Version: Next

Official Lamden Unity Plugin

Visit the Github Repository

A Unity package to simplify the integration of Lamden Blockchain into your Unity project. The plugin also contains an example scene to demonstrate how the package can be used.

Supported Platforms:

  • Standalone (PC)
  • Android
  • iOS (untested)

Key Features

  • Customize the network information
  • Ping the server
  • Wallet
  • Create new wallet
  • Load from SK
  • Execute a transaction (smart contract)
  • Retrieve Currency Balance
  • Retrieve a Contact Variable
  • Retrieve Stamp Ratio
  • Check maximum stamps available
  • Query contact information
    • Get Methods
    • Get contact code

Recomendation

I would suggest you familiarize yourself the the Lamden Contracts by going through these tutorials first. The concepts below will make much more sense if you have the basics of how a Lamden contract works.

Installation

  1. Download the package Lamden-Unity.unitypackage from HERE
  2. In your Unity project select Assets > Import Package > Custom Package
  3. Select the downloaded package Lamden-Unity.unitypackage
  4. Ensure all items are selected and choose Import

Usage

Follow the installation steps above to install the Lamden-Unity asset package.

The LamdenManager from 'Assets/LamdenUnity/Prefabs' is required in your scene to interact with the Lamden blockchain. The attached MasterNodeApi script handles all the calls to the network.

Note: All Lamden Unity classes are in the LamdenUnitynamespace. So a using LamdenUnity statement is required to access the classes and methods.

The MasterNodeApi script can be configured with the follow variables:

  • Timeout: Timeout time in milliseconds before the network request is aborted if not answered by the server, Default value: 10000 ms, Type: int
  • Network Info
  • Hosts: An array of strings that define the URL of nodes on the lamden network that will be called to execute requests, Default value: http://167.172.126.5:18080/ (Lamden Testnet), Type: string
  • Network Type: Type of Lamden network, Default value: testnet, Type: string
  • Currency symbol: Name of the currency used in the network, Default Value: dTAU, Type: string
  • Lamden: Defines if the network is a Lamden network or not, Default Value: true, Type: boolean
  • Block Explorer: URL to the block explorer for the defined network, Default value: https://testnet.lamden.io/

If you are performing testing with a locally hosted Lamden mockchain with the default configuration change the hosts array to only contain one host of http://127.0.0.1:8000. The other settings should not matter for testing.

Afer adding the LamdenManager to the scene the next thing to do is create a Lamden wallet. This is done using the 'LamdenUnity\Core\Wallet' script. A wallet is composed of a VK (verification key or public key) and a SK (signing key or private key) keypair. NOTE: Anyone that has copy of a wallet's SK can perform any action on behalf of the owner, so the SK should stored in a secure place. For testing purposes on a local mockchain or on the testnet it probably ok to store the SK in plain text or in code. NOTE: Keypairs are shared across the lamden testnet and mainnet, ensure that you are not using a keypair that has any TAU or other assets associated with it in your development environment to avoid issues with having the SK post in source or accidently executing a transaction on the mainnet.

Creating or Loading Wallet and Accessing Keys

  • New(): Creates a new keypair (VK and SK)
  • Load(string sk): Regenerates keypair (VK and SK) from sk argument, in other words passing in the SK will regenerate the VK so both do not need to be stored
  • GetVK(): Get hex string of the VK (verification key or public key)
  • GetSK(): Get hex string of the SK (signing key or private key)

API Calls

Once a wallet has been generated or loaded API calls can be made through the MasterNodeApi is added to the LamdenManager gameobject. As the network calls are performed using cooroutines the MasterNodeApi must be called attached to a gameobject. The basic structure on all the API calls is to execute an Action after the request has been executed and return the results in the action arguments. The first argument in the Action will be a bool that indicates if the request was successful. The other arguments generally contain more infomation and are specific to the action.

