Creating a JSON response using Django and Python

Question

I'm trying to convert a server side Ajax response script into a Django HttpResponse, but apparently it's not working.

This is the server-side script:

/* RECEIVE VALUE */
$validateValue=$_POST['validateValue'];
$validateId=$_POST['validateId'];
$validateError=$_POST['validateError'];

/* RETURN VALUE */
$arrayToJs = array();
$arrayToJs[0] = $validateId;
$arrayToJs[1] = $validateError;

if($validateValue =="Testuser"){  // Validate??
    $arrayToJs[2] = "true";       // RETURN TRUE
    echo '{"jsonValidateReturn":'.json_encode($arrayToJs).'}';  // RETURN ARRAY WITH success
}
else{
    for($x=0;$x<1000000;$x++){
        if($x == 990000){
            $arrayToJs[2] = "false";
            echo '{"jsonValidateReturn":'.json_encode($arrayToJs).'}';   // RETURNS ARRAY WITH ERROR.
        }
    }
}

And this is the converted code

def validate_user(request):
    if request.method == 'POST':
        vld_value = request.POST.get('validateValue')
        vld_id = request.POST.get('validateId')
        vld_error = request.POST.get('validateError')

        array_to_js = [vld_id, vld_error, False]

        if vld_value == "TestUser":
            array_to_js[2] = True
            x = simplejson.dumps(array_to_js)
            return HttpResponse(x)
        else:
            array_to_js[2] = False
            x = simplejson.dumps(array_to_js)
            error = 'Error'
            return render_to_response('index.html',{'error':error},context_instance=RequestContext(request))
    return render_to_response('index.html',context_instance=RequestContext(request))

I'm using simplejson to encode the Python list (so it will return a JSON array). I couldn't figure out the problem yet. But I think that I did something wrong about the 'echo'.

Unconscious

You can also use the django-annoying view decorator @ajax_request. – Insignia

Answer 1

I usually use a dictionary, not a list to return JSON content.

import json

from django.http import HttpResponse

response_data = {}
response_data['result'] = 'error'
response_data['message'] = 'Some error message'

Pre-Django 1.7 you'd return it like this:

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

For Django 1.7+, use JsonResponse as shown in this SO answer like so :

from django.http import JsonResponse
return JsonResponse({'foo':'bar'})

Votyak

It is the mimetype, not the list that should be getting him into trouble. While most JSON is typically an object ("dictionary") at the top level, JSON is perfectly happy with an array at the top-level. – Lang

Sorry, it's not clear from what I wrote, but I only meant I use a dictionary because it's cleaner/ easier when serializing it to JSON. – Votyak

'application/json' is not properly supported in older versions of IE. Here is some discussion of the issue github.com/blueimp/jQuery-File-Upload/issues/123 – Sabatier

Answer 2

New in django 1.7

you could use JsonResponse objects.

from the docs:

from django.http import JsonResponse
return JsonResponse({'foo':'bar'})

Roughen

One downside: it defaults to ensure_ascii and I didn't find a way to override it yet. Created a new question for this: https://mcmap.net/q/74238/-creating-utf-8-jsonresponse-in-django/854477 – Milksop

@int_ua: just add json_dumps_params={"ensure_ascii": False} (requires Django 1.9 or newer) – Nomenclature

Answer 3

I use this, it works fine.

from django.utils import simplejson
from django.http import HttpResponse

def some_view(request):
    to_json = {
        "key1": "value1",
        "key2": "value2"
    }
    return HttpResponse(simplejson.dumps(to_json), mimetype='application/json')

Alternative:

from django.utils import simplejson

class JsonResponse(HttpResponse):
    """
        JSON response
    """
    def __init__(self, content, mimetype='application/json', status=None, content_type=None):
        super(JsonResponse, self).__init__(
            content=simplejson.dumps(content),
            mimetype=mimetype,
            status=status,
            content_type=content_type,
        )

In Django 1.7 JsonResponse objects have been added to the Django framework itself which makes this task even easier:

from django.http import JsonResponse
def some_view(request):
    return JsonResponse({"key": "value"})

Homicidal

The problem is here it's not getting the value from the input field vld_value = request.POST.get('validateValue') – Unconscious

With python 2.7, it should just be "import json" – Chiffon

I think from django.utils import simplejson is for backwards compatibility. – Suffer

JsonResponse(status=404, data={'status':'false','message':message}) – Vi

Answer 4

Since Django 1.7 you have a standard JsonResponse that's exactly what you need:

from django.http import JsonResponse
...
return JsonResponse(array_to_js, safe=False)

You don't even need to json.dump your array.

