2016-11-11 11:52:29 +00:00
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< div class = "section" id = "client-rpc-api-tutorial" >
< h1 > Client RPC API Tutorial< a class = "headerlink" href = "#client-rpc-api-tutorial" title = "Permalink to this headline" > ¶< / a > < / h1 >
< p > In this tutorial we will build a simple command line utility that
connects to a node, creates some Cash transactions and meanwhile dumps
the transaction graph to the standard output. We will then put some
simple visualisation on top. For an explanation on how the RPC works
see < a class = "reference internal" href = "clientrpc.html" > < span class = "doc" > Client RPC< / span > < / a > .< / p >
< p > We start off by connecting to the node itself. For the purposes of the tutorial we will use the Driver to start up a notary and a node that issues/exits and moves Cash around for herself. To authenticate we will use the certificates of the nodes directly.< / p >
< p > Note how we configure the node to create a user that has permission to start the CashProtocol.< / p >
< div class = "highlight-kotlin" > < div class = "highlight" > < pre > < span > < / span > enum class PrintOrVisualise {
Print,
Visualise
}
fun main(args: Array< String> ) {
if (args.size < 1) {
throw IllegalArgumentException(" Usage: < binary> [Print|Visualise]" )
}
val printOrVisualise = PrintOrVisualise.valueOf(args[0])
val baseDirectory = Paths.get(" build/rpc-api-tutorial" )
val user = User(" user" , " password" , permissions = setOf(startProtocolPermission< CashProtocol> ()))
driver(driverDirectory = baseDirectory) {
startNode(" Notary" , advertisedServices = setOf(ServiceInfo(ValidatingNotaryService.type)))
val node = startNode(" Alice" , rpcUsers = listOf(user)).get()
val sslConfig = object : NodeSSLConfiguration {
override val certificatesPath = baseDirectory / " Alice" / " certificates"
override val keyStorePassword = " cordacadevpass"
override val trustStorePassword = " trustpass"
}
< / pre > < / div >
< / div >
< p > Now we can connect to the node itself using a valid RPC login. We login using the configured user.< / p >
< div class = "highlight-kotlin" > < div class = "highlight" > < pre > < span > < / span > < span class = "k" > val< / span > < span class = "py" > client< / span > < span class = "p" > =< / span > < span class = "n" > CordaRPCClient< / span > < span class = "p" > (< / span > < span class = "n" > FullNodeConfiguration< / span > < span class = "p" > (< / span > < span class = "n" > node< / span > < span class = "p" > .< / span > < span class = "n" > config< / span > < span class = "p" > ).< / span > < span class = "n" > artemisAddress< / span > < span class = "p" > ,< / span > < span class = "n" > sslConfig< / span > < span class = "p" > )< / span >
< span class = "n" > client< / span > < span class = "p" > .< / span > < span class = "n" > start< / span > < span class = "p" > (< / span > < span class = "s" > " user" < / span > < span class = "p" > ,< / span > < span class = "s" > " password" < / span > < span class = "p" > )< / span >
< span class = "k" > val< / span > < span class = "py" > proxy< / span > < span class = "p" > =< / span > < span class = "n" > client< / span > < span class = "p" > .< / span > < span class = "n" > proxy< / span > < span class = "p" > ()< / span >
< span class = "n" > thread< / span > < span class = "p" > {< / span >
< span class = "n" > generateTransactions< / span > < span class = "p" > (< / span > < span class = "n" > proxy< / span > < span class = "p" > )< / span >
< span class = "p" > }< / span >
< / pre > < / div >
< / div >
< p > We start generating transactions in a different thread (< code class = "docutils literal" > < span class = "pre" > generateTransactions< / span > < / code > to be defined later) using < code class = "docutils literal" > < span class = "pre" > proxy< / span > < / code > , which exposes the full RPC interface of the node:< / p >
< div class = "highlight-kotlin" > < div class = "highlight" > < pre > < span > < / span > /**
* Returns a pair of currently in-progress state machine infos and an observable of future state machine adds/removes.
