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How do I pass a composite JSON structure via AJAX call from JS and on the server side, read it as a "very similar" data structure in python?

I understand that json formatting can be used (simplejson etc), but I somehow feel that the QueryDict itself is malformed or reformatted in my case?

Example:

When passing an array of JSON objects [{"id": 1},{"id": 2},{"id": 3}] via AJAX to Django view, the QueryDict gets formatted as:

POST:<QueryDict: {u'json_data[0][id]': [u'1'], u'type': [u'clone'], 
u'csrfmiddlewaretoken': [u'69bb3c434ced31ab301ede04bf491ec0'], 
u'json_data[1][id]': [u'2'], u'json_data[2][id]': [u'3']}>

How do I even iterate through the json_data?

I want to get something like this instead:

POST:<QueryDict: {u'json_data': [{u'id': [u'1']}, {u'id': [u'2']}, {u'id': [u'3']}]},
u'csrfmiddlewaretoken': [u'69bb3c434ced31ab301ede04bf491ec0'], u'type': [u'clone']>

So that I can access QueryDict as a dictionary and retrieve json_data as a list and process it in a certain order: maybe just iterate through them in sequential list order. Something like:

ret = request.POST
for item in ret['json_data']:
    process(item['id'])

In fact the value that goes into process() could be another dictionary of key value pairs instead of just a number (1,2,3 etc)

Javascript:

var test = [{"id": 1},{"id": 2},{"id": 3}];
$.post(
    "/insert_tc",
    {
      json_data: test,
      "type": 'clone',
      "csrfmiddlewaretoken": $csrf_token
    },  
    function(json) {
        //CALLBACK
    },
    "json"
);  

views.py:

def insert_tc(request):
    if request.method == 'POST':       
    ret = request.POST
    type = ret['type']
    list = ret.getlist(ret)

But list returns empty []

I tried simplejson dumps, loads, items, get methods but none of them helped.

I even tried jQuery.param( obj, true ), but that's not what I want (although somewhat close).

Is there a different/better way to pass composite data structures back and forth Django <-> JS via AJAX?

How do I pass a composite JSON structure via AJAX call from JS and on the server side, read it as a "very similar" data structure in python?

I understand that json formatting can be used (simplejson etc), but I somehow feel that the QueryDict itself is malformed or reformatted in my case?

Example:

When passing an array of JSON objects [{"id": 1},{"id": 2},{"id": 3}] via AJAX to Django view, the QueryDict gets formatted as:

POST:<QueryDict: {u'json_data[0][id]': [u'1'], u'type': [u'clone'], 
u'csrfmiddlewaretoken': [u'69bb3c434ced31ab301ede04bf491ec0'], 
u'json_data[1][id]': [u'2'], u'json_data[2][id]': [u'3']}>

How do I even iterate through the json_data?

I want to get something like this instead:

POST:<QueryDict: {u'json_data': [{u'id': [u'1']}, {u'id': [u'2']}, {u'id': [u'3']}]},
u'csrfmiddlewaretoken': [u'69bb3c434ced31ab301ede04bf491ec0'], u'type': [u'clone']>

So that I can access QueryDict as a dictionary and retrieve json_data as a list and process it in a certain order: maybe just iterate through them in sequential list order. Something like:

ret = request.POST
for item in ret['json_data']:
    process(item['id'])

In fact the value that goes into process() could be another dictionary of key value pairs instead of just a number (1,2,3 etc)

Javascript:

var test = [{"id": 1},{"id": 2},{"id": 3}];
$.post(
    "/insert_tc",
    {
      json_data: test,
      "type": 'clone',
      "csrfmiddlewaretoken": $csrf_token
    },  
    function(json) {
        //CALLBACK
    },
    "json"
);  

views.py:

def insert_tc(request):
    if request.method == 'POST':       
    ret = request.POST
    type = ret['type']
    list = ret.getlist(ret)

But list returns empty []

I tried simplejson dumps, loads, items, get methods but none of them helped.

I even tried jQuery.param( obj, true ), but that's not what I want (although somewhat close).

Is there a different/better way to pass composite data structures back and forth Django <-> JS via AJAX?

• javascript
• ajax
• django
• request
• http-request

Share Improve this question Follow asked Apr 5, 2012 at 20:36 rajivRajarajivRaja 53733 gold badges66 silver badges1616 bronze badges 3

• Something is definitely wrong, because the code as posted would definitely not give that QueryDict result. Please can you post the exact code that outputs that? – Daniel Roseman Commented Apr 5, 2012 at 21:03
• I'm afraid the JS code is accurate. I copy pasted both JS snippet and output of print request from views.py with minor formatting. 'test' is the array of objects that I'm passing. – rajivRaja Commented Apr 5, 2012 at 21:41
• Sorry, my mistake. See my answer below. – Daniel Roseman Commented Apr 5, 2012 at 22:08

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2 Answers 2

Sorted by: Reset to default 14

You should stringify your JSON using JSON.stringify(). This will convert the JSON Object into string format so it can be parsed correctly on the other end. On the other end you will need to use json.loads() to "unstringify" the object.

javascript:

var test = [{"id": 1},{"id": 2},{"id": 3}];
$.post(
    "/insert_tc",
    {
      json_data: JSON.stringify(test),
      "type": 'clone',
      "csrfmiddlewaretoken": $csrf_token
    },  
    function(json) {
        //CALLBACK
    },
    "json"
);  

View:

import json
def insert_tc(request):
    if request.method == 'POST':       
        ret = request.POST
        type = ret['type']
        list = json.loads(ret['json_data'])

This is actually jQuery, not Django, being strange. Your test variable does not contain JSON, but actual JS objects. jQuery, for reasons best known to itself, parses this into some very weird format before posting, hence the result you get. If you did this instead (note the quotes around the whole thing):

var test = '[{"id": 1},{"id": 2},{"id": 3}]';

you'd find you get very nearly the QueryDict you expect: the only thing you then need to do is to call json.loads(ret['json_data']).

Also for reasons that I can't understand. jQuery doesn't contain any functionality to convert your array of objects to JSON. You'll need to find a plugin or separate library for that.

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