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76 lines
2.5 KiB
76 lines
2.5 KiB
"""
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This contains a bunch of RFC7230 definitions and regular expressions that are
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needed to properly parse HTTP messages.
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"""
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import re
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HEXDIG = "[0-9a-fA-F]"
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DIGIT = "[0-9]"
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WS = "[ \t]"
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OWS = WS + "{0,}?"
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RWS = WS + "{1,}?"
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BWS = OWS
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# RFC 7230 Section 3.2.6 "Field Value Components":
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# tchar = "!" / "#" / "$" / "%" / "&" / "'" / "*"
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# / "+" / "-" / "." / "^" / "_" / "`" / "|" / "~"
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# / DIGIT / ALPHA
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# obs-text = %x80-FF
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TCHAR = r"[!#$%&'*+\-.^_`|~0-9A-Za-z]"
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OBS_TEXT = r"\x80-\xff"
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TOKEN = TCHAR + "{1,}"
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# RFC 5234 Appendix B.1 "Core Rules":
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# VCHAR = %x21-7E
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# ; visible (printing) characters
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VCHAR = r"\x21-\x7e"
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# The '\\' between \x5b and \x5d is needed to escape \x5d (']')
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QDTEXT = "[\t \x21\x23-\x5b\\\x5d-\x7e" + OBS_TEXT + "]"
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QUOTED_PAIR = r"\\" + "([\t " + VCHAR + OBS_TEXT + "])"
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QUOTED_STRING = '"(?:(?:' + QDTEXT + ")|(?:" + QUOTED_PAIR + '))*"'
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# header-field = field-name ":" OWS field-value OWS
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# field-name = token
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# field-value = *( field-content / obs-fold )
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# field-content = field-vchar [ 1*( SP / HTAB ) field-vchar ]
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# field-vchar = VCHAR / obs-text
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# Errata from: https://www.rfc-editor.org/errata_search.php?rfc=7230&eid=4189
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# changes field-content to:
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#
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# field-content = field-vchar [ 1*( SP / HTAB / field-vchar )
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# field-vchar ]
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FIELD_VCHAR = "[" + VCHAR + OBS_TEXT + "]"
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# Field content is more greedy than the ABNF, in that it will match the whole value
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FIELD_CONTENT = FIELD_VCHAR + "+(?:[ \t]+" + FIELD_VCHAR + "+)*"
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# Which allows the field value here to just see if there is even a value in the first place
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FIELD_VALUE = "(?:" + FIELD_CONTENT + ")?"
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# chunk-ext = *( ";" chunk-ext-name [ "=" chunk-ext-val ] )
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# chunk-ext-name = token
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# chunk-ext-val = token / quoted-string
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CHUNK_EXT_NAME = TOKEN
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CHUNK_EXT_VAL = "(?:" + TOKEN + ")|(?:" + QUOTED_STRING + ")"
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CHUNK_EXT = (
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"(?:;(?P<extension>" + CHUNK_EXT_NAME + ")(?:=(?P<value>" + CHUNK_EXT_VAL + "))?)*"
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)
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# Pre-compiled regular expressions for use elsewhere
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ONLY_HEXDIG_RE = re.compile(("^" + HEXDIG + "+$").encode("latin-1"))
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ONLY_DIGIT_RE = re.compile(("^" + DIGIT + "+$").encode("latin-1"))
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HEADER_FIELD_RE = re.compile(
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(
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"^(?P<name>" + TOKEN + "):" + OWS + "(?P<value>" + FIELD_VALUE + ")" + OWS + "$"
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).encode("latin-1")
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)
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QUOTED_PAIR_RE = re.compile(QUOTED_PAIR)
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QUOTED_STRING_RE = re.compile(QUOTED_STRING)
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CHUNK_EXT_RE = re.compile(("^" + CHUNK_EXT + "$").encode("latin-1"))
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