Source code for tornado.httputil

#!/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, with_statement

import logging
import urllib
import re

from tornado.util import b, ObjectDict


[docs]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"}) >>> 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
[docs] def add(self, name, value): """Adds a new value for the given key.""" norm_name = HTTPHeaders._normalize_name(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, self[norm_name] + ',' + value) self._as_list[norm_name].append(value) else: self[norm_name] = value
[docs] def get_list(self, name): """Returns all values for the given header as a list.""" norm_name = HTTPHeaders._normalize_name(name) return self._as_list.get(norm_name, [])
[docs] 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, list in self._as_list.iteritems(): for value in list: yield (name, value)
[docs] 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
[docs] 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.iteritems()) [('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 = HTTPHeaders._normalize_name(name) dict.__setitem__(self, norm_name, value) self._as_list[norm_name] = [value] def __getitem__(self, name): return dict.__getitem__(self, HTTPHeaders._normalize_name(name)) def __delitem__(self, name): norm_name = HTTPHeaders._normalize_name(name) dict.__delitem__(self, norm_name) del self._as_list[norm_name] def __contains__(self, name): norm_name = HTTPHeaders._normalize_name(name) return dict.__contains__(self, norm_name) def get(self, name, default=None): return dict.get(self, HTTPHeaders._normalize_name(name), default) def update(self, *args, **kwargs): # dict.update bypasses our __setitem__ for k, v in dict(*args, **kwargs).iteritems(): self[k] = v def copy(self): # default implementation returns dict(self), not the subclass return HTTPHeaders(self) _NORMALIZED_HEADER_RE = re.compile(r'^[A-Z0-9][a-z0-9]*(-[A-Z0-9][a-z0-9]*)*$') _normalized_headers = {} @staticmethod def _normalize_name(name): """Converts a name to Http-Header-Case. >>> HTTPHeaders._normalize_name("coNtent-TYPE") 'Content-Type' """ try: return HTTPHeaders._normalized_headers[name] except KeyError: if HTTPHeaders._NORMALIZED_HEADER_RE.match(name): normalized = name else: normalized = "-".join([w.capitalize() for w in name.split("-")]) HTTPHeaders._normalized_headers[name] = normalized return normalized
[docs]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 + urllib.urlencode(args)
[docs]class HTTPFile(ObjectDict): """Represents an HTTP file. For backwards compatibility, its instance attributes are also accessible as dictionary keys. :ivar filename: :ivar body: :ivar content_type: The content_type comes from the provided HTTP header and should not be trusted outright given that it can be easily forged. """ pass
[docs]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: logging.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: logging.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")): logging.warning("Invalid multipart/form-data") continue value = part[eoh + 4:-2] if not disp_params.get("name"): logging.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) # _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 = parts.next() 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()

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