Add AUDITLOG_TRUNCATE_CHANGES_DISPLAY and AUDITLOG_TRUNCATE_LIMIT (#684)

* Add AUDITLOG_TRUNCATE_CHANGES_DISPLAY and AUDITLOG_TRUNCATE_LIMIT

To configure how many characters will be truncated or disable it

* Add AUDITLOG_CHANGE_DISPLAY_TRUNCATE_LENGTH settings

to keep or truncate strings of `changes_display_dict` property at a variable length

CHANGELOG.md

@@ -6,6 +6,7 @@
 
 - feat: Added `LogEntry.remote_port` field. ([#671](https://github.com/jazzband/django-auditlog/pull/671))
 - feat: Added `truncate` option to `auditlogflush` management command. ([#681](https://github.com/jazzband/django-auditlog/pull/681))
+- feat: Added `AUDITLOG_CHANGE_DISPLAY_TRUNCATE_LENGTH` settings to keep or truncate strings of `changes_display_dict` property at variable length. ([#684](https://github.com/jazzband/django-auditlog/pull/684))
 - Drop Python 3.8 support. ([#678](https://github.com/jazzband/django-auditlog/pull/678))
 - Confirm Django 5.1 support and drop Django 3.2 support. ([#677](https://github.com/jazzband/django-auditlog/pull/677))
 

auditlog/conf.py

@@ -45,3 +45,8 @@
 settings.AUDITLOG_DISABLE_REMOTE_ADDR = getattr(
     settings, "AUDITLOG_DISABLE_REMOTE_ADDR", False
 )
+
+# Number of characters at which changes_display_dict property should be shown
+settings.AUDITLOG_CHANGE_DISPLAY_TRUNCATE_LENGTH = getattr(
+    settings, "AUDITLOG_CHANGE_DISPLAY_TRUNCATE_LENGTH", 140
+)

auditlog/models.py

@@ -506,9 +506,9 @@ def changes_display_dict(self):
                     elif field_type in ["ForeignKey", "OneToOneField"]:
                         value = self._get_changes_display_for_fk_field(field, value)
 
-                    # check if length is longer than 140 and truncate with ellipsis
-                    if len(value) > 140:
-                        value = f"{value[:140]}..."
+                    truncate_at = settings.AUDITLOG_CHANGE_DISPLAY_TRUNCATE_LENGTH
+                    if 0 <= truncate_at < len(value):
+                        value = value[:truncate_at] + ("..." if truncate_at > 0 else "")
 
                     values_display.append(value)
 

auditlog_tests/tests.py

@@ -1561,6 +1561,37 @@ def test_changes_display_dict_longtextfield(self):
             msg="The field should display the entire string because it is less than 140 characters",
         )
 
+    def test_changes_display_dict_longtextfield_to_be_truncated_at_custom_length(self):
+        with override_settings(AUDITLOG_CHANGE_DISPLAY_TRUNCATE_LENGTH=10):
+            length = settings.AUDITLOG_CHANGE_DISPLAY_TRUNCATE_LENGTH
+            self.assertEqual(
+                self.obj.history.latest().changes_display_dict["longtextfield"][1],
+                f"{self.PLACEHOLDER_LONGCHAR[:length]}...",
+                msg=f"The string should be truncated at {length} characters with an ellipsis at the end.",
+            )
+
+    def test_changes_display_dict_longtextfield_to_be_truncated_to_empty_string(self):
+        with override_settings(AUDITLOG_CHANGE_DISPLAY_TRUNCATE_LENGTH=0):
+            length = settings.AUDITLOG_CHANGE_DISPLAY_TRUNCATE_LENGTH
+            self.assertEqual(
+                self.obj.history.latest().changes_display_dict["longtextfield"][1],
+                "",
+                msg=f"The string should be empty as AUDITLOG_TRUNCATE_CHANGES_DISPLAY is set to {length}.",
+            )
+
+    def test_changes_display_dict_longtextfield_with_truncation_disabled(self):
+        with override_settings(AUDITLOG_CHANGE_DISPLAY_TRUNCATE_LENGTH=-1):
+            length = settings.AUDITLOG_CHANGE_DISPLAY_TRUNCATE_LENGTH
+            self.assertEqual(
+                self.obj.history.latest().changes_display_dict["longtextfield"][1],
+                self.PLACEHOLDER_LONGTEXTFIELD,
+                msg=(
+                    "The field should display the entire string "
+                    f"even though it is longer than {length} characters"
+                    "as AUDITLOG_TRUNCATE_CHANGES_DISPLAY is set to a negative number"
+                ),
+            )
+
 
 class PostgresArrayFieldModelTest(TestCase):
     databases = "__all__"

docs/source/usage.rst

@@ -305,6 +305,16 @@ If the value is `None`, the default getter will be used.
 
 .. versionadded:: 3.0.0
 
+**AUDITLOG_CHANGE_DISPLAY_TRUNCATE_LENGTH**
+
+This configuration variable defines the truncation behavior for strings in `changes_display_dict`, with a default value of `140` characters.
+
+0: The entire string is truncated, resulting in an empty output.
+Positive values (e.g., 5): Truncates the string, keeping only the specified number of characters followed by an ellipsis (...) after the limit.
+Negative values: No truncation occurs, and the full string is displayed.
+
+.. versionadded:: 3.1.0
+
 Actors
 ------