SDK

The VSC SDK is a library that abstract away various functionalities that are useful in the context of writing a VSC smart contract.

Go Contract SDK

The Go contract SDK implements the necessary runtime and SDK functions for the VSC smart contract environment.

Example Usage

package main

import (
  "contract-template/sdk"
)

//go:wasmexport entrypoint
func Entrypoint(a *string) *string {
  msg := "Entrypoint logged"
  sdk.Log(a)
  sdk.Log(&msg)
  return a
}

SDK Methods

The below methods are within the sdk namespace. All parameters and return types are *string.

Log

Log a string to the node console for debugging purposes.

//go:wasmexport entrypoint
func Entrypoint(a *string) *string {
  // ...
  sdk.Log(a)
  // ...
}

SetObject

Set the value of a key in the contract database.

//go:wasmexport setString
func SetString(a *string) *string {
  // ...
  key := "myString"
  sdk.SetObject(&key, a)
  // ...
}

GetObject

Retrieve the value of a key from the contract database.

//go:wasmexport getString
func GetString(a *string) *string {
  // ...
  key := "myString"
  value := sdk.GetObject(&key)
  // ...
}

DelObject

Delete the value of a key in the contract database.

//go:wasmexport clearString
func ClearString(a *string) *string {
  // ...
  key := "myString"
  sdk.DelObject(&key)
  // ...
}

Call

Make a system call.

//go:wasmexport systemCall
func SystemCall(a *string) *string {
  // ...
  method := "Method name here"
  payload := "Payload here"
  ret := sdk.Call(&method, &payload)
  // ...
}

GetEnv

Retrieve the current runtime environment variables. List of variable names are listed below.

//go:wasmexport dumpEnv
func DumpEnv(a *string) *string {
  // ...
  varContractId := "contract_id"
  contract_id := sdk.GetEnv(&varContractId)
  // ...
}

Sha256

Calculate the SHA256 hash of a hex-encoded string.

//go:wasmexport sha256
func Sha256(a *string) *string {
  // ...
  input := "abcd"
  sha256hash := sdk.Sha256(&input)
  // ...
}

Ripemd160

Calculate the RIPEMD160 hash of a hex-encoded string.

//go:wasmexport ripemd160
func Ripemd160(a *string) *string {
  // ...
  input := "abcd"
  ripemd160hash := sdk.Ripemd160(&input)
  // ...
}

GetBalance

Retrieve the balance of any VSC account or contract.

//go:wasmexport getBalance
func GetBalance(a *string) *string {
  // ...
  acc := "hive:vaultec.vsc"
  asset := "hive"                       // valid assets: hive, hive_consensus, hbd, hbd_savings
  bal := sdk.GetBalance(&acc, &asset)   // in terms of mHIVE/mHBD
  // ...
}

Draw

Transfer assets from caller account to the contract up to the limit specified in intents. The transaction must be signed using active authority for Hive accounts.

//go:wasmexport drawBalance
func DrawBalance(a *string) *string {
  // ...
  amt := "1000"       // in terms of mHIVE/mHBD
  asset := "hive"     // valid assets: hive, hbd, hbd_savings
  sdk.Draw(&amt, &asset)
  // ...
}

Transfer

Transfer assets from the contract to another account.

//go:wasmexport transferBalance
func TransferBalance(a *string) *string {
  // ...
  toacc := "hive:vaultec.vsc"
  amt := "1000"       // in terms of mHIVE/mHBD
  asset := "hive"     // valid assets: hive, hbd, hbd_savings
  sdk.Transfer(&toacc, &amt, &asset)
  // ...
}

Withdraw

Unmap assets from the contract to a specified Hive account.

//go:wasmexport unmapBalance
func UnmapBalance(a *string) *string {
  // ...
  toacc := "hive:vaultec.vsc"
  amt := "1000"       // in terms of mHIVE/mHBD
  asset := "hive"     // valid assets: hive, hbd, hbd_savings
  sdk.Withdraw(&toacc, &amt, &asset)
  // ...
}

Environment Methods

The below methods are within the env namespace.

Abort

Abort contract execution and revert transaction.

import "contract-template/env"

//go:wasmexport abortMe
func AbortMe(a *string) *string {
  // ...
  err := "some error here"
  fname := "abort.go"
  env.Abort(&err, &fname, 1, 1)
  // ...
}

Env Vars

contract_id: ID of the current contract
msg.sender: Address of the transaction sender. If there are multiple, the first account specified in required_auths or required_posting_auths is returned.
msg.required_auths: The required_auths field of the transaction.
msg.required_posting_auths: The required_posting_auths field of the transaction.
anchor.id: ID of the transaction
anchor.block: L1 block ID in which the transaction is included in. For offchain transactions, this refers to the L1 block ID of the VSC block in which the transaction was included in.
anchor.height: L1 block number in which the transaction is included in. For offchain transactions, this refers to the L1 block number of the VSC block in which the transaction was included in.
anchor.timestamp: Timestamp of when the transaction was included in (i.e. 2025-07-26T14:10:42).
anchor.tx_index: Transaction position in block
anchor.op_index: Operation position in transaction