Django - HttpResponse 2 query result in JSON format - json

Question

I have 2 query results from the database and try to return it in json format like this.
gt_buffer = ev_ground_truth.objects.filter(alg=_alg, exp=_exp,nFrame=_nframe)
dt_buffer = ev_detection.objects.filter(alg = _alg, exp=_exp, nFrame=_nframe)
json_gt_bb = serializers.serialize('json', gt_buffer)
json_dt_bb = serializers.serialize('json', dt_buffer)
dict_bb_buffer = {'gt': json_gt_bb, 'dt': json_dt_bb}
json_bb_buffer = json.dumps(dict_bb_buffer, ensure_ascii=False)
return HttpResponse(dict_bb_buffer, content_type = "application/json")
And at the front-end,
$.ajax({
url: '/results/get_nframebbs',
data: {
'exp':_exp,
'alg':_alg,
'nframe':data[i]['fields'].nFrame
},
dataType: 'json',
success: function (data) {
alert(data.length)
}
});
However the alert never be called. But if I just serialize 1 query result and return the alert is called successful with a popup.
gt_buffer = ev_ground_truth.objects.filter(alg=_alg, exp=_exp,nFrame=_nframe)
json_gt_bb = serializers.serialize('json', gt_buffer)
return HttpResponse(json_gt_bb, content_type = "application/json")
What did I do wrong?

Answer 1

You have the response as an argument in your success function, not the json data directly. you can access to your data like this:
success: function (response) {
var gt = response.responseJSON.gt;
}

Answer 2

Easy. Just return 2 query result as string and parse at the front-end.
gt_buffer = ev_ground_truth.objects.filter(alg=_alg, exp=_exp,nFrame=_nframe)
dt_buffer = ev_detection.objects.filter(alg = _alg, exp=_exp, nFrame=_nframe)
json_gt_bb = serializers.serialize('json', gt_buffer)
json_dt_bb = serializers.serialize('json', dt_buffer)
dict_bb_buffer = {'gt': json_gt_bb, 'dt': json_dt_bb}
return JsonResponse(dict_bb_buffer, status = 201)
and at the front-end:
dataType: 'json',
success: function (data) {
gt = JSON.parse(data.gt.substring(1,data.gt.length-1));
dt = JSON.parse(data.dt.substring(1,data.dt.length-1));
}