"""HTTP library functions."""
# This module contains functions for building an HTTP application
# framework: any one, not just one whose name starts with "Ch". ;) If you
# reference any modules from some popular framework inside *this* module,
# FuManChu will personally hang you up by your thumbs and submit you
# to a public caning.
from binascii import b2a_base64
from BaseHTTPServer import BaseHTTPRequestHandler
response_codes = BaseHTTPRequestHandler.responses.copy()
# From http://www.cherrypy.org/ticket/361
response_codes[500] = ('Internal Server Error',
'The server encountered an unexpected condition '
'which prevented it from fulfilling the request.')
response_codes[503] = ('Service Unavailable',
'The server is currently unable to handle the '
'request due to a temporary overloading or '
'maintenance of the server.')
import re
import urllib
from rfc822 import formatdate as HTTPDate
def urljoin(*atoms):
"""Return the given path *atoms, joined into a single URL.
This will correctly join a SCRIPT_NAME and PATH_INFO into the
original URL, even if either atom is blank.
"""
url = "/".join([x for x in atoms if x])
while "//" in url:
url = url.replace("//", "/")
# Special-case the final url of "", and return "/" instead.
return url or "/"
def protocol_from_http(protocol_str):
"""Return a protocol tuple from the given 'HTTP/x.y' string."""
return int(protocol_str[5]), int(protocol_str[7])
def get_ranges(headervalue, content_length):
"""Return a list of (start, stop) indices from a Range header, or None.
Each (start, stop) tuple will be composed of two ints, which are suitable
for use in a slicing operation. That is, the header "Range: bytes=3-6",
if applied against a Python string, is requesting resource[3:7]. This
function will return the list [(3, 7)].
If this function returns an empty list, you should return HTTP 416.
"""
if not headervalue:
return None
result = []
bytesunit, byteranges = headervalue.split("=", 1)
for brange in byteranges.split(","):
start, stop = [x.strip() for x in brange.split("-", 1)]
if start:
if not stop:
stop = content_length - 1
start, stop = int(start), int(stop)
if start >= content_length:
# From rfc 2616 sec 14.16:
# "If the server receives a request (other than one
# including an If-Range request-header field) with an
# unsatisfiable Range request-header field (that is,
# all of whose byte-range-spec values have a first-byte-pos
# value greater than the current length of the selected
# resource), it SHOULD return a response code of 416
# (Requested range not satisfiable)."
continue
if stop < start:
# From rfc 2616 sec 14.16:
# "If the server ignores a byte-range-spec because it
# is syntactically invalid, the server SHOULD treat
# the request as if the invalid Range header field
# did not exist. (Normally, this means return a 200
# response containing the full entity)."
return None
result.append((start, stop + 1))
else:
if not stop:
# See rfc quote above.
return None
# Negative subscript (last N bytes)
result.append((content_length - int(stop), content_length))
return result
class HeaderElement(object):
"""An element (with parameters) from an HTTP header's element list."""
def __init__(self, value, params=None):
self.value = value
if params is None:
params = {}
self.params = params
def __cmp__(self, other):
return cmp(self.value, other.value)
def __unicode__(self):
p = [";%s=%s" % (k, v) for k, v in self.params.iteritems()]
return u"%s%s" % (self.value, "".join(p))
def __str__(self):
return str(self.__unicode__())
def parse(elementstr):
"""Transform 'token;key=val' to ('token', {'key': 'val'})."""
# Split the element into a value and parameters. The 'value' may
# be of the form, "token=token", but we don't split that here.
atoms = [x.strip() for x in elementstr.split(";") if x.strip()]
if not atoms:
initial_value = ''
else:
initial_value = atoms.pop(0).strip()
params = {}
for atom in atoms:
atom = [x.strip() for x in atom.split("=", 1) if x.strip()]
key = atom.pop(0)
if atom:
val = atom[0]
else:
val = ""
params[key] = val
return initial_value, params
parse = staticmethod(parse)
def from_str(cls, elementstr):
"""Construct an instance from a string of the form 'token;key=val'."""
ival, params = cls.parse(elementstr)
return cls(ival, params)
from_str = classmethod(from_str)
q_separator = re.compile(r'; *q *=')
class AcceptElement(HeaderElement):
"""An element (with parameters) from an Accept* header's element list.