Der

Answer 5

With Django Class-based views you can write:

from django.views import View
from django.http import JsonResponse

class JsonView(View):
    def get(self, request):
        return JsonResponse({'some': 'data'})

and with Django-Rest-Framework you can write:

from rest_framework.views import APIView
from rest_framework.response import Response

class JsonView(APIView):
    def get(self, request):
        return Response({'some': 'data'})

Pelting

Answer 6

For those who use Django 1.7+

from django.http import JsonResponse

def your_view(request):
    json_object = {'key': "value"}
    return JsonResponse(json_object)

official docs

Decry

Answer 7

from django.http import HttpResponse
import json

class JsonResponse(HttpResponse):
    def __init__(self, content={}, mimetype=None, status=None,
             content_type='application/json'):
        super(JsonResponse, self).__init__(json.dumps(content), mimetype=mimetype,
                                           status=status, content_type=content_type)

And in the view:

resp_data = {'my_key': 'my value',}
return JsonResponse(resp_data)

Edith

Answer 8

You'll want to use the django serializer to help with unicode stuff:

from django.core import serializers

json_serializer = serializers.get_serializer("json")()
    response =  json_serializer.serialize(list, ensure_ascii=False, indent=2, use_natural_keys=True)
    return HttpResponse(response, mimetype="application/json")

Coincidence

This was my preferred version, but realized that it eats only Django QuerySets. – Imperturbable

Answer 9

Its very convenient with Django version 1.7 or higher as you have the JsonResponse class, which is a subclass of HttpResponse.

from django.http import JsonResponse
    def profile(request):
        data = {
            'name': 'Raghav',
            'location': 'India',
            'is_active': False,
            'count': 28
        }
        return JsonResponse(data)

For older versions of Django, you must use an HttpResponse object.

import json
from django.http import HttpResponse

def profile(request):
    data = {
        'name': 'Raghav',
        'location': 'India',
        'is_active': False,
        'count': 28
    }
    dump = json.dumps(data)
    return HttpResponse(dump, content_type='application/json')

Practicable

Extractly right! – Universality

Answer 10

How to use google app engine with ajax (json)?

Code Javascript with JQuery:

$.ajax({
    url: '/ajax',
    dataType : 'json',
    cache: false,
    success: function(data) {
        alert('Load was performed.'+data.ajax_resp);
    }
});

Code Python

class Ajax(webapp2.RequestHandler):
    def get(self):
        my_response = {'ajax_resp':'Hello, webapp World!'}
        datos = json.dumps(my_response)

        self.response.headers.add_header('content-type', 'application/json', charset='utf-8')
        self.response.out.write(datos)

Auctorial

Answer 11

First import this:

from django.http import HttpResponse

If you have the JSON already:

def your_method(request):
    your_json = [{'key1': value, 'key2': value}]
    return HttpResponse(your_json, 'application/json')

If you get the JSON from another HTTP request:

def your_method(request):
    response = request.get('https://www.example.com/get/json')
    return HttpResponse(response, 'application/json')

Attlee

Answer 12

This is my preferred version using a class based view. Simply subclass the basic View and override the get()-method.

import json

class MyJsonView(View):

    def get(self, *args, **kwargs):
        resp = {'my_key': 'my value',}
        return HttpResponse(json.dumps(resp), mimetype="application/json" )

Chicky

Answer 13

Django code views.py:

def view(request):
    if request.method == 'POST':
        print request.body
        data = request.body
        return HttpResponse(json.dumps(data))

HTML code view.html:

<!DOCTYPE html>
<html>
<head>
<script src="http://ajax.googleapis.com/ajax/libs/jquery/1.11.1/jquery.min.js"></script>
<script>
$(document).ready(function(){
    $("#mySelect").change(function(){
        selected = $("#mySelect option:selected").text()
        $.ajax({
            type: 'POST',
            dataType: 'json',
            contentType: 'application/json; charset=utf-8',
            url: '/view/',
            data: {
                    'fruit': selected
                  },
            success: function(result) {
                        document.write(result)
                    }
    });
  });
});
</script>
</head>
<body>

<form>
    {{data}}
    <br>
Select your favorite fruit:
<select id="mySelect">
  <option value="apple" selected >Select fruit</option>
  <option value="apple">Apple</option>
  <option value="orange">Orange</option>
  <option value="pineapple">Pineapple</option>
  <option value="banana">Banana</option>
</select>
</form>
</body>
</html>

Dyne

Answer 14

Most of these answers are out of date. JsonResponse is not recommended because it escapes the characters, which is usually undesired. Here's what I use:

views.py (returns HTML)

from django.shortcuts import render
from django.core import serializers

def your_view(request):
    data = serializers.serialize('json', YourModel.objects.all())
    context = {"data":data}
    return render(request, "your_view.html", context)

views.py (returns JSON)

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

def your_view(request):
    data = serializers.serialize('json', YourModel.objects.all())
    return HttpResponse(data, content_type='application/json')

Bonus for Vue Users

If you want to bring your Django Queryset into Vue, you can do the following.

template.html

<div id="dataJson" style="display:none">
{{ data }}
</div>

<script>
let dataParsed = JSON.parse(document.getElementById('dataJson').textContent);
var app = new Vue({
  el: '#app',
  data: {
    yourVariable: dataParsed,
  },
})
</script>

Jamisonjammal

Answer 15

This way the json contents can be downloaded as a file with a specific filename.

import json
from django.http import HttpResponse

def download_json(request):
    data = {'some': 'information'}

    # serialize data obj as a JSON stream 
    data = json.dumps(data)
    response = HttpResponse(data, content_type='application/json charset=utf-8')

    # add filename to response
    response['Content-Disposition'] = 'attachment; filename="filename.json"'
    return response

Cembalo

Answer 16

In View use this:

form.field.errors|striptags

for getting validation messages without html

Similar

Answer 17

def your_view(request):
    response = {'key': "value"}
    return JsonResponse(json.dumps(response), content_type="application/json",safe=False)

#Specify the content_type and use json.dump() son as the content not to be sent as object

Bookcase

If you call django.http.JsonResponse() you dont have to dump the content and the default content_type is already set to application/json – Wraith