Corda: Party rejected session request as Requestor has not been registered - kotlin

Question

I've a Corda application that using M14 to build and run corda to run a TwoPartyProtocol where either parties can exchange data to reach a data validity consensus. I've followed Corda flow cookbook to build a flow.
Also, after reading the docs from several different corda milestones I've understood that M14 no longer needs flowSessions as mentioned in the release notes which also eliminates need to register services.
My TwoPartyFlow with inner FlowLogics:
class TwoPartyFlow{
#InitiatingFlow
#StartableByRPC
open class Requestor(val price: Long,
val otherParty: Party) : FlowLogic<SignedTransaction>(){
#Suspendable
override fun call(): SignedTransaction {
val notary = serviceHub.networkMapCache.notaryNodes.single().notaryIdentity
send(otherParty, price)
/*Some code to generate SignedTransaction*/
}
}
#InitiatedBy(Requestor::class)
open class Responder(val requestingParty : Party) : FlowLogic<SignedTransaction>(){
#Suspendable
override fun call(): SignedTransaction {
val request = receive<Long>(requestor).unwrap { price -> price }
println(request)
/*Some code to generate SignedTransaction*/
}
}
}
But, running the above using startTrackedFlow from Api causes the above error:
Party CN=Other,O=Other,L=NY,C=US rejected session request: com.testapp.flow.TwoPartyFlow$Requestor has not been registered
I had hard time finding the reason from corda docs or logs since Two Party flow implementations have changed among several Milestones of corda. Can someone help me understand the problem here.
My API Call:
#GET
#Path("start-flow")
fun requestOffering(#QueryParam(value = "price") price: String) : Response{
val price : Long = 10L
/*Code to get otherParty details*/
val otherPartyHostAndPort = HostAndPort.fromString("localhost:10031")
val client = CordaRPCClient(otherPartyHostAndPort)
val services : CordaRPCOps = client.start("user1","test").proxy
val otherParty: Party = services.nodeIdentity().legalIdentity
val (status, message) = try {
val flowHandle = services.startTrackedFlow(::Requestor, price, otherParty)
val result = flowHandle.use { it.returnValue.getOrThrow() }
// Return the response.
Response.Status.CREATED to "Transaction id ${result.id} committed to ledger.\n"
} catch (e: Exception) {
Response.Status.BAD_REQUEST to e.message
}
return Response.status(status).entity(message).build()
}
My Gradle deployNodes task:
task deployNodes(type: net.corda.plugins.Cordform, dependsOn: ['build']) {
directory "./build/nodes"
networkMap "CN=Controller,O=R3,OU=corda,L=London,C=UK"
node {
name "CN=Controller,O=R3,OU=corda,L=London,C=UK"
advertisedServices = ["corda.notary.validating"]
p2pPort 10021
rpcPort 10022
cordapps = []
}
node {
name "CN=Subject,O=Subject,L=NY,C=US"
advertisedServices = []
p2pPort 10027
rpcPort 10028
webPort 10029
cordapps = []
rpcUsers = [[ user: "user1", "password": "test", "permissions": []]]
}
node {
name "CN=Other,O=Other,L=NY,C=US"
advertisedServices = []
p2pPort 10030
rpcPort 10031
webPort 10032
cordapps = []
rpcUsers = [[ user: "user1", "password": "test", "permissions": []]]
}

Answer 1

There appears to be a couple of problems with the code you posted:
The annotation should be #StartableByRPC, not #StartableNByRPC
The price passed to startTrackedFlow should be a long, not an int
However, even after fixing these issues, I couldn't replicate your error. Can you apply these fixes, do a clean re-deploy of your nodes (gradlew clean deployNodes), and see whether the error changes?

Answer 2

You shouldn't be connecting to the other node via RPC. RPC is how a node's owner speaks to their node. In the real world, you wouldn't have the other node's RPC credentials, and couldn't log into the node in this way.
Instead, you should use your own node's RPC client to retrieve the counterparty's identity:
val otherParty = services.partyFromX500Name("CN=Other,O=Other,L=NY,C=US")!!
See an M14 example here: https://github.com/corda/cordapp-example/blob/release-M14/kotlin-source/src/main/kotlin/com/example/api/ExampleApi.kt.