*/
@RPCReturnsObservables
fun stateMachinesAndUpdates(): Pair< List< StateMachineInfo> , Observable< StateMachineUpdate> >
/**
* Returns a pair of head states in the vault and an observable of future updates to the vault.
*/
@RPCReturnsObservables
fun vaultAndUpdates(): Pair< List< StateAndRef< ContractState> > , Observable< Vault.Update> >
/**
* Returns a pair of all recorded transactions and an observable of future recorded ones.
*/
@RPCReturnsObservables
fun verifiedTransactions(): Pair< List< SignedTransaction> , Observable< SignedTransaction> >
/**
* Returns a snapshot list of existing state machine id - recorded transaction hash mappings, and a stream of future
* such mappings as well.
*/
@RPCReturnsObservables
fun stateMachineRecordedTransactionMapping(): Pair< List< StateMachineTransactionMapping> , Observable< StateMachineTransactionMapping> >
/**
* Returns all parties currently visible on the network with their advertised services and an observable of future updates to the network.
*/
@RPCReturnsObservables
fun networkMapUpdates(): Pair< List< NodeInfo> , Observable< NetworkMapCache.MapChange> >
/**
* Start the given protocol with the given arguments, returning an [Observable] with a single observation of the
* result of running the protocol.
*/
@RPCReturnsObservables
fun < T: Any> startProtocolDynamic(logicType: Class< out ProtocolLogic< T> > , vararg args: Any?): ProtocolHandle< T>
/**
* Returns Node' s identity, assuming this will not change while the node is running.
*/
fun nodeIdentity(): NodeInfo
/*
* Add note(s) to an existing Vault transaction
*/
fun addVaultTransactionNote(txnId: SecureHash, txnNote: String)
/*
* Retrieve existing note(s) for a given Vault transaction
*/
fun getVaultTransactionNotes(txnId: SecureHash): Iterable< String>
< / pre > < / div >
< / div >
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< p > The one we need in order to dump the transaction graph is < code class = "docutils literal" > < span class = "pre" > verifiedTransactions< / span > < / code > . The type signature tells us that the
RPC will return a list of transactions and an Observable stream. This is a general pattern, we query some data and the
node will return the current snapshot and future updates done to it.< / p >
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< div class = "highlight-kotlin" > < div class = "highlight" > < pre > < span > < / span > val (transactions: List< SignedTransaction> , futureTransactions: Observable< SignedTransaction> ) = proxy.verifiedTransactions()
< / pre > < / div >
< / div >
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< p > The graph will be defined by nodes and edges between them. Each node represents a transaction and edges represent
output-input relations. For now let’ s just print < code class = "docutils literal" > < span class = "pre" > NODE< / span > < span class = "pre" > < txhash> < / span > < / code > for the former and < code class = "docutils literal" > < span class = "pre" > EDGE< / span > < span class = "pre" > < txhash> < / span > < span class = "pre" > < txhash> < / span > < / code > for the
latter.< / p >
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< div class = "highlight-kotlin" > < div class = "highlight" > < pre > < span > < / span > < span class = "k" > when< / span > < span class = "p" > (< / span > < span class = "n" > printOrVisualise< / span > < span class = "p" > )< / span > < span class = "p" > {< / span >
< span class = "n" > PrintOrVisualise< / span > < span class = "p" > .< / span > < span class = "n" > Print< / span > < span class = "p" > -> < / span > < span class = "p" > {< / span >
< span class = "n" > futureTransactions< / span > < span class = "p" > .< / span > < span class = "n" > startWith< / span > < span class = "p" > (< / span > < span class = "n" > transactions< / span > < span class = "p" > ).< / span > < span class = "n" > subscribe< / span > < span class = "p" > {< / span > < span class = "n" > transaction< / span > < span class = "p" > -> < / span >
< span class = "n" > println< / span > < span class = "p" > (< / span > < span class = "s" > " NODE ${transaction.id}" < / span > < span class = "p" > )< / span >
