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.