mirror of
https://github.com/encode/django-rest-framework.git
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73 lines
2.6 KiB
Python
73 lines
2.6 KiB
Python
"""
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..
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>>> from djangorestframework.parsers import FormParser
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>>> from djangorestframework.resource import Resource
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>>> from djangorestframework.compat import RequestFactory
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>>> from urllib import urlencode
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>>> req = RequestFactory().get('/')
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>>> some_resource = Resource()
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>>> trash = some_resource.dispatch(req)# Some variables are set only when calling dispatch
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Data flatening
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----------------
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Here is some example data, which would eventually be sent along with a post request :
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>>> inpt = urlencode([
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... ('key1', 'bla1'),
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... ('key2', 'blo1'), ('key2', 'blo2'),
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... ])
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Default behaviour for :class:`parsers.FormParser`, is to return a single value for each parameter :
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>>> FormParser(some_resource).parse(inpt) == {'key1': 'bla1', 'key2': 'blo1'}
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True
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However, you can customize this behaviour by subclassing :class:`parsers.FormParser`, and overriding :meth:`parsers.FormParser.is_a_list` :
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>>> class MyFormParser(FormParser):
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...
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... def is_a_list(self, key, val_list):
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... return len(val_list) > 1
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This new parser only flattens the lists of parameters that contain a single value.
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>>> MyFormParser(some_resource).parse(inpt) == {'key1': 'bla1', 'key2': ['blo1', 'blo2']}
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True
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Submitting an empty list
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--------------------------
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When submitting an empty select multiple, like this one ::
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<select multiple="multiple" name="key2"></select>
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The browsers usually strip the parameter completely. A hack to avoid this, and therefore being able to submit an empty select multiple, is to submit a value that tells the server that the list is empty ::
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<select multiple="multiple" name="key2"><option value="_empty"></select>
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:class:`parsers.FormParser` provides the server-side implementation for this hack. Considering the following posted data :
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>>> inpt = urlencode([
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... ('key1', 'blo1'), ('key1', '_empty'),
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... ('key2', '_empty'),
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... ])
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:class:`parsers.FormParser` strips the values ``_empty`` from all the lists.
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>>> MyFormParser(some_resource).parse(inpt) == {'key1': 'blo1'}
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True
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Oh ... but wait a second, the parameter ``key2`` isn't even supposed to be a list, so the parser just stripped it.
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>>> class MyFormParser(FormParser):
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...
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... def is_a_list(self, key, val_list):
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... return key == 'key2'
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...
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>>> MyFormParser(some_resource).parse(inpt) == {'key1': 'blo1', 'key2': []}
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True
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Better like that. Note also that you can configure something else than ``_empty`` for the empty value by setting :class:`parsers.FormParser.EMPTY_VALUE`.
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"""
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