""" pygments.lexers.mime ~~~~~~~~~~~~~~~~~~~~ Lexer for Multipurpose Internet Mail Extensions (MIME) data. :copyright: Copyright 2006-2021 by the Pygments team, see AUTHORS. :license: BSD, see LICENSE for details. """ import re from pygments.lexer import RegexLexer, include from pygments.lexers import get_lexer_for_mimetype from pygments.token import Text, Name, String, Operator, Comment, Other from pygments.util import get_int_opt, ClassNotFound __all__ = ["MIMELexer"] class MIMELexer(RegexLexer): """ Lexer for Multipurpose Internet Mail Extensions (MIME) data. This lexer is designed to process the nested mulitpart data. It assumes that the given data contains both header and body (and is splitted by empty line). If no valid header is found, then the entire data would be treated as body. Additional options accepted: `MIME-max-level` Max recurssion level for nested MIME structure. Any negative number would treated as unlimited. (default: -1) `Content-Type` Treat the data as specific content type. Useful when header is missing, or this lexer would try to parse from header. (default: `text/plain`) `Multipart-Boundary` Set the default multipart boundary delimiter. This option is only used when `Content-Type` is `multipart` and header is missing. This lexer would try to parse from header by default. (default: None) `Content-Transfer-Encoding` Treat the data as specific encoding. Or this lexer would try to parse from header by default. (default: None) .. versionadded:: 2.5 """ name = "MIME" aliases = ["mime"] mimetypes = ["multipart/mixed", "multipart/related", "multipart/alternative"] def __init__(self, **options): super().__init__(**options) self.boundary = options.get("Multipart-Boundary") self.content_transfer_encoding = options.get("Content_Transfer_Encoding") self.content_type = options.get("Content_Type", "text/plain") self.max_nested_level = get_int_opt(options, "MIME-max-level", -1) def analyse_text(text): try: header, body = text.strip().split("\n\n", 1) if not body.strip(): return 0.1 invalid_headers = MIMELexer.tokens["header"].sub("", header) if invalid_headers.strip(): return 0.1 else: return 1 except ValueError: return 0 def get_header_tokens(self, match): field = match.group(1) if field.lower() in self.attention_headers: yield match.start(1), Name.Tag, field + ":" yield match.start(2), Text.Whitespace, match.group(2) pos = match.end(2) body = match.group(3) for i, t, v in self.get_tokens_unprocessed(body, ("root", field.lower())): yield pos + i, t, v else: yield match.start(), Comment, match.group() def get_body_tokens(self, match): pos_body_start = match.start() entire_body = match.group() # skip first newline if entire_body[0] == '\n': yield pos_body_start, Text.Whitespace, '\n' pos_body_start = pos_body_start + 1 entire_body = entire_body[1:] # if it is not a mulitpart if not self.content_type.startswith("multipart") or not self.boundary: for i, t, v in self.get_bodypart_tokens(entire_body): yield pos_body_start + i, t, v return # find boundary bdry_pattern = r"^--%s(--)?\n" % re.escape(self.boundary) bdry_matcher = re.compile(bdry_pattern, re.MULTILINE) # some data has prefix text before first boundary m = bdry_matcher.search(entire_body) if m: pos_part_start = pos_body_start + m.end() pos_iter_start = lpos_end = m.end() yield pos_body_start, Text, entire_body[:m.start()] yield pos_body_start + lpos_end, String.Delimiter, m.group() else: pos_part_start = pos_body_start pos_iter_start = 0 # process tokens of each body part for m in bdry_matcher.finditer(entire_body, pos_iter_start): # bodypart lpos_start = pos_part_start - pos_body_start lpos_end = m.start() part = entire_body[lpos_start:lpos_end] for i, t, v in self.get_bodypart_tokens(part): yield pos_part_start + i, t, v # boundary yield pos_body_start + lpos_end, String.Delimiter, m.group() pos_part_start = pos_body_start + m.end() # some data has suffix text after last boundary lpos_start = pos_part_start - pos_body_start if lpos_start != len(entire_body): yield pos_part_start, Text, entire_body[lpos_start:] def get_bodypart_tokens(self, text): # return if: # * no content # * no content type specific # * content encoding is not readable # * max recurrsion exceed if not text.strip() or not self.content_type: return [(0, Other, text)] cte = self.content_transfer_encoding if cte and cte not in {"8bit", "7bit", "quoted-printable"}: return [(0, Other, text)] if self.max_nested_level == 0: return [(0, Other, text)] # get lexer try: lexer = get_lexer_for_mimetype(self.content_type) except ClassNotFound: return [(0, Other, text)] if isinstance(lexer, type(self)): lexer.max_nested_level = self.max_nested_level - 1 return lexer.get_tokens_unprocessed(text) def store_content_type(self, match): self.content_type = match.group(1) prefix_len = match.start(1) - match.start(0) yield match.start(0), Text.Whitespace, match.group(0)[:prefix_len] yield match.start(1), Name.Label, match.group(2) yield match.end(2), String.Delimiter, '/' yield match.start(3), Name.Label, match.group(3) def get_content_type_subtokens(self, match): yield match.start(1), Text, match.group(1) yield match.start(2), Text.Whitespace, match.group(2) yield match.start(3), Name.Attribute, match.group(3) yield match.start(4), Operator, match.group(4) yield match.start(5), String, match.group(5) if match.group(3).lower() == "boundary": boundary = match.group(5).strip() if boundary[0] == '"' and boundary[-1] == '"': boundary = boundary[1:-1] self.boundary = boundary def store_content_transfer_encoding(self, match): self.content_transfer_encoding = match.group(0).lower() yield match.start(0), Name.Constant, match.group(0) attention_headers = {"content-type", "content-transfer-encoding"} tokens = { "root": [ (r"^([\w-]+):( *)([\s\S]*?\n)(?![ \t])", get_header_tokens), (r"^$[\s\S]+", get_body_tokens), ], "header": [ # folding (r"\n[ \t]", Text.Whitespace), (r"\n(?![ \t])", Text.Whitespace, "#pop"), ], "content-type": [ include("header"), ( r"^\s*((multipart|application|audio|font|image|model|text|video" r"|message)/([\w-]+))", store_content_type, ), (r'(;)((?:[ \t]|\n[ \t])*)([\w:-]+)(=)([\s\S]*?)(?=;|\n(?![ \t]))', get_content_type_subtokens), (r';[ \t]*\n(?![ \t])', Text, '#pop'), ], "content-transfer-encoding": [ include("header"), (r"([\w-]+)", store_content_transfer_encoding), ], }