There are several useful API calls built into the MasterNodeApi script:

Ping

  • Method: PingServer(Action<bool, string> callBack)
  • Purpose: Calls the <master node>/ping API to determine if the network is up
  • Action Argurments:
    • bool:The first bool arg will be true if the server responds online, if the server is unreachable or reports offline it will respond with false
    • string: Returns the error message or json response from the server in as a string

Get Currency Balance

  • Method: GetCurrencyBalance(string key, Action<bool, float> callBack):
  • Purpose: Retreives the account balance of for the wallet from the server
  • Argurments:
    • key: The VK of the wallet for the request
  • Action Argurments:
    • bool: true = call successful, false = call failed
    • float: Successful: The balance of the wallet for a request, Failed: -1

Get Stamp Ratio

  • Method: GetStampRatio(Action<bool, int> callBack)
  • Purpose: Get the number of stamps per 1 TAU (stamps are the fee that the sender of the transaction pay for it to be processed)
  • Action Argurments:
    • bool: true = call successful, false = call failed
    • int: Successful: The number of stamps per 1 TAU, failed: -1

Get Max Stamps

  • Method: GetMaxStamps(string key, Action<bool, int> callBack)
  • Purpose: Get the maximum number of stamps a user could spend (stamp ratio * currency balance)
  • Argurments:
    • key: The VK of the wallet for the request
  • Action Argurments:
    • bool: true = call successful, false = call failed
    • int: Successful: The maximum stamps the user could spend, failed: -1

Sending Transactions

While the methods for sending a transaction are exposed via the MasterNodeApi the plugin has a speical class called Transaction to execute smart contracts on the Lamden blockchain. Simple create a new instance of the class passing all the needed variables into the class contstructor and the transaction will be started.

Constructor: Transaction(MasterNodeApi node, TxInfo ti, Action<TransactionStatus, TxResponse> action)

  • Argurments:
  • node: Reference to the MasterNodeApi that has been attached to an active gameobject in the scene
  • ti: An instance of the TxInfo class, more on that below...
  • action: The action that will be executed after the call to the server was made
  • Action Argurments:
    • TransactionStatus: Current status of the transaction enum TransactionStatus { Error, Sending, SubmittedProcessing, Completed };
    • TxResponse: Instance of the TxReposnse, more on that below...

When as transaction is called and executed successfully will move from Sending to SubmittedProcessing and then finally to Completed. At any point it could change to Error if there was a failure with the execution. These different states can be used to update the GUI and let the users know the status of the request. The average for the transaction to be completed is between 400 and 1000 ms which is very fast compared to other blockchains.

When submitting a transaction details are requried that will depend on the contact that is being executed and these detailed are stored int the TxInfo class. Below is an example TxInfo:

TxInfo txInfo = new TxInfo()
{
sender = wallet, // 'public Wallet sender' is wallet that will be the ctx.sender in the contract
contractName = "con_values_testing", // 'public string contractName' is the name of the contract
methodName = "test_values", // 'public string methodName' is the name of the method that will be executed in the contract
stampLimit = 100, // 'public int stampLimit' the maximum number of stamps (fee) that the user is willing to pay to execute the contract method
kwargs = new Dictionary<string, KwargType> // The argument name and arguments that will be passed into the method of the contact
{
{"UID", new KT_UID("testing2")},
{"Str", new KT_String("this is another string")},
{"Float", new KT_Numeric(1.1f)},
{"Int", new KT_Int(2)},
{"Bool", new KT_Bool(false)},
{"Dict", new KT_Dict(new Dictionary<string, KwargType>{ {"test", new KT_String("my test")}})},
{"List", new KT_List(new List<KwargType>{ new KT_Numeric(1.2f), new KT_String("test2")})},
{"ANY", new KT_Numeric(1.1f) },
{"DateTime", new KT_DateTime(DateTime.Now)},
{"TimeDelta", new KT_TimeDelta(4898)}
}
};

Note all the KT_ classes hold the specific contract argument types that relate the Python code. The above examples relates to the smart contract called on_values_testing that accepts one of every argument type for testing. The kwargs variable will need to match the arguments of the contract with names and types.

