelogViewSet
+
+
+def register_logs_urls(router, path):
+    """
+    Configure router for Activity REST API.
+    """
+    router.register(path, ChangelogViewSet)

apps/logs/api/views.py

@@ -0,0 +1,28 @@
+# Copyright (C) 2018-2020 by BDE ENS Paris-Saclay
+# SPDX-License-Identifier: GPL-3.0-or-later
+
+from django_filters.rest_framework import DjangoFilterBackend
+from rest_framework.filters import OrderingFilter
+from rest_framework.viewsets import ModelViewSet
+
+from .serializers import ChangelogSerializer
+from ..models import Changelog
+
+
+class ChangelogViewSet(ModelViewSet):
+    """
+    REST API View set.
+    The djangorestframework plugin will get all `Changelog` objects, serialize it to JSON with the given serializer,
+    then render it on /api/logs/
+    """
+
+    def check_permissions(self, request):
+        # Only superusers can get access to logs
+        return self.request.user and self.request.user.is_superuser
+
+    queryset = Changelog.objects.all()
+    serializer_class = ChangelogSerializer
+    filter_backends = [DjangoFilterBackend, OrderingFilter]
+    filterset_fields = ['model', 'action', "instance_pk", 'user', 'ip', ]
+    ordering_fields = ['timestamp', 'id', ]
+    ordering = ['-id', ]

apps/logs/apps.py

@@ -0,0 +1,18 @@
+# Copyright (C) 2018-2020 by BDE ENS Paris-Saclay
+# SPDX-License-Identifier: GPL-3.0-or-later
+
+from django.apps import AppConfig
+from django.db.models.signals import pre_save, post_save, post_delete
+from django.utils.translation import gettext_lazy as _
+
+
+class LogsConfig(AppConfig):
+    name = 'logs'
+    verbose_name = _('Logs')
+
+    def ready(self):
+        # noinspection PyUnresolvedReferences
+        from . import signals
+        pre_save.connect(signals.pre_save_object)
+        post_save.connect(signals.save_object)
+        post_delete.connect(signals.delete_object)

apps/logs/migrations/0001_initial.py

@@ -0,0 +1,37 @@
+# Generated by Django 3.1.1 on 2020-09-21 15:33
+
+from django.conf import settings
+from django.db import migrations, models
+import django.db.models.deletion
+import django.utils.timezone
+
+
+class Migration(migrations.Migration):
+
+    initial = True
+
+    dependencies = [
+        ('contenttypes', '0002_remove_content_type_name'),
+        migrations.swappable_dependency(settings.AUTH_USER_MODEL),
+    ]
+
+    operations = [
+        migrations.CreateModel(
+            name='Changelog',
+            fields=[
+                ('id', models.AutoField(auto_created=True, primary_key=True, serialize=False, verbose_name='ID')),
+                ('ip', models.GenericIPAddressField(blank=True, null=True, verbose_name='IP Address')),
+                ('instance_pk', models.CharField(max_length=255, verbose_name='identifier')),
+                ('previous', models.TextField(blank=True, default='', verbose_name='previous data')),
+                ('data', models.TextField(blank=True, default='', verbose_name='new data')),
+                ('action', models.CharField(choices=[('create', 'create'), ('edit', 'edit'), ('delete', 'delete')], default='edit', max_length=16, verbose_name='action')),
+                ('timestamp', models.DateTimeField(default=django.utils.timezone.now, verbose_name='timestamp')),
+                ('model', models.ForeignKey(on_delete=django.db.models.deletion.PROTECT, to='contenttypes.contenttype', verbose_name='model')),
+                ('user', models.ForeignKey(null=True, on_delete=django.db.models.deletion.PROTECT, to=settings.AUTH_USER_MODEL, verbose_name='user')),
+            ],
+            options={
+                'verbose_name': 'changelog',
+                'verbose_name_plural': 'changelogs',
+            },
+        ),
+    ]

