在R3 Corda中，如何触发另一个节点在流的内部运行特定的流？

Question

我有这段代码，我想触发另一个节点在流内部运行特定的流。当请求者节点运行IssuanceFlow时，当它触发Approver以运行ApproverIssuanceFlow时，我希望在该流中有一些代码。我想使用ApproverIssuanceFlow的输出作为IssuanceFlow下一步的输入。

公共类IssuanceFlow {

@InitiatingFlow
@StartableByRPC
public static class IssuanceInitiator extends FlowLogic<SignedTransaction> {
    private Amount<Currency> amount;

    public IssuanceInitiator(Amount<Currency> amount) {
        this.amount = amount;
    }

    //STEP GENERATOR
    private final ProgressTracker.Step GENERATE_TRX = new ProgressTracker.Step("Generating trx.");
    private final ProgressTracker.Step VERIFY_TRX = new ProgressTracker.Step("Verify trx.");
    private final ProgressTracker.Step SIGN_TRX = new ProgressTracker.Step("Sign trx.");
    private final ProgressTracker.Step GATHER_SIGN = new ProgressTracker.Step("Collecting other sign.") {
        @Override
        public ProgressTracker childProgressTracker() {
            return CollectSignaturesFlow.Companion.tracker();
        }
    };
    private final ProgressTracker.Step FINALIZE_TRX = new ProgressTracker.Step("Notarize and record.") {
        @Override
        public ProgressTracker childProgressTracker() {
            return FinalityFlow.Companion.tracker();
        }
    };

    public ProgressTracker progressTracker = new ProgressTracker(
            GENERATE_TRX,
            VERIFY_TRX,
            SIGN_TRX,
            GATHER_SIGN,
            FINALIZE_TRX
    );

    @Override
    public ProgressTracker getProgressTracker() {
        return progressTracker;
    }

    @Suspendable
    @Override
    public SignedTransaction call() throws FlowException {
        //obtain notary
        final Party notary =getServiceHub().getNetworkMapCache().getNotaryIdentities().get(0);

        progressTracker.setCurrentStep(GENERATE_TRX);
        UniqueIdentifier linearID = new UniqueIdentifier();
        Date issuanceDate = new Date();
        Party approver = getServiceHub().getNetworkMapCache().getPeerByLegalName(CordaX500Name.parse("O=Approver,L=Jakarta,C=ID")); //always choose Central Bank as approver

        **// I want to trigger another node to run another flow, and use the output in this flow**

        //build output
        IssuanceState newIssuance = new IssuanceState(linearID, this.amount, this.getOurIdentity(), approver, issuanceDate);

        //build transaction
        TransactionBuilder transactionBuilder = new TransactionBuilder(notary)
                .addOutputState(newIssuance)
                .addCommand(new IssuanceContract.Commands.Issue(), Arrays.asList(getOurIdentity().getOwningKey(), approver.getOwningKey()));

        progressTracker.setCurrentStep(VERIFY_TRX);
        //verify transaction
        transactionBuilder.verify(getServiceHub());

        progressTracker.setCurrentStep(SIGN_TRX);
        //sign transaction
        final SignedTransaction partiallySign = getServiceHub().signInitialTransaction(transactionBuilder);

        progressTracker.setCurrentStep(GATHER_SIGN);
        //send to counterparty, back with signature
        FlowSession otherPartySession = initiateFlow(approver);
        final SignedTransaction fullySign = subFlow(new CollectSignaturesFlow(partiallySign,Arrays.asList(otherPartySession)));

        progressTracker.setCurrentStep(FINALIZE_TRX);
        //notarize, record transaction
        final SignedTransaction finalityFlow = subFlow(new FinalityFlow(fullySign, Arrays.asList(otherPartySession)));

        return finalityFlow;
    }
}

@InitiatedBy(IssuanceInitiator.class)
public static class IssuanceResponder extends FlowLogic<Void> {
    private FlowSession otherPartySession;

    public IssuanceResponder(FlowSession otherPartySession) {
        this.otherPartySession = otherPartySession;
    }

    @Override
    @Suspendable
    public Void call() throws FlowException {
        SignedTransaction signedTransaction = subFlow(new SignTransactionFlow(otherPartySession) {
            @Override
            @Suspendable
            protected void checkTransaction(@NotNull SignedTransaction stx) throws FlowException {

            }
        });

        //stored to db
        subFlow(new ReceiveFinalityFlow(otherPartySession,signedTransaction.getId()));
        return null;
    }
}

Answer 1

您不能在其他节点中触发任何东西，如果一方能够在其他各方的节点中触发意外行为，则这将是对安全性的重大破坏。记住，其他节点一般都是其他公司、竞争对手、法律实体。

您想要做的事情可以通过使用p2p或sendAndReceive在各方之间进行简单的sendAndReceive通信来实现(文档是这里)。它们允许启动器流向接收方发送消息，接收方可以发送回另一条消息。这个响应可能是您下一步需要做的任何事情的输入。无论如何，所有这些都需要在流中的会话中完成，因此在PartyA (发起者)和接收方( PartyB )之间的事务中。