serialize_according_to_widget (#472)

Co-authored-by: Сергей Юрченко <s.yurchenko@softpro.com>

constance/admin.py

@@ -202,11 +202,16 @@ class ConstanceAdmin(admin.ModelAdmin):
 
     def get_config_value(self, name, options, form, initial):
         default, help_text = options[0], options[1]
+        field_type = None
+        if len(options) == 3:
+            field_type = options[2]
         # First try to load the value from the actual backend
         value = initial.get(name)
         # Then if the returned value is None, get the default
         if value is None:
             value = getattr(config, name)
+
+        form_field = form[name]
         config_value = {
             'name': name,
             'default': localize(default),
@@ -214,12 +219,17 @@ class ConstanceAdmin(admin.ModelAdmin):
             'help_text': _(help_text),
             'value': localize(value),
             'modified': localize(value) != localize(default),
-            'form_field': form[name],
+            'form_field': form_field,
             'is_date': isinstance(default, date),
             'is_datetime': isinstance(default, datetime),
-            'is_checkbox': isinstance(form[name].field.widget, forms.CheckboxInput),
-            'is_file': isinstance(form[name].field.widget, forms.FileInput),
+            'is_checkbox': isinstance(form_field.field.widget, forms.CheckboxInput),
+            'is_file': isinstance(form_field.field.widget, forms.FileInput),
         }
+        if field_type and field_type in settings.ADDITIONAL_FIELDS:
+            serialized_default = form[name].field.prepare_value(default)
+            config_value['default'] = serialized_default
+            config_value['raw_default'] = serialized_default
+            config_value['value'] = form[name].field.prepare_value(value)
 
         return config_value
 

example/cheeseshop/fields.py

@@ -0,0 +1,24 @@
+import json
+from django.forms import fields, widgets
+
+
+class JsonField(fields.CharField):
+    widget = widgets.Textarea
+
+    def __init__(self, rows: int = 5, **kwargs):
+        self.rows = rows
+        super().__init__(**kwargs)
+
+    def widget_attrs(self, widget: widgets.Widget):
+        attrs = super().widget_attrs(widget)
+        attrs['rows'] = self.rows
+        return attrs
+
+    def to_python(self, value):
+        if value:
+            return json.loads(value)
+        else:
+            return {}
+
+    def prepare_value(self, value):
+        return json.dumps(value)

example/cheeseshop/settings.py

@@ -102,6 +102,7 @@ CONSTANCE_ADDITIONAL_FIELDS = {
         }
     ],
     'email': ('django.forms.fields.EmailField',),
+    'json_field': ['cheeseshop.fields.JsonField']
 }
 
 CONSTANCE_CONFIG = {
@@ -112,6 +113,11 @@ CONSTANCE_CONFIG = {
     'DATE_ESTABLISHED': (date(1972, 11, 30), "the shop's first opening"),
     'MY_SELECT_KEY': ('yes', 'select yes or no', 'yes_no_null_select'),
     'MULTILINE': ('Line one\nLine two', 'multiline string'),
+    'JSON_DATA': (
+        {'a': 1_000, 'b': 'test', 'max': 30_000_000},
+        'Some test data for json',
+        'json_field',
+    ),
 }
 
 CONSTANCE_BACKEND = 'constance.backends.database.DatabaseBackend'