apps/logs/models.py

@@ -0,0 +1,88 @@
+# Copyright (C) 2018-2020 by BDE ENS Paris-Saclay
+# SPDX-License-Identifier: GPL-3.0-or-later
+
+from django.conf import settings
+from django.contrib.contenttypes.models import ContentType
+from django.core.exceptions import ValidationError
+from django.db import models
+from django.utils import timezone
+from django.utils.translation import gettext_lazy as _
+
+
+class Changelog(models.Model):
+    """
+    Store each modification in the database (except sessions and logging),
+    including creating, editing and deleting models.
+    """
+
+    user = models.ForeignKey(
+        settings.AUTH_USER_MODEL,
+        on_delete=models.PROTECT,
+        null=True,
+        verbose_name=_('user'),
+    )
+
+    ip = models.GenericIPAddressField(
+        null=True,
+        blank=True,
+        verbose_name=_("IP Address")
+    )
+
+    model = models.ForeignKey(
+        ContentType,
+        on_delete=models.PROTECT,
+        null=False,
+        blank=False,
+        verbose_name=_('model'),
+    )
+
+    instance_pk = models.CharField(
+        max_length=255,
+        null=False,
+        blank=False,
+        verbose_name=_('identifier'),
+    )
+
+    previous = models.TextField(
+        blank=True,
+        default="",
+        verbose_name=_('previous data'),
+    )
+
+    data = models.TextField(
+        blank=True,
+        default="",
+        verbose_name=_('new data'),
+    )
+
+    action = models.CharField(  # create, edit or delete
+        max_length=16,
+        null=False,
+        blank=False,
+        choices=[
+            ('create', _('create')),
+            ('edit', _('edit')),
+            ('delete', _('delete')),
+        ],
+        default='edit',
+        verbose_name=_('action'),
+    )
+
+    timestamp = models.DateTimeField(
+        null=False,
+        blank=False,
+        default=timezone.now,
+        name='timestamp',
+        verbose_name=_('timestamp'),
+    )
+
+    def delete(self, using=None, keep_parents=False):
+        raise ValidationError(_("Logs cannot be destroyed."))
+
+    class Meta:
+        verbose_name = _("changelog")
+        verbose_name_plural = _("changelogs")
+
+    def __str__(self):
+        return _("Changelog of type \"{action}\" for model {model} at {timestamp}").format(
+            action=self.get_action_display(), model=str(self.model), timestamp=str(self.timestamp))

