/usr/lib/python2.7/dist-packages/openid/yadis/accept.py is in python-openid 2.2.5-6.
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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 | """Functions for generating and parsing HTTP Accept: headers for
supporting server-directed content negotiation.
"""
def generateAcceptHeader(*elements):
"""Generate an accept header value
[str or (str, float)] -> str
"""
parts = []
for element in elements:
if type(element) is str:
qs = "1.0"
mtype = element
else:
mtype, q = element
q = float(q)
if q > 1 or q <= 0:
raise ValueError('Invalid preference factor: %r' % q)
qs = '%0.1f' % (q,)
parts.append((qs, mtype))
parts.sort()
chunks = []
for q, mtype in parts:
if q == '1.0':
chunks.append(mtype)
else:
chunks.append('%s; q=%s' % (mtype, q))
return ', '.join(chunks)
def parseAcceptHeader(value):
"""Parse an accept header, ignoring any accept-extensions
returns a list of tuples containing main MIME type, MIME subtype,
and quality markdown.
str -> [(str, str, float)]
"""
chunks = [chunk.strip() for chunk in value.split(',')]
accept = []
for chunk in chunks:
parts = [s.strip() for s in chunk.split(';')]
mtype = parts.pop(0)
if '/' not in mtype:
# This is not a MIME type, so ignore the bad data
continue
main, sub = mtype.split('/', 1)
for ext in parts:
if '=' in ext:
k, v = ext.split('=', 1)
if k == 'q':
try:
q = float(v)
break
except ValueError:
# Ignore poorly formed q-values
pass
else:
q = 1.0
accept.append((q, main, sub))
accept.sort()
accept.reverse()
return [(main, sub, q) for (q, main, sub) in accept]
def matchTypes(accept_types, have_types):
"""Given the result of parsing an Accept: header, and the
available MIME types, return the acceptable types with their
quality markdowns.
For example:
>>> acceptable = parseAcceptHeader('text/html, text/plain; q=0.5')
>>> matchTypes(acceptable, ['text/plain', 'text/html', 'image/jpeg'])
[('text/html', 1.0), ('text/plain', 0.5)]
Type signature: ([(str, str, float)], [str]) -> [(str, float)]
"""
if not accept_types:
# Accept all of them
default = 1
else:
default = 0
match_main = {}
match_sub = {}
for (main, sub, q) in accept_types:
if main == '*':
default = max(default, q)
continue
elif sub == '*':
match_main[main] = max(match_main.get(main, 0), q)
else:
match_sub[(main, sub)] = max(match_sub.get((main, sub), 0), q)
accepted_list = []
order_maintainer = 0
for mtype in have_types:
main, sub = mtype.split('/')
if (main, sub) in match_sub:
q = match_sub[(main, sub)]
else:
q = match_main.get(main, default)
if q:
accepted_list.append((1 - q, order_maintainer, q, mtype))
order_maintainer += 1
accepted_list.sort()
return [(mtype, q) for (_, _, q, mtype) in accepted_list]
def getAcceptable(accept_header, have_types):
"""Parse the accept header and return a list of available types in
preferred order. If a type is unacceptable, it will not be in the
resulting list.
This is a convenience wrapper around matchTypes and
parseAcceptHeader.
(str, [str]) -> [str]
"""
accepted = parseAcceptHeader(accept_header)
preferred = matchTypes(accepted, have_types)
return [mtype for (mtype, _) in preferred]
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