mirror of https://github.com/glitch-soc/mastodon
41 lines
1.5 KiB
Ruby
41 lines
1.5 KiB
Ruby
# frozen_string_literal: true
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class SignatureParser
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class ParsingError < StandardError; end
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# The syntax of this header is defined in:
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# https://datatracker.ietf.org/doc/html/draft-cavage-http-signatures-12#section-4
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# See https://datatracker.ietf.org/doc/html/rfc7235#appendix-C
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# and https://datatracker.ietf.org/doc/html/rfc7230#section-3.2.6
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# In addition, ignore a `Signature ` string prefix that was added by old versions
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# of `node-http-signatures`
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TOKEN_RE = /[0-9a-zA-Z!#$%&'*+.^_`|~-]+/
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# qdtext and quoted_pair are not exactly according to spec but meh
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QUOTED_STRING_RE = /"([^\\"]|(\\.))*"/
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PARAM_RE = /(?<key>#{TOKEN_RE})\s*=\s*((?<value>#{TOKEN_RE})|(?<quoted_value>#{QUOTED_STRING_RE}))/
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def self.parse(raw_signature)
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# Old versions of node-http-signature add an incorrect "Signature " prefix to the header
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raw_signature = raw_signature.delete_prefix('Signature ')
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params = {}
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scanner = StringScanner.new(raw_signature)
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# Use `skip` instead of `scan` as we only care about the subgroups
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while scanner.skip(PARAM_RE)
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# This is not actually correct with regards to quoted pairs, but it's consistent
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# with our previous implementation, and good enough in practice.
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params[scanner[:key]] = scanner[:value] || scanner[:quoted_value][1...-1]
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scanner.skip(/\s*/)
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return params if scanner.eos?
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raise ParsingError unless scanner.skip(/\s*,\s*/)
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end
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raise ParsingError
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end
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end
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