why there is like Bunch of backslash in my JSON output

Question

I m trying to send model data as json using below code

Views.py

def autocomplete(request):
    model = NewCarModel.objects.only('car_model_new')
    print('model is',model)
   # users_list = list(model)
    posts_serialized = serializers.serialize('json', model)
    print('post is',posts_serialized)

    return JsonResponse(posts_serialized,safe=False)

models.py

class NewCarModel(models.Model):
    car_model_new = models.CharField(max_length=100, unique=True)

    def __str__(self):
        return self.car_model_new

output:

"[{\"model\": \"core.newcarmodel\", \"pk\": 1, \"fields\": {\"car_model_new\": \"swift\"}}, {\"model\": \"core.newcarmodel\", \"pk\": 2, \"fields\": {\"car_model_new\": \"wagonr\"}}, {\"model\": \"core.newcarmodel\", \"pk\": 3, \"fields\": {\"car_model_new\": \"baleno\"}}, {\"model\": \"core.newcarmodel\", \"pk\": 4, \"fields\": {\"car_model_new\": \"breeza\"}}, {\"model\": \"core.newcarmodel\", \"pk\": 5, \"fields\": {\"car_model_new\": \"spresso\"}}]"

why there is bunch of backslash in my JSON output and how i can remove them and Mozilla Firefox default JSON filter is also not working, neither i am able to extract data from it using java script(as i am able to extract data from some public API so there is no problem with extract code)

edit:

how I m trying to extract data after parsing JSON into variable myArr

const carModelsArr = myArr.data.map((d) => d.fields.car_model_new

edit 2: so solution of not able to extact is instead of

var myArr = JSON.parse(this.responseText);

used this:

var myArr = JSON.parse(JSON.parse(this.responseText));

and extract code is able to work

but still, doesn't solve backslash problem and I would like to avoid using DRF if possible

use `print("[{\"model\":)` and you will no see slashes. It is only information that `"` is inside `" "` and it is not end of string. — furas, Feb 24 '20 at 13:01
when i parse data in javascript ,they gone but i am unable to extract any data from it — Paritosh Yadav, Feb 24 '20 at 13:09
create minimal working code which show it. Or at least show JavaScript code — furas, Feb 24 '20 at 13:12

MaNKuR · Accepted Answer · 2020-02-25T07:15:38.823

5

I think serializer does this to enclose double quote " around the dict object while converting them to Json object. Possibly that dict object already have either key or value enclosed with same double quote ". Hence that backslash.

To get rid of that you have to use json.loads if using Python otherwise JSON.parse if using JS

Python3:

json.loads(response)

JS:

JSON.parse(data)

Edit

You are serializing the data twice hence that backslash and you're forced to use JSON.parse twice. Since you already serialized the response you can simply use HttpResponse or Response to return that serialized data.

Solution-1:

from django.http import HttpResponse
return HttpResponse(posts_serialized, content_type='application/json')

Solution-2:

from rest_framework.response import Response
return Response(posts_serialized, content_type='application/json')

edited Feb 25 '20 at 07:15

answered Feb 24 '20 at 13:00

MaNKuR

2,578
1
19
31

i tried JSON.parse(data) and giving same output as yours and tried to extract data but i am unable to extract any of data either its shows nothing or shows undefined – Paritosh Yadav Feb 24 '20 at 13:06
how you extract? – MaNKuR Feb 24 '20 at 13:18
after parsing in myArr vaiable```const carModelsArr = myArr.map((d) => d.fields.car_model_new)``` – Paritosh Yadav Feb 24 '20 at 13:21
Does `myArr` holds the correct value? If yes then check the `map` how can be used in the appropriate way. – MaNKuR Feb 25 '20 at 05:51
actually it's working now, I solve the extract problem by calling var myArr = ```JSON.parse(JSON.parse(this.responseText));``` i have to call parse two times – Paritosh Yadav Feb 25 '20 at 06:17
Glad to hear that. If my answer helped you in any way, you may accept it. – MaNKuR Feb 25 '20 at 06:50
plan to do so but I will wait till evening – Paritosh Yadav Feb 25 '20 at 06:53
You require `JSON.parse` twice because you are serializing the response twice. Replace `return Json...` with `return HttpResponse(posts_serialized, mimetype='application/json')`. Should work – MaNKuR Feb 25 '20 at 06:58
got error: __init__() got an unexpected keyword argument 'mimetype' – Paritosh Yadav Feb 25 '20 at 07:06
1

its should be content_type instead of mimetype – Paritosh Yadav Feb 25 '20 at 07:08
and its working, can you re-edit your answer with this – Paritosh Yadav Feb 25 '20 at 07:09
You may try using `Response` instread. `from rest_framework.response import Response`. https://www.django-rest-framework.org/api-guide/responses/ – MaNKuR Feb 25 '20 at 07:10
as I edit in my question, I would like to avoid DRF if possible and your answer is satisfying – Paritosh Yadav Feb 25 '20 at 07:12

Teddy Markov · Answer 2 · 2020-02-24T13:24:12.497

2

It's because of JsonResponse. As you can see in the documentation od JsonResponse it expects a dictionary and you already created a JSON string. I assume that due to the fact that you said safe=False it accepted the string.

I suggest replacing it with the DRF Response or parsing it from a Query to a Python dict. (I would prefer the DRF Response option).

For more info, please check out the docs in the links.

Note: I have not run the code myself - it is my assumption.

edited Feb 24 '20 at 13:24

answered Feb 24 '20 at 13:18

Teddy Markov

266
3
15

As you can see i commented the code where tried to parse it in list first but it causing error, i will look into DRF Response if it give better result or not – Paritosh Yadav Feb 24 '20 at 13:25
In order to use JsonResponse you need not to serialize, which turns the data into a JSON, but parse it directly to a dict. Like it is said here. https://stackoverflow.com/questions/21925671/convert-django-model-object-to-dict-with-all-of-the-fields-intact In your case, by running `posts_serialized = serializers.serialize('json', model)` you make it a JSON - which is the more correct way of handling it in my opinion.I would just advise to keep using DRF and return the Response object I suggested. – Teddy Markov Feb 24 '20 at 13:31

why there is like Bunch of backslash in my JSON output

2 Answers2

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