< span class = "n" > transaction< / span > < span class = "p" > .< / span > < span class = "n" > tx< / span > < span class = "p" > .< / span > < span class = "n" > inputs< / span > < span class = "p" > .< / span > < span class = "n" > forEach< / span > < span class = "p" > {< / span > < span class = "n" > input< / span > < span class = "p" > -> < / span >
< span class = "n" > println< / span > < span class = "p" > (< / span > < span class = "s" > " EDGE ${input.txhash} ${transaction.id}" < / span > < span class = "p" > )< / span >
< span class = "p" > }< / span >
< span class = "p" > }< / span >
< span class = "p" > }< / span >
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< / pre > < / div >
< / div >
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< p > Now we just need to create the transactions themselves!< / p >
< div class = "highlight-kotlin" > < div class = "highlight" > < pre > < span > < / span > < span class = "k" > fun< / span > < span class = "nf" > generateTransactions< / span > < span class = "p" > (< / span > < span class = "n" > proxy< / span > < span class = "p" > :< / span > < span class = "n" > CordaRPCOps< / span > < span class = "p" > )< / span > < span class = "p" > {< / span >
< span class = "k" > var< / span > < span class = "py" > ownedQuantity< / span > < span class = "p" > =< / span > < span class = "n" > proxy< / span > < span class = "p" > .< / span > < span class = "n" > vaultAndUpdates< / span > < span class = "p" > ().< / span > < span class = "n" > first< / span > < span class = "p" > .< / span > < span class = "n" > fold< / span > < span class = "p" > (< / span > < span class = "m" > 0L< / span > < span class = "p" > )< / span > < span class = "p" > {< / span > < span class = "n" > sum< / span > < span class = "p" > ,< / span > < span class = "n" > state< / span > < span class = "p" > -> < / span >
< span class = "n" > sum< / span > < span class = "p" > +< / span > < span class = "p" > (< / span > < span class = "n" > state< / span > < span class = "p" > .< / span > < span class = "n" > state< / span > < span class = "p" > .< / span > < span class = "k" > data< / span > < span class = "k" > as< / span > < span class = "n" > Cash< / span > < span class = "p" > .< / span > < span class = "n" > State< / span > < span class = "p" > ).< / span > < span class = "n" > amount< / span > < span class = "p" > .< / span > < span class = "n" > quantity< / span >
< span class = "p" > }< / span >
< span class = "k" > val< / span > < span class = "py" > issueRef< / span > < span class = "p" > =< / span > < span class = "n" > OpaqueBytes< / span > < span class = "p" > .< / span > < span class = "n" > of< / span > < span class = "p" > (< / span > < span class = "m" > 0< / span > < span class = "p" > )< / span >
< span class = "k" > val< / span > < span class = "py" > notary< / span > < span class = "p" > =< / span > < span class = "n" > proxy< / span > < span class = "p" > .< / span > < span class = "n" > networkMapUpdates< / span > < span class = "p" > ().< / span > < span class = "n" > first< / span > < span class = "p" > .< / span > < span class = "n" > first< / span > < span class = "p" > {< / span > < span class = "n" > it< / span > < span class = "p" > .< / span > < span class = "n" > advertisedServices< / span > < span class = "p" > .< / span > < span class = "n" > any< / span > < span class = "p" > {< / span > < span class = "n" > it< / span > < span class = "p" > .< / span > < span class = "n" > info< / span > < span class = "p" > .< / span > < span class = "n" > type< / span > < span class = "p" > .< / span > < span class = "n" > isNotary< / span > < span class = "p" > ()< / span > < span class = "p" > }< / span > < span class = "p" > }.< / span > < span class = "n" > notaryIdentity< / span >
< span class = "k" > val< / span > < span class = "py" > me< / span > < span class = "p" > =< / span > < span class = "n" > proxy< / span > < span class = "p" > .< / span > < span class = "n" > nodeIdentity< / span > < span class = "p" > ().< / span > < span class = "n" > legalIdentity< / span >
