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calibre-web/lib/tornado/httputil.py

446 lines
14 KiB
Python

#!/usr/bin/env python
#
# Copyright 2009 Facebook
#
# 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.
"""HTTP utility code shared by clients and servers."""
from __future__ import absolute_import, division, print_function, with_statement
import calendar
import collections
import datetime
import email.utils
import numbers
import time
from tornado.escape import native_str, parse_qs_bytes, utf8
from tornado.log import gen_log
from tornado.util import ObjectDict
try:
from httplib import responses # py2
except ImportError:
from http.client import responses # py3
# responses is unused in this file, but we re-export it to other files.
# Reference it so pyflakes doesn't complain.
responses
try:
from urllib import urlencode # py2
except ImportError:
from urllib.parse import urlencode # py3
class _NormalizedHeaderCache(dict):
"""Dynamic cached mapping of header names to Http-Header-Case.
Implemented as a dict subclass so that cache hits are as fast as a
normal dict lookup, without the overhead of a python function
call.
>>> normalized_headers = _NormalizedHeaderCache(10)
>>> normalized_headers["coNtent-TYPE"]
'Content-Type'
"""
def __init__(self, size):
super(_NormalizedHeaderCache, self).__init__()
self.size = size
self.queue = collections.deque()
def __missing__(self, key):
normalized = "-".join([w.capitalize() for w in key.split("-")])
self[key] = normalized
self.queue.append(key)
if len(self.queue) > self.size:
# Limit the size of the cache. LRU would be better, but this
# simpler approach should be fine. In Python 2.7+ we could
# use OrderedDict (or in 3.2+, @functools.lru_cache).
old_key = self.queue.popleft()
del self[old_key]
return normalized
_normalized_headers = _NormalizedHeaderCache(1000)
class HTTPHeaders(dict):
"""A dictionary that maintains ``Http-Header-Case`` for all keys.
Supports multiple values per key via a pair of new methods,
`add()` and `get_list()`. The regular dictionary interface
returns a single value per key, with multiple values joined by a
comma.
>>> h = HTTPHeaders({"content-type": "text/html"})
>>> list(h.keys())
['Content-Type']
>>> h["Content-Type"]
'text/html'
>>> h.add("Set-Cookie", "A=B")
>>> h.add("Set-Cookie", "C=D")
>>> h["set-cookie"]
'A=B,C=D'
>>> h.get_list("set-cookie")
['A=B', 'C=D']
>>> for (k,v) in sorted(h.get_all()):
... print('%s: %s' % (k,v))
...
Content-Type: text/html
Set-Cookie: A=B
Set-Cookie: C=D
"""
def __init__(self, *args, **kwargs):
# Don't pass args or kwargs to dict.__init__, as it will bypass
# our __setitem__
dict.__init__(self)
self._as_list = {}
self._last_key = None
if (len(args) == 1 and len(kwargs) == 0 and
isinstance(args[0], HTTPHeaders)):
# Copy constructor
for k, v in args[0].get_all():
self.add(k, v)
else:
# Dict-style initialization
self.update(*args, **kwargs)
# new public methods
def add(self, name, value):
"""Adds a new value for the given key."""
norm_name = _normalized_headers[name]
self._last_key = norm_name
if norm_name in self:
# bypass our override of __setitem__ since it modifies _as_list
dict.__setitem__(self, norm_name,
native_str(self[norm_name]) + ',' +
native_str(value))
self._as_list[norm_name].append(value)
else:
self[norm_name] = value
def get_list(self, name):
"""Returns all values for the given header as a list."""
norm_name = _normalized_headers[name]
return self._as_list.get(norm_name, [])
def get_all(self):
"""Returns an iterable of all (name, value) pairs.
If a header has multiple values, multiple pairs will be
returned with the same name.
"""
for name, values in self._as_list.items():
for value in values:
yield (name, value)
def parse_line(self, line):
"""Updates the dictionary with a single header line.
