285 lines
10 KiB
Python
285 lines
10 KiB
Python
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# -*- coding: utf-8 -*-
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"""
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werkzeug.contrib.wrappers
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~~~~~~~~~~~~~~~~~~~~~~~~~
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Extra wrappers or mixins contributed by the community. These wrappers can
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be mixed in into request objects to add extra functionality.
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Example::
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from werkzeug.wrappers import Request as RequestBase
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from werkzeug.contrib.wrappers import JSONRequestMixin
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class Request(RequestBase, JSONRequestMixin):
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pass
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Afterwards this request object provides the extra functionality of the
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:class:`JSONRequestMixin`.
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:copyright: (c) 2014 by the Werkzeug Team, see AUTHORS for more details.
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:license: BSD, see LICENSE for more details.
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"""
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import codecs
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try:
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from simplejson import loads
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except ImportError:
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from json import loads
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from werkzeug.exceptions import BadRequest
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from werkzeug.utils import cached_property
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from werkzeug.http import dump_options_header, parse_options_header
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from werkzeug._compat import wsgi_decoding_dance
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def is_known_charset(charset):
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"""Checks if the given charset is known to Python."""
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try:
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codecs.lookup(charset)
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except LookupError:
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return False
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return True
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class JSONRequestMixin(object):
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"""Add json method to a request object. This will parse the input data
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through simplejson if possible.
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:exc:`~werkzeug.exceptions.BadRequest` will be raised if the content-type
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is not json or if the data itself cannot be parsed as json.
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"""
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@cached_property
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def json(self):
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"""Get the result of simplejson.loads if possible."""
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if 'json' not in self.environ.get('CONTENT_TYPE', ''):
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raise BadRequest('Not a JSON request')
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try:
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return loads(self.data.decode(self.charset, self.encoding_errors))
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except Exception:
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raise BadRequest('Unable to read JSON request')
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class ProtobufRequestMixin(object):
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"""Add protobuf parsing method to a request object. This will parse the
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input data through `protobuf`_ if possible.
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:exc:`~werkzeug.exceptions.BadRequest` will be raised if the content-type
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is not protobuf or if the data itself cannot be parsed property.
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.. _protobuf: http://code.google.com/p/protobuf/
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"""
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#: by default the :class:`ProtobufRequestMixin` will raise a
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#: :exc:`~werkzeug.exceptions.BadRequest` if the object is not
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#: initialized. You can bypass that check by setting this
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#: attribute to `False`.
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protobuf_check_initialization = True
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def parse_protobuf(self, proto_type):
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"""Parse the data into an instance of proto_type."""
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if 'protobuf' not in self.environ.get('CONTENT_TYPE', ''):
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raise BadRequest('Not a Protobuf request')
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obj = proto_type()
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try:
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obj.ParseFromString(self.data)
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except Exception:
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raise BadRequest("Unable to parse Protobuf request")
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# Fail if not all required fields are set
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if self.protobuf_check_initialization and not obj.IsInitialized():
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raise BadRequest("Partial Protobuf request")
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return obj
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class RoutingArgsRequestMixin(object):
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"""This request mixin adds support for the wsgiorg routing args
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`specification`_.
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.. _specification: https://wsgi.readthedocs.io/en/latest/specifications/routing_args.html
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"""
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def _get_routing_args(self):
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return self.environ.get('wsgiorg.routing_args', (()))[0]
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def _set_routing_args(self, value):
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if self.shallow:
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raise RuntimeError('A shallow request tried to modify the WSGI '
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'environment. If you really want to do that, '
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'set `shallow` to False.')
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self.environ['wsgiorg.routing_args'] = (value, self.routing_vars)
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routing_args = property(_get_routing_args, _set_routing_args, doc='''
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The positional URL arguments as `tuple`.''')
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del _get_routing_args, _set_routing_args
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def _get_routing_vars(self):
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rv = self.environ.get('wsgiorg.routing_args')
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if rv is not None:
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return rv[1]
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rv = {}
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if not self.shallow:
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self.routing_vars = rv
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return rv
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def _set_routing_vars(self, value):
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if self.shallow:
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raise RuntimeError('A shallow request tried to modify the WSGI '
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'environment. If you really want to do that, '
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'set `shallow` to False.')
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self.environ['wsgiorg.routing_args'] = (self.routing_args, value)
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routing_vars = property(_get_routing_vars, _set_routing_vars, doc='''
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The keyword URL arguments as `dict`.''')
