Django JSon响应格式，嵌套字段

Question

I just made an ajax request to a DJango View, it give me back the data, but i don't know how to get only the fields that i want.

This is the part of my view:

if request.method == 'POST':
        txt_codigo_producto = request.POST.get('codigobarras_producto') 
        response_data = {} 
            resp_producto=Producto.objects.all().filter(codigobarras_producto=txt_codigo_producto)
            resp_inventario=InventarioProducto.objects.all().filter(producto_codigo_producto__in=resp_producto).order_by('-idinventario_producto')[:1]
            resp_precio=Precio.objects.all().filter(producto_codigo_producto__in=resp_producto,estado_precio=1).order_by('-idprecio')[:1] #

            response_data['codprod']=serializers.serialize('json', list(resp_producto), fields=('codigo_producto')) 
            response_data['inventario']=serializers.serialize('json', list(resp_inventario), fields=('idinventario_producto'))
            response_data['nombre']=serializers.serialize('json', list(resp_producto), fields=('nombre_producto'))
            response_data['valorprod']=serializers.serialize('json', list(resp_precio), fields=('valor_precio'))

            return HttpResponse(
                json.dumps(response_data),
                content_type="application/json"
            )

"json" is the name of the array that I get as response from the view, I send it to the console, as this:

console.log(JSON.stringify(json));

And i get this:

{"codprod":"[{\"model\": \"myapp.producto\", \"fields\": {}, \"pk\": 1}]",
    "nombre":"[{\"model\": \"myapp.producto\", \"fields\": {\"nombre_producto\": \"Pantal\\u00f3n de lona \"}, \"pk\": 1}]",
    "valorprod":"[{\"model\": \"myapp.precio\", \"fields\": {\"valor_precio\": \"250.00\"}, \"pk\": 1}]",
    "inventario":"[{\"model\": \"myapp.inventarioproducto\", \"fields\": {}, \"pk\": 1}]"}

I tried this:

console.log(JSON.stringify(json.codprod));

With that I get this:

"[{\"model\": \"myapp.producto\", \"fields\": {}, \"pk\": 1}]" 

But if I try something like json.codprod.pk or json.codprod[0] or json.codprod["pk] I get undefined in the console.

I want to know how to acces to those fields, in "valorprod" I want the "valor_precio" value, so it must be "250.00", in "nombre" I want the value of "nombre_producto" it must be "Pantal\ón de lona".

Hope you can give me a hint. I think this is a JSON syntax problem, but I'm new with this.

---

Following Piyush S. Wanare and Roshan instructions, I have made some changes on the view:

    resp_producto=Producto.objects.filter(codigobarras_producto=txt_codigo_producto)
            resp_inventario=InventarioProducto.objects.filter(producto_codigo_producto__in=resp_producto).order_by('-idinventario_producto')[:1].only('idinventario_producto') 
            resp_precio=Precio.objects.filter(producto_codigo_producto__in=resp_producto,estado_precio=1).order_by('-idprecio')[:1].only('valor_precio') 
            resp_productonombre=Producto.objects.filter(codigobarras_producto=txt_codigo_producto).only('nombre_producto')
            resp_productocodigo=Producto.objects.filter(codigobarras_producto=txt_codigo_producto).only('codigo_producto')

            response_data = {'codprod': resp_productocodigo,'inventario':resp_inventario,'nombre':resp_productonombre,'valorprod':resp_precio}
    return HttpResponse(
            json.dumps(list(response_data)),
            content_type="application/json"
        )

But I get empty fields in the console:

["nombre","valorprod","codprod","inventario"]

---

Another edit, and the code that worked:

I used the views as they was at the beginning, with the double encoding, I just deleted the "codprod" part, but I wrote this on the ajax response code:

var res_valorprod=JSON.parse(json.valorprod);
var res_inventario=JSON.parse(json.inventario);
var res_nombre=JSON.parse(json.nombre);
var campos_valorprod =res_valorprod[0].fields;
var campos_nombre =res_nombre[0].fields;
console.log(res_nombre[0].pk);
console.log(campos_valorprod.valor_precio);
console.log(res_inventario[0].pk);
console.log(campos_nombre.nombre_producto);

This is working, I get what I want, but if you know something better to acces to the multiple nested JSON fields, I will be glad to know it. User dsgdfg gave me a hint.

Answer 1

You are doing multiple encoding, ie first you using serializers.serialize and then json.dumps.

Use only json.dumps and content_type as json like this, without using serializers.

response_dict = {'your_data_key': 'and your values'}
return HttpResponse(
                json.dumps(response_data),
                content_type="application/json"
            )

and then in client side you are not required to do JSON.stringify(json.codprod) .

As you sent content_type='application/json' , it parse response as json.

console.log(resp.your_data_key); #will print proper response yor data values.

Answer 2

Answer to your first question:- You can change your queries as follows:

resp_producto=Producto.objects.filter(codigobarras_producto=txt_codigo_producto).only('requiredField')
resp_inventario=InventarioProducto.objects.filter(producto_codigo_producto__in=resp_producto).only('requiredField').order_by('-idinventario_producto')[:1]
resp_precio=Precio.objects.filter(producto_codigo_producto__in=resp_producto,estado_precio=1).only('requiredField').order_by('-idprecio')[:1]

Then serialize it.

response_data['codprod']=serializers.serialize('json', list(resp_producto), fields=('codigo_producto')) 
            response_data['inventario']=serializers.serialize('json', list(resp_inventario), fields=('idinventario_producto'))
            response_data['nombre']=serializers.serialize('json', list(resp_producto), fields=('nombre_producto'))
            response_data['valorprod']=serializers.serialize('json', list(resp_precio), fields=('valor_precio'))

Suggestion:- It will be better if you create single {} by iterating through each required objects and create list [{},{}] rather than serializing it, and dump it as you have done like,

return HttpResponse(
                json.dumps(response_data),
                content_type="application/json"
            )

Then at FrontEnd you should use JSON.parse(responceData) for indexing over it.