You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
310 lines
9.0 KiB
310 lines
9.0 KiB
6 years ago
|
# This module implements the RFCs 3490 (IDNA) and 3491 (Nameprep)
|
||
|
|
|
||
|
|
import stringprep, re, codecs
|
||
|
|
from unicodedata import ucd_3_2_0 as unicodedata
|
||
|
|
|
||
|
|
# IDNA section 3.1
|
||
|
|
dots = re.compile("[\u002E\u3002\uFF0E\uFF61]")
|
||
|
|
|
||
|
|
# IDNA section 5
|
||
|
|
ace_prefix = b"xn--"
|
||
|
|
sace_prefix = "xn--"
|
||
|
|
|
||
|
|
# This assumes query strings, so AllowUnassigned is true
|
||
|
|
def nameprep(label):
|
||
|
|
# Map
|
||
|
|
newlabel = []
|
||
|
|
for c in label:
|
||
|
|
if stringprep.in_table_b1(c):
|
||
|
|
# Map to nothing
|
||
|
|
continue
|
||
|
|
newlabel.append(stringprep.map_table_b2(c))
|
||
|
|
label = "".join(newlabel)
|
||
|
|
|
||
|
|
# Normalize
|
||
|
|
label = unicodedata.normalize("NFKC", label)
|
||
|
|
|
||
|
|
# Prohibit
|
||
|
|
for c in label:
|
||
|
|
if stringprep.in_table_c12(c) or \
|
||
|
|
stringprep.in_table_c22(c) or \
|
||
|
|
stringprep.in_table_c3(c) or \
|
||
|
|
stringprep.in_table_c4(c) or \
|
||
|
|
stringprep.in_table_c5(c) or \
|
||
|
|
stringprep.in_table_c6(c) or \
|
||
|
|
stringprep.in_table_c7(c) or \
|
||
|
|
stringprep.in_table_c8(c) or \
|
||
|
|
stringprep.in_table_c9(c):
|
||
|
|
raise UnicodeError("Invalid character %r" % c)
|
||
|
|
|
||
|
|
# Check bidi
|
||
|
|
RandAL = [stringprep.in_table_d1(x) for x in label]
|
||
|
|
for c in RandAL:
|
||
|
|
if c:
|
||
|
|
# There is a RandAL char in the string. Must perform further
|
||
|
|
# tests:
|
||
|
|
# 1) The characters in section 5.8 MUST be prohibited.
|
||
|
|
# This is table C.8, which was already checked
|
||
|
|
# 2) If a string contains any RandALCat character, the string
|
||
|
|
# MUST NOT contain any LCat character.
|
||
|
|
if any(stringprep.in_table_d2(x) for x in label):
|
||
|
|
raise UnicodeError("Violation of BIDI requirement 2")
|
||
|
|
|
||
|
|
# 3) If a string contains any RandALCat character, a
|
||
|
|
# RandALCat character MUST be the first character of the
|
||
|
|
# string, and a RandALCat character MUST be the last
|
||
|
|
# character of the string.
|
||
|
|
if not RandAL[0] or not RandAL[-1]:
|
||
|
|
raise UnicodeError("Violation of BIDI requirement 3")
|
||
|
|
|
||
|
|
return label
|
||
|
|
|
||
|
|
def ToASCII(label):
|
||
|
|
try:
|
||
|
|
# Step 1: try ASCII
|
||
|
|
label = label.encode("ascii")
|
||
|
|
except UnicodeError:
|
||
|
|
pass
|
||
|
|
else:
|
||
|
|
# Skip to step 3: UseSTD3ASCIIRules is false, so
|
||
|
|
# Skip to step 8.
|
||
|
|
if 0 < len(label) < 64:
|
||
|
|
return label
|
||
|
|
raise UnicodeError("label empty or too long")
|
||
|
|
|
||
|
|
# Step 2: nameprep
|
||
|
|
label = nameprep(label)
|
||
|
|
|
||
|
|
# Step 3: UseSTD3ASCIIRules is false
|
||
|
|
# Step 4: try ASCII
|
||
|
|
try:
|
||
|
|
label = label.encode("ascii")
|
||
|
|
except UnicodeError:
|
||
|
|
pass
|
||
|
|
else:
