Class: X402::PaymentValidator

Inherits:
Object
  • Object
show all
Defined in:
lib/x402/payment_validator.rb

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(facilitator_client = nil) ⇒ PaymentValidator

Returns a new instance of PaymentValidator.



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# File 'lib/x402/payment_validator.rb', line 7

def initialize(facilitator_client = nil)
  @facilitator_client = facilitator_client || FacilitatorClient.new
end

Instance Attribute Details

#facilitator_client ⇒ Object (readonly)

Returns the value of attribute facilitator_client.



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# File 'lib/x402/payment_validator.rb', line 5

def facilitator_client
  @facilitator_client
end

Instance Method Details

#validate(payment_payload, requirement) ⇒ Object 



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# File 'lib/x402/payment_validator.rb', line 11

def validate(payment_payload, requirement)
  # Validate scheme
  unless payment_payload.scheme == requirement.scheme
    return validation_error("Scheme mismatch: expected #{requirement.scheme}, got #{payment_payload.scheme}")
  end

  # Validate network
  unless payment_payload.network == requirement.network
    return validation_error("Network mismatch: expected #{requirement.network}, got #{payment_payload.network}")
  end

  # For EVM chains, validate recipient and amount locally before calling facilitator
  # For Solana chains, the facilitator handles all validation of the transaction
  if payment_payload.evm_chain?
    # Validate recipient address
    unless payment_payload.to_address&.downcase == requirement.pay_to&.downcase
      return validation_error("Recipient mismatch: expected #{requirement.pay_to}, got #{payment_payload.to_address}")
    end

    # Validate amount
    payment_value = payment_payload.value.to_i
    required_value = requirement.max_amount_required.to_i

    if payment_value < required_value
      return validation_error("Insufficient amount: expected at least #{required_value}, got #{payment_value}")
    end
  else
    # Solana: verify transaction payload exists
    unless payment_payload.transaction
      return validation_error("Solana payment missing transaction payload")
    end
  end

  # Call facilitator to verify payment (does NOT settle on blockchain yet)
  begin
    verify_result = facilitator_client.verify(payment_payload, requirement.to_h)

    unless verify_result["isValid"]
      return validation_error("Facilitator validation failed: #{verify_result['invalidReason']}")
    end

    if verify_result["payer"].nil?
      return validation_error("Verification failed: no payer address returned")
    end

    validation_success(verify_result["payer"], verify_result)
  rescue InvalidPaymentError => e
    validation_error("Facilitator validation failed: #{e.message}")
  rescue FacilitatorError => e
    validation_error("Facilitator error: #{e.message}")
  end
end