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corda - 线性状态的 Corda 转移，收集签名

问题描述

我已经实现了几个命令，其中公证人签名满足用例。有两种情况我有未解决的问题：

@InitiatingFlow
@StartableByRPC
class DeviceFlow(private val deviceState: DeviceState,
                 private val stateAndRef: Optional<StateAndRef<DeviceState>>,
                 private val command: DeviceContract.Commands)
    : FlowLogic<SignedTransaction>() {
    override val progressTracker = tracker()

    companion object {
        object GENERATING_TRANSACTION : Step("Generating transaction based on new IOU.")
        object VERIFYING_TRANSACTION : Step("Verifying contract constraints.")
        object SIGNING_TRANSACTION : Step("Signing transaction with our private key.")
        object GATHERING_SIGS : Step("Gathering the counterparty's signature.") {
            override fun childProgressTracker() = CollectSignaturesFlow.tracker()
        }

        object FINALISING_TRANSACTION : Step("Obtaining notary signature and recording transaction.") {
            override fun childProgressTracker() = FinalityFlow.tracker()
        }

        fun tracker() = ProgressTracker(
                GENERATING_TRANSACTION,
                VERIFYING_TRANSACTION,
                SIGNING_TRANSACTION,
                GATHERING_SIGS,
                FINALISING_TRANSACTION
        )
    }

    @Suspendable
    override fun call(): SignedTransaction {
        progressTracker.currentStep = GENERATING_TRANSACTION
        val notary = serviceHub.networkMapCache.getNotary(CordaX500Name("Notary", "London", "GB"))
        val transactionBuilder = TransactionBuilder(notary = notary)
                .addCommand(command, deviceState.participants.map { it.owningKey })
                .addOutputState(deviceState, DeviceContract.ID)
        if (stateAndRef.isPresent)
            transactionBuilder.addInputState(stateAndRef.get())
        progressTracker.currentStep = VERIFYING_TRANSACTION
        transactionBuilder.verify(serviceHub)
        progressTracker.currentStep = SIGNING_TRANSACTION
        val signedTransaction = serviceHub.signInitialTransaction(transactionBuilder)
        val otherPartySession = initiateFlow(notary!!)
        val fullySignedTx = subFlow(
                CollectSignaturesFlow(signedTransaction, setOf(otherPartySession), GATHERING_SIGS.childProgressTracker()))
        progressTracker.currentStep = FINALISING_TRANSACTION
        return subFlow(FinalityFlow(fullySignedTx, setOf(otherPartySession), FINALISING_TRANSACTION.childProgressTracker()))
    }
}

@InitiatedBy(DeviceFlow::class)
class DeviceCreateFlowResponder(val flowSession: FlowSession) : FlowLogic<SignedTransaction>() {
    @Suspendable
    override fun call(): SignedTransaction {
        val signTransactionFlow = object : SignTransactionFlow(flowSession) {
            override fun checkTransaction(stx: SignedTransaction) = requireThat {
                val output = stx.tx.outputs.single().data
                "This must be a Device transaction." using (output is DeviceState)
            }
        }
        val txId = subFlow(signTransactionFlow).id
        return subFlow(ReceiveFinalityFlow(flowSession, expectedTxId = txId))
    }
}

标签： corda

解决方案

新主人签字

  • 您将从保险库中检索最新版本的状态。最新版本应该是未使用的。
  • 创建一个 TransactionBuilder 并将此状态添加为输入。
  • 创建此状态的副本，但更改所有者属性以反映新所有者。将此作为输出添加到 TransactionBuilder。
  • 确保您管理该州的合同规则强制执行前所有者和新所有者都是必需的签名者。

完成线性（或任何状态）

  • 您可以向状态添加一个属性，并让您的合同强制一旦设置此属性，该状态就不能再进化。
  • 您可以通过将状态作为输入添加到事务中而不添加输出来使用状态。（同样，您的联系人必须允许这样做）

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