Fixed #25995 -- Added an encoder option to JSONField

Thanks Berker Peksag and Tim Graham for the reviews.

1 files changed, 28 insertions, 2 deletions

diff --git a/django/contrib/postgres/fields/jsonb.py b/django/contrib/postgres/fields/jsonb.py
index ae83d9e379..e333f30619 100644
--- a/django/contrib/postgres/fields/jsonb.py
+++ b/django/contrib/postgres/fields/jsonb.py
@@ -10,6 +10,19 @@ from django.utils.translation import ugettext_lazy as _
 __all__ = ['JSONField']
 
 
+class JsonAdapter(Json):
+    """
+    Customized psycopg2.extras.Json to allow for a custom encoder.
+    """
+    def __init__(self, adapted, dumps=None, encoder=None):
+        self.encoder = encoder
+        super(JsonAdapter, self).__init__(adapted, dumps=dumps)
+
+    def dumps(self, obj):
+        options = {'cls': self.encoder} if self.encoder else {}
+        return json.dumps(obj, **options)
+
+
 class JSONField(Field):
     empty_strings_allowed = False
     description = _('A JSON object')
@@ -17,9 +30,21 @@ class JSONField(Field):
         'invalid': _("Value must be valid JSON."),
     }
 
+    def __init__(self, verbose_name=None, name=None, encoder=None, **kwargs):
+        if encoder and not callable(encoder):
+            raise ValueError("The encoder parameter must be a callable object.")
+        self.encoder = encoder
+        super(JSONField, self).__init__(verbose_name, name, **kwargs)
+
     def db_type(self, connection):
         return 'jsonb'
 
+    def deconstruct(self):
+        name, path, args, kwargs = super(JSONField, self).deconstruct()
+        if self.encoder is not None:
+            kwargs['encoder'] = self.encoder
+        return name, path, args, kwargs
+
     def get_transform(self, name):
         transform = super(JSONField, self).get_transform(name)
         if transform:
@@ -28,13 +53,14 @@ class JSONField(Field):
 
     def get_prep_value(self, value):
         if value is not None:
-            return Json(value)
+            return JsonAdapter(value, encoder=self.encoder)
         return value
 
     def validate(self, value, model_instance):
         super(JSONField, self).validate(value, model_instance)
+        options = {'cls': self.encoder} if self.encoder else {}
         try:
-            json.dumps(value)
+            json.dumps(value, **options)
         except TypeError:
             raise exceptions.ValidationError(
                 self.error_messages['invalid'],