openstack/deb-python-falcon
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e1d92ebd896234df76a6d1a1327be7aad1310da2
deb-python-falcon/falcon/request.py
Kurt Griffiths e1d92ebd89 fix(Request): Improve support for content-length under wsgiref 
Under wsgiref, if no content-length header is provided, an empty
string is inserted. Update falcon.Request to handle this case,
as well as to more gracefully handle the case that the header is
set to any invalid value.
2014-10-29 14:23:37 -05:00

912 lines
33 KiB
Python
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# Copyright 2013 by Rackspace Hosting, Inc.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
from datetime import datetime
try:
# NOTE(kgrifs): In Python 2.6 and 2.7, socket._fileobject is a
# standard way of exposing a socket as a file-like object, and
# is used by wsgiref for wsgi.input.
import socket
NativeStream = socket._fileobject
except AttributeError: # pragma nocover
# NOTE(kgriffs): In Python 3.3, wsgiref implements wsgi.input
# using _io.BufferedReader which is an alias of io.BufferedReader
import io
NativeStream = io.BufferedReader
import mimeparse
import six
from falcon.exceptions import *
from falcon import util
from falcon.util import uri
from falcon import request_helpers as helpers
DEFAULT_ERROR_LOG_FORMAT = (u'{0:%Y-%m-%d %H:%M:%S} [FALCON] [ERROR]'
u' {1} {2}{3} => ')
TRUE_STRINGS = ('true', 'True', 'yes')
FALSE_STRINGS = ('false', 'False', 'no')
WSGI_CONTENT_HEADERS = ('CONTENT_TYPE', 'CONTENT_LENGTH')
class Request(object):
"""Represents a client's HTTP request.
Note:
`Request` is not meant to be instantiated directly by responders.
Args:
env (dict): A WSGI environment dict passed in from the server. See
also the PEP-3333 spec.
options (dict): Set of global options passed from the API handler.
Attributes:
protocol (str): Either 'http' or 'https'.
method (str): HTTP method requested (e.g., GET, POST, etc.)
host (str): Hostname requested by the client
subdomain (str): Leftmost (i.e., most specific) subdomain from the
hostname. If only a single domain name is given, `subdomain`
will be *None*.
Note:
If the hostname in the request is an IP address, the value
for `subdomain` is undefined.
user_agent (str): Value of the User-Agent header, or *None* if the
header is missing.
app (str): Name of the WSGI app (if using WSGI's notion of virtual
hosting).
env (dict): Reference to the WSGI *environ* dict passed in from the
server. See also PEP-3333.
context (dict): Dictionary to hold any data about the request which is
specific to your app (e.g. session object). Falcon itself will
not interact with this attribute after it has been initialized.
context_type (None): Custom callable/type to use for initializing the
``context`` attribute. To change this value so that ``context``
is initialized to the type of your choice (e.g. OrderedDict), you
will need to extend this class and pass that new type to the
``request_type`` argument of ``falcon.API()``.
uri (str): The fully-qualified URI for the request.
url (str): alias for ``uri``.
relative_uri (str): The path + query string portion of the full URI.
path (str): Path portion of the request URL (not including query
string).
query_string (str): Query string portion of the request URL, without
the preceding '?' character.
accept (str): Value of the Accept header, or '*/*' if the header is
missing.
auth (str): Value of the Authorization header, or *None* if the header
is missing.
client_accepts_json (bool): True if the Accept header includes JSON,
otherwise False.
client_accepts_msgpack (bool): True if the Accept header includes
msgpack, otherwise False.
client_accepts_xml (bool): True if the Accept header includes XML,
otherwise False.
content_type (str): Value of the Content-Type header, or *None* if
the header is missing.
content_length (int): Value of the Content-Length header converted
to an int, or *None* if the header is missing.
stream: File-like object for reading the body of the request, if any.
Note:
If an HTML form is POSTed to the API using the
*application/x-www-form-urlencoded* media type, Falcon
will consume `stream` in order to parse the parameters
and merge them into the query string parameters. In this
case, the stream will be left at EOF.
Note also that the character encoding for fields, before
percent-encoding non-ASCII bytes, is assumed to be
UTF-8. The special "_charset_" field is ignored if present.
