django-rest-framework/rest_framework/parsers.py

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"""
Parsers are used to parse the content of incoming HTTP requests.
They give us a generic way of being able to handle various media types
on the request, such as form content or json encoded data.
"""
from __future__ import unicode_literals
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from django.conf import settings
from django.http import QueryDict
from django.http.multipartparser import MultiPartParser as DjangoMultiPartParser
from django.http.multipartparser import MultiPartParserError
from rest_framework.compat import yaml, etree
from rest_framework.exceptions import ParseError
from rest_framework.compat import six
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import json
import datetime
import decimal
class DataAndFiles(object):
def __init__(self, data, files):
self.data = data
self.files = files
class BaseParser(object):
"""
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All parsers should extend `BaseParser`, specifying a `media_type`
attribute, and overriding the `.parse()` method.
"""
media_type = None
def parse(self, stream, media_type=None, parser_context=None):
"""
Given a stream to read from, return the parsed representation.
Should return parsed data, or a `DataAndFiles` object consisting of the
parsed data and files.
"""
raise NotImplementedError(".parse() must be overridden.")
class JSONParser(BaseParser):
"""
Parses JSON-serialized data.
"""
media_type = 'application/json'
def parse(self, stream, media_type=None, parser_context=None):
"""
Returns a 2-tuple of `(data, files)`.
`data` will be an object which is the parsed content of the response.
`files` will always be `None`.
"""
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parser_context = parser_context or {}
encoding = parser_context.get('encoding', settings.DEFAULT_CHARSET)
try:
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data = stream.read().decode(encoding)
return json.loads(data)
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except ValueError as exc:
raise ParseError('JSON parse error - %s' % six.text_type(exc))
class YAMLParser(BaseParser):
"""
Parses YAML-serialized data.
"""
media_type = 'application/yaml'
def parse(self, stream, media_type=None, parser_context=None):
"""
Returns a 2-tuple of `(data, files)`.
`data` will be an object which is the parsed content of the response.
`files` will always be `None`.
"""
assert yaml, 'YAMLParser requires pyyaml to be installed'
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parser_context = parser_context or {}
encoding = parser_context.get('encoding', settings.DEFAULT_CHARSET)
try:
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data = stream.read().decode(encoding)
return yaml.safe_load(data)
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except (ValueError, yaml.parser.ParserError) as exc:
raise ParseError('YAML parse error - %s' % six.u(exc))
class FormParser(BaseParser):
"""
Parser for form data.
"""
media_type = 'application/x-www-form-urlencoded'
def parse(self, stream, media_type=None, parser_context=None):
"""
Returns a 2-tuple of `(data, files)`.
`data` will be a :class:`QueryDict` containing all the form parameters.
`files` will always be :const:`None`.
"""
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parser_context = parser_context or {}
encoding = parser_context.get('encoding', settings.DEFAULT_CHARSET)
data = QueryDict(stream.read(), encoding=encoding)
return data
class MultiPartParser(BaseParser):
"""
Parser for multipart form data, which may include file data.
"""
media_type = 'multipart/form-data'
def parse(self, stream, media_type=None, parser_context=None):
"""
Returns a DataAndFiles object.
`.data` will be a `QueryDict` containing all the form parameters.
`.files` will be a `QueryDict` containing all the form files.
"""
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parser_context = parser_context or {}
request = parser_context['request']
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encoding = parser_context.get('encoding', settings.DEFAULT_CHARSET)
meta = request.META
upload_handlers = request.upload_handlers
try:
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parser = DjangoMultiPartParser(meta, stream, upload_handlers, encoding)
data, files = parser.parse()
return DataAndFiles(data, files)
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except MultiPartParserError as exc:
raise ParseError('Multipart form parse error - %s' % six.u(exc))
class XMLParser(BaseParser):
"""
XML parser.
"""
media_type = 'application/xml'
def parse(self, stream, media_type=None, parser_context=None):
assert etree, 'XMLParser requires defusedxml to be installed'
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parser_context = parser_context or {}
encoding = parser_context.get('encoding', settings.DEFAULT_CHARSET)
parser = etree.DefusedXMLParser(encoding=encoding)
try:
tree = etree.parse(stream, parser=parser, forbid_dtd=True)
except (etree.ParseError, ValueError) as exc:
raise ParseError('XML parse error - %s' % six.u(exc))
data = self._xml_convert(tree.getroot())
return data
def _xml_convert(self, element):
"""
convert the xml `element` into the corresponding python object
"""
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children = list(element)
if len(children) == 0:
return self._type_convert(element.text)
else:
# if the fist child tag is list-item means all children are list-item
if children[0].tag == "list-item":
data = []
for child in children:
data.append(self._xml_convert(child))
else:
data = {}
for child in children:
data[child.tag] = self._xml_convert(child)
return data
def _type_convert(self, value):
"""
Converts the value returned by the XMl parse into the equivalent
Python type
"""
if value is None:
return value
try:
return datetime.datetime.strptime(value, '%Y-%m-%d %H:%M:%S')
except ValueError:
pass
try:
return int(value)
except ValueError:
pass
try:
return decimal.Decimal(value)
except decimal.InvalidOperation:
pass
return value