AcceptElement objects are comparable; the more-preferred object will be
"less than" the less-preferred object. They are also therefore sortable;
if you sort a list of AcceptElement objects, they will be listed in
priority order; the most preferred value will be first. Yes, it should
have been the other way around, but it's too late to fix now.
"""
def from_str(cls, elementstr):
qvalue = None
# The first "q" parameter (if any) separates the initial
# media-range parameter(s) (if any) from the accept-params.
atoms = q_separator.split(elementstr, 1)
media_range = atoms.pop(0).strip()
if atoms:
# The qvalue for an Accept header can have extensions. The other
# headers cannot, but it's easier to parse them as if they did.
qvalue = HeaderElement.from_str(atoms[0].strip())
media_type, params = cls.parse(media_range)
if qvalue is not None:
params["q"] = qvalue
return cls(media_type, params)
from_str = classmethod(from_str)
def qvalue(self):
val = self.params.get("q", "1")
if isinstance(val, HeaderElement):
val = val.value
return float(val)
qvalue = property(qvalue, doc="The qvalue, or priority, of this value.")
def __cmp__(self, other):
diff = cmp(self.qvalue, other.qvalue)
if diff == 0:
diff = cmp(str(self), str(other))
return diff
def header_elements(fieldname, fieldvalue):
"""Return a sorted HeaderElement list from a comma-separated header str."""
if not fieldvalue:
return []
result = []
for element in fieldvalue.split(","):
if fieldname.startswith("Accept") or fieldname == 'TE':
hv = AcceptElement.from_str(element)
else:
hv = HeaderElement.from_str(element)
result.append(hv)
result.sort()
result.reverse()
return result
def decode_TEXT(value):
"""Decode RFC-2047 TEXT (e.g. "=?utf-8?q?f=C3=BCr?=" -> u"f\xfcr")."""
from email.Header import decode_header
atoms = decode_header(value)
decodedvalue = ""
for atom, charset in atoms:
if charset is not None:
atom = atom.decode(charset)
decodedvalue += atom
return decodedvalue
def valid_status(status):
"""Return legal HTTP status Code, Reason-phrase and Message.
The status arg must be an int, or a str that begins with an int.
If status is an int, or a str and no reason-phrase is supplied,
a default reason-phrase will be provided.
"""
if not status:
status = 200
status = str(status)
parts = status.split(" ", 1)
if len(parts) == 1:
# No reason supplied.
code, = parts
reason = None
else:
code, reason = parts
reason = reason.strip()
try:
code = int(code)
except ValueError:
raise ValueError("Illegal response status from server "
"(%s is non-numeric)." % repr(code))
if code < 100 or code > 599:
raise ValueError("Illegal response status from server "
"(%s is out of range)." % repr(code))
if code not in response_codes:
# code is unknown but not illegal
default_reason, message = "", ""
else:
default_reason, message = response_codes[code]
if reason is None:
reason = default_reason
return code, reason, message
def _parse_qs(qs, keep_blank_values=0, strict_parsing=0, encoding='utf-8'):
"""Parse a query given as a string argument.
Arguments:
qs: URL-encoded query string to be parsed
keep_blank_values: flag indicating whether blank values in
URL encoded queries should be treated as blank strings. A
true value indicates that blanks should be retained as blank
strings. The default false value indicates that blank values
are to be ignored and treated as if they were not included.
strict_parsing: flag indicating what to do with parsing errors. If
false (the default), errors are silently ignored. If true,
errors raise a ValueError exception.
Returns a dict, as G-d intended.
"""
pairs = [s2 for s1 in qs.split('&') for s2 in s1.split(';')]
d = {}
for name_value in pairs:
if not name_value and not strict_parsing:
continue
nv = name_value.split('=', 1)
if len(nv) != 2:
if strict_parsing:
raise ValueError("bad query field: %r" % (name_value,))
# Handle case of a control-name with no equal sign
if keep_blank_values:
nv.append('')
else:
continue
if len(nv[1]) or keep_blank_values:
name = urllib.unquote(nv[0].replace('+', ' '))
name = name.decode(encoding, 'strict')
value = urllib.unquote(nv[1].replace('+', ' '))
value = value.decode(encoding, 'strict')
if name in d:
if not isinstance(d[name], list):
d[name] = [d[name]]
d[name].append(value)
else:
d[name] = value
return d
image_map_pattern = re.compile(r"[0-9]+,[0-9]+")
def parse_query_string(query_string, keep_blank_values=True, encoding='utf-8'):
"""Build a params dictionary from a query_string.