|
||
|
|
# Skip to step 8.
|
||
|
|
if 0 < len(label) < 64:
|
||
|
|
return label
|
||
|
|
raise UnicodeError("label empty or too long")
|
||
|
|
|
||
|
|
# Step 5: Check ACE prefix
|
||
|
|
if label.startswith(sace_prefix):
|
||
|
|
raise UnicodeError("Label starts with ACE prefix")
|
||
|
|
|
||
|
|
# Step 6: Encode with PUNYCODE
|
||
|
|
label = label.encode("punycode")
|
||
|
|
|
||
|
|
# Step 7: Prepend ACE prefix
|
||
|
|
label = ace_prefix + label
|
||
|
|
|
||
|
|
# Step 8: Check size
|
||
|
|
if 0 < len(label) < 64:
|
||
|
|
return label
|
||
|
|
raise UnicodeError("label empty or too long")
|
||
|
|
|
||
|
|
def ToUnicode(label):
|
||
|
|
# Step 1: Check for ASCII
|
||
|
|
if isinstance(label, bytes):
|
||
|
|
pure_ascii = True
|
||
|
|
else:
|
||
|
|
try:
|
||
|
|
label = label.encode("ascii")
|
||
|
|
pure_ascii = True
|
||
|
|
except UnicodeError:
|
||
|
|
pure_ascii = False
|
||
|
|
if not pure_ascii:
|
||
|
|
# Step 2: Perform nameprep
|
||
|
|
label = nameprep(label)
|
||
|
|
# It doesn't say this, but apparently, it should be ASCII now
|
||
|
|
try:
|
||
|
|
label = label.encode("ascii")
|
||
|
|
except UnicodeError:
|
||
|
|
raise UnicodeError("Invalid character in IDN label")
|
||
|
|
# Step 3: Check for ACE prefix
|
||
|
|
if not label.startswith(ace_prefix):
|
||
|
|
return str(label, "ascii")
|
||
|
|
|
||
|
|
# Step 4: Remove ACE prefix
|
||
|
|
label1 = label[len(ace_prefix):]
|
||
|
|
|
||
|
|
# Step 5: Decode using PUNYCODE
|
||
|
|
result = label1.decode("punycode")
|
||
|
|
|
||
|
|
# Step 6: Apply ToASCII
|
||
|
|
label2 = ToASCII(result)
|
||
|
|
|
||
|
|
# Step 7: Compare the result of step 6 with the one of step 3
|
||
|
|
# label2 will already be in lower case.
|
||
|
|
if str(label, "ascii").lower() != str(label2, "ascii"):
|
||
|
|
raise UnicodeError("IDNA does not round-trip", label, label2)
|
||
|
|
|
||
|
|
# Step 8: return the result of step 5
|
||
|
|
return result
|
||
|
|
|
||
|
|
### Codec APIs
|
||
|
|
|
||
|
|
class Codec(codecs.Codec):
|
||
|
|
def encode(self, input, errors='strict'):
|
||
|
|
|
||
|
|
if errors != 'strict':
|
||
|
|
# IDNA is quite clear that implementations must be strict
|
||
|
|
raise UnicodeError("unsupported error handling "+errors)
|
||
|
|
|
||
|
|
if not input:
|
||
|
|
return b'', 0
|
||
|
|
|
||
|
|
try:
|
||
|
|
result = input.encode('ascii')
|
||
|
|
except UnicodeEncodeError:
|
||
|
|
pass
|
||
|
|
else:
|
||
|
|
# ASCII name: fast path
|
||
|
|
labels = result.split(b'.')
|
||
|
|
for label in labels[:-1]:
|
||
|
|
if not (0 < len(label) < 64):
|
||
|
|
raise UnicodeError("label empty or too long")
|
||
|
|
if len(labels[-1]) >= 64:
|
||
|
|
raise UnicodeError("label too long")
|
||
|
|
return result, len(input)
|
||
|
|
|
||
|
|
result = bytearray()
|
||
|
|
labels = dots.split(input)
|
||
|
|
if labels and not labels[-1]:
|
||
|
|
trailing_dot = b'.'
|
||
|
|
del labels[-1]
|
||
|
|
else:
|
||
|
|
trailing_dot = b''
|
||
|
|
for label in labels:
|
||
|
|
if result:
|
||
|
|
# Join with U+002E
|
||
|
|
result.extend(b'.')
|
||
|
|
result.extend(ToASCII(label))
|
||
|
|
return bytes(result+trailing_dot), len(input)
|
||
|
|
|
||
|
|
def decode(self, input, errors='strict'):
|
||
|
|
|
||
|
|
if errors != 'strict':
|
||
|
|
raise UnicodeError("Unsupported error handling "+errors)
|
||
|
|
|
||
|
|
if not input:
|
||
|
|
return "", 0
|
||
|
|
|
||
|
|
# IDNA allows decoding to operate on Unicode strings, too.
|
||
|
|
if not isinstance(input, bytes):
|
||
|
|
# XXX obviously wrong, see #3232
|
||
|
|
input = bytes(input)
|
||
|
|
|
||
|
|
if ace_prefix not in input:
|
||
|
|
# Fast path
|
||
|
|
try:
|
||
|
|
return input.decode('ascii'), len(input)
|
||
|
|
except UnicodeDecodeError:
|
||
|
|
pass
|
||
|
|
|
||
|
|
labels = input.split(b".")