>>> h = HTTPHeaders()
>>> h.parse_line("Content-Type: text/html")
>>> h.get('content-type')
'text/html'
"""
if line[0].isspace():
# continuation of a multi-line header
new_part = ' ' + line.lstrip()
self._as_list[self._last_key][-1] += new_part
dict.__setitem__(self, self._last_key,
self[self._last_key] + new_part)
else:
name, value = line.split(":", 1)
self.add(name, value.strip())
@classmethod
def parse(cls, headers):
"""Returns a dictionary from HTTP header text.
>>> h = HTTPHeaders.parse("Content-Type: text/html\\r\\nContent-Length: 42\\r\\n")
>>> sorted(h.items())
[('Content-Length', '42'), ('Content-Type', 'text/html')]
"""
h = cls()
for line in headers.splitlines():
if line:
h.parse_line(line)
return h
# dict implementation overrides
def __setitem__(self, name, value):
norm_name = _normalized_headers[name]
dict.__setitem__(self, norm_name, value)
self._as_list[norm_name] = [value]
def __getitem__(self, name):
return dict.__getitem__(self, _normalized_headers[name])
def __delitem__(self, name):
norm_name = _normalized_headers[name]
dict.__delitem__(self, norm_name)
del self._as_list[norm_name]
def __contains__(self, name):
norm_name = _normalized_headers[name]
return dict.__contains__(self, norm_name)
def get(self, name, default=None):
return dict.get(self, _normalized_headers[name], default)
def update(self, *args, **kwargs):
# dict.update bypasses our __setitem__
for k, v in dict(*args, **kwargs).items():
self[k] = v
def copy(self):
# default implementation returns dict(self), not the subclass
return HTTPHeaders(self)
def url_concat(url, args):
"""Concatenate url and argument dictionary regardless of whether
url has existing query parameters.
>>> url_concat("http://example.com/foo?a=b", dict(c="d"))
'http://example.com/foo?a=b&c=d'
"""
if not args:
return url
if url[-1] not in ('?', '&'):
url += '&' if ('?' in url) else '?'
return url + urlencode(args)
class HTTPFile(ObjectDict):
"""Represents a file uploaded via a form.
For backwards compatibility, its instance attributes are also
accessible as dictionary keys.
* ``filename``
* ``body``
* ``content_type``
"""
pass
def _parse_request_range(range_header):
"""Parses a Range header.
Returns either ``None`` or tuple ``(start, end)``.
Note that while the HTTP headers use inclusive byte positions,
this method returns indexes suitable for use in slices.
>>> start, end = _parse_request_range("bytes=1-2")
>>> start, end
(1, 3)
>>> [0, 1, 2, 3, 4][start:end]
[1, 2]
>>> _parse_request_range("bytes=6-")
(6, None)
>>> _parse_request_range("bytes=-6")
(-6, None)
>>> _parse_request_range("bytes=-0")
(None, 0)
>>> _parse_request_range("bytes=")
(None, None)
>>> _parse_request_range("foo=42")
>>> _parse_request_range("bytes=1-2,6-10")
Note: only supports one range (ex, ``bytes=1-2,6-10`` is not allowed).
See [0] for the details of the range header.
[0]: http://greenbytes.de/tech/webdav/draft-ietf-httpbis-p5-range-latest.html#byte.ranges
"""
unit, _, value = range_header.partition("=")
unit, value = unit.strip(), value.strip()
if unit != "bytes":
return None
start_b, _, end_b = value.partition("-")
try:
start = _int_or_none(start_b)
end = _int_or_none(end_b)
except ValueError:
return None
if end is not None:
if start is None:
if end != 0:
start = -end
end = None
else:
end += 1
return (start, end)
def _get_content_range(start, end, total):
"""Returns a suitable Content-Range header:
>>> print(_get_content_range(None, 1, 4))
bytes 0-0/4
>>> print(_get_content_range(1, 3, 4))
bytes 1-2/4
>>> print(_get_content_range(None, None, 4))
bytes 0-3/4
"""
start = start or 0
end = (end or total) - 1
return "bytes %s-%s/%s" % (start, end, total)
def _int_or_none(val):
val = val.strip()
if val == "":
return None
return int(val)
def parse_body_arguments(content_type, body, arguments, files):
"""Parses a form request body.
Supports ``application/x-www-form-urlencoded`` and
``multipart/form-data``. The ``content_type`` parameter should be
a string and ``body`` should be a byte string. The ``arguments``
and ``files`` parameters are dictionaries that will be updated
with the parsed contents.
