Corda 开发流程

blockchain

git clone https://github.com/corda/cordapp-example

定义 Contract

1. 继承 Contract 并覆盖其中的 verify 方法

open class TemplateContract : Contract {
    override fun verify(tx: LedgerTransaction) {
        TODO()
    }
}

2. 定义 Contract ID，用于构建 tx 的 output: StateAndContract

    companion object {
        @JvmStatic
        val TEMPLATE_CONTRACT_ID = "com.example.contract.TemplateContract"
    }

3. 定义 Contract 中的 command, command 提供了 tx 的意图和交易双方的签名，用于 contract 中的验证

 interface Commands : CommandData {
        class Action : TypeOnlyCommandData(), Commands
    }

如：

val command = tx.commands.requireSingleCommand<TemplateContract.Commands>()
...
when (command.value) {
    is Commands.Action -> {
        val input = tx.inputs.single()
        requireThat {
            "the transaction is signed by the owner" using (input.owner.owningKey in command.signers)
            "the state is propagated" using (outputs.size == 1)
        }
    }

定义 API

1. 继承 WebServerPluginRegistry

// List of lambdas returning JAX-RS objects
val webApis: List<Function<CordaRPCOps, out Any>> get() = emptyList()
// Map of static serving endpoints to the matching resource directory.
val staticServeDirs: Map<String, String> get() = emptyMap()

重写其中的变量webApis

class TemplateWebPlugin : WebServerPluginRegistry {
    override val webApis: List<Function<CordaRPCOps, out Any>> = listOf(Function(::TemplateApi))
...

注意： 实例化Plugin之后，rpcOps 依赖注入会在这里发生。
这个例子中的TemplateApi即是实现了JAX-RS的类，如下：

@Path("template")
class TemplateApi(val rpcOps: CordaRPCOps) {
    // Accessible at /api/template/templateGetEndpoint.
    @GET
    @Path("templateGetEndpoint")
    @Produces(MediaType.APPLICATION_JSON)
    fun templateGetEndpoint(): Response {
        return Response.ok("Template GET endpoint.").build()
    }
}

2. 注册Plugin
在路径META-INF/services/net.corda.webserver.services.WebServerPluginRegistry文件中填写类TemplateWebPlugin的限定名，这里是com.template.TemplateWebPlugin.

3. 对象的序列化白名单

class TemplateSerializationWhitelist : SerializationWhitelist {
    override val whitelist: List<Class<*>> = listOf(TemplateData::class.java)
}
// This class is not annotated with @CordaSerilizable, so it must be added to the serialization whitelist.
data class TemplateData(val payload: String)

注意这里提到，如果Class没有@CordaSerilizable注解，那么需要放到白名单中。

4. 注册序列化白名单
在路径META-INF/services/net.corda.core.serialization.SerializationWhitelist文件中填写白名单的类限定名com.template.TemplateSerializationWhitelist.

使用 CordaRPCOps

cordaRPCOps可以用来操作 Party Node。

1. Retrieve party

rpcOps.wellKnownPartyFromX500Name(partyName);

2. Start flow

rpcOps.startTrackedFlowDynamic(ExampleFlow.Initiator.class, iouValue, otherParty);

3. Vault query

Corda 部署流程

1. git clone corda docker

$ git clone https://github.com/qianyan/corda-docker.git

2. Build docker image

$ docker-compose build

3. Deploy your Cordapp

1. download the project cordapp-template-kotlin
2. run ./gradlew deployNodes
3. copy cordapps under any node of build/nodes, e.g. NetworkMapAndNotary/cordapps, to corda-docker/cordapps in first step.
4. copy each node.conf under build/nodes, e.g. NetworkMapAndNotary/node.conf, to corda-docker/nodes and rename as NetworkMapAndNotary.conf. so do PartyA/node.conf to PartyA.conf

