extensions/signals.py

@@ -5,7 +5,6 @@ from django.dispatch import receiver
 import django.dispatch
 
 import extensions.models
-import extensions.tasks
 import files.models
 
 version_changed = django.dispatch.Signal()

files/migrations/0005_alter_filevalidation_validation.py

@@ -1,18 +0,0 @@
-# Generated by Django 4.2.11 on 2024-04-11 17:13
-
-from django.db import migrations, models
-
-
-class Migration(migrations.Migration):
-
-    dependencies = [
-        ('files', '0004_alter_file_status'),
-    ]
-
-    operations = [
-        migrations.AlterField(
-            model_name='filevalidation',
-            name='validation',
-            field=models.JSONField(),
-        ),
-    ]

files/migrations/0005_rename_validation_filevalidation_results_and_more.py

@@ -0,0 +1,35 @@
+# Generated by Django 4.2.11 on 2024-04-12 09:05
+
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('files', '0004_alter_file_status'),
+    ]
+
+    operations = [
+        migrations.RenameField(
+            model_name='filevalidation',
+            old_name='validation',
+            new_name='results',
+        ),
+        migrations.AlterField(
+            model_name='filevalidation',
+            name='results',
+            field=models.JSONField(),
+        ),
+        migrations.RemoveField(
+            model_name='filevalidation',
+            name='errors',
+        ),
+        migrations.RemoveField(
+            model_name='filevalidation',
+            name='notices',
+        ),
+        migrations.RemoveField(
+            model_name='filevalidation',
+            name='warnings',
+        ),
+    ]

files/models.py

@@ -1,14 +1,12 @@
 from pathlib import Path
 from typing import Dict, Any
 import logging
-import os.path
 
-from django.conf import settings
 from django.contrib.auth import get_user_model
 from django.db import models
 
 from common.model_mixins import CreatedModifiedMixin, TrackChangesMixin, SoftDeleteMixin
-from files.utils import get_sha256, guess_mimetype_from_ext, scan
+from files.utils import get_sha256, guess_mimetype_from_ext
 from constants.base import (
     FILE_STATUS_CHOICES,
     FILE_TYPE_CHOICES,
@@ -206,32 +204,10 @@ class File(CreatedModifiedMixin, TrackChangesMixin, SoftDeleteMixin, models.Mode
     def get_submit_url(self) -> str:
         return self.extension.get_draft_url()
 
-    def scan(self) -> 'FileValidation':
-        """Run a scanner on the source file and save its output as a FileValidation record."""
-        abs_path = os.path.join(settings.MEDIA_ROOT, self.source.path)
-        completed_process = scan(abs_path)
-        validation = {
-            'args': completed_process.args,
-            'stdout': completed_process.stdout.decode(),
-            'stderr': completed_process.stderr.decode(),
-            'returncode': completed_process.returncode,
-        }
-        file_validation, is_new = FileValidation.objects.get_or_create(
-            file=self, defaults={'validation': validation}
-        )
-        file_validation.is_valid = completed_process.returncode == 0
-        # FIXME: do we need `errors`/`warnings`/`notices` counters at all?
-        file_validation.errors = 1 if not file_validation.is_valid else 0
-        file_validation.save()
-        return file_validation
-
 
 class FileValidation(CreatedModifiedMixin, TrackChangesMixin, models.Model):
     track_changes_to_fields = {'is_valid', 'errors', 'warnings', 'notices', 'validation'}
 
     file = models.OneToOneField(File, related_name='validation', on_delete=models.CASCADE)
     is_valid = models.BooleanField(default=False)
-    errors = models.IntegerField(default=0)
-    warnings = models.IntegerField(default=0)
-    notices = models.IntegerField(default=0)
-    validation = models.JSONField()
+    results = models.JSONField()

files/signals.py

@@ -1,7 +1,12 @@
-from django.db.models.signals import pre_save
+import logging
+
+from django.db.models.signals import pre_save, post_save
 from django.dispatch import receiver
 
 import files.models
+import files.tasks
+
+logger = logging.getLogger(__name__)
 
 
 @receiver(pre_save, sender=files.models.File)
@@ -9,3 +14,14 @@ def _record_changes(sender: object, instance: files.models.File, **kwargs: objec
     was_changed, old_state = instance.pre_save_record()
 
     instance.record_status_change(was_changed, old_state, **kwargs)
+
+
+@receiver(post_save, sender=files.models.File)
+def _scan_new_file(
+    sender: object, instance: files.models.File, created: bool, **kwargs: object
+) -> None:
+    if not created:
+        return
+
+    logger.info('Initiating a scan for file pk=%s', instance.pk)
+    files.tasks.scan(file_id=instance.pk, creator=instance)

files/tasks.py

@@ -0,0 +1,26 @@
+import os.path
+
+from background_task import background
+from django.conf import settings
+
+import files.models
+import files.utils
+
+
+@background()
+def scan(file_id: int):
+    """Run a scan on a given file and save its output as a FileValidation record."""
+    file = files.models.File.objects.get(pk=file_id)
+    abs_path = os.path.join(settings.MEDIA_ROOT, file.source.path)
+    completed_process = files.utils.run_clamdscan(abs_path)
+    scan_result = {
+        'args': completed_process.args,
+        'stdout': completed_process.stdout.decode(),
+        'stderr': completed_process.stderr.decode(),
+        'returncode': completed_process.returncode,
+    }
+    file_validation, is_new = files.models.FileValidation.objects.get_or_create(
+        file=file, defaults={'results': {completed_process.args[0]: scan_result}}
+    )
+    file_validation.is_valid = completed_process.returncode == 0
+    file_validation.save()

files/tests/test_models.py

@@ -1,7 +1,11 @@
 import json
+import os
 import shutil
 import tempfile
+import unittest
 