"""
if content_type.startswith("application/x-www-form-urlencoded"):
uri_arguments = parse_qs_bytes(native_str(body), keep_blank_values=True)
for name, values in uri_arguments.items():
if values:
arguments.setdefault(name, []).extend(values)
elif content_type.startswith("multipart/form-data"):
fields = content_type.split(";")
for field in fields:
k, sep, v = field.strip().partition("=")
if k == "boundary" and v:
parse_multipart_form_data(utf8(v), body, arguments, files)
break
else:
gen_log.warning("Invalid multipart/form-data")
def parse_multipart_form_data(boundary, data, arguments, files):
"""Parses a ``multipart/form-data`` body.
The ``boundary`` and ``data`` parameters are both byte strings.
The dictionaries given in the arguments and files parameters
will be updated with the contents of the body.
"""
# The standard allows for the boundary to be quoted in the header,
# although it's rare (it happens at least for google app engine
# xmpp). I think we're also supposed to handle backslash-escapes
# here but I'll save that until we see a client that uses them
# in the wild.
if boundary.startswith(b'"') and boundary.endswith(b'"'):
boundary = boundary[1:-1]
final_boundary_index = data.rfind(b"--" + boundary + b"--")
if final_boundary_index == -1:
gen_log.warning("Invalid multipart/form-data: no final boundary")
return
parts = data[:final_boundary_index].split(b"--" + boundary + b"\r\n")
for part in parts:
if not part:
continue
eoh = part.find(b"\r\n\r\n")
if eoh == -1:
gen_log.warning("multipart/form-data missing headers")
continue
headers = HTTPHeaders.parse(part[:eoh].decode("utf-8"))
disp_header = headers.get("Content-Disposition", "")
disposition, disp_params = _parse_header(disp_header)
if disposition != "form-data" or not part.endswith(b"\r\n"):
gen_log.warning("Invalid multipart/form-data")
continue
value = part[eoh + 4:-2]
if not disp_params.get("name"):
gen_log.warning("multipart/form-data value missing name")
continue
name = disp_params["name"]
if disp_params.get("filename"):
ctype = headers.get("Content-Type", "application/unknown")
files.setdefault(name, []).append(HTTPFile(
filename=disp_params["filename"], body=value,
content_type=ctype))
else:
arguments.setdefault(name, []).append(value)
def format_timestamp(ts):
"""Formats a timestamp in the format used by HTTP.
The argument may be a numeric timestamp as returned by `time.time`,
a time tuple as returned by `time.gmtime`, or a `datetime.datetime`
object.
>>> format_timestamp(1359312200)
'Sun, 27 Jan 2013 18:43:20 GMT'
"""
if isinstance(ts, numbers.Real):
pass
elif isinstance(ts, (tuple, time.struct_time)):
ts = calendar.timegm(ts)
elif isinstance(ts, datetime.datetime):
ts = calendar.timegm(ts.utctimetuple())
else:
raise TypeError("unknown timestamp type: %r" % ts)
return email.utils.formatdate(ts, usegmt=True)
# _parseparam and _parse_header are copied and modified from python2.7's cgi.py
# The original 2.7 version of this code did not correctly support some
# combinations of semicolons and double quotes.
def _parseparam(s):
while s[:1] == ';':
s = s[1:]
end = s.find(';')
while end > 0 and (s.count('"', 0, end) - s.count('\\"', 0, end)) % 2:
end = s.find(';', end + 1)
if end < 0:
end = len(s)
f = s[:end]
yield f.strip()
s = s[end:]
def _parse_header(line):
"""Parse a Content-type like header.
Return the main content-type and a dictionary of options.
"""
parts = _parseparam(';' + line)
key = next(parts)
pdict = {}
for p in parts:
i = p.find('=')
if i >= 0:
name = p[:i].strip().lower()
value = p[i + 1:].strip()
if len(value) >= 2 and value[0] == value[-1] == '"':
value = value[1:-1]
value = value.replace('\\\\', '\\').replace('\\"', '"')
pdict[name] = value
return key, pdict
def doctests():
import doctest
return doctest.DocTestSuite()