Django: Can I create a QueryDict from a dictionary?

Question

Imagine that I have a dictionary in my Django application:

dict = {'a': 'one', 'b': 'two', }

Now I want to easily create an urlencoded list of GET parameters from this dictionary. Of course I could loop through the dictionary, urlencode keys and values and then concatenate the string by myself, but there must be an easier way. I would like to use a QueryDict instance. QueryDict is a subclass of dict, so it should be possible somehow.

qdict = QueryDict(dict) # this does not actually work
print qdict.urlencode()

How would I make the second to last line work?

score 90 · Accepted Answer · edited Sep 18 '19 at 13:48

90

How about?

from django.http import QueryDict

ordinary_dict = {'a': 'one', 'b': 'two', }
query_dict = QueryDict('', mutable=True)
query_dict.update(ordinary_dict)

edited Sep 18 '19 at 13:48

valex

5,163
2
33
40

answered Nov 13 '12 at 15:34

miki725

27,207
17
105
121

Not according to the docs: https://docs.djangoproject.com/en/dev/ref/request-response/#django.http.QueryDict.update – miki725 Nov 13 '12 at 15:36
1

should be `qdict = QueryDict('')`, and then this indeed works. Thank you. – winsmith Nov 13 '12 at 15:36
1

Thanx. Did not know the other approach. Cool. – miki725 Nov 13 '12 at 15:41
8

Instead of copying, you can create a mutable QueryDict straight away: `QueryDict('', mutable=True)` – Ivan Ivanov May 25 '14 at 23:55
3

This option works incorrect with dictionary of lists. See @Arpit Singh answer. – valex Sep 18 '19 at 12:35

score 24 · Answer 2 · edited Jul 30 '18 at 07:56

24

Python has a built in tool for encoding a dictionary (any mapping object) into a query string

params = {'a': 'one', 'b': 'two', }

urllib.urlencode(params)

'a=one&b=two'

http://docs.python.org/2/library/urllib.html#urllib.urlencode

QueryDict takes a querystring as first param of its contstructor

def __init__(self, query_string, mutable=False, encoding=None):

q = QueryDict('a=1&b=2')

https://github.com/django/django/blob/master/django/http/request.py#L260

Update: in Python3, urlencode has moved to urllib.parse:

from urllib.parse import urlencode

params = {'a': 'one', 'b': 'two', }
urlencode(params)
'a=one&b=two'

edited Jul 30 '18 at 07:56

Mathieu Dhondt

8,405
5
37
58

answered Nov 13 '12 at 15:34

dm03514

54,664
18
108
145

1

m) it's so obvious in hindsight. – winsmith Nov 13 '12 at 15:35
Your answer is what I wanted, but not the exact answer for the question. Do you mind if accept the other answer, but create a new question where you can post this answer again? – winsmith Nov 15 '12 at 09:42
This works, but is a very inefficient round-trip to make! – Leon Matthews Oct 26 '21 at 22:39

score 16 · Answer 3 · edited Aug 04 '16 at 00:23

16

Actually a little indirect but more logical way to achieve this is using MultiValueDict. This way multiple values per key can be stored in a QueryDict and .getlist method should then work fine.

from django.http.request import QueryDict, MultiValueDict
dictionary = {'my_age': ['23'], 'my_girlfriend_age': ['25', '27'], }

qdict = QueryDict('', mutable=True)
qdict.update(MultiValueDict(dictionary))

print qdict.get('my_age')  # 23
print qdict['my_girlfriend_age']  # 27
print qdict.getlist('my_girlfriend_age')  # ['25', '27']

edited Aug 04 '16 at 00:23

Koterpillar

7,883
2
25
41

answered Jul 01 '15 at 16:11

Arpit Singh

3,387
2
17
11

2

Hm.. Unlike the others, which only handle single values, this one requires value to be lists (it breaks strings into a list of characters). Seems there's no simple way to handle both. – Izkata Jun 18 '18 at 18:05

score 5 · Answer 4 · answered Jul 19 '18 at 13:18

My solution works both for single and multiple key values:

def dict_to_querydict(dictionary):
    from django.http import QueryDict
    from django.utils.datastructures import MultiValueDict

    qdict = QueryDict('', mutable=True)

    for key, value in dictionary.items():
        d = {key: value}
        qdict.update(MultiValueDict(d) if isinstance(value, list) else d)

    return qdict

score 0 · Answer 5 · answered Oct 26 '21 at 22:45

I couldn't be much more late to the party, but I recently needed to do the same - but to preserve the read-only behaviour of a 'real' QueryDict from a response object.

Adapting the code from QueryDict.fromkeys() method gave a nice function:

from django.http import QueryDict

def querydict_from_dict(data: Dict[str, Any],  mutable=False) -> QueryDict:
    """
    Return a new QueryDict with keys (may be repeated) from an iterable and
    values from value.
    """
    q = QueryDict('', mutable=True)

    for key in data:
        q.appendlist(key, data[key])

    if not mutable:
        q._mutable = False

    return q

Django: Can I create a QueryDict from a dictionary?

5 Answers5

Linked