< span class = "k" > val< / span > < span class = "py" > meAndRef< / span > < span class = "p" > =< / span > < span class = "n" > PartyAndReference< / span > < span class = "p" > (< / span > < span class = "n" > me< / span > < span class = "p" > ,< / span > < span class = "n" > issueRef< / span > < span class = "p" > )< / span >
< span class = "k" > while< / span > < span class = "p" > (< / span > < span class = "k" > true< / span > < span class = "p" > )< / span > < span class = "p" > {< / span >
< span class = "n" > Thread< / span > < span class = "p" > .< / span > < span class = "n" > sleep< / span > < span class = "p" > (< / span > < span class = "m" > 1000< / span > < span class = "p" > )< / span >
< span class = "k" > val< / span > < span class = "py" > random< / span > < span class = "p" > =< / span > < span class = "n" > SplittableRandom< / span > < span class = "p" > ()< / span >
< span class = "k" > val< / span > < span class = "py" > n< / span > < span class = "p" > =< / span > < span class = "n" > random< / span > < span class = "p" > .< / span > < span class = "n" > nextDouble< / span > < span class = "p" > ()< / span >
< span class = "k" > if< / span > < span class = "p" > (< / span > < span class = "n" > ownedQuantity< / span > < span class = "p" > > < / span > < span class = "m" > 10000< / span > < span class = "p" > & & < / span > < span class = "n" > n< / span > < span class = "p" > > < / span > < span class = "m" > 0.8< / span > < span class = "p" > )< / span > < span class = "p" > {< / span >
< span class = "k" > val< / span > < span class = "py" > quantity< / span > < span class = "p" > =< / span > < span class = "n" > Math< / span > < span class = "p" > .< / span > < span class = "n" > abs< / span > < span class = "p" > (< / span > < span class = "n" > random< / span > < span class = "p" > .< / span > < span class = "n" > nextLong< / span > < span class = "p" > ())< / span > < span class = "p" > %< / span > < span class = "m" > 2000< / span >
< span class = "n" > proxy< / span > < span class = "p" > .< / span > < span class = "n" > startProtocol< / span > < span class = "p" > (< / span > < span class = "o" > ::< / span > < span class = "n" > CashProtocol< / span > < span class = "p" > ,< / span > < span class = "n" > CashCommand< / span > < span class = "p" > .< / span > < span class = "n" > ExitCash< / span > < span class = "p" > (< / span > < span class = "n" > Amount< / span > < span class = "p" > (< / span > < span class = "n" > quantity< / span > < span class = "p" > ,< / span > < span class = "n" > USD< / span > < span class = "p" > ),< / span > < span class = "n" > issueRef< / span > < span class = "p" > ))< / span >
< span class = "n" > ownedQuantity< / span > < span class = "p" > -=< / span > < span class = "n" > quantity< / span >
< span class = "p" > }< / span > < span class = "k" > else< / span > < span class = "k" > if< / span > < span class = "p" > (< / span > < span class = "n" > ownedQuantity< / span > < span class = "p" > > < / span > < span class = "m" > 1000< / span > < span class = "p" > & & < / span > < span class = "n" > n< / span > < span class = "p" > < < / span > < span class = "m" > 0.7< / span > < span class = "p" > )< / span > < span class = "p" > {< / span >
< span class = "k" > val< / span > < span class = "py" > quantity< / span > < span class = "p" > =< / span > < span class = "n" > Math< / span > < span class = "p" > .< / span > < span class = "n" > abs< / span > < span class = "p" > (< / span > < span class = "n" > random< / span > < span class = "p" > .< / span > < span class = "n" > nextLong< / span > < span class = "p" > ()< / span > < span class = "p" > %< / span > < span class = "n" > Math< / span > < span class = "p" > .< / span > < span class = "n" > min< / span > < span class = "p" > (< / span > < span class = "n" > ownedQuantity< / span > < span class = "p" > ,< / span > < span class = "m" > 2000< / span > < span class = "p" > ))< / span >
