Fixed #29522 -- Refactored the Deserializer functions to classes.

Co-authored-by: Emad Mokhtar <emad.mokhtar@veneficus.nl>

docs/topics/serialization.txt

@@ -347,6 +347,86 @@ again a mapping with the key being name of the field and the value the value:
 
 Referential fields are again represented by the PK or sequence of PKs.
 
+.. _custom-serialization-formats:
+
+Custom serialization formats
+----------------------------
+
+In addition to the default formats, you can create a custom serialization
+format.
+
+For example, let’s consider a csv serializer and deserializer. First, define a
+``Serializer`` and a ``Deserializer`` class. These can override existing
+serialization format classes:
+
+.. code-block:: python
+   :caption: ``path/to/custom_csv_serializer.py``
+
+    import csv
+
+    from django.apps import apps
+    from django.core import serializers
+    from django.core.serializers.base import DeserializationError
+
+
+    class Serializer(serializers.python.Serializer):
+        def get_dump_object(self, obj):
+            dumped_object = super().get_dump_object(obj)
+            row = [dumped_object["model"], str(dumped_object["pk"])]
+            row += [str(value) for value in dumped_object["fields"].values()]
+            return ",".join(row), dumped_object["model"]
+
+        def end_object(self, obj):
+            dumped_object_str, model = self.get_dump_object(obj)
+            if self.first:
+                fields = [field.name for field in apps.get_model(model)._meta.fields]
+                header = ",".join(fields)
+                self.stream.write(f"model,{header}\n")
+            self.stream.write(f"{dumped_object_str}\n")
+
+        def getvalue(self):
+            return super(serializers.python.Serializer, self).getvalue()
+
+
+    class Deserializer(serializers.python.Deserializer):
+        def __init__(self, stream_or_string, **options):
+            if isinstance(stream_or_string, bytes):
+                stream_or_string = stream_or_string.decode()
+            if isinstance(stream_or_string, str):
+                stream_or_string = stream_or_string.splitlines()
+            try:
+                objects = csv.DictReader(stream_or_string)
+            except Exception as exc:
+                raise DeserializationError() from exc
+            super().__init__(objects, **options)
+
+        def _handle_object(self, obj):
+            try:
+                model_fields = apps.get_model(obj["model"])._meta.fields
+                obj["fields"] = {
+                    field.name: obj[field.name]
+                    for field in model_fields
+                    if field.name in obj
+                }
+                yield from super()._handle_object(obj)
+            except (GeneratorExit, DeserializationError):
+                raise
+            except Exception as exc:
+                raise DeserializationError(f"Error deserializing object: {exc}") from exc
+
+Then add the module containing the serializer definitions to your
+:setting:`SERIALIZATION_MODULES` setting::
+
+    SERIALIZATION_MODULES = {
+        "csv": "path.to.custom_csv_serializer",
+        "json": "django.core.serializers.json",
+    }
+
+.. versionchanged:: 5.2
+
+    A ``Deserializer`` class definition was added to each of the provided
+    serialization formats.
+
 .. _topics-serialization-natural-keys:
 
 Natural keys