bc8cc56a2a
This is the project guideline and the reasons are:
* That follows standard Ruby semantics.
* Allows the implementation to avoid artificial code like !! or something ? true : false
* You do not need to rely on the exact type of 3rd party code. For
example, if your method returns str.end_with?('foo') you do not need to
make sure end_with? returns a singleton. Your predicate just propagates
predicate semantics up regardless of what end_with? returns.
80 lines
2.3 KiB
Ruby
80 lines
2.3 KiB
Ruby
require 'base64'
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require 'active_support/core_ext/object/blank'
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require 'active_support/security_utils'
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module ActiveSupport
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# +MessageVerifier+ makes it easy to generate and verify messages which are
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# signed to prevent tampering.
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#
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# This is useful for cases like remember-me tokens and auto-unsubscribe links
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# where the session store isn't suitable or available.
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#
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# Remember Me:
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# cookies[:remember_me] = @verifier.generate([@user.id, 2.weeks.from_now])
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#
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# In the authentication filter:
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#
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# id, time = @verifier.verify(cookies[:remember_me])
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# if time < Time.now
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# self.current_user = User.find(id)
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# end
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#
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# By default it uses Marshal to serialize the message. If you want to use
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# another serialization method, you can set the serializer in the options
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# hash upon initialization:
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#
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# @verifier = ActiveSupport::MessageVerifier.new('s3Krit', serializer: YAML)
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class MessageVerifier
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class InvalidSignature < StandardError; end
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def initialize(secret, options = {})
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raise ArgumentError, 'Secret should not be nil.' unless secret
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@secret = secret
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@digest = options[:digest] || 'SHA1'
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@serializer = options[:serializer] || Marshal
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end
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def valid_message?(signed_message)
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return if signed_message.blank?
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data, digest = signed_message.split("--")
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data.present? && digest.present? && ActiveSupport::SecurityUtils.secure_compare(digest, generate_digest(data))
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end
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def verified(signed_message)
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if valid_message?(signed_message)
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begin
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data = signed_message.split("--")[0]
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@serializer.load(decode(data))
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rescue ArgumentError => argument_error
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return if argument_error.message =~ %r{invalid base64}
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raise
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end
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end
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end
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def verify(signed_message)
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verified(signed_message) || raise(InvalidSignature)
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end
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def generate(value)
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data = encode(@serializer.dump(value))
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"#{data}--#{generate_digest(data)}"
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end
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private
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def encode(data)
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::Base64.strict_encode64(data)
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end
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def decode(data)
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::Base64.strict_decode64(data)
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end
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def generate_digest(data)
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require 'openssl' unless defined?(OpenSSL)
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OpenSSL::HMAC.hexdigest(OpenSSL::Digest.const_get(@digest).new, @secret, data)
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end
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end
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end
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