idna.py 文件源码

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