Files
deb-python-falcon/falcon/request.py
kgriffs 6cf8c6e2b7 doc: Remove module docstrings
The docstrings were only adding clutter to the generated docs on RTD.
2014-04-04 15:40:34 -05:00

752 lines
26 KiB
Python

# 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 HTTPBadRequest
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')
class InvalidHeaderValueError(HTTPBadRequest):
def __init__(self, msg, href=None, href_text=None):
super(InvalidHeaderValueError, self).__init__(
'Invalid header value', msg, href=href, href_text=None)
class InvalidParamValueError(HTTPBadRequest):
def __init__(self, msg, href=None, href_text=None):
super(InvalidParamValueError, self).__init__(
'Invalid query parameter', msg, href=href, href_text=None)
class Request(object):
"""Represents a client's HTTP request
Attributes:
method (str): HTTP method requested (e.g., GET, POST, etc.)
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.
stream: Stream-like object for reading the body of the request, if any.
"""
__slots__ = (
'_cached_headers',
'_cached_uri',
'_cached_relative_uri',
'env',
'method',
'_params',
'path',
'query_string',
'stream',
'_wsgierrors'
)
def __init__(self, env):
"""Initialize attributes based on a WSGI environment dict
Note: Request is not meant to be instantiated directory by responders.
Args:
env (dict): A WSGI environment dict passed in from the server. See
also the PEP-3333 spec.
"""
self.env = env
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 = '/'
# QUERY_STRING isn't required to be in env, so let's check
# PERF: if...in is faster than using env.get(...)
if 'QUERY_STRING' in env and env['QUERY_STRING']:
# TODO(kgriffs): Should this escape individual values instead
# of the entire string? The way it is now, this:
#
# x=ab%2Bcd%3D42%2C9
#
# becomes this:
#
# x=ab+cd=42,9
#
self.query_string = uri.decode(env['QUERY_STRING'])
else:
self.query_string = six.text_type()
# PERF: Don't parse it if we don't have to!
if self.query_string:
self._params = uri.parse_query_string(self.query_string)
else:
self._params = {}
helpers.normalize_headers(env)
self._cached_headers = {}
self._cached_uri = None
self._cached_relative_uri = 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): # pragma: nocover
# NOTE(kgriffs): coverage can't detect that this *is* actually
# covered since the test that does so uses multiprocessing.
self.stream = helpers.Body(self.stream, self.content_length)
# TODO(kgriffs): Use the nocover pragma only for the six.PY3 if..else
def log_error(self, message): # pragma: no cover
"""Log an error to wsgi.error
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')
@property
def client_accepts_json(self):
"""Return True if the Accept header indicates JSON support."""
return self.client_accepts('application/json')
@property
def client_accepts_xml(self):
"""Return True if the Accept header indicates XML support."""
return self.client_accepts('application/xml')
def client_accepts(self, media_type):
"""Returns the client's preferred media type.
Args:
media_type (str): Media type to check
Returns:
bool: True IFF the client has indicated in the Accept header that
they accept at least one of the specified media types.
"""
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): One or more 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,
or None if the client does not accept any of the specified
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)
@property
def accept(self):
"""Value of the Accept header, or */* if not found per RFC."""
accept = self._get_header_by_wsgi_name('HTTP_ACCEPT')
# NOTE(kgriffs): Per RFC, missing accept header is
# equivalent to '*/*'
return '*/*' if accept is None else accept
@property
def app(self):
"""Name of the WSGI app (if using WSGI's notion of virtual hosting)."""
return self.env['SCRIPT_NAME']
@property
def auth(self):
"""Value of the Authorization header, or None if not found."""
return self._get_header_by_wsgi_name('HTTP_AUTHORIZATION')
@property
def content_length(self):
"""Value of the Content-Length header
Returns:
int: Value converted to an int, or None if missing.
Raises:
HTTPBadRequest: The header had a value, but it wasn't
formatted correctly or was a negative number.
"""
value = self._get_header_by_wsgi_name('HTTP_CONTENT_LENGTH')
if value:
try:
value_as_int = int(value)
except ValueError:
msg = ('The value of the content-length header must be '
'a number.')
raise InvalidHeaderValueError(msg)
if value_as_int < 0:
msg = ('The value of the content-length header must be '
'a positive number.')
raise InvalidHeaderValueError(msg)
else:
return value_as_int
return None
@property
def content_type(self):
"""Value of the Content-Type header, or None if not found."""
return self._get_header_by_wsgi_name('HTTP_CONTENT_TYPE')
@property
def date(self):
"""Value of the Date header, converted to a datetime instance.
Returns:
datetime.datetime: An instance of datetime.datetime representing
the value of the Date header, or None if the Date header is
not present in the request.
Raises:
HTTPBadRequest: The date value could not be parsed, likely
because it does not confrom to RFC 1123.
"""
http_date = self._get_header_by_wsgi_name('HTTP_DATE')
try:
return util.http_date_to_dt(http_date)
except ValueError:
msg = ('The value of the Date header could not be parsed. It '
'must be formatted according to RFC 1123.')
raise InvalidHeaderValueError(msg)
@property
def expect(self):
"""Value of the Expect header, or None if missing."""
return self._get_header_by_wsgi_name('HTTP_EXPECT')
@property
def if_match(self):
"""Value of the If-Match header, or None if missing."""
return self._get_header_by_wsgi_name('HTTP_IF_MATCH')
@property
def if_none_match(self):
"""Value of the If-None-Match header, or None if missing."""
return self._get_header_by_wsgi_name('HTTP_IF_NONE_MATCH')
@property
def if_modified_since(self):
"""Value of the If-Modified-Since header, or None if missing."""
return self._get_header_by_wsgi_name('HTTP_IF_MODIFIED_SINCE')
@property
def if_unmodified_since(self):
"""Value of the If-Unmodified-Since header, or None if missing."""
return self._get_header_by_wsgi_name('HTTP_IF_UNMODIFIED_SINCE')
@property
def if_range(self):
"""Value of the If-Range header, or None if missing."""
return self._get_header_by_wsgi_name('HTTP_IF_RANGE')
@property
def protocol(self):
"""Will be either 'http' or 'https'."""
return self.env['wsgi.url_scheme']
@property
def range(self):
"""A 2-member tuple representing the value of the Range header.
