datetime filter

src/documents/templating/filepath.py

@@ -2,10 +2,12 @@ import logging
 import os
 import re
 from collections.abc import Iterable
+from datetime import datetime
 from pathlib import PurePath
 
 import pathvalidate
 from django.utils import timezone
+from django.utils.dateparse import parse_date
 from jinja2 import StrictUndefined
 from jinja2 import Template
 from jinja2 import TemplateSyntaxError
@@ -90,6 +92,15 @@ def get_cf_value(
 _template_environment.filters["get_cf_value"] = get_cf_value
 
 
+def format_datetime(value: str | datetime, format: str) -> str:
+    if isinstance(value, str):
+        value = parse_date(value)
+    return value.strftime(format=format)
+
+
+_template_environment.filters["datetime"] = format_datetime
+
+
 def create_dummy_document():
     """
     Create a dummy Document instance with all possible fields filled

src/documents/tests/test_file_handling.py

@@ -1382,3 +1382,58 @@ class TestFilenameGeneration(DirectoriesMixin, TestCase):
                 generate_filename(doc_a),
                 "invoices/0.pdf",
             )
+
+    def test_datetime_filter(self):
+        """
+        GIVEN:
+            - Filename format with datetime filter
+        WHEN:
+            - Filepath for a document with this format is called
+        THEN:
+            - The datetime filter is rendered
+        """
+        doc_a = Document.objects.create(
+            title="Some Title",
+            created=timezone.make_aware(datetime.datetime(2020, 6, 25, 7, 36, 51, 153)),
+            added=timezone.make_aware(datetime.datetime(2024, 10, 1, 7, 36, 51, 153)),
+            mime_type="application/pdf",
+            pk=2,
+            checksum="2",
+            archive_serial_number=25,
+        )
+
+        CustomField.objects.create(
+            name="Invoice Date",
+            data_type=CustomField.FieldDataType.DATE,
+        )
+        CustomFieldInstance.objects.create(
+            document=doc_a,
+            field=CustomField.objects.get(name="Invoice Date"),
+            value_date=timezone.make_aware(
+                datetime.datetime(2024, 10, 1, 7, 36, 51, 153),
+            ),
+        )
+
+        with override_settings(
+            FILENAME_FORMAT="{{ created | datetime('%Y') }}/{{ title }}",
+        ):
+            self.assertEqual(
+                generate_filename(doc_a),
+                "2020/Some Title.pdf",
+            )
+
+        with override_settings(
+            FILENAME_FORMAT="{{ created | datetime('%Y-%m-%d') }}/{{ title }}",
+        ):
+            self.assertEqual(
+                generate_filename(doc_a),
+                "2020-06-25/Some Title.pdf",
+            )
+
+        with override_settings(
+            FILENAME_FORMAT="{{ custom_fields | get_cf_value('Invoice Date') | datetime('%Y-%m-%d') }}/{{ title }}",
+        ):
+            self.assertEqual(
+                generate_filename(doc_a),
+                "2024-10-01/Some Title.pdf",
+            )