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54 lines
2 KiB
Ruby
54 lines
2 KiB
Ruby
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# 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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class SignatureParamsParser < Parslet::Parser
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rule(:token) { match("[0-9a-zA-Z!#$%&'*+.^_`|~-]").repeat(1).as(:token) }
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rule(:quoted_string) { str('"') >> (qdtext | quoted_pair).repeat.as(:quoted_string) >> str('"') }
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# qdtext and quoted_pair are not exactly according to spec but meh
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rule(:qdtext) { match('[^\\\\"]') }
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rule(:quoted_pair) { str('\\') >> any }
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rule(:bws) { match('\s').repeat }
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rule(:param) { (token.as(:key) >> bws >> str('=') >> bws >> (token | quoted_string).as(:value)).as(:param) }
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rule(:comma) { bws >> str(',') >> bws }
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# Old versions of node-http-signature add an incorrect "Signature " prefix to the header
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rule(:buggy_prefix) { str('Signature ') }
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rule(:params) { buggy_prefix.maybe >> (param >> (comma >> param).repeat).as(:params) }
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root(:params)
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end
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class SignatureParamsTransformer < Parslet::Transform
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rule(params: subtree(:param)) do
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(param.is_a?(Array) ? param : [param]).each_with_object({}) { |(key, value), hash| hash[key] = value }
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end
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rule(param: { key: simple(:key), value: simple(:val) }) do
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[key, val]
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end
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rule(quoted_string: simple(:string)) do
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string.to_s
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end
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rule(token: simple(:string)) do
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string.to_s
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end
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end
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def self.parse(raw_signature)
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tree = SignatureParamsParser.new.parse(raw_signature)
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SignatureParamsTransformer.new.apply(tree)
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rescue Parslet::ParseFailed
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raise ParsingError
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end
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end
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