445 lines
14 KiB
Python
445 lines
14 KiB
Python
#!/usr/bin/env python
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#
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# Copyright 2009 Facebook
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#
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# Licensed under the Apache License, Version 2.0 (the "License"); you may
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# not use this file except in compliance with the License. You may obtain
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# a copy of the License at
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#
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# http://www.apache.org/licenses/LICENSE-2.0
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#
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# Unless required by applicable law or agreed to in writing, software
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# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
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# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
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# License for the specific language governing permissions and limitations
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# under the License.
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"""HTTP utility code shared by clients and servers."""
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from __future__ import absolute_import, division, print_function, with_statement
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import calendar
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import collections
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import datetime
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import email.utils
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import numbers
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import time
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from tornado.escape import native_str, parse_qs_bytes, utf8
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from tornado.log import gen_log
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from tornado.util import ObjectDict
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try:
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from httplib import responses # py2
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except ImportError:
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from http.client import responses # py3
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# responses is unused in this file, but we re-export it to other files.
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# Reference it so pyflakes doesn't complain.
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responses
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try:
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from urllib import urlencode # py2
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except ImportError:
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from urllib.parse import urlencode # py3
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class _NormalizedHeaderCache(dict):
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"""Dynamic cached mapping of header names to Http-Header-Case.
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Implemented as a dict subclass so that cache hits are as fast as a
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normal dict lookup, without the overhead of a python function
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call.
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>>> normalized_headers = _NormalizedHeaderCache(10)
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>>> normalized_headers["coNtent-TYPE"]
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'Content-Type'
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"""
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def __init__(self, size):
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super(_NormalizedHeaderCache, self).__init__()
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self.size = size
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self.queue = collections.deque()
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def __missing__(self, key):
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normalized = "-".join([w.capitalize() for w in key.split("-")])
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self[key] = normalized
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self.queue.append(key)
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if len(self.queue) > self.size:
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# Limit the size of the cache. LRU would be better, but this
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# simpler approach should be fine. In Python 2.7+ we could
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# use OrderedDict (or in 3.2+, @functools.lru_cache).
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old_key = self.queue.popleft()
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del self[old_key]
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return normalized
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_normalized_headers = _NormalizedHeaderCache(1000)
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class HTTPHeaders(dict):
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"""A dictionary that maintains ``Http-Header-Case`` for all keys.
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Supports multiple values per key via a pair of new methods,
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`add()` and `get_list()`. The regular dictionary interface
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returns a single value per key, with multiple values joined by a
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comma.
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>>> h = HTTPHeaders({"content-type": "text/html"})
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>>> list(h.keys())
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['Content-Type']
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>>> h["Content-Type"]
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'text/html'
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>>> h.add("Set-Cookie", "A=B")
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>>> h.add("Set-Cookie", "C=D")
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>>> h["set-cookie"]
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'A=B,C=D'
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>>> h.get_list("set-cookie")
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['A=B', 'C=D']
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>>> for (k,v) in sorted(h.get_all()):
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... print('%s: %s' % (k,v))
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...
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Content-Type: text/html
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Set-Cookie: A=B
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Set-Cookie: C=D
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"""
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def __init__(self, *args, **kwargs):
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# Don't pass args or kwargs to dict.__init__, as it will bypass
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# our __setitem__
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dict.__init__(self)
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self._as_list = {}
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self._last_key = None
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if (len(args) == 1 and len(kwargs) == 0 and
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isinstance(args[0], HTTPHeaders)):
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# Copy constructor
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for k, v in args[0].get_all():
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self.add(k, v)
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else:
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# Dict-style initialization
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self.update(*args, **kwargs)
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# new public methods
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def add(self, name, value):
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"""Adds a new value for the given key."""
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norm_name = _normalized_headers[name]
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self._last_key = norm_name
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if norm_name in self:
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# bypass our override of __setitem__ since it modifies _as_list
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dict.__setitem__(self, norm_name,
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native_str(self[norm_name]) + ',' +
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native_str(value))
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self._as_list[norm_name].append(value)
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else:
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self[norm_name] = value
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def get_list(self, name):
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"""Returns all values for the given header as a list."""
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norm_name = _normalized_headers[name]
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return self._as_list.get(norm_name, [])
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def get_all(self):
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"""Returns an iterable of all (name, value) pairs.
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If a header has multiple values, multiple pairs will be
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returned with the same name.
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"""
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for name, values in self._as_list.items():
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for value in values:
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yield (name, value)
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def parse_line(self, line):
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"""Updates the dictionary with a single header line.