Falcon expects form-encoded request bodies to be
encoded according to the standard W3C algorithm (see
also http://goo.gl/6rlcux).
date (datetime): Value of the Date header, converted to a
`datetime.datetime` instance. The header value is assumed to
conform to RFC 1123.
expect (str): Value of the Expect header, or *None* if the
header is missing.
range (tuple of int): A 2-member tuple parsed from the value of the
Range header.
The two members correspond to the first and last byte
positions of the requested resource, inclusive. Negative
indices indicate offset from the end of the resource,
where -1 is the last byte, -2 is the second-to-last byte,
and so forth.
Only continous ranges are supported (e.g., "bytes=0-0,-1" would
result in an HTTPBadRequest exception when the attribute is
accessed.)
if_match (str): Value of the If-Match header, or *None* if the
header is missing.
if_none_match (str): Value of the If-None-Match header, or *None*
if the header is missing.
if_modified_since (str): Value of the If-Modified-Since header, or
None if the header is missing.
if_unmodified_since (str): Value of the If-Unmodified-Sinc header,
or *None* if the header is missing.
if_range (str): Value of the If-Range header, or *None* if the
header is missing.
headers (dict): Raw HTTP headers from the request with
canonical dash-separated names. Parsing all the headers
to create this dict is done the first time this attribute
is accessed. This parsing can be costly, so unless you
need all the headers in this format, you should use the
``get_header`` method or one of the convenience attributes
instead, to get a value for a specific header.
params (dict): The mapping of request query parameter names to their
values. Where the parameter appears multiple times in the query
string, the value mapped to that parameter key will be a list of
all the values in the order seen.
options (dict): Set of global options passed from the API handler.
"""
__slots__ = (
'_cached_headers',
'_cached_uri',
'_cached_relative_uri',
'content_type',
'env',
'method',
'_params',
'path',
'query_string',
'stream',
'context',
'_wsgierrors',
'options',
)
# Allow child classes to override this
context_type = None
def __init__(self, env, options=None):
self.env = env
self.options = options if options else RequestOptions()
if self.context_type is None:
# Literal syntax is more efficient than using dict()
self.context = {}
else:
# pylint will detect this as not-callable because it only sees the
# declaration of None, not whatever type a subclass may have set.
self.context = self.context_type() # pylint: disable=not-callable
self._wsgierrors = env['wsgi.errors']
self.stream = env['wsgi.input']
self.method = env['REQUEST_METHOD']
# Normalize path
path = env['PATH_INFO']
if path:
if len(path) != 1 and path.endswith('/'):
self.path = path[:-1]
else:
self.path = path
else:
self.path = '/'
self._params = {}
# PERF(kgriffs): if...in is faster than using env.get(...)
if 'QUERY_STRING' in env:
query_str = env['QUERY_STRING']
if query_str:
self.query_string = uri.decode(query_str)
self._params = uri.parse_query_string(
self.query_string,
keep_blank_qs_values=self.options.keep_blank_qs_values,
)
else:
self.query_string = six.text_type()
else:
self.query_string = six.text_type()
self._cached_headers = None
self._cached_uri = None
self._cached_relative_uri = None
try:
self.content_type = self.env['CONTENT_TYPE']
except KeyError:
self.content_type = None
# NOTE(kgriffs): Wrap wsgi.input if needed to make read() more robust,
# normalizing semantics between, e.g., gunicorn and wsgiref.
if isinstance(self.stream, NativeStream):
self._wrap_stream()
