Go SDK for the Phantasma blockchain.
This project aims to be an easy to use SDK for the Phantasma blockchain.
PhantasmaGo is distributed as a library that includes all the functionality provided.
go get -u github.com/phantasma-io/phantasma-go
To start interacting with Phantasma blockchain you need to choose network you are planning to use (mainnet or testnet) and create corresponding RPC client.
Creation of testnet RPC client:
client = rpc.NewRPCTestnet()
Creation of mainnet RPC client:
client = rpc.NewRPCMainnet()
To create a new key pair structure from private key in WIF format use following code:
keyPair, err := cryptography.FromWIF("put WIF here")
if err != nil {
panic("Creating keyPair failed!")
}
To get detailed description of tokens deployed on the chain you can use following code:
var chainTokens []response.TokenResult
func getChainToken(symbol string) response.TokenResult {
for _, t := range chainTokens {
if t.Symbol == symbol {
return t
}
}
panic("Token not found")
}
chainTokens, _ = client.GetTokens(false)
This will allow you to get token characteristics this way:
t := getChainToken("SOUL")
if t.IsFungible() {
fmt.Println("Token SOUL is fungible")
}
Code samples in the following sections of this documentation use client and keyPair structures and method getChainToken which should be initialized in advance.
Building a script is the most important part of interacting with the Phantasma blockchain. Without a propper script, the Phantasma blockchain will not know what you are trying to do.
These functions, CallContract and CallInterop, are your bread and butter for creating new scripts.
func (s ScriptBuilder) CallContract(contractName, method string, args ...interface{})
func (s ScriptBuilder) CallInterop(method string, args ...interface{})
You can find out all the diffrent CallInterop functions below.
For CallContract, you will have to look through the ABI's of all the diffrent smart contracts currently deployed on the Phantasma 'mainnet': Link Here. To see all methods of a contract, for example stake, you can check it with explorer: Link Here.
Following code generates script to transfer tokenAmount amount of token tokenSymbol from wallet from to wallet to
from := "put sender address here" // Phantasma address, starting with capital 'P'
to := "put recepient address here" // Phantasma address, starting with capital 'P'
tokenAmount := big.NewInt(1000000000) // Token amount in the form of big integer
tokenSymbol := "SOUL"
sb := scriptbuilder.BeginScript()
script := sb.CallContract("gas", "AllowGas", from, cryptography.NullAddress().String(), big.NewInt(100000), big.NewInt(21000)).
CallInterop("Runtime.TransferTokens", from, to, tokenSymbol, tokenAmount).
CallContract("gas", "SpendGas", from).
EndScript()
And here we generate script to make a call which does not require transaction, for this we use CallContract method:
address := "put caller address here" // Phantasma address, starting with capital 'P'
tokenAmount := big.NewInt(1000000000) // Token amount in the form of big integer
sb := scriptbuilder.BeginScript().
CallContract("gas", "AllowGas", address, cryptography.NullAddress().String(), big.NewInt(100000), big.NewInt(21000)).
CallContract("stake", "Stake", address, tokenAmount).
CallContract("gas", "SpendGas", address)
script := sb.EndScript()
For some widely used contract calls SDK has special extension methods which make code more compact. Here's the list of available extensions:
func (s ScriptBuilder) AllowGas(from, to string, gasPrice, gasLimit *big.Int)
func (s ScriptBuilder) SpendGas(address string)
func (s ScriptBuilder) MintTokens(symbol, from, to string, amount *big.Int)
func (s ScriptBuilder) Stake(address string, amount *big.Int)
func (s ScriptBuilder) Unstake(address string, amount *big.Int)
func (s ScriptBuilder) TransferTokens(symbol, from, to string, amount *big.Int)
func (s ScriptBuilder) TransferBalance(symbol, from, to string)
We can rewrite examples from previous section using AllowGas() and SpendGas() extensions:
sb := scriptbuilder.BeginScript()
script := sb.AllowGas(from, cryptography.NullAddress().String(), big.NewInt(100000), big.NewInt(21000)).
CallInterop("Runtime.TransferTokens", from, to, tokenSymbol, tokenAmount).
SpendGas(from).
EndScript()
sb := scriptbuilder.BeginScript().
AllowGas(address, crypto.NullAddress().String(), big.NewInt(100000), big.NewInt(21000)).
CallContract("stake", "Stake", address, tokenAmount).
SpendGas(address)
script := sb.EndScript()
We can also rewrite main contract calls in these examples:
sb := scriptbuilder.BeginScript()
script := sb.AllowGas(from, cryptography.NullAddress().String(), big.NewInt(100000), big.NewInt(21000)).
TransferTokens(from, to, tokenSymbol, tokenAmount).
SpendGas(from).
EndScript()
sb := scriptbuilder.BeginScript().
AllowGas(address, crypto.NullAddress().String(), big.NewInt(100000), big.NewInt(21000)).
Stake(address, tokenAmount).
SpendGas(address)
script := sb.EndScript()
Scripts which does not require transaction can be sent to the chain directly using InvokeRawScript() call.
Here's an example of such call to get SoulMaster count from the chain:
// Build script
sb := scriptbuilder.BeginScript().
CallContract("stake", "GetMasterCount")
script := sb.EndScript()
// Before sending script to the chain we need to encode it into Base16 encoding (HEX)
encodedScript := hex.EncodeToString(script)
// Make the call itself
result, err := client.InvokeRawScript("main", encodedScript)
if err != nil {
panic("Script invocation failed! Error: " + err.Error())
}
// `DecodeResult()` decodes HEX-encoded byte array result, stored in `.Result` field, into `vm.VMObject` structure
// `AsNumber()` returns value stored in `vm.VMObject` structure, in `.Data` field, as a *big.Int number (in our case value is stored in `vm.VMObject` as big integer serialized into byte array)
fmt.Println("Current SoulMasters count: ", result.DecodeResult().AsNumber().String())
To build a transaction you will first need to build a script.
