openstack/deb-python-falcon
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0f64e94a5ab49b58b9efa8462fe8c0369428243d
deb-python-falcon/falcon/request.py
Kurt Griffiths 0f64e94a5a feat(util,Request): Add options to disable csv parsing of query params (#820) 
* Add option to to_query_str to encode lists as multiple occurences of
  the same parameter.
* Add option to parse_query_string to not split comma-delimited values.
* Add an option to RequestOptions for toggling csv parsing.

In all cases, the options default to the previous behavior in order to
avoid introducing any breaking changes.

Co-Authored-By: Daniel Schwarz <qwesda@me.com>
Co-Authored-By: Steven Ly <sly@openroad.ca>
Co-Authored-By: Kurt Griffiths <inbox@kgriffs.com>

Closes #749
2016-07-09 10:34:01 -06:00

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# 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
import json
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:
# 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
from wsgiref.validate import InputWrapper
import mimeparse
import six
from six.moves import http_cookies
from falcon import errors
from falcon import request_helpers as helpers
from falcon import util
from falcon.util.uri import parse_host, parse_query_string, unquote_string
# NOTE(tbug): In some cases, http_cookies is not a module
# but a dict-like structure. This fixes that issue.
# See issue https://github.com/falconry/falcon/issues/556
SimpleCookie = http_cookies.SimpleCookie
DEFAULT_ERROR_LOG_FORMAT = (u'{0:%Y-%m-%d %H:%M:%S} [FALCON] [ERROR]'
u' {1} {2}{3} => ')
TRUE_STRINGS = ('true', 'True', 'yes', '1')
FALSE_STRINGS = ('false', 'False', 'no', '0')
WSGI_CONTENT_HEADERS = ('CONTENT_TYPE', 'CONTENT_LENGTH')
_maybe_wrap_wsgi_stream = True
# PERF(kgriffs): Avoid an extra namespace lookup when using these functions
strptime = datetime.strptime
now = datetime.now
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 PEP-3333.
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.
env (dict): Reference to the WSGI environ ``dict`` passed in from the
server. See also PEP-3333.
app (str): Name of the WSGI app (if using WSGI's notion of virtual
hosting).
access_route(list): IP address of the original client, as well
as any known addresses of proxies fronting the WSGI server.
The following request headers are checked, in order of
preference, to determine the addresses:
- ``Forwarded``
- ``X-Forwarded-For``
- ``X-Real-IP``
If none of these headers are available, the value of
:py:attr:`~.remote_addr` is used instead.
Note:
Per `RFC 7239`_, the access route may contain "unknown"
and obfuscated identifiers, in addition to IPv4 and
IPv6 addresses
.. _RFC 7239: https://tools.ietf.org/html/rfc7239
Warning:
Headers can be forged by any client or proxy. Use this
property with caution and validate all values before
using them. Do not rely on the access route to authorize
requests.
remote_addr(str): IP address of the closest client or proxy to
the WSGI server.
This property is determined by the value of ``REMOTE_ADDR``
in the WSGI environment dict. Since this address is not
derived from an HTTP header, clients and proxies can not
forge it.
Note:
If your application is behind one or more reverse
proxies, you can use :py:attr:`~.access_route`
to retrieve the real IP address of the client.
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 (class): Class variable that determines the
factory or type to use for initializing the
`context` attribute. By default, the framework will
instantiate standard
``dict`` objects. However, You may override this behavior
by creating a custom child class of ``falcon.Request``, and
then passing that new class to `falcon.API()` by way of the
latter's `request_type` parameter.
Note:
When overriding `context_type` with a factory function (as
opposed to a class), the function is called like a method of
the current Request instance. Therefore the first argument is
the Request instance itself (self).
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.
user_agent (str): Value of the User-Agent header, or ``None`` if the
header is missing.
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 indicates
that the client is willing to receive JSON, otherwise ``False``.
client_accepts_msgpack (bool): ``True`` if the Accept header indicates
that the client is willing to receive MessagePack, otherwise
``False``.
client_accepts_xml (bool): ``True`` if the Accept header indicates that
the client is willing to receive 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, and
the :py:attr:`~.RequestOptions.auto_parse_form_urlencoded`
option is set, the framework
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.
date (datetime): Value of the Date header, converted to a
``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.)
range_unit (str): Unit of the range parsed from the value of the
Range header, or ``None`` if the header is missing
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 (datetime): Value of the If-Modified-Since header,
or ``None`` if the header is missing.
if_unmodified_since (datetime): Value of the If-Unmodified-Since
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.
cookies (dict):
A dict of name/value cookie pairs.