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>>> h = HTTPHeaders()
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>>> h.parse_line("Content-Type: text/html")
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>>> h.get('content-type')
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'text/html'
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"""
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if line[0].isspace():
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# continuation of a multi-line header
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new_part = ' ' + line.lstrip()
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self._as_list[self._last_key][-1] += new_part
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dict.__setitem__(self, self._last_key,
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self[self._last_key] + new_part)
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else:
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name, value = line.split(":", 1)
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self.add(name, value.strip())
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@classmethod
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def parse(cls, headers):
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"""Returns a dictionary from HTTP header text.
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>>> h = HTTPHeaders.parse("Content-Type: text/html\\r\\nContent-Length: 42\\r\\n")
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>>> sorted(h.items())
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[('Content-Length', '42'), ('Content-Type', 'text/html')]
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"""
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h = cls()
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for line in headers.splitlines():
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if line:
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h.parse_line(line)
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return h
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# dict implementation overrides
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def __setitem__(self, name, value):
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norm_name = _normalized_headers[name]
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dict.__setitem__(self, norm_name, value)
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self._as_list[norm_name] = [value]
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def __getitem__(self, name):
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return dict.__getitem__(self, _normalized_headers[name])
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def __delitem__(self, name):
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norm_name = _normalized_headers[name]
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dict.__delitem__(self, norm_name)
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del self._as_list[norm_name]
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def __contains__(self, name):
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norm_name = _normalized_headers[name]
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return dict.__contains__(self, norm_name)
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def get(self, name, default=None):
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return dict.get(self, _normalized_headers[name], default)
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def update(self, *args, **kwargs):
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# dict.update bypasses our __setitem__
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for k, v in dict(*args, **kwargs).items():
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self[k] = v
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def copy(self):
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# default implementation returns dict(self), not the subclass
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return HTTPHeaders(self)
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def url_concat(url, args):
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"""Concatenate url and argument dictionary regardless of whether
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url has existing query parameters.
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>>> url_concat("http://example.com/foo?a=b", dict(c="d"))
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'http://example.com/foo?a=b&c=d'
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"""
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if not args:
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return url
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if url[-1] not in ('?', '&'):
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url += '&' if ('?' in url) else '?'
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return url + urlencode(args)
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class HTTPFile(ObjectDict):
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"""Represents a file uploaded via a form.
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For backwards compatibility, its instance attributes are also
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accessible as dictionary keys.
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* ``filename``
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* ``body``
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* ``content_type``
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"""
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pass
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def _parse_request_range(range_header):
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"""Parses a Range header.
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Returns either ``None`` or tuple ``(start, end)``.
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Note that while the HTTP headers use inclusive byte positions,
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this method returns indexes suitable for use in slices.
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>>> start, end = _parse_request_range("bytes=1-2")
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>>> start, end
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(1, 3)
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>>> [0, 1, 2, 3, 4][start:end]
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[1, 2]
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>>> _parse_request_range("bytes=6-")
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(6, None)
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>>> _parse_request_range("bytes=-6")
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(-6, None)
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>>> _parse_request_range("bytes=-0")
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(None, 0)
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>>> _parse_request_range("bytes=")
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(None, None)
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>>> _parse_request_range("foo=42")
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>>> _parse_request_range("bytes=1-2,6-10")
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Note: only supports one range (ex, ``bytes=1-2,6-10`` is not allowed).
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See [0] for the details of the range header.
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[0]: http://greenbytes.de/tech/webdav/draft-ietf-httpbis-p5-range-latest.html#byte.ranges
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"""
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unit, _, value = range_header.partition("=")
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unit, value = unit.strip(), value.strip()
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if unit != "bytes":
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return None
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start_b, _, end_b = value.partition("-")
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try:
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start = _int_or_none(start_b)
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end = _int_or_none(end_b)
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except ValueError:
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return None
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if end is not None:
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if start is None:
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if end != 0:
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start = -end
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end = None
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else:
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end += 1
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return (start, end)
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def _get_content_range(start, end, total):
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"""Returns a suitable Content-Range header:
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>>> print(_get_content_range(None, 1, 4))
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bytes 0-0/4
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>>> print(_get_content_range(1, 3, 4))
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bytes 1-2/4
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>>> print(_get_content_range(None, None, 4))
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bytes 0-3/4
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"""
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start = start or 0
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end = (end or total) - 1
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return "bytes %s-%s/%s" % (start, end, total)
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def _int_or_none(val):
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val = val.strip()
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if val == "":
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return None
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return int(val)
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def parse_body_arguments(content_type, body, arguments, files):
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"""Parses a form request body.