Note, building a transaction is for transactional scripts only. Non transactional scripts should use the RPC function InvokeRawScript().
// Build script
sb := scriptbuilder.BeginScript()
script := sb.AllowGas(keyPair.Address().String(), cryptography.NullAddress().String(), big.NewInt(100000), big.NewInt(21000)).
TransferTokens(tokenSymbol, keyPair.Address().String(), to, tokenAmount).
SpendGas(keyPair.Address().String()).
EndScript()
// Build transaction
expire := time.Now().UTC().Add(time.Second * time.Duration(30)).Unix()
tx := blockchain.NewTransaction(netSelected, "main", script, uint32(expire), domain.SDKPayload)
// Sign transaction
tx.Sign(keyPair)
// Before sending script to the chain we need to encode it into Base16 encoding (HEX)
txHex := hex.EncodeToString(tx.Bytes(true))
Here we send transaction prepared in previous block of code and stored as HEX in txHex variable.
txHash, err := client.SendRawTransaction(txHex)
if err != nil {
panic("Broadcasting tx failed! Error: " + err.Error())
} else {
if util.ErrorDetect(txHash) {
panic("Broadcasting tx failed! Error: " + txHash)
} else {
fmt.Println("Tx successfully broadcasted! Tx hash: " + txHash)
}
}
We need to wait for transaction to be minted on the chain to get its status:
for {
txResult, _ := client.GetTransaction(txHash)
if txResult.StateIsSuccess() {
fmt.Println("Transaction was successfully minted, tx hash: " + fmt.Sprint(txResult.Hash))
break // Funds were transferred successfully
}
if txResult.StateIsFault() {
fmt.Println("Transaction failed, tx hash: " + fmt.Sprint(txResult.Hash))
break // Funds were not transferred, transaction failed
}
time.Sleep(200 * time.Millisecond)
}
Following code shows how to stake SOUL token:
// Build script
sb := scriptbuilder.BeginScript().
AllowGas(address, crypto.NullAddress().String(), big.NewInt(100000), big.NewInt(21000)).
Stake(address, tokenAmount).
SpendGas(address)
script := sb.EndScript()
// Build transaction
expire := time.Now().UTC().Add(time.Second * time.Duration(30)).Unix()
tx := chain.NewTransaction(netSelected, "main", script, uint32(expire), domain.SDKPayload)
// Sign transaction
tx.Sign(keyPair)
// Before sending script to the chain we need to encode it into Base16 encoding (HEX)
txHex := hex.EncodeToString(tx.Bytes(true))
txHash, err := client.SendRawTransaction(txHex)
if err != nil {
panic("Broadcasting tx failed! Error: " + err.Error())
} else {
if util.ErrorDetect(txHash) {
panic("Broadcasting tx failed! Error: " + txHash)
} else {
fmt.Println("Tx successfully broadcasted! Tx hash: " + txHash)
}
}
for {
txResult, _ := client.GetTransaction(txHash)
if txResult.StateIsSuccess() {
fmt.Println("Transaction was successfully minted, tx hash: " + fmt.Sprint(txResult.Hash))
break // Funds were transferred successfully
}
if txResult.StateIsFault() {
fmt.Println("Transaction failed, tx hash: " + fmt.Sprint(txResult.Hash))
break // Funds were not transferred, transaction failed
}
time.Sleep(200 * time.Millisecond)
}
In the following code we monitor the blockchain by checking all the new blocks minted on the blockchain and waiting for TokenReceive event for given address. This event for address means that address has received some tokens.
func onTransactionReceived(address, symbol, amount string) {
fmt.Printf("Address %s received %s %s\n", address, amount, symbol)
}
func waitForIncomingTransfers(address string) {
// Get current block height
height, _ := client.GetBlockHeight("main")
for {
// Get block's data by its height
block, err := client.GetBlockByHeight("main", height.String())
if err != nil {
panic("GetBlockByHeight call failed! Error: " + err.Error())
}
// Iterate throough all transactions in the block
for _, tx := range block.Txs {
// Skip failed trasactions
if !tx.StateIsSuccess() {
continue
}
// Iterate throough all events in the transaction
for _, e := range tx.Events {
if e.Kind == event.TokenReceive.String() && e.Address == address {
// We found TokenReceive event for given address
// Decode event data into event.TokenEventData structure
decoded, _ := hex.DecodeString(e.Data)
br := io.NewBinReaderFromBuf(decoded)
var data event.TokenEventData
data.Deserialize(br)
// Apply decimals to the token amount
t := getChainToken(data.Symbol)
tokenAmount := util.ConvertDecimals(data.Value, int(t.Decimals))
// Call our callback function
onTransactionReceived(e.Address, data.Symbol, tokenAmount)
}
}
}
// Wait for next block to appear on the blockchain
for {
newHeight, _ := client.GetBlockHeight("main")
if newHeight.Cmp(height) == 1 {
// New block was minted (at least 1 new block)
height = height.Add(height, big.NewInt(1))
break
}
// Wait 200 milliseconds before making next RPC call
time.Sleep(200 * time.Millisecond)
}
}
}
This repository has examples folder with some code which can be easily reused. Examples are grouped into a single console application.
To run this application switch to examples folder and run:
go run .
or
sh run.sh
Application entry point is main() function in main.go source file. Once launched it will display the following menu:
Wallet submenu:
Chain stats submenu:
Feel free to contribute to this project after reading the contributing guidelines.
Before starting to work on a certain topic, create an new issue first, describing the feature/topic you are going to implement.
- Get in contact with us on the Phantasma Discord
- Open-source MIT