< span class = "n" > proxy< / span > < span class = "p" > .< / span > < span class = "n" > startProtocol< / span > < span class = "p" > (< / span > < span class = "o" > ::< / span > < span class = "n" > CashProtocol< / span > < span class = "p" > ,< / span > < span class = "n" > CashCommand< / span > < span class = "p" > .< / span > < span class = "n" > PayCash< / span > < span class = "p" > (< / span > < span class = "n" > Amount< / span > < span class = "p" > (< / span > < span class = "n" > quantity< / span > < span class = "p" > ,< / span > < span class = "n" > Issued< / span > < span class = "p" > (< / span > < span class = "n" > meAndRef< / span > < span class = "p" > ,< / span > < span class = "n" > USD< / span > < span class = "p" > )),< / span > < span class = "n" > me< / span > < span class = "p" > ))< / span >
< span class = "p" > }< / span > < span class = "k" > else< / span > < span class = "p" > {< / span >
< span class = "k" > val< / span > < span class = "py" > quantity< / span > < span class = "p" > =< / span > < span class = "n" > Math< / span > < span class = "p" > .< / span > < span class = "n" > abs< / span > < span class = "p" > (< / span > < span class = "n" > random< / span > < span class = "p" > .< / span > < span class = "n" > nextLong< / span > < span class = "p" > ()< / span > < span class = "p" > %< / span > < span class = "m" > 1000< / span > < span class = "p" > )< / span >
< span class = "n" > proxy< / span > < span class = "p" > .< / span > < span class = "n" > startProtocol< / span > < span class = "p" > (< / span > < span class = "o" > ::< / span > < span class = "n" > CashProtocol< / span > < span class = "p" > ,< / span > < span class = "n" > CashCommand< / span > < span class = "p" > .< / span > < span class = "n" > IssueCash< / span > < span class = "p" > (< / span > < span class = "n" > Amount< / span > < span class = "p" > (< / span > < span class = "n" > quantity< / span > < span class = "p" > ,< / span > < span class = "n" > USD< / span > < span class = "p" > ),< / span > < span class = "n" > issueRef< / span > < span class = "p" > ,< / span > < span class = "n" > me< / span > < span class = "p" > ,< / span > < span class = "n" > notary< / span > < span class = "p" > ))< / span >
< span class = "n" > ownedQuantity< / span > < span class = "p" > +=< / span > < span class = "n" > quantity< / span >
< span class = "p" > }< / span >
< span class = "p" > }< / span >
< span class = "p" > }< / span >
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< / pre > < / div >
< / div >
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< p > We utilise several RPC functions here to query things like the notaries in the node cluster or our own vault.< / p >
< p > Then in a loop we generate randomly either an Issue, a Pay or an Exit transaction.< / p >
< p > The RPC we need to initiate a Cash transaction is < code class = "docutils literal" > < span class = "pre" > startProtocolDynamic< / span > < / code > which may start an arbitrary protocol, given sufficient permissions to do so. We won’ t use this function directly, but rather a type-safe wrapper around it < code class = "docutils literal" > < span class = "pre" > startProtocol< / span > < / code > that type-checks the arguments for us.< / p >
< p > Finally we have everything in place: we start a couple of nodes, connect to them, and start creating transactions while listening on successfully created ones, which are dumped to the console. We just need to run it!:< / p >
< blockquote >
< div > # Build the example
./gradlew docs/source/example-code:installDist
# Start it
./docs/source/example-code/build/install/docs/source/example-code/bin/client-rpc-tutorial Print< / div > < / blockquote >
< p > Now let’ s try to visualise the transaction graph. We will use a graph drawing library called < a class = "reference external" href = "http://graphstream-project.org/" > graphstream< / a > < / p >
< div class = "highlight-kotlin" > < div class = "highlight" > < pre > < span > < / span > < span class = "n" > PrintOrVisualise< / span > < span class = "p" > .< / span > < span class = "n" > Visualise< / span > < span class = "p" > -> < / span > < span class = "p" > {< / span >