+from background_task.models import Task
+from django.conf import settings
 from django.contrib.auth import get_user_model
 from django.test import TestCase, override_settings
 
@@ -9,6 +13,7 @@ from common.admin import get_admin_change_path
 from common.log_entries import entries_for
 from common.tests.factories.files import FileFactory
 from files.models import File
+import files.tasks
 
 User = get_user_model()
 
@@ -80,23 +85,64 @@ class FileTest(TestCase):
         self.assertEqual(response.status_code, 200, path)
 
 
-@override_settings(MEDIA_ROOT='./files/tests/files')
+@unittest.skipUnless(shutil.which('clamdscan'), 'requires clamdscan')
+@override_settings(MEDIA_ROOT='/tmp/')
 class FileScanTest(TestCase):
     def setUp(self):
         super().setUp()
-        self.temp_directory = tempfile.mkdtemp()
+        self.temp_directory = tempfile.mkdtemp(prefix=settings.MEDIA_ROOT)
 
     def tearDown(self):
         super().tearDown()
         shutil.rmtree(self.temp_directory)
 
-    def test_scan(self):
-        # TODO: write the test files on the fly
-        file = FileFactory(source='Win.Test.EICAR_HDB-1.zip')
+    def test_scan_flags_found_invalid(self):
+        test_file_path = os.path.join(self.temp_directory, 'test_file.zip')
+        test_content = (
+            b'X5O!P%@AP[4\PZX54(P^)7CC)7}$EICAR-STANDARD-ANTIVIRUS-TEST-FILE!$H+H*'  # noqa: W605
+        )
+        with open(test_file_path, 'wb+') as test_file:
+            test_file.write(test_content)
 
-        file_validation = file.scan()
+        file = FileFactory(source=test_file_path)
 
-        self.assertEqual(file_validation.validation['returncode'], 1)
-        stdout_lines = file_validation.validation['stdout'].split('\n')
+        # A background task should have been created
+        task = Task.objects.created_by(creator=file).first()
+        self.assertIsNotNone(task)
+        self.assertEqual(task.task_name, 'files.tasks.scan')
+        self.assertEqual(task.task_params, f'[[], {{"file_id": {file.pk}}}]')
+
+        # Actually run the task as if by background runner
+        task_args, task_kwargs = task.params()
+        files.tasks.scan.task_function(*task_args, **task_kwargs)
+
+        self.assertFalse(file.validation.is_valid)
+        result = file.validation.results['clamdscan']
+        self.assertEqual(result['returncode'], 1)
+        stdout_lines = result['stdout'].split('\n')
         self.assertIn(f'{file.source.name}: Win.Test.EICAR_HDB-1 FOUND', stdout_lines[0])
-        self.assertEqual(file_validation.validation['stderr'], '')
+        self.assertEqual(result['stderr'], '')
+
+    def test_scan_flags_nothing_found_valid(self):
+        test_file_path = os.path.join(self.temp_directory, 'test_file.zip')
+        with open(test_file_path, 'wb+') as test_file:
+            test_file.write(b'some file')
+
+        file = FileFactory(source=test_file_path)
+
+        # A background task should have been created
+        task = Task.objects.created_by(creator=file).first()
+        self.assertIsNotNone(task)
+        self.assertEqual(task.task_name, 'files.tasks.scan')
+        self.assertEqual(task.task_params, f'[[], {{"file_id": {file.pk}}}]')
+
+        # Actually run the task as if by background runner
+        task_args, task_kwargs = task.params()
+        files.tasks.scan.task_function(*task_args, **task_kwargs)
+
+        self.assertTrue(file.validation.is_valid)
+        result = file.validation.results['clamdscan']
+        self.assertEqual(result['returncode'], 0)
+        stdout_lines = result['stdout'].split('\n')
+        self.assertIn(f'{file.source.name}: OK', stdout_lines[0])
+        self.assertEqual(result['stderr'], '')

files/utils.py

@@ -165,7 +165,7 @@ def guess_mimetype_from_content(file_obj) -> str:
     return mimetype_from_bytes
 
 
-def scan(abs_path: str) -> 'subprocess.CompletedProcess':
+def run_clamdscan(abs_path: str) -> 'subprocess.CompletedProcess':
     scan_args = ['clamdscan', '--fdpass', abs_path]
     logger.info('Running %s', scan_args)
     return subprocess.run(scan_args, capture_output=True)