PiggyBank

To interact with the PiggyBank Smart Contract, you would need to have erdpy

To derive the wallet pem file, check the docs Deriving the Wallet PEM file

Blog post

• Smart Contract for Elrond and Arwen

Walkthrough videos

• Elrond Smart Contracts - interacting using erdpy
• Elrond Smart Contracts - interacting using simple front-end app

Frontend App

• FE App repo
• https://elven-piggy-bank.netlify.app/

Start with contract build**

erdpy contract build

Important You would need some xEGLD on the testnet. There is one faucet which you can use: https://r3d4.fr/elrond/testnet/. Sometimes it won't be able to send a lot of xEGLD. You can also use devnet, where you should be able to use a web wallet's built-in faucet.

Example erdpy interaction commands

Deploy the contract:

erdpy --verbose contract deploy --chain="T" --project=piggybank --pem="wallets/test.pem" --gas-limit=80000000 --proxy="https://testnet-gateway.elrond.com" --recall-nonce --send

Smart Contract deployment. You will need to do this once. The project name is piggybank, and the pem file is located in wallets/test.pem.

Upgrade the contract:

erdpy --verbose contract upgrade {smart_contract_address_here} --chain="T" --project=piggybank --pem="wallets/test.pem" --gas-limit=80000000 --proxy="https://testnet-gateway.elrond.com" --recall-nonce --send

If there are changes in the contract, you can upgrade it.

Create the Piggy:

erdpy --verbose contract call {smart_contract_address_here} --chain="T" --pem="wallets/test.pem" --gas-limit=5000000 --function="create_piggy" --arguments 1628619457 --proxy="https://testnet-gateway.elrond.com" --recall-nonce --send

As an argument for the create_piggy function, we will pass the timestamp for the lock time (should be in the future of course).

Add amount:

erdpy --verbose contract call {smart_contract_address_here} --chain="T" --pem="wallets/test.pem" --gas-limit=5000000 --function="add_amount" --value=1000000000000000000 --proxy="https://testnet-gateway.elrond.com" --recall-nonce --send

We are adding one xEGLD (denomination 18, this is why it is, in fact, 1000000000000000000).

Get amount:

erdpy --verbose contract call {smart_contract_address_here} --chain="T" --pem="wallets/test.pem" --gas-limit=5000000 --function="amount" --proxy="https://testnet-gateway.elrond.com" --recall-nonce --send

Payout:

erdpy --verbose contract call {smart_contract_address_here} --chain="T" --pem="wallets/test.pem" --gas-limit=5000000 --function="pay_out" --proxy="https://testnet-gateway.elrond.com" --recall-nonce --send

It will check if you can withdraw. It will compare lock time and the current block timestamp.