Django Admin Decimal Serialization Error

The error you're encountering is related to Django's inability to serialize the decimal.Decimal object in your admin interface. This typically happens when Django tries to store form data in the session, which requires serialization.

Solution Options

1. Convert Decimal to Float in Admin Form

Create a custom form for your admin that converts the Decimal field to a float before saving:

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from django import forms

class ResponseAdminForm(forms.ModelForm):
    class Meta:
        model = Response
        fields = '__all__'
    
    def clean_alpha_score(self):
        # Convert Decimal to float for serialization
        alpha_score = self.cleaned_data.get('alpha_score')
        if alpha_score is not None:
            return float(alpha_score)
        return alpha_score

class ResponseAdmin(admin.ModelAdmin):
    form = ResponseAdminForm
    search_fields = ('post__title', 'response')
    list_display = ('post', 'response', 'created_at', 'scheduled_release', 
                   'delivered', 'abandoned', 'alpha_score')

2. Use a Custom JSON Encoder

If the issue is related to JSON serialization, you can define a custom JSON encoder in your settings:

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# In settings.py
SESSION_SERIALIZER = 'django.contrib.sessions.serializers.JSONSerializer'

# Define a custom JSON encoder
import json
from decimal import Decimal

class DecimalEncoder(json.JSONEncoder):
    def default(self, obj):
        if isinstance(obj, Decimal):
            return float(obj)
        return super(DecimalEncoder, self).default(obj)

# Use this encoder in your Django REST Framework settings if applicable
REST_FRAMEWORK = {
    'DEFAULT_RENDERER_CLASSES': (
        'rest_framework.renderers.JSONRenderer',
    ),
    'DEFAULT_PARSER_CLASSES': (
        'rest_framework.parsers.JSONParser',
    ),
    'JSON_ENCODER': 'your_app.settings.DecimalEncoder',
}

3. Override the Admin's Save Method

Another approach is to override the admin's save method:

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class ResponseAdmin(admin.ModelAdmin):
    search_fields = ('post__title', 'response')
    list_display = ('post', 'response', 'created_at', 'scheduled_release', 
                   'delivered', 'abandoned', 'alpha_score')
    
    def save_model(self, request, obj, form, change):
        # Convert Decimal to float before saving if needed
        if obj.alpha_score is not None:
            obj.alpha_score = float(obj.alpha_score)
        super().save_model(request, obj, form, change)

Try implementing one of these solutions based on your specific setup. The first option (custom form) is usually the most straightforward approach for Django admin-specific serialization issues.