apps/logs/signals.py

@@ -0,0 +1,136 @@
+# Copyright (C) 2018-2020 by BDE ENS Paris-Saclay
+# SPDX-License-Identifier: GPL-3.0-or-later
+from django.contrib.auth.models import User
+from django.contrib.contenttypes.models import ContentType
+from rest_framework.renderers import JSONRenderer
+from rest_framework.serializers import ModelSerializer
+from corres2math.middlewares import get_current_authenticated_user, get_current_ip
+
+from .models import Changelog
+
+import getpass
+
+
+# Ces modèles ne nécessitent pas de logs
+EXCLUDED = [
+    'admin.logentry',
+    'authtoken.token',
+    'contenttypes.contenttype',
+    'logs.changelog',  # Never remove this line
+    'mailer.dontsendentry',
+    'mailer.message',
+    'mailer.messagelog',
+    'migrations.migration',
+    'sessions.session',
+]
+
+
+def pre_save_object(sender, instance, **kwargs):
+    """
+    Before a model get saved, we get the previous instance that is currently in the database
+    """
+    qs = sender.objects.filter(pk=instance.pk).all()
+    if qs.exists():
+        instance._previous = qs.get()
+    else:
+        instance._previous = None
+
+
+def save_object(sender, instance, **kwargs):
+    """
+    Each time a model is saved, an entry in the table `Changelog` is added in the database
+    in order to store each modification made
+    """
+    # noinspection PyProtectedMember
+    if instance._meta.label_lower in EXCLUDED or hasattr(instance, "_no_signal"):
+        return
+
+    # noinspection PyProtectedMember
+    previous = instance._previous
+
+    # Si un utilisateur est connecté, on récupère l'utilisateur courant ainsi que son adresse IP
+    user, ip = get_current_authenticated_user(), get_current_ip()
+
+    if user is None:
+        # Si la modification n'a pas été faite via le client Web, on suppose que c'est du à `manage.py`
+        # On récupère alors l'utilisateur·trice connecté·e à la VM, et on récupère la note associée
+        ip = "127.0.0.1"
+        username = getpass.getuser()
+        if User.objects.filter(username=username).exists():
+            user = User.objects.get(username=username)
+
+    # noinspection PyProtectedMember
+    if user is not None and instance._meta.label_lower == "auth.user" and previous:
+        # On n'enregistre pas les connexions
+        if instance.last_login != previous.last_login:
+            return
+
+    changed_fields = '__all__'
+    if previous:
+        # On ne garde que les champs modifiés
+        changed_fields = []
+        for field in instance._meta.fields:
+            if field.name.endswith("_ptr"):
+                # A field ending with _ptr is a OneToOneRel with a subclass, e.g. NoteClub.note_ptr -> Note
+                continue
+            if getattr(instance, field.name) != getattr(previous, field.name):
+                changed_fields.append(field.name)
+
+    if len(changed_fields) == 0:
+        # Pas de log s'il n'y a pas de modification
+        return
+
+    # On crée notre propre sérialiseur JSON pour pouvoir sauvegarder les modèles avec uniquement les champs modifiés
+    class CustomSerializer(ModelSerializer):
+        class Meta:
+            model = instance.__class__
+            fields = changed_fields
+
+    previous_json = JSONRenderer().render(CustomSerializer(previous).data).decode("UTF-8") if previous else ""
+    instance_json = JSONRenderer().render(CustomSerializer(instance).data).decode("UTF-8")
+
+    Changelog.objects.create(user=user,
+                             ip=ip,
+                             model=ContentType.objects.get_for_model(instance),
+                             instance_pk=instance.pk,
+                             previous=previous_json,
+                             data=instance_json,
+                             action=("edit" if previous else "create")
+                             ).save()
+
+
+def delete_object(sender, instance, **kwargs):
+    """
+    Each time a model is deleted, an entry in the table `Changelog` is added in the database
+    """
+    # noinspection PyProtectedMember
+    if instance._meta.label_lower in EXCLUDED or hasattr(instance, "_no_signal"):
+        return
+
+    # Si un utilisateur est connecté, on récupère l'utilisateur courant ainsi que son adresse IP
+    user, ip = get_current_authenticated_user(), get_current_ip()
+
+    if user is None:
+        # Si la modification n'a pas été faite via le client Web, on suppose que c'est du à `manage.py`
+        # On récupère alors l'utilisateur·trice connecté·e à la VM, et on récupère la note associée
+        ip = "127.0.0.1"
+        username = getpass.getuser()
+        if User.objects.filter(username=username).exists():
+            user = User.objects.get(username=username)
+
+    # On crée notre propre sérialiseur JSON pour pouvoir sauvegarder les modèles
+    class CustomSerializer(ModelSerializer):
+        class Meta:
+            model = instance.__class__
+            fields = '__all__'
+
+    instance_json = JSONRenderer().render(CustomSerializer(instance).data).decode("UTF-8")
+
+    Changelog.objects.create(user=user,
+                             ip=ip,
+                             model=ContentType.objects.get_for_model(instance),
+                             instance_pk=instance.pk,
+                             previous=instance_json,
+                             data="",
+                             action="delete"
+                             ).save()

corres2math/settings.py

@@ -54,6 +54,7 @@ INSTALLED_APPS = [
     'crispy_forms',
     'django_extensions',
     'django_tables2',
+    'logs',
     'mailer',
     'polymorphic',
     'rest_framework',