cordapp-template-java (Corda v5.2)

This template repository provides:

• A pre-setup Cordapp Project which you can use as a starting point to develop your own prototypes.

• A base Gradle configuration which brings in the dependencies you need to write and test a Corda 5 Cordapp.

• A set of Gradle helper tasks, provided by the Corda runtime gradle plugin, which speed up and simplify the development and deployment process.

• Debug configuration for debugging a local Corda cluster.

• The MyFirstFlow code which forms the basis of this getting started documentation, this is located in package com.r3.developers.cordapptemplate.flowexample

• A UTXO example in package com.r3.developers.cordapptemplate.utxoexample packages

• Ability to configure the Members of the Local Corda Network.

To find out how to use the template, please refer to the CorDapp Template subsection within the Developing Applications section in the latest Corda 5 documentation at https://docs.r3.com/

Prerequisite

1. Java 17
2. Corda-cli (v5.2), Download here. You need to install Java 17 first.
3. Docker Desktop

Setting up

1. We will begin our test deployment with clicking the startCorda. This task will load up the combined Corda workers in docker. A successful deployment will allow you to open the REST APIs at: https://localhost:8888/api/v5_2/swagger#. You can test out some of the functions to check connectivity. (GET /cpi function call should return an empty list as for now.)
2. We will now deploy the cordapp with a click of vNodeSetup task. Upon successful deployment of the CPI, the GET /cpi function call should now return the meta data of the cpi you just upload

Flow Management Tool[Optional]

We had developed a simple GUI for you to interact with the cordapp. You can access the website by using https://localhost:5000 or https://127.0.0.1:5000. The Flow Management Tool will automatically connect with the CorDapp running locally from your Corda cluster. You can test the connection by click on the dropdown list at the Flow Initiator section. You should be able to see the vNodes of your started CorDapp. You can easily trigger and query a Corda flow.

Running the Chat app

We have built a simple one to one chat app to demo some functionalities of the next gen Corda platform.

In this app you can:

1. Create a new chat with a counterparty. CreateNewChatFlow
2. List out the chat entries you had. ListChatsFlow
3. Individually query out the history of one chat entry. GetChatFlowArgs
4. Continue chatting within the chat entry with the counterparty. UpdateChatFlow

Running the chat app

In Corda 5, flows will be triggered via POST /flow/{holdingidentityshorthash} and flow result will need to be view at GET /flow/{holdingidentityshorthash}/{clientrequestid}

• holdingidentityshorthash: the id of the network participants, ie Bob, Alice, Charlie. You can view all the short hashes of the network member with another gradle task called listVNodes
• clientrequestid: the id you specify in the flow requestBody when you trigger a flow.

Step 1: Create Chat Entry

Pick a VNode identity to initiate the chat, and get its short hash. (Let's pick Alice. Dont pick Bob because Bob is the person who we will have the chat with).

Go to POST /flow/{holdingidentityshorthash}, enter the identity short hash(Alice's hash) and request body:

{
    "clientRequestId": "create-1",
    "flowClassName": "com.r3.developers.cordapptemplate.utxoexample.workflows.CreateNewChatFlow",
    "requestBody": {
        "chatName":"Chat with Bob",
        "otherMember":"CN=Bob, OU=Test Dept, O=R3, L=London, C=GB",
        "message": "Hello Bob"
        }
}

After trigger the create-chat flow, hop to GET /flow/{holdingidentityshorthash}/{clientrequestid} and enter the short hash(Alice's hash) and clientrequestid to view the flow result

Step 2: List the chat

In order to continue the chat, we would need the chat ID. This step will bring out all the chat entries this entity (Alice) has. Go to POST /flow/{holdingidentityshorthash}, enter the identity short hash(Alice's hash) and request body:

{
    "clientRequestId": "list-1",
    "flowClassName": "com.r3.developers.cordapptemplate.utxoexample.workflows.ListChatsFlow",
    "requestBody": {}
}

After trigger the list-chats flow, again, we need to hop to GET /flow/{holdingidentityshorthash}/{clientrequestid} and check the result. As the screenshot shows, in the response body, we will see a list of chat entries, but it currently only has one entry. And we can see the id of the chat entry. Let's record that id.

Step 3: Continue the chat with UpdateChatFlow

In this step, we will continue the chat between Alice and Bob. Goto POST /flow/{holdingidentityshorthash}, enter the identity short hash and request body. Note that here we can have either Alice or Bob's short hash. If you enter Alice's hash, this message will be recorded as a message from Alice, vice versa. And the id field is the chat entry id we got from the previous step.

{
    "clientRequestId": "update-1",
    "flowClassName": "com.r3.developers.cordapptemplate.utxoexample.workflows.UpdateChatFlow",
    "requestBody": {
        "id":" ** fill in id **",
        "message": "How are you today?"
        }
}

And as for the result of this flow, go to GET /flow/{holdingidentityshorthash}/{clientrequestid} and enter the required fields.

Step 4: See the whole chat history of one chat entry

After a few back and forth of the messaging, you can view entire chat history by calling GetChatFlow.

{
    "clientRequestId": "get-1",
    "flowClassName": "com.r3.developers.cordapptemplate.utxoexample.workflows.GetChatFlow",
    "requestBody": {
        "id":" ** fill in id **",
        "numberOfRecords":"4"
    }
}

And as for the result, you need to go to the Get API again and enter the short hash and client request ID.

Thus, we have concluded a full run through of the chat app.