Using the Scripts the API

• These scripts will build the transactions required to call Harmony's production API, for more instructions on how to use the API check the webserver repo

• Make sure to rename the env_file to .env and add your private key.

• To run a script just execute the node file e.g. node bridge_eth_to_one.js

The Scripts

• bridge_eth_to_one.js This script bridges ethereum BUSD to Harmony's ethereum BUSD

• bridge_one_to_bsc.js This script bridges Harmony's BSC BUSD to BSC BUSD

• viper_swap.js This script swaps Harmony's ethereum BUSD to Harmony's BSC BUSD to BSC BUSD

• end_to_end.js This script performs a full end-to-end swap from Ethereum BUSD to BSC BUSD

In order to test the API, you need to complete the following checklist:

• Get tokens

• Make sure that there is enough liquidity in the BSUD/bscBUSD pool in Viper and/or add liquidity

• Start the webserver

• Try the examples in this folder!

Getting tokens

• You need the following tokens:

  • BUSD in the Ethereum Kovan testnet

  • Harmony's ONE tokens (for paying gas)

  • Harmony's BUSD and bscBUSD for adding liquidity

Getting BUSD in the Ethereum Kovan testnet

• You can get these tokens from Harmony's Horizon Bridge Faucet

Getting Harmony's ONE token

• You can get these tokens from the Harmony testnet faucet

Getting Harmony's BUSD and bscBUSD bridged tokens

• For getting Harmony's BUSD you need to bridge from Ethereum BUSD using Harmony's Horizon Bridge

• For getting Harmony's bscBUSD you need to bridge from Harmony's BUSD using ViperSwap

This is a webserver using node and express, in order to start it you need to run the following commands in the terminal:

• npm install

• node index.js

We assume that it will run in port 3000 but feel free to change it. Don't forget to update the scritps accordingly though.

Endpoints

The general architecture of the API is the following

• Endpoints that receive signed transactions as inputs and they will complete the required transactions. This allow you to sign the transactions of the front end and it is safe to use on a production server because the private key is never sent to the endpoints. To sign the transactions you can see the examples in the scripts folder of this repo.

• You can make and end-to-end swap using the /swap endpoints. But this is a multi-step process that will fail if one of the single steps fails. It uses Harmony's Horizon Bridge and Viper DEX, so for example, the bridging part can work but if there is no liquidity in the pool so the who transaction will fail. Therefore use this enpoint only if you are sure that Viper's LPs have enough liquidity.

• If you prefer to do it setp-by-step, you should use the following end-points in the specified order:

  • /swap/bridge-in - Bridges BUSD in ethereum to Harmony's BUSD

  • /swap/viper/ - Swaps Harmony's BUSD to bscBUSD (Both are bridged assets in the Harmony network)

  • /swap/bridge-out - Bridges bscBUSD into Binance's BUSD

Right now the following endpoints are enabled, but we will keep adding more reguarly, so remember to pull once in a while.

POST /swap

This endpoint will swap balances between Ethereum BUSD and Binance BUSD, the body for this request should look like this:

{
    "amount" : amount,
    "oneAddress" : oneAddress,
    "ethAddress" : ethAddress
    "lockApproveTxnHash" : approveTxnHash
    "lockTxnHash" : lockTxnHash
    "burnApproveTxnHash" : approveTxnHash
    "depositTxnHash" : depositTxnHash
    "burnTxnHash" : burnTxnHash
    "routerContract" : routerContract
    "fromTokenContract" : fromTokenContract
}

{ 
    trx: "swap", 
    success: bool, 
    error_message: message, 
    error_body: body
}

• amount: this is a string with the amount in decimals (e.g. "10.50") that you want to swap

• oneAddress: this is a string with the address of the wallet owned by the private key in the Harmony wallet format i.e. oneaxxxxxxxx

• ethAddress: this is a string with the address of the wallet owned by the private key in the Ethereum wallet format i.e. Oxaxxxxxxxx

• lockApproveTxnHash : this is a string with the hash of the contract manager's approval for the lock transaction