After these operations, you will see directories in corda-docker as below:

nodes
├── NetworkMapAndNotary.conf
├── PartyA.conf
└── PartyB.conf

5. download network-bootstrapper-corda-3.0.jar in corda-docker, refer to corda network

aria2c -x3 http://downloads.corda.net/network-bootstrapper-corda-3.0.jar

6. generate real nodes in corda-docker

java -jar network-bootstrapper-corda-3.0.jar nodes

The command will generate a directory structures as below:

nodes
├── NetworkMapAndNotary
│   ├── additional-node-infos
│   ├── certificates
│   ├── corda.jar
│   ├── cordapps
│   ├── logs
│   ├── network-parameters
│   ├── node.conf
│   ├── nodeInfo-9D193AC8883388E96664F3B0CC0AD3D162114F85F1633A69EF8CB30DA0993065
│   └── persistence.mv.db
├── PartyA
│   ├── additional-node-infos
│   ├── certificates
│   ├── corda.jar
│   ├── cordapps
│   ├── logs
│   ├── network-parameters
│   ├── node.conf
│   ├── nodeInfo-E4477B559304AADFC0638772C0956A38FA2E2A7A5EB0E65D0D83E5884831879A
│   └── persistence.mv.db
├── PartyB
│   ├── additional-node-infos
│   ├── certificates
│   ├── corda.jar
│   ├── cordapps
│   ├── logs
│   ├── network-parameters
│   ├── node.conf
│   ├── nodeInfo-B1F1FD9F15FCFDE1C9EE7A59504A44D669AB67B655597D60B691138E9C12E93C
│   └── persistence.mv.db
└── whitelist.txt

7. replace each localhost in node.conf with its container name, for eaxmple:

myLegalName="O=NetworkMapAndNotary,L=London,C=GB"
notary {
    validating=true
}
p2pAddress="localhost:10002"
rpcUsers=[]
webAddress="localhost:10004"
--> #change to container name
myLegalName="O=NetworkMapAndNotary,L=London,C=GB"
notary {
    validating=true
}
p2pAddress="NetworkMapAndNotary:10002"
rpcUsers=[]
webAddress="NetworkMapAndNotary:10004"

8. start containers with docker-compose up

$ docker-compose up
...
NetworkMapAndNotary    | Loaded CorDapps                         : corda-core-corda-3.0
NetworkMapAndNotary    | Node for "NetworkMapAndNotary" started up and registered in 31.61 sec
PartyB                 | Advertised P2P messaging addresses      : PartyB:10008
PartyB                 | RPC connection address                  : PartyB:10009
PartyB                 | RPC admin connection address            : PartyB:10049
PartyA                 | Advertised P2P messaging addresses      : PartyA:10005
PartyA                 | RPC connection address                  : PartyA:10006
PartyA                 | RPC admin connection address            : PartyA:10046
PartyB                 | Loaded CorDapps                         : cordapp-template-kotlin-0.1, cordapp-contracts-states-0.1, cordapp-0.1, corda-finance-corda-3.0, corda-core-corda-3.0
PartyB                 | Node for "PartyB" started up and registered in 40.21 sec
PartyA                 | Loaded CorDapps                         : cordapp-template-kotlin-0.1, cordapp-contracts-states-0.1, cordapp-0.1, corda-finance-corda-3.0, corda-core-corda-3.0
PartyA                 | Node for "PartyA" started up and registered in 40.88 sec
PartyB                 | Webserver started up in 46.92 sec
PartyA                 | Webserver started up in 47.23 sec

