admin_v2.py

import tempfile

from django.contrib import admin
from django.core import serializers
from django.http import HttpResponse

from example_app.models import *


@admin.action(description="Export Model")
def export_model(modeladmin, request, queryset):
    # Initialize temporary file so we can write on it during the iteration
    model_file = tempfile.TemporaryFile()
    with model_file as tmp_file:
    
        # Apply serialization
        serialized_objects = serializers.serialize(
            "json", queryset
        )
        
        # Write in file
        tmp_file.write(serialized_objects.encode("utf-8"))
        
        # Go to the beggining of the file
        tmp_file.seek(0)
        
        response = HttpResponse(tmp_file.read(), content_type="application/json")
        response["Content-Disposition"] = "attachment; filename=model.json"
        return response


class PersonAdmin(admin.ModelAdmin):
    actions = [export_model]


admin.site.register(Person, PersonAdmin)