See also: :ref:`Getting Cookies <getting-cookies>`
"""
__slots__ = (
'_cached_headers',
'_cached_uri',
'_cached_relative_uri',
'content_type',
'env',
'method',
'_params',
'path',
'query_string',
'stream',
'context',
'_wsgierrors',
'options',
'_cookies',
'_cached_access_route',
)
# Allow child classes to override this
context_type = None
def __init__(self, env, options=None):
global _maybe_wrap_wsgi_stream
self.env = env
self.options = options if options else RequestOptions()
self._wsgierrors = env['wsgi.errors']
self.stream = env['wsgi.input']
self.method = env['REQUEST_METHOD']
# Normalize path
path = env['PATH_INFO']
if path:
if six.PY3:
# PEP 3333 specifies that PATH_INFO variable are always
# "bytes tunneled as latin-1" and must be encoded back
path = path.encode('latin1').decode('utf-8', 'replace')
if len(path) != 1 and path.endswith('/'):
self.path = path[:-1]
else:
self.path = path
else:
self.path = '/'
# PERF(ueg1990): try/catch cheaper and faster (and more Pythonic)
try:
self.query_string = env['QUERY_STRING']
except KeyError:
self.query_string = ''
self._params = {}
else:
if self.query_string:
self._params = parse_query_string(
self.query_string,
keep_blank_qs_values=self.options.keep_blank_qs_values,
parse_qs_csv=self.options.auto_parse_qs_csv,
)
else:
self._params = {}
self._cookies = None
self._cached_headers = None
self._cached_uri = None
self._cached_relative_uri = None
self._cached_access_route = 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 _maybe_wrap_wsgi_stream:
if isinstance(self.stream, (NativeStream, InputWrapper,)):
self._wrap_stream()
else:
# PERF(kgriffs): If self.stream does not need to be wrapped
# this time, it never needs to be wrapped since the server
# will continue using the same type for wsgi.input.
_maybe_wrap_wsgi_stream = False
# 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.options.auto_parse_form_urlencoded and
self.content_type is not None and
'application/x-www-form-urlencoded' in self.content_type):
self._parse_form_urlencoded()
if self.context_type is None:
# Literal syntax is more efficient than using dict()
self.context = {}
else:
self.context = self.context_type()
# ------------------------------------------------------------------------
# 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_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') or
self.client_accepts('application/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 errors.HTTPInvalidHeader(msg, 'Content-Length')
if value_as_int < 0:
msg = 'The value of the header must be a positive number.'
raise errors.HTTPInvalidHeader(msg, 'Content-Length')
return value_as_int
@property
def date(self):
return self.get_header_as_datetime('Date')
@property
def if_modified_since(self):
return self.get_header_as_datetime('If-Modified-Since')
@property
def if_unmodified_since(self):
return self.get_header_as_datetime('If-Unmodified-Since')
@property
def range(self):
try:
value = self.env['HTTP_RANGE']
if '=' in value:
unit, sep, req_range = value.partition('=')
else:
msg = "The value must be prefixed with a range unit, e.g. 'bytes='"
raise errors.HTTPInvalidHeader(msg, 'Range')
except KeyError:
return None
if ',' in req_range:
msg = 'The value must be a continuous range.'
raise errors.HTTPInvalidHeader(msg, 'Range')
try:
first, sep, last = req_range.partition('-')
if not sep:
raise ValueError()
if first:
return (int(first), int(last or -1))
elif last:
return (-int(last), -1)
else:
msg = 'The range offsets are missing.'
raise errors.HTTPInvalidHeader(msg, 'Range')
except ValueError:
href = 'http://goo.gl/zZ6Ey'
href_text = 'HTTP/1.1 Range Requests'
msg = ('It must be a range formatted according to RFC 7233.')
raise errors.HTTPInvalidHeader(msg, 'Range', href=href,
href_text=href_text)
@property
def range_unit(self):
try:
value = self.env['HTTP_RANGE']
if '=' in value:
unit, sep, req_range = value.partition('=')
return unit
else:
msg = "The value must be prefixed with a range unit, e.g. 'bytes='"
raise errors.HTTPInvalidHeader(msg, 'Range')
except KeyError:
return None
@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 = 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
@property
def cookies(self):
if self._cookies is None:
# NOTE(tbug): We might want to look into parsing
# cookies ourselves. The SimpleCookie is doing a
# lot if stuff only required to SEND cookies.
parser = SimpleCookie(self.get_header('Cookie'))
cookies = {}
for morsel in parser.values():
cookies[morsel.key] = morsel.value
self._cookies = cookies
return self._cookies.copy()
@property
def access_route(self):
if self._cached_access_route is None:
