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deb-python-falcon/falcon/request.py
2013-03-18 10:21:44 -05:00

366 lines
12 KiB
Python

"""Defines the Request class.
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
import six
from falcon.request_helpers import *
from falcon.exceptions import *
DEFAULT_ERROR_LOG_FORMAT = ('{0:%Y-%m-%d %H:%M:%S} [FALCON] [ERROR]'
' {1} {2}?{3} => {4}\n')
class Request(object):
"""Represents a client's HTTP request
Attributes:
url: The fully-qualified request URL
protocol: Will be either 'http' or 'https'.
app: Name of the WSGI app (if using WSGI's notion of virtual hosting).
method: HTTP method requested (e.g., GET, POST, etc.)
path: Path portion of the request URL (not including query string).
query_string: Query string portion of the request URL.
stream: Stream-like object for reading the body of the request, if any.
accept: Value of the Accept header, or None if not found.
auth: Value of the Authorization header, or None if not found.
content_length: Value of the Content-Length header, converted to an
int, or None if missing or not an integer.
content_type: Value of the Content-Type header, or None if not found.
date: Value of the Date header, or None if missing.
expect: Value of the Expect header, or None if missing.
if_match: Value of the If-Match header, or None if missing.
if_none_match: Value of the If-None-Match header, or None if missing.
if_modified_since: Value of the If-Modified-Since header, or None if
missing.
if_unmodified_since: Value of the If-Unmodified-Since header, or None
if missing.
if_range: Value of the If-Range header, or None if missing.
range: A 2-member tuple representing the value of the Range header, or
None if missing. 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.
user_agent: Value of the User-Agent string, or None if not found.
"""
__slots__ = (
'app',
'_headers',
'method',
'_params',
'path',
'protocol',
'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: A WSGI environment dict passed in from the server. See also
the PEP-333 spec.
"""
self._wsgierrors = env['wsgi.errors']
self.stream = env['wsgi.input']
self.protocol = env['wsgi.url_scheme']
self.app = env['SCRIPT_NAME']
self.method = env['REQUEST_METHOD']
self.path = env['PATH_INFO'] or '/'
# QUERY_STRING isn't required to be in env, so let's check
if 'QUERY_STRING' in env:
self.query_string = query_string = env['QUERY_STRING']
else:
self.query_string = query_string = ''
self._params = parse_query_string(query_string)
self._headers = parse_headers(env)
def log_error(self, message):
"""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: A string describing the problem. If a byte-string and
running under Python 2, the string is assumed to be encoded
as UTF-8.
"""
if not six.PY3 and isinstance(message, unicode):
message = message.encode('utf-8')
log_line = (
DEFAULT_ERROR_LOG_FORMAT.
format(datetime.now(), self.method, self.path,
self.query_string, message)
)
self._wsgierrors.write(log_line)
def client_accepts_json(self):
"""Return True if the Accept header indicates JSON support"""
accept = self.get_header('Accept')
return ((accept is not None) and
(('application/json' in accept) or ('*/*' in accept)))
@property
def url(self):
return ''.join([
self.protocol,
'://',
self.get_header('host'),
self.app,
self.path,
self.query_string
])
@property
def accept(self):
return self._get_header_by_wsgi_name('ACCEPT')
@property
def auth(self):
return self._get_header_by_wsgi_name('AUTHORIZATION')
@property
def content_length(self):
value = self._get_header_by_wsgi_name('CONTENT_LENGTH')
if value is not None:
try:
return int(value)
except ValueError:
pass
return None
@property
def content_type(self):
return self._get_header_by_wsgi_name('CONTENT_TYPE')
@property
def date(self):
return self._get_header_by_wsgi_name('DATE')
@property
def expect(self):
return self._get_header_by_wsgi_name('EXPECT')
@property
def if_match(self):
return self._get_header_by_wsgi_name('IF_MATCH')
@property
def if_none_match(self):
return self._get_header_by_wsgi_name('IF_NONE_MATCH')
@property
def if_modified_since(self):
return self._get_header_by_wsgi_name('IF_MODIFIED_SINCE')
@property
def if_unmodified_since(self):
return self._get_header_by_wsgi_name('IF_UNMODIFIED_SINCE')
@property
def if_range(self):
return self._get_header_by_wsgi_name('IF_RANGE')
@property
def range(self):
value = self._get_header_by_wsgi_name('RANGE')
if (value is None) or ('-' not in value):
return None
try:
first, last = value.split('-')
except ValueError:
return None
if first:
if not last:
last = -1
return (int(first), int(last))
elif last:
return (-int(last), -1)
return None
@property
def user_agent(self):
return self._get_header_by_wsgi_name('USER_AGENT')
def get_header(self, name, required=False):
"""Return a header value as a string
Args:
name: Header name, case-insensitive (e.g., 'Content-Type')
required: Set to True to raise HttpBadRequest instead
of returning gracefully when the header is not found
(default False)
Returns:
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._headers[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):
"""Return the value of a query string parameter as a string
Args:
name: Parameter name, case-sensitive (e.g., 'sort')
required: Set to True to raise HTTPBadRequest instead of returning
gracefully when the parameter is not found (default False)
Returns:
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.
"""
# 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 self._params:
return self._params[name]
if not required:
return None
message = 'The "' + name + '" query parameter is required.'
raise HTTPBadRequest('Missing query parameter', message)
def get_param_as_int(self, name, required=False):
"""Return the value of a query string parameter as an int
Args:
name: Parameter name, case-sensitive (e.g., 'limit')
required: Set to True to raise HTTPBadRequest instead of returning
gracefully when the parameter is not found or is not an
integer (default False)
Returns:
The value of the param if it is found and can be converted to an
integer. Otherwise, returns None unless required is True.
Raises
HTTPBadRequest: The param was not found in the request, but was
required.
"""
# 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 self._params:
val = self._params[name]
try:
return int(val)
except ValueError:
pass
if not required:
return None
message = 'The "' + name + '" query parameter is required.'
raise HTTPBadRequest('Missing query parameter', message)
def get_param_as_list(self, name, required=False):
"""Return the value of a query string parameter as an int
Args:
name: Parameter name, case-sensitive (e.g., 'limit')
required: Set to True to raise HTTPBadRequest instead of returning
gracefully when the parameter is not found or is not an
integer (default False)
Returns:
The value of the param if it is found and can be converted to an
integer. Otherwise, returns None unless required is True.
Raises
HTTPBadRequest: The param was not found in the request, but was
required.
"""
# 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 self._params:
return self._params[name].split(',')
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: Name of the header, already uppercased, and underscored
Returns:
Value of the specified header, or None if not found
"""
try:
return self._headers[name]
except KeyError:
return None