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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
import json
from django.conf import settings
from django.core.files.uploadhandler import StopFutureHandlers
from django.http import QueryDict
from django.http.multipartparser import \
MultiPartParser as DjangoMultiPartParser
from django.http.multipartparser import (
ChunkIter, MultiPartParserError, parse_header
)
from django.utils import six
from django.utils.encoding import force_text
from django.utils.six.moves.urllib import parse as urlparse
from rest_framework import renderers
from rest_framework.exceptions import ParseError
class DataAndFiles(object):
def __init__(self, data, files):
self.data = data
self.files = files
class BaseParser(object):
"""
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'
renderer_class = renderers.JSONRenderer
def parse(self, stream, media_type=None, parser_context=None):
"""
Parses the incoming bytestream as JSON and returns the resulting data.
"""
parser_context = parser_context or {}
encoding = parser_context.get('encoding', settings.DEFAULT_CHARSET)
try:
data = stream.read().decode(encoding)
return json.loads(data)
except ValueError as exc:
raise ParseError('JSON parse error - %s' % six.text_type(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):
"""
Parses the incoming bytestream as a URL encoded form,
and returns the resulting QueryDict.
"""
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):
"""
Parses the incoming bytestream as a multipart encoded form,
and returns a DataAndFiles object.
`.data` will be a `QueryDict` containing all the form parameters.
`.files` will be a `QueryDict` containing all the form files.
"""
parser_context = parser_context or {}
request = parser_context['request']
encoding = parser_context.get('encoding', settings.DEFAULT_CHARSET)
meta = request.META.copy()
meta['CONTENT_TYPE'] = media_type
upload_handlers = request.upload_handlers
try:
parser = DjangoMultiPartParser(meta, stream, upload_handlers, encoding)
data, files = parser.parse()
return DataAndFiles(data, files)
except MultiPartParserError as exc:
raise ParseError('Multipart form parse error - %s' % six.text_type(exc))
class FileUploadParser(BaseParser):
"""
Parser for file upload data.
"""
media_type = '*/*'
errors = {
'unhandled': 'FileUpload parse error - none of upload handlers can handle the stream',
'no_filename': 'Missing filename. Request should include a Content-Disposition header with a filename parameter.',
}
def parse(self, stream, media_type=None, parser_context=None):
"""
Treats the incoming bytestream as a raw file upload and returns
a `DataAndFiles` object.
`.data` will be None (we expect request body to be a file content).
`.files` will be a `QueryDict` containing one 'file' element.
"""
parser_context = parser_context or {}
request = parser_context['request']
encoding = parser_context.get('encoding', settings.DEFAULT_CHARSET)
meta = request.META
upload_handlers = request.upload_handlers
filename = self.get_filename(stream, media_type, parser_context)
if not filename:
raise ParseError(self.errors['no_filename'])
# Note that this code is extracted from Django's handling of
# file uploads in MultiPartParser.
content_type = meta.get('HTTP_CONTENT_TYPE',
meta.get('CONTENT_TYPE', ''))
try:
content_length = int(meta.get('HTTP_CONTENT_LENGTH',
meta.get('CONTENT_LENGTH', 0)))
except (ValueError, TypeError):
content_length = None
# See if the handler will want to take care of the parsing.
for handler in upload_handlers:
result = handler.handle_raw_input(stream,
meta,
content_length,
None,
encoding)
if result is not None:
return DataAndFiles({}, {'file': result[1]})
# This is the standard case.
possible_sizes = [x.chunk_size for x in upload_handlers if x.chunk_size]
chunk_size = min([2 ** 31 - 4] + possible_sizes)
chunks = ChunkIter(stream, chunk_size)
counters = [0] * len(upload_handlers)
for index, handler in enumerate(upload_handlers):
try:
handler.new_file(None, filename, content_type,
content_length, encoding)
except StopFutureHandlers:
upload_handlers = upload_handlers[:index + 1]
break
for chunk in chunks:
for index, handler in enumerate(upload_handlers):
chunk_length = len(chunk)
chunk = handler.receive_data_chunk(chunk, counters[index])
counters[index] += chunk_length
if chunk is None:
break
for index, handler in enumerate(upload_handlers):
file_obj = handler.file_complete(counters[index])
if file_obj is not None:
return DataAndFiles({}, {'file': file_obj})
raise ParseError(self.errors['unhandled'])
def get_filename(self, stream, media_type, parser_context):
"""
Detects the uploaded file name. First searches a 'filename' url kwarg.
Then tries to parse Content-Disposition header.
"""
try:
return parser_context['kwargs']['filename']
except KeyError:
pass
try:
meta = parser_context['request'].META
disposition = parse_header(meta['HTTP_CONTENT_DISPOSITION'].encode('utf-8'))
filename_parm = disposition[1]
if 'filename*' in filename_parm:
return self.get_encoded_filename(filename_parm)
return force_text(filename_parm['filename'])
except (AttributeError, KeyError, ValueError):
pass
def get_encoded_filename(self, filename_parm):
"""
Handle encoded filenames per RFC6266. See also:
http://tools.ietf.org/html/rfc2231#section-4
"""
encoded_filename = force_text(filename_parm['filename*'])
try:
charset, lang, filename = encoded_filename.split('\'', 2)
filename = urlparse.unquote(filename)
except (ValueError, LookupError):
filename = force_text(filename_parm['filename'])
return filename