# NOTE(kgriffs): Try different headers in order of
# preference; if none are found, fall back to REMOTE_ADDR.
#
# If one of these headers is present, but its value is
# malformed such that we end up with an empty list, or
# a non-empty list containing malformed values, go ahead
# and return the results as-is. The alternative would be
# to fall back to another header or to REMOTE_ADDR, but
# that only masks the problem; the operator needs to be
# aware that an upstream proxy is malfunctioning.
if 'HTTP_FORWARDED' in self.env:
self._cached_access_route = self._parse_rfc_forwarded()
elif 'HTTP_X_FORWARDED_FOR' in self.env:
addresses = self.env['HTTP_X_FORWARDED_FOR'].split(',')
self._cached_access_route = [ip.strip() for ip in addresses]
elif 'HTTP_X_REAL_IP' in self.env:
self._cached_access_route = [self.env['HTTP_X_REAL_IP']]
elif 'REMOTE_ADDR' in self.env:
self._cached_access_route = [self.env['REMOTE_ADDR']]
else:
self._cached_access_route = []
return self._cached_access_route
@property
def remote_addr(self):
return self.env.get('REMOTE_ADDR')
# ------------------------------------------------------------------------
# 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):
"""Retrieve the raw string value for the given header.
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 errors.HTTPMissingHeader(name)
def get_header_as_datetime(self, header, required=False, obs_date=False):
"""Return an HTTP header with HTTP-Date values as a datetime.
Args:
name (str): Header name, case-insensitive (e.g., 'Date')
required (bool, optional): Set to ``True`` to raise
``HTTPBadRequest`` instead of returning gracefully when the
header is not found (default ``False``).
obs_date (bool, optional): Support obs-date formats according to
RFC 7231, e.g.: "Sunday, 06-Nov-94 08:49:37 GMT"
(default ``False``).
Returns:
datetime: 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.
HttpInvalidHeader: The header contained a malformed/invalid value.
"""
try:
http_date = self.get_header(header, required=required)
return util.http_date_to_dt(http_date, obs_date=obs_date)
except TypeError:
# When the header does not exist and isn't required
return None
except ValueError:
msg = ('It must be formatted according to RFC 7231, '
'Section 7.1.1.1')
raise errors.HTTPInvalidHeader(msg, header)
def get_param(self, name, required=False, store=None, default=None):
"""Return the raw 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 `req.get_param_as_list()` to retrieve all the values.
Note:
Similar to the way multiple keys in form data is handled,
if a query parameter is assigned a comma-separated list of
values (e.g., 'foo=a,b,c'), only one of those values will be
returned, and it is undefined which one. Use
`req.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 ``None`` 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 present.
default (any, optional): If the param is not found returns the
given value instead of None
Returns:
str: The value of the param as a string, or ``None`` if param is
not found and is not required.
Raises:
HTTPBadRequest: A required param is missing from the request.
"""
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 default
raise errors.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 ``None`` 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 errors.HTTPInvalidParam(msg, name)
if min is not None and val < min:
msg = 'The value must be at least ' + str(min)
raise errors.HTTPInvalidParam(msg, name)
if max is not None and max < val:
msg = 'The value may not exceed ' + str(max)
raise errors.HTTPInvalidParam(msg, name)
if store is not None:
store[name] = val
return val
if not required:
return None
raise errors.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 boolean strings are supported::
TRUE_STRINGS = ('true', 'True', 'yes', '1')
FALSE_STRINGS = ('false', 'False', 'no', '0')
Args:
name (str): Parameter name, case-sensitive (e.g., 'detailed').
required (bool, optional): Set to ``True`` to raise
``HTTPBadRequest`` instead of returning ``None`` when the
parameter is not found or is not a recognized boolean
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``, an empty string value will be
treated as ``True``. Normally empty strings are ignored; if
you would like to recognize such parameters, you must set the
`keep_blank_qs_values` request option to ``True``. Request
options are set globally for each instance of ``falcon.API``
through the `req_options` attribute.
Returns:
bool: The value of the param if it is found and can be converted
to a ``bool``. If the param is not found, returns ``None``
unless required is ``True``.
Raises:
HTTPBadRequest: A required param is missing from the request.
"""
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 errors.HTTPInvalidParam(msg, name)
if store is not None:
store[name] = val
return val
if not required:
return None
raise errors.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., 'ids').
transform (callable, optional): An optional transform function
that takes as input each element in the list as a ``str`` and
outputs a transformed element for inclusion in the list that
will be returned. For example, passing ``int`` will
transform list items into numbers.
required (bool, optional): Set to ``True`` to raise
``HTTPBadRequest`` instead of returning ``None`` 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 (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, the following query strings would
both result in `['1', '3']`::
things=1,,3
things=1&things=&things=3
Raises:
HTTPBadRequest: A required param is missing from the request.
HTTPInvalidParam: A transform function raised an instance of
``ValueError``.