# PERF(kgriffs): Technically, we should spend a few more
# cycles and parse the content type for real, but
# this heuristic will work virtually all the time.
if (self.content_type is not None and
'application/x-www-form-urlencoded' in self.content_type):
self._parse_form_urlencoded()
# ------------------------------------------------------------------------
# Properties
# ------------------------------------------------------------------------
user_agent = helpers.header_property('HTTP_USER_AGENT')
auth = helpers.header_property('HTTP_AUTHORIZATION')
expect = helpers.header_property('HTTP_EXPECT')
if_match = helpers.header_property('HTTP_IF_MATCH')
if_none_match = helpers.header_property('HTTP_IF_NONE_MATCH')
if_modified_since = helpers.header_property('HTTP_IF_MODIFIED_SINCE')
if_unmodified_since = helpers.header_property('HTTP_IF_UNMODIFIED_SINCE')
if_range = helpers.header_property('HTTP_IF_RANGE')
@property
def client_accepts_json(self):
return self.client_accepts('application/json')
@property
def client_accepts_msgpack(self):
return self.client_accepts('application/x-msgpack')
@property
def client_accepts_xml(self):
return self.client_accepts('application/xml')
@property
def accept(self):
# NOTE(kgriffs): Per RFC, a missing accept header is
# equivalent to '*/*'
try:
return self.env['HTTP_ACCEPT'] or '*/*'
except KeyError:
return '*/*'
@property
def content_length(self):
try:
value = self.env['CONTENT_LENGTH']
except KeyError:
return None
# NOTE(kgriffs): Normalize an empty value to behave as if
# the header were not included; wsgiref, at least, inserts
# an empty CONTENT_LENGTH value if the request does not
# set the header. Gunicorn and uWSGI do not do this, but
# others might if they are trying to match wsgiref's
# behavior too closely.
if not value:
return None
try:
value_as_int = int(value)
except ValueError:
msg = 'The value of the header must be a number.'
raise HTTPInvalidHeader(msg, 'Content-Length')
if value_as_int < 0:
msg = 'The value of the header must be a positive number.'
raise HTTPInvalidHeader(msg, 'Content-Length')
return value_as_int
@property
def date(self):
try:
http_date = self.env['HTTP_DATE']
except KeyError:
return None
try:
return util.http_date_to_dt(http_date)
except ValueError:
msg = ('It must be formatted according to RFC 1123.')
raise HTTPInvalidHeader(msg, 'Date')
@property
def range(self):
try:
value = self.env['HTTP_RANGE']
except KeyError:
return None
if ',' in value:
msg = 'The value must be a continuous byte range.'
raise HTTPInvalidHeader(msg, 'Range')
try:
first, sep, last = value.partition('-')
if not sep:
raise ValueError()
if first:
return (int(first), int(last or -1))
elif last:
return (-int(last), -1)
else:
msg = 'The byte offsets are missing.'
raise HTTPInvalidHeader(msg, 'Range')
except ValueError:
href = 'http://goo.gl/zZ6Ey'
href_text = 'HTTP/1.1 Range Requests'
msg = ('It must be a byte range formatted according to RFC 2616.')
raise HTTPInvalidHeader(msg, 'Range', href=href,
href_text=href_text)
@property
def app(self):
return self.env.get('SCRIPT_NAME', '')
@property
def protocol(self):
return self.env['wsgi.url_scheme']
@property
def uri(self):
if self._cached_uri is None:
env = self.env
protocol = env['wsgi.url_scheme']
# NOTE(kgriffs): According to PEP-3333 we should first
# try to use the Host header if present.
#
# PERF(kgriffs): try..except is faster than .get
try:
host = env['HTTP_HOST']
except KeyError:
host = env['SERVER_NAME']
port = env['SERVER_PORT']
if protocol == 'https':
if port != '443':
host += ':' + port
else:
if port != '80':
host += ':' + port
# PERF: For small numbers of items, '+' is faster
# than ''.join(...). Concatenation is also generally
# faster than formatting.
value = (protocol + '://' +
host +
self.app +
self.path)
if self.query_string:
value = value + '?' + self.query_string
self._cached_uri = value
return self._cached_uri
url = uri
@property
def host(self):
try:
# NOTE(kgriffs): Prefer the host header; the web server
# isn't supposed to mess with it, so it should be what
# the client actually sent.
host_header = self.env['HTTP_HOST']
host, port = uri.parse_host(host_header)
except KeyError:
# PERF(kgriffs): According to PEP-3333, this header
# will always be present.
host = self.env['SERVER_NAME']
return host
@property
def subdomain(self):
# PERF(kgriffs): .partition is slightly faster than .split
subdomain, sep, remainder = self.host.partition('.')