After the transaction has been sumbitted the status will be returned the Action passed into the transaction contructor. I like using lamba expressions for the Action below is an example that updates a text field as the transaction is processed.

Transaction tx = new Transaction(lamdenTest.masterNodeApi, txInfo, (Transaction.TransactionStatus txStatus, TxResponse txResponse) => {
if (txStatus == Transaction.TransactionStatus.SubmittedProcessing)
txtStatus.text = "Sumbitted and processing...";
if (txStatus == Transaction.TransactionStatus.Completed)
txtStatus.text = "Processed successfully!";
if (txStatus == Transaction.TransactionStatus.Error)
txtStatus.text = txResponse.error;
});

The TxResponse class will contain extra infomation about the transaction including the updated state of the contract.

public class TxResponse
{
public string success ="";
public string hash = "";
public string error = "";
public CheckTransactionData transactionData;
}

If the transaction TransactionStatus returned as error there will be more information in the TransactionStatus.error string. If the transaction status was returned as Completed the TransactionStatus.transactionData will contain a lot of data about the transacation that was completed held in the CheckTransactionData class. Below is the JSON data that is returned.

{
"hash":"e05c4e5024bca67dcf7a8688f10692af435b3f7466cd06ed9596e9097b0a65e4",
"result":"None",
"stamps_used":18,
"state":[
{
"key":"currency.balances:960c002a36c30c3aec8bc670e9b8b40eebcfd545f4e9237579fd7395a21ccebb",
"value":{
"__fixed__":"98.1"
}
},
{
"key":"currency.balances:4680c6ea89ffc29b0b670a5712edef2b62bc0cf40bfba2f20bbba759cdd185b9",
"value":{
"__fixed__":"101.0"
}
}
],
"status":0,
"transaction":{
"metadata":{
"signature":"d15ec95533cd930628a4190594ed1ca6587a199cfac744059a7ada1a099bd7a12f5b96318c332efbdf7eeaf091b3afab466a689d594d317a996612c30e8ec908",
"timestamp":1600749858
},
"payload":{
"contract":"currency",
"function":"transfer",
"kwargs":{
"amount":{
"__fixed__":"1.0"
},
"to":"4680c6ea89ffc29b0b670a5712edef2b62bc0cf40bfba2f20bbba759cdd185b9"
},
"nonce":0,
"processor":"89f67bb871351a1629d66676e4bd92bbacb23bd0649b890542ef98f1b664a497",
"sender":"960c002a36c30c3aec8bc670e9b8b40eebcfd545f4e9237579fd7395a21ccebb",
"stamps_supplied":100
}
}
}

MORE

For more details there are unit tests that run the Unity Test Framework to test all the methods that provide good example of usage. Also, there is a example scene under Assets\Lamden UI Example that implements a GUI that can create a wallet, ping the server and submit a transaction.

My image

Create New Wallet will create a new random keypair that can be used as a wallet Ping Server will ping the server configured in the Lamden Manager/MasterNodeApi script and the image to the right will turn green if the server is online and red if unreaachable.

Create Wallet from SK will generate the VK from the SK that is entered into the field to the left of it NOTE: Copy and paste works with keyboard short cuts for all the input fields).

VK is the wallets verification key or public key.

SK is the wallets signature key or private key NOTE: In non-development situations this the SK is extremely senstive and should kept secert. Do not use your mainnet wallet for development!

Get Balance will update the wallet currency amount in the field to the right of it.

Get dTAU "Testnet TAU" will copy the wallets VK to the clipboard and open the Testnet Faucet webpage, where you can paste the VK and get 100 dTAU a day for development purposes.

Test Contract Submission is actually testing the contract excecution of the con_values_testing/test_values, the submit button will send the contract to the server Note: you need to have a wallet with dTAU or TAU in it to execute a contract on the testnet or mainnet respectively

Test Signature Generation will create a signature using the SK of the test in the top input field.