"""
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 errors.HTTPInvalidParam(msg, name)
if store is not None:
store[name] = items
return items
if not required:
return None
raise errors.HTTPMissingParam(name)
def get_param_as_date(self, name, format_string='%Y-%m-%d',
required=False, store=None):
"""Return the value of a query string parameter as a date.
Args:
name (str): Parameter name, case-sensitive (e.g., 'ids').
format_string (str): String used to parse the param value into a
date.
Any format recognized by strptime() is supported.
(default ``"%Y-%m-%d"``)
required (bool, optional): Set to ``True`` to raise
``HTTPBadRequest`` instead of returning ``None`` 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 (default
``None``).
Returns:
datetime.date: The value of the param if it is found and can be
converted to a ``date`` according to the supplied format
string. If the param is not found, returns ``None`` unless
required is ``True``.
Raises:
HTTPBadRequest: A required param is missing from the request.
HTTPInvalidParam: A transform function raised an instance of
``ValueError``.
"""
param_value = self.get_param(name, required=required)
if param_value is None:
return None
try:
date = strptime(param_value, format_string).date()
except ValueError:
msg = 'The date value does not match the required format.'
raise errors.HTTPInvalidParam(msg, name)
if store is not None:
store[name] = date
return date
def get_param_as_dict(self, name, required=False, store=None):
"""Return the value of a query string parameter as a dict.
Given a JSON value, parse and return it as a dict.
Args:
name (str): Parameter name, case-sensitive (e.g., 'payload').
required (bool, optional): Set to ``True`` to raise
``HTTPBadRequest`` instead of returning ``None`` 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 (default
``None``).
Returns:
dict: The value of the param if it is found. Otherwise, returns
``None`` unless required is ``True``.
Raises:
HTTPBadRequest: A required param is missing from the request.
HTTPInvalidParam: The parameter's value could not be parsed as JSON.
"""
param_value = self.get_param(name, required=required)
if param_value is None:
return None
try:
val = json.loads(param_value)
except ValueError:
msg = 'It could not be parsed as JSON.'
raise errors.HTTPInvalidParam(msg, name)
if store is not None:
store[name] = val
return val
def log_error(self, message):
"""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 or unicode): Description of the problem. On Python 2,
instances of ``unicode`` 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(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:
content_length = self.content_length or 0
# NOTE(kgriffs): This branch is indeed covered in test_wsgi.py
# even though coverage isn't able to detect it.
except errors.HTTPInvalidHeader: # pragma: no cover
# NOTE(kgriffs): The content-length header was specified,
# but it had an invalid value. Assume no content.
content_length = 0
self.stream = helpers.Body(self.stream, content_length)
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 = parse_query_string(
body,
keep_blank_qs_values=self.options.keep_blank_qs_values,
parse_qs_csv=self.options.auto_parse_qs_csv,
)
self._params.update(extra_params)
def _parse_rfc_forwarded(self):
"""Parse RFC 7239 "Forwarded" header.
Returns:
list: addresses derived from "for" parameters.
"""
addr = []
for forwarded in self.env['HTTP_FORWARDED'].split(','):
for param in forwarded.split(';'):
# PERF(kgriffs): Partition() is faster than split().
key, _, val = param.strip().partition('=')
if not val:
# NOTE(kgriffs): The '=' separator was not found or
# it was, but the value was missing.
continue
if key.lower() != 'for':
# We only want "for" params
continue
host, _ = parse_host(unquote_string(val))
addr.append(host)
return addr
# PERF: To avoid typos and improve storage space and speed over a dict.
class RequestOptions(object):
"""This class is a container for ``Request`` options.
Attributes:
keep_blank_qs_values (bool): Set to ``True`` to keep query string
fields even if they do not have a value (default ``False``).
For comma-separated values, this option also determines
whether or not empty elements in the parsed list are
retained.
auto_parse_form_urlencoded: Set to ``True`` in order to
automatically consume the request stream and merge the
results into the request's query string params when the
request's content type is
*application/x-www-form-urlencoded* (default ``False``). In
this case, the request's content stream will be left at EOF.
Note:
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).
auto_parse_qs_csv: Set to ``False`` to treat commas in a query
string value as literal characters, rather than as a comma-
separated list (default ``True``). When this option is
enabled, the value will be split on any non-percent-encoded
commas. Disable this option when encoding lists as multiple
occurrences of the same parameter, and when values may be
encoded in alternative formats in which the comma character
is significant.
"""
__slots__ = (
'keep_blank_qs_values',
'auto_parse_form_urlencoded',
'auto_parse_qs_csv',
)
def __init__(self):
self.keep_blank_qs_values = False
self.auto_parse_form_urlencoded = False
self.auto_parse_qs_csv = True
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