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Supports ``application/x-www-form-urlencoded`` and
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``multipart/form-data``. The ``content_type`` parameter should be
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a string and ``body`` should be a byte string. The ``arguments``
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and ``files`` parameters are dictionaries that will be updated
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with the parsed contents.
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"""
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if content_type.startswith("application/x-www-form-urlencoded"):
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uri_arguments = parse_qs_bytes(native_str(body), keep_blank_values=True)
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for name, values in uri_arguments.items():
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if values:
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arguments.setdefault(name, []).extend(values)
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elif content_type.startswith("multipart/form-data"):
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fields = content_type.split(";")
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for field in fields:
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k, sep, v = field.strip().partition("=")
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if k == "boundary" and v:
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parse_multipart_form_data(utf8(v), body, arguments, files)
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break
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else:
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gen_log.warning("Invalid multipart/form-data")
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def parse_multipart_form_data(boundary, data, arguments, files):
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"""Parses a ``multipart/form-data`` body.
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The ``boundary`` and ``data`` parameters are both byte strings.
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The dictionaries given in the arguments and files parameters
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will be updated with the contents of the body.
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"""
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# The standard allows for the boundary to be quoted in the header,
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# although it's rare (it happens at least for google app engine
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# xmpp). I think we're also supposed to handle backslash-escapes
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# here but I'll save that until we see a client that uses them
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# in the wild.
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if boundary.startswith(b'"') and boundary.endswith(b'"'):
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boundary = boundary[1:-1]
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final_boundary_index = data.rfind(b"--" + boundary + b"--")
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if final_boundary_index == -1:
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gen_log.warning("Invalid multipart/form-data: no final boundary")
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return
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parts = data[:final_boundary_index].split(b"--" + boundary + b"\r\n")
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for part in parts:
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if not part:
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continue
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eoh = part.find(b"\r\n\r\n")
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if eoh == -1:
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gen_log.warning("multipart/form-data missing headers")
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continue
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headers = HTTPHeaders.parse(part[:eoh].decode("utf-8"))
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disp_header = headers.get("Content-Disposition", "")
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disposition, disp_params = _parse_header(disp_header)
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if disposition != "form-data" or not part.endswith(b"\r\n"):
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gen_log.warning("Invalid multipart/form-data")
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continue
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value = part[eoh + 4:-2]
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if not disp_params.get("name"):
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gen_log.warning("multipart/form-data value missing name")
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continue
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name = disp_params["name"]
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if disp_params.get("filename"):
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ctype = headers.get("Content-Type", "application/unknown")
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files.setdefault(name, []).append(HTTPFile(
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filename=disp_params["filename"], body=value,
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content_type=ctype))
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else:
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arguments.setdefault(name, []).append(value)
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def format_timestamp(ts):
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"""Formats a timestamp in the format used by HTTP.
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The argument may be a numeric timestamp as returned by `time.time`,
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a time tuple as returned by `time.gmtime`, or a `datetime.datetime`
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object.
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>>> format_timestamp(1359312200)
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'Sun, 27 Jan 2013 18:43:20 GMT'
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"""
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if isinstance(ts, numbers.Real):
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pass
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elif isinstance(ts, (tuple, time.struct_time)):
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ts = calendar.timegm(ts)
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elif isinstance(ts, datetime.datetime):
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ts = calendar.timegm(ts.utctimetuple())
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else:
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raise TypeError("unknown timestamp type: %r" % ts)
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return email.utils.formatdate(ts, usegmt=True)
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# _parseparam and _parse_header are copied and modified from python2.7's cgi.py
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# The original 2.7 version of this code did not correctly support some
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# combinations of semicolons and double quotes.
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def _parseparam(s):
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while s[:1] == ';':
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s = s[1:]
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end = s.find(';')
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while end > 0 and (s.count('"', 0, end) - s.count('\\"', 0, end)) % 2:
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end = s.find(';', end + 1)
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if end < 0:
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end = len(s)
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f = s[:end]
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yield f.strip()
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s = s[end:]
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def _parse_header(line):
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"""Parse a Content-type like header.
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Return the main content-type and a dictionary of options.
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"""
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parts = _parseparam(';' + line)
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key = next(parts)
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pdict = {}
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for p in parts:
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i = p.find('=')
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if i >= 0:
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name = p[:i].strip().lower()
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value = p[i + 1:].strip()
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if len(value) >= 2 and value[0] == value[-1] == '"':
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value = value[1:-1]
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value = value.replace('\\\\', '\\').replace('\\"', '"')
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pdict[name] = value
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return key, pdict
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def doctests():
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import doctest
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return doctest.DocTestSuite()
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