9. Access each node via web server

localhost:10007
or
localhost:10010

总结

异常

启动docker-compose时，发现了network parameters有问题

PartyB                 | E 01:41:49+0000 [main] cordapp.CordappProviderImpl.verifyInstalledCordapps - Contract com.template.TemplateContract found in attachment 514EA81F872492BD293B8B60B924D52B4F2A850AA90C9298732F1CF66EE7B420 is not whitelisted in the network parameters. If this is a production node contact your zone operator. See https://docs.corda.net/network-map.html {}
PartyB                 | E 01:41:49+0000 [main] cordapp.CordappProviderImpl.verifyInstalledCordapps - Contract net.corda.finance.contracts.JavaCommercialPaper found in attachment C26A176F7448571B553D96D8EB61B44B10F6CB18A7E5C862AC7794705F07A417 is not whitelisted in the network parameters. If this is a production node contact your zone operator. See https://docs.corda.net/network-map.html {}
PartyB                 | E 01:41:49+0000 [main] cordapp.CordappProviderImpl.verifyInstalledCordapps - Contract net.corda.finance.contracts.asset.Cash found in attachment C26A176F7448571B553D96D8EB61B44B10F6CB18A7E5C862AC7794705F07A417 is not whitelisted in the network parameters. If this is a production node contact your zone operator. See https://docs.corda.net/network-map.html {}
PartyB                 | E 01:41:49+0000 [main] cordapp.CordappProviderImpl.verifyInstalledCordapps - Contract net.corda.finance.contracts.asset.CommodityContract found in attachment C26A176F7448571B553D96D8EB61B44B10F6CB18A7E5C862AC7794705F07A417 is not whitelisted in the network parameters. If this is a production node contact your zone operator. See https://docs.corda.net/network-map.html {}
PartyB                 | E 01:41:49+0000 [main] cordapp.CordappProviderImpl.verifyInstalledCordapps - Contract net.corda.finance.contracts.asset.Obligation found in attachment C26A176F7448571B553D96D8EB61B44B10F6CB18A7E5C862AC7794705F07A417 is not whitelisted in the network parameters. If this is a production node contact your zone operator. See https://docs.corda.net/network-map.html {}
PartyB                 | E 01:41:49+0000 [main] cordapp.CordappProviderImpl.verifyInstalledCordapps - Contract net.corda.finance.contracts.CommercialPaper found in attachment C26A176F7448571B553D96D8EB61B44B10F6CB18A7E5C862AC7794705F07A417 is not whitelisted in the network parameters. If this is a production node contact your zone operator. See https://docs.corda.net/network-map.html {}
PartyA                 | E 01:41:50+0000 [main] cordapp.CordappProviderImpl.verifyInstalledCordapps - Contract com.template.TemplateContract found in attachment 514EA81F872492BD293B8B60B924D52B4F2A850AA90C9298732F1CF66EE7B420 is not whitelisted in the network parameters. If this is a production node contact your zone operator. See https://docs.corda.net/network-map.html {}
PartyA                 | E 01:41:50+0000 [main] cordapp.CordappProviderImpl.verifyInstalledCordapps - Contract net.corda.finance.contracts.JavaCommercialPaper found in attachment C26A176F7448571B553D96D8EB61B44B10F6CB18A7E5C862AC7794705F07A417 is not whitelisted in the network parameters. If this is a production node contact your zone operator. See https://docs.corda.net/network-map.html {}
PartyA                 | E 01:41:50+0000 [main] cordapp.CordappProviderImpl.verifyInstalledCordapps - Contract net.corda.finance.contracts.asset.Cash found in attachment C26A176F7448571B553D96D8EB61B44B10F6CB18A7E5C862AC7794705F07A417 is not whitelisted in the network parameters. If this is a production node contact your zone operator. See https://docs.corda.net/network-map.html {}
PartyA                 | E 01:41:50+0000 [main] cordapp.CordappProviderImpl.verifyInstalledCordapps - Contract net.corda.finance.contracts.asset.CommodityContract found in attachment C26A176F7448571B553D96D8EB61B44B10F6CB18A7E5C862AC7794705F07A417 is not whitelisted in the network parameters. If this is a production node contact your zone operator. See https://docs.corda.net/network-map.html {}
PartyA                 | E 01:41:50+0000 [main] cordapp.CordappProviderImpl.verifyInstalledCordapps - Con

Corda很不错的解释文章，后面有例子