/Express-Corda

Primary LanguageKotlinOtherNOASSERTION

Corda

CorDapp Template - Kotlin

Welcome to the Kotlin CorDapp template. The CorDapp template is a stubbed-out CorDapp that you can use to bootstrap your own CorDapps.

This is the Kotlin version of the CorDapp template. The Java equivalent is here.

Pre-Requisites

See https://docs.corda.net/getting-set-up.html.

Usage

Running tests inside IntelliJ

We recommend editing your IntelliJ preferences so that you use the Gradle runner - this means that the quasar utils plugin will make sure that some flags (like -javaagent - see below) are set for you.

To switch to using the Gradle runner:

  • Navigate to Build, Execution, Deployment -> Build Tools -> Gradle -> Runner (or search for runner)
    • Windows: this is in "Settings"
    • MacOS: this is in "Preferences"
  • Set "Delegate IDE build/run actions to gradle" to true
  • Set "Run test using:" to "Gradle Test Runner"

If you would prefer to use the built in IntelliJ JUnit test runner, you can run gradlew installQuasar which will copy your quasar JAR file to the lib directory. You will then need to specify -javaagent:lib/quasar.jar and set the run directory to the project root directory for each test.

Running the nodes

See https://docs.corda.net/tutorial-cordapp.html#running-the-example-cordapp.

Interacting with the nodes

Shell

When started via the command line, each node will display an interactive shell:

Welcome to the Corda interactive shell.
Useful commands include 'help' to see what is available, and 'bye' to shut down the node.

Tue Nov 06 11:58:13 GMT 2018>>>

You can use this shell to interact with your node. For example, enter run networkMapSnapshot to see a list of the other nodes on the network:

Tue Nov 06 11:58:13 GMT 2018>>> run networkMapSnapshot
[
  {
  "addresses" : [ "localhost:10002" ],
  "legalIdentitiesAndCerts" : [ "O=Notary, L=London, C=GB" ],
  "platformVersion" : 3,
  "serial" : 1541505484825
},
  {
  "addresses" : [ "localhost:10005" ],
  "legalIdentitiesAndCerts" : [ "O=PartyA, L=London, C=GB" ],
  "platformVersion" : 3,
  "serial" : 1541505382560
},
  {
  "addresses" : [ "localhost:10008" ],
  "legalIdentitiesAndCerts" : [ "O=PartyB, L=New York, C=US" ],
  "platformVersion" : 3,
  "serial" : 1541505384742
}
]

Tue Nov 06 12:30:11 GMT 2018>>>

You can find out more about the node shell here.

Client

clients/src/main/kotlin/com/template/Client.kt defines a simple command-line client that connects to a node via RPC and prints a list of the other nodes on the network.

Running the client

Via the command line

Run the runTemplateClient Gradle task. By default, it connects to the node with RPC address localhost:10006 with the username user1 and the password test.

Via IntelliJ

Run the Run Template Client run configuration. By default, it connects to the node with RPC address localhost:10006 with the username user1 and the password test.

Webserver

clients/src/main/kotlin/com/template/webserver/ defines a simple Spring webserver that connects to a node via RPC and allows you to interact with the node over HTTP.

The API endpoints are defined here:

 clients/src/main/kotlin/com/template/webserver/Controller.kt

And a static webpage is defined here:

 clients/src/main/resources/static/

Running the webserver

Via the command line

Run the runTemplateServer Gradle task. By default, it connects to the node with RPC address localhost:10006 with the username user1 and the password test, and serves the webserver on port localhost:10050.

Via IntelliJ

Run the Run Template Server run configuration. By default, it connects to the node with RPC address localhost:10006 with the username user1 and the password test, and serves the webserver on port localhost:10050.

Interacting with the webserver

The static webpage is served on:

http://localhost:10050

While the sole template endpoint is served on:

http://localhost:10050/templateendpoint

Extending the template

You should extend this template as follows:

  • Add your own state and contract definitions under contracts/src/main/kotlin/
  • Add your own flow definitions under workflows/src/main/kotlin/
  • Extend or replace the client and webserver under clients/src/main/kotlin/

For a guided example of how to extend this template, see the Hello, World! tutorial here.