return subdomain if sep else None
@property
def relative_uri(self):
if self._cached_relative_uri is None:
if self.query_string:
self._cached_relative_uri = (self.app + self.path + '?' +
self.query_string)
else:
self._cached_relative_uri = self.app + self.path
return self._cached_relative_uri
@property
def headers(self):
# NOTE(kgriffs: First time here will cache the dict so all we
# have to do is clone it in the future.
if self._cached_headers is None:
headers = self._cached_headers = {}
env = self.env
for name, value in env.items():
if name.startswith('HTTP_'):
# NOTE(kgriffs): Don't take the time to fix the case
# since headers are supposed to be case-insensitive
# anyway.
headers[name[5:].replace('_', '-')] = value
elif name in WSGI_CONTENT_HEADERS:
headers[name.replace('_', '-')] = value
return self._cached_headers.copy()
@property
def params(self):
return self._params
# ------------------------------------------------------------------------
# Methods
# ------------------------------------------------------------------------
def client_accepts(self, media_type):
"""Determines whether or not the client accepts a given media type.
Args:
media_type (str): An Internet media type to check.
Returns:
bool: True if the client has indicated in the Accept header that
it accepts the specified media type. Otherwise, returns
False.
"""
accept = self.accept
# PERF(kgriffs): Usually the following will be true, so
# try it first.
if (accept == media_type) or (accept == '*/*'):
return True
# Fall back to full-blown parsing
try:
return mimeparse.quality(media_type, accept) != 0.0
except ValueError:
return False
def client_prefers(self, media_types):
"""Returns the client's preferred media type given several choices.
Args:
media_types (iterable of str): One or more Internet media types
from which to choose the client's preferred type. This value
**must** be an iterable collection of strings.
Returns:
str: The client's preferred media type, based on the Accept
header. Returns *None* if the client does not accept any
of the given types.
"""
try:
# NOTE(kgriffs): best_match will return '' if no match is found
preferred_type = mimeparse.best_match(media_types, self.accept)
except ValueError:
# Value for the accept header was not formatted correctly
preferred_type = ''
return (preferred_type if preferred_type else None)
def get_header(self, name, required=False):
"""Return a header value as a string.
Args:
name (str): Header name, case-insensitive (e.g., 'Content-Type')
required (bool, optional): Set to True to raise HttpBadRequest
instead of returning gracefully when the header is not found
(default False).
Returns:
str: The value of the specified header if it exists, or *None* if
the header is not found and is not required.
Raises:
HTTPBadRequest: The header was not found in the request, but
it was required.
"""
wsgi_name = name.upper().replace('-', '_')
# Use try..except to optimize for the header existing in most cases
try:
# Don't take the time to cache beforehand, using HTTP naming.
# This will be faster, assuming that most headers are looked
# up only once, and not all headers will be requested.
return self.env['HTTP_' + wsgi_name]
except KeyError:
# NOTE(kgriffs): There are a couple headers that do not
# use the HTTP prefix in the env, so try those. We expect
# people to usually just use the relevant helper properties
# to access these instead of .get_header.
if wsgi_name in WSGI_CONTENT_HEADERS:
try:
return self.env[wsgi_name]
except KeyError:
pass
if not required:
return None
raise HTTPMissingParam(name)
def get_param(self, name, required=False, store=None):
"""Return the value of a query string parameter as a string.
Note:
If an HTML form is POSTed to the API using the
*application/x-www-form-urlencoded* media type, the
parameters from the request body will be merged into
the query string parameters.
If a key appears more than once in the form data, one of the
values will be returned as a string, but it is undefined which
one. Use .get_param_as_list() to retrieve all the values.
Note:
If a query parameter is assigned a comma-separated list of
values (e.g., foo=a,b,c) then only one of the values will be
returned, and it is undefined which one. Use
.get_param_as_list() to retrieve all the values.
Args:
name (str): Parameter name, case-sensitive (e.g., 'sort')
required (bool, optional): Set to True to raise HTTPBadRequest
instead of returning gracefully when the parameter is not
found (default False)
store (dict, optional): A dict-like object in which to place the
value of the param, but only if the param is found.