• lockTxnHash : this is a string with the hash of the lock transaction

• burnApproveTxnHash : this is a string with the hash of the contract manager's approval for the burn transaction

• depositTxnHash : this is a string with the hash of the deposit transaction

• burnTxnHash : this is a string with the hash of the burn transaction

• routerContract : This is a string with the writing approval for Viper's swap router contract

• fromTokenContract : This is a string with the transaction approval for the account swapping in Viper

POST /swap/bridge-in

This enpoint will bridges BUSD in ethereum to Harmony's BUSD, it is the first step of the step-by-step swap, the body for this request should look like this:

{
    "amount" : amount,
    "oneAddress" : oneAddress,
    "ethAddress" : ethAddress,
    "lockApproveTxnHash" : approveTxnHash,
    "lockTxnHash" : lockTxnHash
}

{ 
    trx: "bridge", 
    success: bool, 
    error_message: message, 
    error_body: body
}

• amount: this is a string with amount in decimals (e.g. "10.50") that you want to swap

• oneAddress: the address of the wallet owned by the private key in the Harmony wallet format i.e. oneaxxxxxxxx

• ethAddress: the address of the wallet owned by the private key in the Ethereum wallet format i.e. Oxaxxxxxxxx

• lockApproveTxnHash : this is a string with the hash of the contract manager's approval for the lock transaction

• lockTxnHash : this is a string with the hash of the lock transaction

You can see an example of this call in the bridge_eth_to_one.js file in the scripts folder of the repo

POST /swap/viper

This enpoint will swap Harmony's BUSD to bscBUSD (Both are bridged assets in the Harmony network), it is the second step of the step-by-step swap, the body for this request should look like this:

{
    "amount" : amount,
    "oneAddress" : oneAddress,
    "ethAddress" : ethAddress
    "routerContract" : routerContract
    "fromTokenContract" : fromTokenContract
}

{ 
    trx: "viper", 
    success: bool, 
    error_message: message, 
    error_body: body
}

• amount: this is a string with amount in decimals (e.g. "10.50") that you want to swap

• wallet: this is the private key of the wallets with the funds, please use an .env or equivalent to store this key, never put it in your code

• oneAddress: the address of the wallet owned by the private key in the Harmony wallet format i.e. oneaxxxxxxxx

• routerContract : This is a string with the writing approval for Viper's swap router contract

• fromTokenContract : This is a string with the transaction approval for the account swapping in Viper

You can see an example of this call in the viper_swap.js file in the scripts folder of the repo

POST /swap/bridge-out

{
    "amount" : amount,
    "oneAddress" : oneAddress,
    "ethAddress" : ethAddress,
    "burnApproveTxnHash" : approveTxnHash,
    "depositTxnHash" : depositTxnHash,
    "burnTxnHash" : burnTxnHash
}

{ 
    trx: "bridge", 
    success: bool, 
    error_message: message, 
    error_body: body
}

• amount: this is a string with amount in decimals (e.g. "10.50") that you want to swap

• oneAddress: the address of the wallet owned by the private key in the Harmony wallet format i.e. oneaxxxxxxxx

• ethAddress: the address of the wallet owned by the private key in the Ethereum wallet format i.e. Oxaxxxxxxxx

• burnApproveTxnHash : this is a string with the hash of the contract manager's approval for the burn transaction

• depositTxnHash : this is a string with the hash of the deposit transaction

• burnTxnHash : this is a string with the hash of the burn transaction

You can see an example of this call in the bridge_one_to_bsc.js file in the scripts folder of the repo

Local Endpoints

POST /local/swap

This enpoint will swap balances between Ethereum BUSD and Binance BUSD, the body for this request should look like this:

{
    "amount" : amount,
    "wallet" : wallet,
    "oneAddress" : oneAddress,
    "ethAddress" : ethAddress
}

{ 
    trx: "swap", 
    success: bool, 
    error_message: message, 
    error_body: body
}

• amount: this is a string with amount in decimals (e.g. "10.50") that you want to swap

• wallet: this is the private key of the wallets with the funds, please use an .env or equivalent to store this key, never put it in your code