Duplicate key/value pairs in the provided query_string will be
returned as {'key': [val1, val2, ...]}. Single key/values will
be returned as strings: {'key': 'value'}.
"""
if image_map_pattern.match(query_string):
# Server-side image map. Map the coords to 'x' and 'y'
# (like CGI::Request does).
pm = query_string.split(",")
pm = {'x': int(pm[0]), 'y': int(pm[1])}
else:
pm = _parse_qs(query_string, keep_blank_values, encoding=encoding)
return pm
class CaseInsensitiveDict(dict):
"""A case-insensitive dict subclass.
Each key is changed on entry to str(key).title().
"""
def __getitem__(self, key):
return dict.__getitem__(self, str(key).title())
def __setitem__(self, key, value):
dict.__setitem__(self, str(key).title(), value)
def __delitem__(self, key):
dict.__delitem__(self, str(key).title())
def __contains__(self, key):
return dict.__contains__(self, str(key).title())
def get(self, key, default=None):
return dict.get(self, str(key).title(), default)
def has_key(self, key):
return dict.has_key(self, str(key).title())
def update(self, E):
for k in E.keys():
self[str(k).title()] = E[k]
def fromkeys(cls, seq, value=None):
newdict = cls()
for k in seq:
newdict[str(k).title()] = value
return newdict
fromkeys = classmethod(fromkeys)
def setdefault(self, key, x=None):
key = str(key).title()
try:
return self[key]
except KeyError:
self[key] = x
return x
def pop(self, key, default):
return dict.pop(self, str(key).title(), default)
class HeaderMap(CaseInsensitiveDict):
"""A dict subclass for HTTP request and response headers.
Each key is changed on entry to str(key).title(). This allows headers
to be case-insensitive and avoid duplicates.
Values are header values (decoded according to RFC 2047 if necessary).
"""
protocol=(1, 1)
def elements(self, key):
"""Return a sorted list of HeaderElements for the given header."""
key = str(key).title()
value = self.get(key)
return header_elements(key, value)
def values(self, key):
"""Return a sorted list of HeaderElement.value for the given header."""
return [e.value for e in self.elements(key)]
def output(self):
"""Transform self into a list of (name, value) tuples."""
header_list = []
for k, v in self.items():
if isinstance(k, unicode):
k = k.encode("ISO-8859-1")
if not isinstance(v, basestring):
v = str(v)
if isinstance(v, unicode):
v = self.encode(v)
header_list.append((k, v))
return header_list
def encode(self, v):
"""Return the given header value, encoded for HTTP output."""
# HTTP/1.0 says, "Words of *TEXT may contain octets
# from character sets other than US-ASCII." and
# "Recipients of header field TEXT containing octets
# outside the US-ASCII character set may assume that
# they represent ISO-8859-1 characters."
try:
v = v.encode("ISO-8859-1")
except UnicodeEncodeError:
if self.protocol == (1, 1):
# Encode RFC-2047 TEXT
# (e.g. u"\u8200" -> "=?utf-8?b?6IiA?=").
# We do our own here instead of using the email module
# because we never want to fold lines--folding has
# been deprecated by the HTTP working group.
v = b2a_base64(v.encode('utf-8'))
v = ('=?utf-8?b?' + v.strip('\n') + '?=')
else:
raise
return v
class Host(object):
"""An internet address.
name should be the client's host name. If not available (because no DNS
lookup is performed), the IP address should be used instead.
"""
ip = "0.0.0.0"
port = 80
name = "unknown.tld"
def __init__(self, ip, port, name=None):
self.ip = ip
self.port = port
if name is None:
name = ip
self.name = name
def __repr__(self):
return "httputil.Host(%r, %r, %r)" % (self.ip, self.port, self.name)