Class: Mpp::Methods::Evm::ChargeIntent

Inherits:
Object
  • Object
show all
Defined in:
lib/mpp/methods/evm/charge_intent.rb

Overview

Server-side EVM charge intent: recover EIP-3009, then settle via facilitator.

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(authorization:, facilitator:, max_timeout_seconds: 300, route_binding: :resource) ⇒ ChargeIntent

Returns a new instance of ChargeIntent.



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# File 'lib/mpp/methods/evm/charge_intent.rb', line 13

def initialize(authorization:, facilitator:, max_timeout_seconds: 300, route_binding: :resource)
  @name = "charge"
  @authorization = authorization
  @facilitator = facilitator
  @max_timeout_seconds = max_timeout_seconds
  @route_binding = route_binding
end

Instance Attribute Details

#authorization ⇒ Object (readonly)

Returns the value of attribute authorization.



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# File 'lib/mpp/methods/evm/charge_intent.rb', line 11

def authorization
  @authorization
end

#facilitator ⇒ Object (readonly)

Returns the value of attribute facilitator.



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# File 'lib/mpp/methods/evm/charge_intent.rb', line 11

def facilitator
  @facilitator
end

#max_timeout_seconds ⇒ Object (readonly)

Returns the value of attribute max_timeout_seconds.



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# File 'lib/mpp/methods/evm/charge_intent.rb', line 11

def max_timeout_seconds
  @max_timeout_seconds
end

#name ⇒ Object (readonly)

Returns the value of attribute name.



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# File 'lib/mpp/methods/evm/charge_intent.rb', line 11

def name
  @name
end

#route_binding ⇒ Object (readonly)

Returns the value of attribute route_binding.



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# File 'lib/mpp/methods/evm/charge_intent.rb', line 11

def route_binding
  @route_binding
end

Instance Method Details

#payment_requirements(request) ⇒ Object 



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# File 'lib/mpp/methods/evm/charge_intent.rb', line 72

def payment_requirements(request)
  Mpp::X402::Server.to_payment_requirements(
    request,
    authorization: @authorization,
    max_timeout_seconds: @max_timeout_seconds
  )
end

#verify(credential, request) ⇒ Object

Raises:



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# File 'lib/mpp/methods/evm/charge_intent.rb', line 21

def verify(credential, request)
  payload = credential.payload
  unless payload.is_a?(Hash) && payload["type"] == "authorization"
    raise Mpp::VerificationError, "EVM authorization credentials are not supported for this challenge"
  end

  if request.dig("methodDetails", "splits")
    raise Mpp::VerificationFailedError.new(reason: "EVM authorization credentials do not support splits")
  end

  unless addresses_equal?(payload["to"], request["recipient"])
    raise Mpp::VerificationFailedError.new(reason: "EVM authorization recipient mismatch")
  end
  unless payload["value"].to_s == request["amount"].to_s
    raise Mpp::VerificationFailedError.new(reason: "EVM authorization amount mismatch")
  end

  unless x402_credential?(credential)
    expected_nonce = Authorization.challenge_hash(credential.challenge)
    unless payload["nonce"].to_s.downcase == expected_nonce.downcase
      raise Mpp::VerificationFailedError.new(reason: "EVM authorization challenge hash mismatch")
    end
  end

  now = Time.now.to_i
  raise Mpp::VerificationFailedError.new(reason: "EVM authorization is not valid yet") if Integer(payload["validAfter"]) > now
  raise Mpp::VerificationFailedError.new(reason: "EVM authorization has expired") if Integer(payload["validBefore"]) <= now

  chain_id = request.dig("methodDetails", "chainId")
  raise Mpp::VerificationFailedError.new(reason: "EVM authorization requires chainId") if chain_id.nil?

  signer = Authorization.recover(
    authorization: @authorization,
    chain_id: chain_id,
    currency: request["currency"],
    payload: payload
  )
  unless signer && addresses_equal?(signer, payload["from"])
    raise Mpp::VerificationFailedError.new(reason: "EVM authorization signature mismatch")
  end

  checksummed_from = Authorization.checksum_address(payload["from"])
  source = "did:pkh:eip155:#{chain_id}:#{checksummed_from}"
  if credential.source && credential.source != source
    raise Mpp::VerificationFailedError.new(reason: "EVM authorization source mismatch")
  end

  settled = settle(payload, request)
  Mpp::Receipt.success(settled.fetch("transaction"), method: "evm")
end