The two members correspond to 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.)
Returns:
int: Parse range value, or None if the header is not present.
Raises:
HTTPBadRequest: The header had a value, but it wasn't
formatted correctly.
"""
value = self._get_header_by_wsgi_name('HTTP_RANGE')
if value:
if ',' in value:
raise InvalidHeaderValueError('Only continuous byte ranges '
'are supported.')
try:
first, last = value.split('-')
if first:
return (int(first), int(last or -1))
elif last:
return (-int(last), -1)
else:
raise InvalidHeaderValueError(
'Range value is missing offsets')
except ValueError:
href = 'http://goo.gl/zZ6Ey'
href_text = 'HTTP/1.1 Range Requests'
raise InvalidHeaderValueError('Range string must be formatted '
'according to RFC 2616.',
href=href,
href_text=href_text)
return None
@property
def uri(self):
"""The fully-qualified URI for the request."""
if self._cached_uri is None:
# PERF: For small numbers of items, '+' is faster
# than ''.join(...). Concatenation is also generally
# faster than formatting.
value = (self.protocol + '://' +
self.get_header('host') +
self.app +
self.path)
if self.query_string:
value = value + '?' + self.query_string
self._cached_uri = value
return self._cached_uri
url = uri
"""Alias for uri"""
@property
def relative_uri(self):
"""The path + query string portion of the full URI."""
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 user_agent(self):
"""Value of the User-Agent string, or None if missing."""
return self._get_header_by_wsgi_name('HTTP_USER_AGENT')
@property
def headers(self):
"""Get raw HTTP headers
Build a temporary dictionary of dash-separated HTTP headers,
which can be used as a whole, like, to perform an HTTP request.
If you want to lookup a header, please use `get_header` instead.
Returns:
dict: A new dictionary of HTTP headers.
"""
# NOTE(kgriffs: First time here will cache the dict so all we
# have to do is clone it in the future.
if not self._cached_headers:
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
return self._cached_headers.copy()
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.
"""
# 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_' + name.upper().replace('-', '_')]
except KeyError:
if not required:
return None
description = 'The "' + name + '" header is required.'
raise HTTPBadRequest('Missing header', description)
def get_param(self, name, required=False, store=None):
"""Return the value of a query string parameter as a string
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:
if store is not None:
store[name] = params[name]
return params[name]
if not required:
return None
description = 'The "' + name + '" query parameter is required.'
raise HTTPBadRequest('Missing query parameter', description)
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]
try:
val = int(val)
except ValueError:
description = ('The value of the "' + name + '" query '
'parameter must be an integer.')
raise InvalidParamValueError(description)
if min is not None and val < min:
description = ('The value of the "' + name + '" query '
'parameter must be at least %d') % min
raise InvalidHeaderValueError(description)
if max is not None and max < val:
description = ('The value of the "' + name + '" query '
'parameter may not exceed %d') % max
raise InvalidHeaderValueError(description)
if store is not None:
store[name] = val
return val
if not required:
return None
description = 'The "' + name + '" query parameter is required.'
raise HTTPBadRequest('Missing query parameter', description)
def get_param_as_bool(self, name, required=False, store=None):
"""Return the value of a query string parameter as a boolean
The following bool-ish strings are supported:
True: ('true', 'True', 'yes')
False: ('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)
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 val in TRUE_STRINGS:
val = True
elif val in FALSE_STRINGS:
val = False
else:
description = ('The value of the "' + name + '" query '
'parameter must be "true" or "false".')
raise InvalidParamValueError(description)
if store is not None:
store[name] = val
return val
if not required:
return None
description = 'The "' + name + '" query parameter is required.'
raise HTTPBadRequest('Missing query parameter', description)
def get_param_as_list(self, name,
transform=None, required=False, store=None):
"""Return the value of a query string parameter as a list
Note that list items must be comma-separated.
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. for partial lists, None will be
returned as a placeholder. For example:
things=1,,3
would be returned as:
['1', None, '3']
while this:
things=,,,
would just be retured as:
[None, None, None, None]
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].split(',')
# PERF(kgriffs): Use if-else rather than a DRY approach
# that sets transform to a passthrough function; avoids
# function calling overhead.
if transform is None:
items = [i if i != '' else None
for i in items]
else:
try:
items = [transform(i) if i != '' else None
for i in items]
except ValueError:
desc = ('The value of the "' + name + '" query parameter '
'is not formatted correctly.')
raise InvalidParamValueError(desc)
if store is not None:
store[name] = items
return items
if not required:
return None
raise HTTPBadRequest('Missing query parameter',
'The "' + name + '" query parameter is required.')
# -------------------------------------------------------------------------
# Helpers
# -------------------------------------------------------------------------
def _get_header_by_wsgi_name(self, name):
"""Looks up a header, assuming name is already UPPERCASE_UNDERSCORE
Args:
name (str): Name of the header, already uppercased, and
underscored
Returns:
str: Value of the specified header, or None if the header was not
found. Also returns None if the value of the header was blank.
"""
try:
return self.env[name] or None
except KeyError:
return None