< span class = "k" > val< / span > < span class = "py" > graph< / span > < span class = "p" > =< / span > < span class = "n" > MultiGraph< / span > < span class = "p" > (< / span > < span class = "s" > " transactions" < / span > < span class = "p" > )< / span >
< span class = "n" > transactions< / span > < span class = "p" > .< / span > < span class = "n" > forEach< / span > < span class = "p" > {< / span > < span class = "n" > transaction< / span > < span class = "p" > -> < / span >
< span class = "n" > graph< / span > < span class = "p" > .< / span > < span class = "n" > addNode< / span > < span class = "p" > < < / span > < span class = "n" > Node< / span > < span class = "p" > > (< / span > < span class = "s" > " ${transaction.id}" < / span > < span class = "p" > )< / span >
< span class = "p" > }< / span >
< span class = "n" > transactions< / span > < span class = "p" > .< / span > < span class = "n" > forEach< / span > < span class = "p" > {< / span > < span class = "n" > transaction< / span > < span class = "p" > -> < / span >
< span class = "n" > transaction< / span > < span class = "p" > .< / span > < span class = "n" > tx< / span > < span class = "p" > .< / span > < span class = "n" > inputs< / span > < span class = "p" > .< / span > < span class = "n" > forEach< / span > < span class = "p" > {< / span > < span class = "n" > ref< / span > < span class = "p" > -> < / span >
< span class = "n" > graph< / span > < span class = "p" > .< / span > < span class = "n" > addEdge< / span > < span class = "p" > < < / span > < span class = "n" > Edge< / span > < span class = "p" > > (< / span > < span class = "s" > " $ref" < / span > < span class = "p" > ,< / span > < span class = "s" > " ${ref.txhash}" < / span > < span class = "p" > ,< / span > < span class = "s" > " ${transaction.id}" < / span > < span class = "p" > )< / span >
< span class = "p" > }< / span >
< span class = "p" > }< / span >
< span class = "n" > futureTransactions< / span > < span class = "p" > .< / span > < span class = "n" > subscribe< / span > < span class = "p" > {< / span > < span class = "n" > transaction< / span > < span class = "p" > -> < / span >
< span class = "n" > graph< / span > < span class = "p" > .< / span > < span class = "n" > addNode< / span > < span class = "p" > < < / span > < span class = "n" > Node< / span > < span class = "p" > > (< / span > < span class = "s" > " ${transaction.id}" < / span > < span class = "p" > )< / span >
< span class = "n" > transaction< / span > < span class = "p" > .< / span > < span class = "n" > tx< / span > < span class = "p" > .< / span > < span class = "n" > inputs< / span > < span class = "p" > .< / span > < span class = "n" > forEach< / span > < span class = "p" > {< / span > < span class = "n" > ref< / span > < span class = "p" > -> < / span >
< span class = "n" > graph< / span > < span class = "p" > .< / span > < span class = "n" > addEdge< / span > < span class = "p" > < < / span > < span class = "n" > Edge< / span > < span class = "p" > > (< / span > < span class = "s" > " $ref" < / span > < span class = "p" > ,< / span > < span class = "s" > " ${ref.txhash}" < / span > < span class = "p" > ,< / span > < span class = "s" > " ${transaction.id}" < / span > < span class = "p" > )< / span >
< span class = "p" > }< / span >
< span class = "p" > }< / span >
< span class = "n" > graph< / span > < span class = "p" > .< / span > < span class = "n" > display< / span > < span class = "p" > ()< / span >
< span class = "p" > }< / span >
< span class = "p" > }< / span >
< span class = "n" > waitForAllNodesToFinish< / span > < span class = "p" > ()< / span >
< span class = "p" > }< / span >
< span class = "p" > }< / span >
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< / pre > < / div >
< / div >
2016-11-18 12:57:39 +00:00
< p > If we run the client with < code class = "docutils literal" > < span class = "pre" > Visualise< / span > < / code > we should see a simple random graph being drawn as new transactions are being created.< / p >
2016-11-11 11:52:29 +00:00
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