226 lines
7.8 KiB
Python
226 lines
7.8 KiB
Python
# -*- coding: utf-8 -*-
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"""
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pygments.lexers.mime
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~~~~~~~~~~~~~~~~~~~~
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Lexer for Multipurpose Internet Mail Extensions (MIME) data.
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:copyright: Copyright 2006-2020 by the Pygments team, see AUTHORS.
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:license: BSD, see LICENSE for details.
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"""
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import re
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from pygments.lexer import RegexLexer, include
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from pygments.lexers import get_lexer_for_mimetype
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from pygments.token import Text, Name, String, Operator, Comment, Other
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from pygments.util import get_int_opt, ClassNotFound
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__all__ = ["MIMELexer"]
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class MIMELexer(RegexLexer):
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"""
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Lexer for Multipurpose Internet Mail Extensions (MIME) data. This lexer is
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designed to process the nested mulitpart data.
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It assumes that the given data contains both header and body (and is
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splitted by empty line). If no valid header is found, then the entire data
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would be treated as body.
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Additional options accepted:
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`MIME-max-level`
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Max recurssion level for nested MIME structure. Any negative number
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would treated as unlimited. (default: -1)
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`Content-Type`
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Treat the data as specific content type. Useful when header is
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missing, or this lexer would try to parse from header. (default:
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`text/plain`)
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`Multipart-Boundary`
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Set the default multipart boundary delimiter. This option is only used
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when `Content-Type` is `multipart` and header is missing. This lexer
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would try to parse from header by default. (default: None)
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`Content-Transfer-Encoding`
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Treat the data as specific encoding. Or this lexer would try to parse
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from header by default. (default: None)
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.. versionadded:: 2.5
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"""
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name = "MIME"
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aliases = ["mime"]
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mimetypes = ["multipart/mixed",
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"multipart/related",
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"multipart/alternative"]
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def __init__(self, **options):
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super().__init__(**options)
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self.boundary = options.get("Multipart-Boundary")
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self.content_transfer_encoding = options.get("Content_Transfer_Encoding")
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self.content_type = options.get("Content_Type", "text/plain")
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self.max_nested_level = get_int_opt(options, "MIME-max-level", -1)
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def analyse_text(text):
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try:
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header, body = text.strip().split("\n\n", 1)
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if not body.strip():
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return 0.1
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invalid_headers = MIMELexer.tokens["header"].sub("", header)
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if invalid_headers.strip():
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return 0.1
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else:
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return 1
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except ValueError:
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return 0.1
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def get_header_tokens(self, match):
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field = match.group(1)
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if field.lower() in self.attention_headers:
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yield match.start(1), Name.Tag, field + ":"
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yield match.start(2), Text.Whitespace, match.group(2)
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pos = match.end(2)
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body = match.group(3)
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for i, t, v in self.get_tokens_unprocessed(body, ("root", field.lower())):
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yield pos + i, t, v
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else:
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yield match.start(), Comment, match.group()
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def get_body_tokens(self, match):
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pos_body_start = match.start()
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entire_body = match.group()
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# skip first newline
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if entire_body[0] == '\n':
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yield pos_body_start, Text.Whitespace, '\n'
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pos_body_start = pos_body_start + 1
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entire_body = entire_body[1:]
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# if it is not a mulitpart
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if not self.content_type.startswith("multipart") or not self.boundary:
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for i, t, v in self.get_bodypart_tokens(entire_body):
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yield pos_body_start + i, t, v
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return
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# find boundary
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bdry_pattern = r"^--%s(--)?\n" % re.escape(self.boundary)
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bdry_matcher = re.compile(bdry_pattern, re.MULTILINE)
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# some data has prefix text before first boundary
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m = bdry_matcher.search(entire_body)
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if m:
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pos_part_start = pos_body_start + m.end()
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pos_iter_start = lpos_end = m.end()
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yield pos_body_start, Text, entire_body[:m.start()]
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yield pos_body_start + lpos_end, String.Delimiter, m.group()
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else:
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pos_part_start = pos_body_start
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pos_iter_start = 0
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# process tokens of each body part
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for m in bdry_matcher.finditer(entire_body, pos_iter_start):
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# bodypart
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lpos_start = pos_part_start - pos_body_start
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lpos_end = m.start()
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part = entire_body[lpos_start:lpos_end]
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for i, t, v in self.get_bodypart_tokens(part):
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yield pos_part_start + i, t, v
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# boundary
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yield pos_body_start + lpos_end, String.Delimiter, m.group()
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pos_part_start = pos_body_start + m.end()
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# some data has suffix text after last boundary
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lpos_start = pos_part_start - pos_body_start
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if lpos_start != len(entire_body):
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yield pos_part_start, Text, entire_body[lpos_start:]
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def get_bodypart_tokens(self, text):
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# return if:
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# * no content
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# * no content type specific
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# * content encoding is not readable
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# * max recurrsion exceed
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if not text.strip() or not self.content_type:
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return [(0, Other, text)]
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cte = self.content_transfer_encoding
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if cte and cte not in {"8bit", "7bit", "quoted-printable"}:
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return [(0, Other, text)]
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if self.max_nested_level == 0:
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return [(0, Other, text)]
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# get lexer
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try:
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lexer = get_lexer_for_mimetype(self.content_type)
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except ClassNotFound:
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return [(0, Other, text)]
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if isinstance(lexer, type(self)):
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lexer.max_nested_level = self.max_nested_level - 1
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return lexer.get_tokens_unprocessed(text)
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def store_content_type(self, match):
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self.content_type = match.group(1)
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prefix_len = match.start(1) - match.start(0)
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yield match.start(0), Text.Whitespace, match.group(0)[:prefix_len]
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yield match.start(1), Name.Label, match.group(2)
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yield match.end(2), String.Delimiter, '/'
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yield match.start(3), Name.Label, match.group(3)
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def get_content_type_subtokens(self, match):
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yield match.start(1), Text, match.group(1)
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yield match.start(2), Text.Whitespace, match.group(2)
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yield match.start(3), Name.Attribute, match.group(3)
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yield match.start(4), Operator, match.group(4)
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yield match.start(5), String, match.group(5)
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if match.group(3).lower() == "boundary":
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boundary = match.group(5).strip()
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if boundary[0] == '"' and boundary[-1] == '"':
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boundary = boundary[1:-1]
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self.boundary = boundary
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def store_content_transfer_encoding(self, match):
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self.content_transfer_encoding = match.group(0).lower()
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yield match.start(0), Name.Constant, match.group(0)
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attention_headers = {"content-type", "content-transfer-encoding"}
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tokens = {
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"root": [
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(r"^([\w-]+):( *)([\s\S]*?\n)(?![ \t])", get_header_tokens),
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(r"^$[\s\S]+", get_body_tokens),
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],
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"header": [
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# folding
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(r"\n[ \t]", Text.Whitespace),
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(r"\n(?![ \t])", Text.Whitespace, "#pop"),
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],
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"content-type": [
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include("header"),
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(
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r"^\s*((multipart|application|audio|font|image|model|text|video"
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r"|message)/([\w-]+))",
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store_content_type,
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),
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(r'(;)((?:[ \t]|\n[ \t])*)([\w:-]+)(=)([\s\S]*?)(?=;|\n(?![ \t]))',
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get_content_type_subtokens),
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(r';[ \t]*\n(?![ \t])', Text, '#pop'),
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],
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"content-transfer-encoding": [
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include("header"),
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(r"([\w-]+)", store_content_transfer_encoding),
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],
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}
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