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|
import ply.lex as lex
import logging
import six
log = logging.getLogger(__name__)
log.setLevel(logging.INFO)
states = (
('domain', 'exclusive'),
('quote', 'exclusive'),
('comment', 'exclusive'),
)
tokens = (
'FWSP',
'AT',
'DOT',
'COMMA',
'SEMICOLON',
'LANGLE',
'RANGLE',
'ATOM',
'DOT_ATOM',
'LBRACKET',
'RBRACKET',
'DTEXT',
'DQUOTE',
'QTEXT',
'QPAIR',
'LPAREN',
'RPAREN',
'CTEXT',
'URL'
)
# Urls - Not a part of the message format RFC but we permit these currently
def t_URL(t):
r'http(s)?://[^\s<>{}|^~\[\]`;,]+'
return t
# Atoms - https://tools.ietf.org/html/rfc5322#section-3.2.3
t_FWSP = r'([\s\t]*\r\n)?[\s\t]+' # folding whitespace
t_AT = r'\@' # '@'
t_DOT = r'\.' # '.'
t_COMMA = r'\,' # ','
t_LANGLE = r'\<' # '<'
t_RANGLE = r'\>' # '>'
t_SEMICOLON = r'\;' # ';'
if six.PY2:
_UTF8_2 = r'[\xC2-\xDF][\x80-\xBF]'
_UTF8_3 = (r'(\xE0[\xA0-\xBF][\x80-\xBF]'
r'|[\xE1-\xEC][\x80-\xBF]{2}'
r'|\xED[\x80-\x9F][\x80-\xBF]'
r'|[\xEE-\xEF][\x80-\xBF]{2}'
r')')
_UTF8_4 = (r'(\xF0[\x90-\xBF][\x80-\xBF]{2}'
r'|[\xF1-\xF3][\x80-\xBF]{3}'
r'|\xF4[\x80-\x8F][\x80-\xBF]{2}'
r')')
else:
_UTF8_2 = r'[\u0080-\u07ff]'
_UTF8_3 = (r'([\u0800-\u0fff]'
r'|[\u1000-\ucfff]'
r'|[\ud000-\ud7ff]'
r'|[\ue000-\uffff]'
r')')
_UTF8_4 = (r'([\U00010000-\U0003ffff]'
r'|[\U00040000-\U000fffff]'
r'|[\U00100000-\U0010ffff]'
r')')
_UNICODE_CHAR = '({}|{}|{})'.format(_UTF8_2, _UTF8_3, _UTF8_4)
t_ATOM = r'''
( [a-zA-Z0-9!#$%&\'*+\-/=?^_`{{|}}~] # Visible ASCII except (),.:;<>@[\]
| {unicode_char}
)+
'''.format(unicode_char=_UNICODE_CHAR)
# NOTE: Our expression for dot_atom here differs from RFC 5322. In the RFC
# dot_atom is expressed as a superset of atom. That makes it difficult to write
# unambiguous parsing rules so we've defined it here in such a way that it
# doesn't conflict. As a result, any rules that accept dot_atom should also
# accept atom.
t_DOT_ATOM = r'{atom}(\.{atom})+'.format(atom=t_ATOM)
def t_error(t):
log.warning("syntax error in default lexer, token=%s", t)
# Domain literals - https://tools.ietf.org/html/rfc5322#section-3.4.1
def t_LBRACKET(t):
r'\['
t.lexer.begin('domain')
return t
def t_domain_RBRACKET(t):
r'\]'
t.lexer.begin('INITIAL')
return t
t_domain_DTEXT = r'''
( [\x21-\x5A\x5E-\x7E] # Visible ASCII except '[', '\', ']',
| {unicode_char}
)+
'''.format(unicode_char=_UNICODE_CHAR)
t_domain_FWSP = r'([\s\t]*\r\n)?[\s\t]+' # folding whitespace
def t_domain_error(t):
log.warning("syntax error in domain lexer, token=%s", t)
# Quoted strings - https://tools.ietf.org/html/rfc5322#section-3.2.4
def t_DQUOTE(t):
r'\"'
t.lexer.begin('quote')
return t
def t_quote_DQUOTE(t):
r'\"'
t.lexer.begin('INITIAL')
return t
t_quote_QTEXT = r'''
( [\x21\x23-\x5B\x5D-\x7E] # Visible ASCII except '"', '\'
| {unicode_char}
)+
'''.format(unicode_char=_UNICODE_CHAR)
t_quote_QPAIR = r'''
\\ # '\'
( [\x21-\x7E] # Visible ASCII
| \s # ' ' technically not valid
| {unicode_char}
)
'''.format(unicode_char=_UNICODE_CHAR)
t_quote_FWSP = r'([\s\t]*\r\n)?[\s\t]+' # folding whitespace
def t_quote_error(t):
log.warning("syntax error in quoted string lexer, token=%s", t)
# Comments - https://tools.ietf.org/html/rfc5322#section-3.2.2
def t_LPAREN(t):
r'\('
t.lexer.begin('comment')
return t
def t_comment_RPAREN(t):
r'\)'
t.lexer.begin('INITIAL')
return t
t_comment_CTEXT = r'''
( [\x21-\x27\x2A-\x5B\x5D-\x7E] # Visible ASCII except '(', ')', or '\'
| {unicode_char} )+
'''.format(unicode_char=_UNICODE_CHAR)
# Folding whitespace.
t_comment_FWSP = r'([\s\t]*\r\n)?[\s\t]+'
def t_comment_error(t):
log.warning("syntax error in comment lexer, token=%s", t)
# Build the lexer
lexer = lex.lex(errorlog=log)
|