|
||
|
|
|
||
|
|
if labels and len(labels[-1]) == 0:
|
||
|
|
trailing_dot = '.'
|
||
|
|
del labels[-1]
|
||
|
|
else:
|
||
|
|
trailing_dot = ''
|
||
|
|
|
||
|
|
result = []
|
||
|
|
for label in labels:
|
||
|
|
result.append(ToUnicode(label))
|
||
|
|
|
||
|
|
return ".".join(result)+trailing_dot, len(input)
|
||
|
|
|
||
|
|
class IncrementalEncoder(codecs.BufferedIncrementalEncoder):
|
||
|
|
def _buffer_encode(self, input, errors, final):
|
||
|
|
if errors != 'strict':
|
||
|
|
# IDNA is quite clear that implementations must be strict
|
||
|
|
raise UnicodeError("unsupported error handling "+errors)
|
||
|
|
|
||
|
|
if not input:
|
||
|
|
return (b'', 0)
|
||
|
|
|
||
|
|
labels = dots.split(input)
|
||
|
|
trailing_dot = b''
|
||
|
|
if labels:
|
||
|
|
if not labels[-1]:
|
||
|
|
trailing_dot = b'.'
|
||
|
|
del labels[-1]
|
||
|
|
elif not final:
|
||
|
|
# Keep potentially unfinished label until the next call
|
||
|
|
del labels[-1]
|
||
|
|
if labels:
|
||
|
|
trailing_dot = b'.'
|
||
|
|
|
||
|
|
result = bytearray()
|
||
|
|
size = 0
|
||
|
|
for label in labels:
|
||
|
|
if size:
|
||
|
|
# Join with U+002E
|
||
|
|
result.extend(b'.')
|
||
|
|
size += 1
|
||
|
|
result.extend(ToASCII(label))
|
||
|
|
size += len(label)
|
||
|
|
|
||
|
|
result += trailing_dot
|
||
|
|
size += len(trailing_dot)
|
||
|
|
return (bytes(result), size)
|
||
|
|
|
||
|
|
class IncrementalDecoder(codecs.BufferedIncrementalDecoder):
|
||
|
|
def _buffer_decode(self, input, errors, final):
|
||
|
|
if errors != 'strict':
|
||
|
|
raise UnicodeError("Unsupported error handling "+errors)
|
||
|
|
|
||
|
|
if not input:
|
||
|
|
return ("", 0)
|
||
|
|
|
||
|
|
# IDNA allows decoding to operate on Unicode strings, too.
|
||
|
|
if isinstance(input, str):
|
||
|
|
labels = dots.split(input)
|
||
|
|
else:
|
||
|
|
# Must be ASCII string
|
||
|
|
input = str(input, "ascii")
|
||
|
|
labels = input.split(".")
|
||
|
|
|
||
|
|
trailing_dot = ''
|
||
|
|
if labels:
|
||
|
|
if not labels[-1]:
|
||
|
|
trailing_dot = '.'
|
||
|
|
del labels[-1]
|
||
|
|
elif not final:
|
||
|
|
# Keep potentially unfinished label until the next call
|
||
|
|
del labels[-1]
|
||
|
|
if labels:
|
||
|
|
trailing_dot = '.'
|
||
|
|
|
||
|
|
result = []
|
||
|
|
size = 0
|
||
|
|
for label in labels:
|
||
|
|
result.append(ToUnicode(label))
|
||
|
|
if size:
|
||
|
|
size += 1
|
||
|
|
size += len(label)
|
||
|
|
|
||
|
|
result = ".".join(result) + trailing_dot
|
||
|
|
size += len(trailing_dot)
|
||
|
|
return (result, size)
|
||
|
|
|
||
|
|
class StreamWriter(Codec,codecs.StreamWriter):
|
||
|
|
pass
|
||
|
|
|
||
|
|
class StreamReader(Codec,codecs.StreamReader):
|
||
|
|
pass
|
||
|
|
|
||
|
|
### encodings module API
|
||
|
|
|
||
|
|
def getregentry():
|
||
|
|
return codecs.CodecInfo(
|
||
|
|
name='idna',
|
||
|
|
encode=Codec().encode,
|
||
|
|
decode=Codec().decode,
|
||
|
|
incrementalencoder=IncrementalEncoder,
|
||
|
|
incrementaldecoder=IncrementalDecoder,
|
||
|
|
streamwriter=StreamWriter,
|
||
|
|
streamreader=StreamReader,
|
||
|
|
)
|