Returns:
string: The value of the param as a string, or *None* if param is
not found and is not required.
Raises:
HTTPBadRequest: The param was not found in the request, but was
required.
"""
params = self._params
# PERF: Use if..in since it is a good all-around performer; we don't
# know how likely params are to be specified by clients.
if name in params:
# NOTE(warsaw): If the key appeared multiple times, it will be
# stored internally as a list. We do not define which one
# actually gets returned, but let's pick the last one for grins.
param = params[name]
if isinstance(param, list):
param = param[-1]
if store is not None:
store[name] = param
return param
if not required:
return None
raise HTTPMissingParam(name)
def get_param_as_int(self, name,
required=False, min=None, max=None, store=None):
"""Return the value of a query string parameter as an int.
Args:
name (str): Parameter name, case-sensitive (e.g., 'limit')
required (bool, optional): Set to True to raise HTTPBadRequest
instead of returning gracefully when the parameter is not
found or is not an integer (default False).
min (int, optional): Set to the minimum value allowed for this
param. If the param is found and it is less than min, an
HTTPError is raised.
max (int, optional): Set to the maximum value allowed for this
param. If the param is found and its value is greater than
max, an HTTPError is raised.
store (dict, optional): A dict-like object in which to place the
value of the param, but only if the param is found (default
*None*).
Returns:
int: The value of the param if it is found and can be converted to
an integer. If the param is not found, returns *None*, unless
``required`` is True.
Raises
HTTPBadRequest: The param was not found in the request, even though
it was required to be there. Also raised if the param's value
falls outside the given interval, i.e., the value must be in
the interval: min <= value <= max to avoid triggering an error.
"""
params = self._params
# PERF: Use if..in since it is a good all-around performer; we don't
# know how likely params are to be specified by clients.
if name in params:
val = params[name]
if isinstance(val, list):
val = val[-1]
try:
val = int(val)
except ValueError:
msg = 'The value must be an integer.'
raise HTTPInvalidParam(msg, name)
if min is not None and val < min:
msg = 'The value must be at least ' + str(min)
raise HTTPInvalidParam(msg, name)
if max is not None and max < val:
msg = 'The value may not exceed ' + str(max)
raise HTTPInvalidParam(msg, name)
if store is not None:
store[name] = val
return val
if not required:
return None
raise HTTPMissingParam(name)
def get_param_as_bool(self, name, required=False, store=None,
blank_as_true=False):
"""Return the value of a query string parameter as a boolean
The following bool-like strings are supported::
TRUE_STRINGS = ('true', 'True', 'yes')
FALSE_STRINGS = ('false', 'False', 'no')
Args:
name (str): Parameter name, case-sensitive (e.g., 'limit')
required (bool, optional): Set to True to raise HTTPBadRequest
instead of returning gracefully when the parameter is not
found or is not a recognized bool-ish string (default False).
store (dict, optional): A dict-like object in which to place the
value of the param, but only if the param is found (default
*None*).
blank_as_true (bool): If True, empty strings will be treated as
True. keep_blank_qs_values must be set on the Request (or API
object and inherited) for empty strings to not be filtered.
Returns:
bool: The value of the param if it is found and can be converted
to a boolean. If the param is not found, returns *None* unless
required is True.
Raises
HTTPBadRequest: The param was not found in the request, even though
it was required to be there.
"""
params = self._params
# PERF: Use if..in since it is a good all-around performer; we don't
# know how likely params are to be specified by clients.
if name in params:
val = params[name]
if isinstance(val, list):
val = val[-1]
if val in TRUE_STRINGS:
val = True
elif val in FALSE_STRINGS:
val = False
elif blank_as_true and not val:
val = True
else:
msg = 'The value of the parameter must be "true" or "false".'
raise HTTPInvalidParam(msg, name)
if store is not None:
store[name] = val
return val
if not required:
return None
raise HTTPMissingParam(name)
def get_param_as_list(self, name,
transform=None, required=False, store=None):
"""Return the value of a query string parameter as a list.
List items must be comma-separated or must be provided
as multiple instances of the same param in the query string
ala *application/x-www-form-urlencoded*.
