From d4f99c272963766e4accc2e747bb99c1e6641bc8 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Ho=C3=A0ng=20Qu=E1=BB=91c=20H=C6=B0ng?=
 <40592382+hoangquochung1110@users.noreply.github.com>
Date: Mon, 4 Nov 2024 20:39:25 +0700
Subject: [PATCH] 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            |  1 +
 auditlog/conf.py        |  5 +++++
 auditlog/models.py      |  6 +++---
 auditlog_tests/tests.py | 31 +++++++++++++++++++++++++++++++
 docs/source/usage.rst   | 10 ++++++++++
 5 files changed, 50 insertions(+), 3 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index d2f3b43..ebd95d7 100644
--- a/CHANGELOG.md
+++ b/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))
 
diff --git a/auditlog/conf.py b/auditlog/conf.py
index dbdfc5b..fe347cc 100644
--- a/auditlog/conf.py
+++ b/auditlog/conf.py
@@ -45,3 +45,8 @@ settings.AUDITLOG_USE_TEXT_CHANGES_IF_JSON_IS_NOT_PRESENT = getattr(
 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
+)
diff --git a/auditlog/models.py b/auditlog/models.py
index 3d10633..49e7aba 100644
--- a/auditlog/models.py
+++ b/auditlog/models.py
@@ -506,9 +506,9 @@ class LogEntry(models.Model):
                     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)
 
diff --git a/auditlog_tests/tests.py b/auditlog_tests/tests.py
index 8f8b825..d94db9f 100644
--- a/auditlog_tests/tests.py
+++ b/auditlog_tests/tests.py
@@ -1561,6 +1561,37 @@ class CharFieldTextFieldModelTest(TestCase):
             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__"
diff --git a/docs/source/usage.rst b/docs/source/usage.rst
index 843c189..0c79a56 100644
--- a/docs/source/usage.rst
+++ b/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
 ------