Parser for nested data for multipart/form, usable in any Python project or via the Django Rest Framework integration..
pip install nested-multipart-parserfrom nested_multipart_parser import NestedParser
options = {
"separator": "bracket"
}
def my_view():
# `options` is optional
parser = NestedParser(data, options)
if parser.is_valid():
validate_data = parser.validate_data
...
else:
print(parser.errors)you can define parser for all view in settings.py
REST_FRAMEWORK = {
"DEFAULT_PARSER_CLASSES": [
"nested_multipart_parser.drf.DrfNestedParser",
]
}or directly in your view
from nested_multipart_parser.drf import DrfNestedParser
...
class YourViewSet(viewsets.ViewSet):
parser_classes = (DrfNestedParser,)The parser takes the request data and transforms it into a Python dictionary.
example:
# input:
{
'title': 'title',
'date': "time",
'simple_object.my_key': 'title'
'simple_object.my_list[0]': True,
'langs[0].id': 666,
'langs[0].title': 'title',
'langs[0].description': 'description',
'langs[0].language': "language",
'langs[1].id': 4566,
'langs[1].title': 'title1',
'langs[1].description': 'description1',
'langs[1].language': "language1"
}
# result:
{
'title': 'title',
'date': "time",
'simple_object': {
'my_key': 'title',
'my_list': [
True
]
},
'langs': [
{
'id': 666,
'title': 'title',
'description': 'description',
'language': 'language'
},
{
'id': 4566,
'title': 'title1',
'description': 'description1',
'language': 'language1'
}
]
}Attributes whose sub‑keys are only numbers become Python lists:
data = {
'title[0]': 'my-value',
'title[1]': 'my-second-value'
}
output = {
'title': [
'my-value',
'my-second-value'
]
}Important notes
- Indices must be contiguous and start at 0.
- You cannot turn a primitive (int, bool, str) into a list later, e.g.
'title': 42,
'title[object]': 42 # ❌ invalidAttributes whose sub‑keys are not pure numbers become nested dictionaries:
data = {
'title.key0': 'my-value',
'title.key7': 'my-second-value'
}
output = {
'title': {
'key0': 'my-value',
'key7': 'my-second-value'
}
}Keys can be chained arbitrarily. Below are examples for each separator option:
| Separator | Example key | Meaning |
|---|---|---|
| mixed‑dot | the[0].chained.key[0].are.awesome[0][0] | List → object → list → object … |
| mixed | the[0]chained.key[0]are.awesome[0][0] | Same as mixed‑dot but without the dot after a list |
| bracket | the[0][chained][key][0][are][awesome][0][0] | Every sub‑key is wrapped in brackets |
| dot | the.0.chained.key.0.are.awesome.0.0 | Dots separate every level; numeric parts become lists |
Rules to keep in mind
- First key must exist – e.g. title[0] or just title.
- For mixed / mixed‑dot, [] denotes a list and . denotes an object.
- mixed‑dot behaves like mixed but inserts a dot when an object follows a list.
- For bracket, each sub‑key must be surrounded by brackets ([ ]).
- For bracket or dot, numeric sub‑keys become list elements; non‑numeric become objects.
- No spaces between separators.
- By default, duplicate keys are disallowed (see options).
- Empty structures are supported: Empty list → "article.authors[]": None → {"article": {"authors": []}} Empty dict → "article.": None → {"article": {}} (available with dot, mixed, mixed‑dot)
{
# Separator (default: 'mixed‑dot')
# mixed‑dot : article[0].title.authors[0] -> "john doe"
# mixed : article[0]title.authors[0] -> "john doe"
# bracket : article[0][title][authors][0] -> "john doe"
# dot : article.0.title.authors.0 -> "john doe"
'separator': 'bracket' | 'dot' | 'mixed' | 'mixed‑dot',
# Raise an exception when duplicate keys are encountered
# Example:
# {
# "article": 42,
# "article[title]": 42,
# }
'raise_duplicate': True, # default: True
# Override duplicate keys (requires raise_duplicate=False)
# Example:
# {
# "article": 42,
# "article[title]": 42,
# }
# Result:
# {
# "article": {
# "title": 42
# }
# }
'assign_duplicate': False, # default: False
}# settings.py
DRF_NESTED_MULTIPART_PARSER = {
"separator": "mixed‑dot",
"raise_duplicate": True,
"assign_duplicate": False,
# If True, the parser’s output is converted to a QueryDict;
# if False, a plain Python dict is returned.
"querydict": True,
}A companion multipart-object library exists to convert a JavaScript object into the flat, nested format expected by this parser.