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del _get_routing_vars, _set_routing_vars
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class ReverseSlashBehaviorRequestMixin(object):
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"""This mixin reverses the trailing slash behavior of :attr:`script_root`
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and :attr:`path`. This makes it possible to use :func:`~urlparse.urljoin`
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directly on the paths.
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Because it changes the behavior or :class:`Request` this class has to be
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mixed in *before* the actual request class::
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class MyRequest(ReverseSlashBehaviorRequestMixin, Request):
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pass
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This example shows the differences (for an application mounted on
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`/application` and the request going to `/application/foo/bar`):
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+---------------+-------------------+---------------------+
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| | normal behavior | reverse behavior |
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+===============+===================+=====================+
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| `script_root` | ``/application`` | ``/application/`` |
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+---------------+-------------------+---------------------+
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| `path` | ``/foo/bar`` | ``foo/bar`` |
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+---------------+-------------------+---------------------+
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"""
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@cached_property
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def path(self):
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"""Requested path as unicode. This works a bit like the regular path
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info in the WSGI environment but will not include a leading slash.
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"""
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path = wsgi_decoding_dance(self.environ.get('PATH_INFO') or '',
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self.charset, self.encoding_errors)
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return path.lstrip('/')
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@cached_property
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def script_root(self):
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"""The root path of the script includling a trailing slash."""
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path = wsgi_decoding_dance(self.environ.get('SCRIPT_NAME') or '',
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self.charset, self.encoding_errors)
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return path.rstrip('/') + '/'
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class DynamicCharsetRequestMixin(object):
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""""If this mixin is mixed into a request class it will provide
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a dynamic `charset` attribute. This means that if the charset is
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transmitted in the content type headers it's used from there.
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Because it changes the behavior or :class:`Request` this class has
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to be mixed in *before* the actual request class::
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class MyRequest(DynamicCharsetRequestMixin, Request):
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pass
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By default the request object assumes that the URL charset is the
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same as the data charset. If the charset varies on each request
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based on the transmitted data it's not a good idea to let the URLs
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change based on that. Most browsers assume either utf-8 or latin1
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for the URLs if they have troubles figuring out. It's strongly
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recommended to set the URL charset to utf-8::
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class MyRequest(DynamicCharsetRequestMixin, Request):
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url_charset = 'utf-8'
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.. versionadded:: 0.6
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"""
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#: the default charset that is assumed if the content type header
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#: is missing or does not contain a charset parameter. The default
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#: is latin1 which is what HTTP specifies as default charset.
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#: You may however want to set this to utf-8 to better support
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#: browsers that do not transmit a charset for incoming data.
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default_charset = 'latin1'
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def unknown_charset(self, charset):
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"""Called if a charset was provided but is not supported by
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the Python codecs module. By default latin1 is assumed then
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to not lose any information, you may override this method to
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change the behavior.
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:param charset: the charset that was not found.
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:return: the replacement charset.
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"""
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return 'latin1'
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@cached_property
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def charset(self):
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"""The charset from the content type."""
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header = self.environ.get('CONTENT_TYPE')
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if header:
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ct, options = parse_options_header(header)
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charset = options.get('charset')
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if charset:
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if is_known_charset(charset):
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return charset
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return self.unknown_charset(charset)
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return self.default_charset
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class DynamicCharsetResponseMixin(object):
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"""If this mixin is mixed into a response class it will provide
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a dynamic `charset` attribute. This means that if the charset is
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looked up and stored in the `Content-Type` header and updates
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itself automatically. This also means a small performance hit but
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can be useful if you're working with different charsets on
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responses.
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Because the charset attribute is no a property at class-level, the
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default value is stored in `default_charset`.
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Because it changes the behavior or :class:`Response` this class has
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to be mixed in *before* the actual response class::
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class MyResponse(DynamicCharsetResponseMixin, Response):
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pass
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.. versionadded:: 0.6
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"""
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#: the default charset.
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default_charset = 'utf-8'
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def _get_charset(self):
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header = self.headers.get('content-type')
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if header:
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charset = parse_options_header(header)[1].get('charset')
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if charset:
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return charset
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return self.default_charset
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def _set_charset(self, charset):
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header = self.headers.get('content-type')
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ct, options = parse_options_header(header)
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if not ct:
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raise TypeError('Cannot set charset if Content-Type '
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'header is missing.')
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options['charset'] = charset
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self.headers['Content-Type'] = dump_options_header(ct, options)
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charset = property(_get_charset, _set_charset, doc="""
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The charset for the response. It's stored inside the
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Content-Type header as a parameter.""")
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del _get_charset, _set_charset
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