• oneAddress: the address of the wallet owned by the private key in the Harmony wallet format i.e. oneaxxxxxxxx

• ethAddress: the address of the wallet owned by the private key in the Ethereum wallet format i.e. Oxaxxxxxxxx

You can see an example of this call in the swap.js file in the testing folder of the repo

POST /local/swap/bridge-in

This enpoint will bridges BUSD in ethereum to Harmony's BUSD, it is the first step of the step-by-step swap, the body for this request should look like this:

{
    "amount" : amount,
    "wallet" : wallet,
    "oneAddress" : oneAddress,
    "ethAddress" : ethAddress
}

{ 
    trx: "bridge", 
    success: bool, 
    error_message: message, 
    error_body: body
}

• amount: this is a string with amount in decimals (e.g. "10.50") that you want to swap

• wallet: this is the private key of the wallets with the funds, please use an .env or equivalent to store this key, never put it in your code

• oneAddress: the address of the wallet owned by the private key in the Harmony wallet format i.e. oneaxxxxxxxx

• ethAddress: the address of the wallet owned by the private key in the Ethereum wallet format i.e. Oxaxxxxxxxx

You can see an example of this call in the bridge-lock.js file in the testing folder of the repo

POST /local/swap/viper

This enpoint will swap Harmony's BUSD to bscBUSD (Both are bridged assets in the Harmony network), it is the second step of the step-by-step swap, the body for this request should look like this:

{
    "amount" : amount,
    "wallet" : wallet,
    "oneAddress" : oneAddress,
}

{ 
    trx: "viper", 
    success: bool, 
    error_message: message, 
    error_body: body
}

• amount: this is a string with amount in decimals (e.g. "10.50") that you want to swap

• wallet: this is the private key of the wallets with the funds, please use an .env or equivalent to store this key, never put it in your code

• oneAddress: the address of the wallet owned by the private key in the Harmony wallet format i.e. oneaxxxxxxxx

You can see an example of this call in the viper.js file in the testing folder of this repo

POST /local/swap/bridge-out

This enpoint will bridges bscBUSD into Binance's BUSD, it is the third step of the step-by-step swap, the body for this request should look like this:

{
    "amount" : amount,
    "wallet" : wallet,
    "oneAddress" : oneAddress,
    "ethAddress" : ethAddress
}

{ 
    trx: "bridge", 
    success: bool, 
    error_message: message, 
    error_body: body
}

• amount: this is a string with amount in decimals (e.g. "10.50") that you want to swap

• wallet: this is the private key of the wallets with the funds, please use an .env or equivalent to store this key, never put it in your code

• oneAddress: the address of the wallet owned by the private key in the Harmony wallet format i.e. oneaxxxxxxxx

• ethAddress: the address of the wallet owned by the private key in the Ethereum wallet format i.e. Oxaxxxxxxxx

You can see an example of this call in the bridge-burn.js file in the testing folder of this repo

This API will let you swap assets between different chains, this is the current status:

Version: B0.1

• This version allow you to swap BUSD in Ethereum into BUSD in Binance, we thought this is a good first step because it will serve as a vehicle between any assets between the two networks.

• Testnets required for running this versions are:

  • Harmony Testnet (https://api.s0.b.hmny.io)

  • Ethereum Kovan (https://kovan.infura.io/v3/acb534b53d3a47b09d7886064f8e51b6)

  • BSC Testnet (https://docs.binance.org/smart-chain/developer/rpc.html)

Some Basic Instructions

• Right now you see two folders, webserver and testing. The former contains the webserver that must be started to call the API endpoints locally in you machine (read this for more detailed instructions), the latter contains scripts in javascript and postman that can be used to test the endpoints once you have the webserber running. It also has examples of how to make calls to the API.

• You will need to set .env files in both folders, we are adding samples for those files (they are called env_file), so you can just go ahead and rename them to .env. You will also need to add your private key to the .env file in the testing folder if you plan to use the .js file. If you plan to use postman, you will need to paste it into the workspace, so make sure that you create it outside the repo. In any case we encourage you to add .env files to the .gitignore and never paste you private keys in the code.

Enjoy!