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| # We use native strings for all the re patterns, to take advantage of string | |
| # formatting, and then convert to bytestrings when compiling the final re | |
| # objects. | |
| # https://svn.tools.ietf.org/svn/wg/httpbis/specs/rfc7230.html#whitespace | |
| # OWS = *( SP / HTAB ) | |
| # ; optional whitespace | |
| OWS = r"[ \t]*" | |
| # https://svn.tools.ietf.org/svn/wg/httpbis/specs/rfc7230.html#rule.token.separators | |
| # token = 1*tchar | |
| # | |
| # tchar = "!" / "#" / "$" / "%" / "&" / "'" / "*" | |
| # / "+" / "-" / "." / "^" / "_" / "`" / "|" / "~" | |
| # / DIGIT / ALPHA | |
| # ; any VCHAR, except delimiters | |
| token = r"[-!#$%&'*+.^_`|~0-9a-zA-Z]+" | |
| # https://svn.tools.ietf.org/svn/wg/httpbis/specs/rfc7230.html#header.fields | |
| # field-name = token | |
| field_name = token | |
| # The standard says: | |
| # | |
| # field-value = *( field-content / obs-fold ) | |
| # field-content = field-vchar [ 1*( SP / HTAB ) field-vchar ] | |
| # field-vchar = VCHAR / obs-text | |
| # obs-fold = CRLF 1*( SP / HTAB ) | |
| # ; obsolete line folding | |
| # ; see Section 3.2.4 | |
| # | |
| # https://tools.ietf.org/html/rfc5234#appendix-B.1 | |
| # | |
| # VCHAR = %x21-7E | |
| # ; visible (printing) characters | |
| # | |
| # https://svn.tools.ietf.org/svn/wg/httpbis/specs/rfc7230.html#rule.quoted-string | |
| # obs-text = %x80-FF | |
| # | |
| # However, the standard definition of field-content is WRONG! It disallows | |
| # fields containing a single visible character surrounded by whitespace, | |
| # e.g. "foo a bar". | |
| # | |
| # See: https://www.rfc-editor.org/errata_search.php?rfc=7230&eid=4189 | |
| # | |
| # So our definition of field_content attempts to fix it up... | |
| # | |
| # Also, we allow lots of control characters, because apparently people assume | |
| # that they're legal in practice (e.g., google analytics makes cookies with | |
| # \x01 in them!): | |
| # https://github.com/python-hyper/h11/issues/57 | |
| # We still don't allow NUL or whitespace, because those are often treated as | |
| # meta-characters and letting them through can lead to nasty issues like SSRF. | |
| vchar = r"[\x21-\x7e]" | |
| vchar_or_obs_text = r"[^\x00\s]" | |
| field_vchar = vchar_or_obs_text | |
| field_content = r"{field_vchar}+(?:[ \t]+{field_vchar}+)*".format(**globals()) | |
| # We handle obs-fold at a different level, and our fixed-up field_content | |
| # already grows to swallow the whole value, so ? instead of * | |
| field_value = r"({field_content})?".format(**globals()) | |
| # header-field = field-name ":" OWS field-value OWS | |
| header_field = ( | |
| r"(?P<field_name>{field_name})" | |
| r":" | |
| r"{OWS}" | |
| r"(?P<field_value>{field_value})" | |
| r"{OWS}".format(**globals()) | |
| ) | |
| # https://svn.tools.ietf.org/svn/wg/httpbis/specs/rfc7230.html#request.line | |
| # | |
| # request-line = method SP request-target SP HTTP-version CRLF | |
| # method = token | |
| # HTTP-version = HTTP-name "/" DIGIT "." DIGIT | |
| # HTTP-name = %x48.54.54.50 ; "HTTP", case-sensitive | |
| # | |
| # request-target is complicated (see RFC 7230 sec 5.3) -- could be path, full | |
| # URL, host+port (for connect), or even "*", but in any case we are guaranteed | |
| # that it contists of the visible printing characters. | |
| method = token | |
| request_target = r"{vchar}+".format(**globals()) | |
| http_version = r"HTTP/(?P<http_version>[0-9]\.[0-9])" | |
| request_line = ( | |
| r"(?P<method>{method})" | |
| r" " | |
| r"(?P<target>{request_target})" | |
| r" " | |
| r"{http_version}".format(**globals()) | |
| ) | |
| # https://svn.tools.ietf.org/svn/wg/httpbis/specs/rfc7230.html#status.line | |
| # | |
| # status-line = HTTP-version SP status-code SP reason-phrase CRLF | |
| # status-code = 3DIGIT | |
| # reason-phrase = *( HTAB / SP / VCHAR / obs-text ) | |
| status_code = r"[0-9]{3}" | |
| reason_phrase = r"([ \t]|{vchar_or_obs_text})*".format(**globals()) | |
| status_line = ( | |
| r"{http_version}" | |
| r" " | |
| r"(?P<status_code>{status_code})" | |
| # However, there are apparently a few too many servers out there that just | |
| # leave out the reason phrase: | |
| # https://github.com/scrapy/scrapy/issues/345#issuecomment-281756036 | |
| # https://github.com/seanmonstar/httparse/issues/29 | |
| # so make it optional. ?: is a non-capturing group. | |
| r"(?: (?P<reason>{reason_phrase}))?".format(**globals()) | |
| ) | |
| HEXDIG = r"[0-9A-Fa-f]" | |
| # Actually | |
| # | |
| # chunk-size = 1*HEXDIG | |
| # | |
| # but we impose an upper-limit to avoid ridiculosity. len(str(2**64)) == 20 | |
| chunk_size = r"({HEXDIG}){{1,20}}".format(**globals()) | |
| # Actually | |
| # | |
| # chunk-ext = *( ";" chunk-ext-name [ "=" chunk-ext-val ] ) | |
| # | |
| # but we aren't parsing the things so we don't really care. | |
| chunk_ext = r";.*" | |
| chunk_header = ( | |
| r"(?P<chunk_size>{chunk_size})" | |
| r"(?P<chunk_ext>{chunk_ext})?" | |
| r"{OWS}\r\n".format( | |
| **globals() | |
| ) # Even though the specification does not allow for extra whitespaces, | |
| # we are lenient with trailing whitespaces because some servers on the wild use it. | |
| ) | |