Args:
name (str): Parameter name, case-sensitive (e.g., 'limit')
transform (callable, optional): An optional transform function
that takes as input each element in the list as a string and
outputs a transformed element for inclusion in the list that
will be returned. For example, passing the int function will
transform list items into numbers.
required (bool, optional): Set to True to raise HTTPBadRequest
instead of returning gracefully when the parameter is not
found or is not an integer (default False)
store (dict, optional): A dict-like object in which to place the
value of the param, but only if the param is found (default
*None*).
Returns:
list: The value of the param if it is found. Otherwise, returns
*None* unless required is True. Empty list elements will be
discarded. For example a query string containing this::
things=1,,3
or a query string containing this::
things=1&things=&things=3
would both result in::
['1', '3']
Raises
HTTPBadRequest: The param was not found in the request, but was
required.
"""
params = self._params
# PERF: Use if..in since it is a good all-around performer; we don't
# know how likely params are to be specified by clients.
if name in params:
items = params[name]
# NOTE(warsaw): When a key appears multiple times in the request
# query, it will already be represented internally as a list.
# NOTE(kgriffs): Likewise for comma-delimited values.
if not isinstance(items, list):
items = [items]
# PERF(kgriffs): Use if-else rather than a DRY approach
# that sets transform to a passthrough function; avoids
# function calling overhead.
if transform is not None:
try:
items = [transform(i) for i in items]
except ValueError:
msg = 'The value is not formatted correctly.'
raise HTTPInvalidParam(msg, name)
if store is not None:
store[name] = items
return items
if not required:
return None
raise HTTPMissingParam(name)
# TODO(kgriffs): Use the nocover pragma only for the six.PY3 if..else
def log_error(self, message): # pragma: no cover
"""Write an error message to the server's log.
Prepends timestamp and request info to message, and writes the
result out to the WSGI server's error stream (`wsgi.error`).
Args:
message (str): A string describing the problem. If a byte-string
it is simply written out as-is. Unicode strings will be
converted to UTF-8.
"""
if self.query_string:
query_string_formatted = '?' + self.query_string
else:
query_string_formatted = ''
log_line = (
DEFAULT_ERROR_LOG_FORMAT.
format(datetime.now(), self.method, self.path,
query_string_formatted)
)
if six.PY3:
self._wsgierrors.write(log_line + message + '\n')
else:
if isinstance(message, unicode):
message = message.encode('utf-8')
self._wsgierrors.write(log_line.encode('utf-8'))
self._wsgierrors.write(message + '\n')
# ------------------------------------------------------------------------
# Helpers
# ------------------------------------------------------------------------
def _wrap_stream(self):
try:
# NOTE(kgriffs): We can only add the wrapper if the
# content-length header was provided.
if self.content_length is not None:
self.stream = helpers.Body(self.stream, self.content_length)
except HTTPInvalidHeader:
# NOTE(kgriffs): The content-length header was specified,
# but it had an invalid value.
pass
def _parse_form_urlencoded(self):
# NOTE(kgriffs): This assumes self.stream has been patched
# above in the case of wsgiref, so that self.content_length
# is not needed. Normally we just avoid accessing
# self.content_length, because it is a little expensive
# to call. We could cache self.content_length, but the
# overhead to do that won't usually be helpful, since
# content length will only ever be read once per
# request in most cases.
body = self.stream.read()
# NOTE(kgriffs): According to http://goo.gl/6rlcux the
# body should be US-ASCII. Enforcing this also helps
# catch malicious input.
try:
body = body.decode('ascii')
except UnicodeDecodeError:
body = None
self.log_error('Non-ASCII characters found in form body '
'with Content-Type of '
'application/x-www-form-urlencoded. Body '
'will be ignored.')
if body:
extra_params = uri.parse_query_string(
uri.decode(body),
keep_blank_qs_values=self.options.keep_blank_qs_values,
)
self._params.update(extra_params)
class RequestOptions(object):
"""This class is a container for Request options.
PERF: To avoid typos and improve storage space and speed over a dict.
"""
__slots__ = (
'keep_blank_qs_values',
)
def __init__(self):
self.keep_blank_qs_values = False
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