Sample Code for Non Fungible Token Contract

Non-fungible Token Contract

Using the VSYS Python API Wrapper pyvsystems

To generate and broadcast transactions, we can use pyvsystems to test contract functionalities on vsys chain.

Install pyvsystems

pyvsystems can be installed by first cloning the github repository

git clone https://github.com/virtualeconomy/pyvsystems.git

Then using pip, we can install the repository as a package

pip3 install pyvsystems/.

Then we can simply import pyvsystems in your own workplace

Register a Non-fungible Token Contract

Initialize API connection

import pyvsystems as pv
from pyvsystems import Account
from pyvsystems.contract import token_id_from_contract_id
from pyvsystems.contract_helper import *

custom_wrapper = pv.create_api_wrapper("<your_node_address>", api_key="<your_node_api_key (optional)>")
# chain = pv.Chain(chain_name='mainnet', chain_id='M', address_version=5, api_wrapper=custom_wrapper)
chain = pv.Chain(chain_name='testnet', chain_id='T', address_version=5, api_wrapper=custom_wrapper)
sender = Account(chain=chain, seed="<your_sender_seed>")

Register the non fungible token contract

Non fungible token Contract ByteString:

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

Triggers	Inputs	Input Types	Description
Init	()	()	Register a Non Fungible Token Contract

non_fungible_contract_helper = NonFungibleContractHelper()

non_fungible_contract_object = non_fungible_contract_helper.contract_object

register_non_fungible_data_stack = non_fungible_contract_helper.register_data_stack_generator()

sender.register_contract(non_fungible_contract_object, register_non_fungible_data_stack)

Using Non Fungible Token Contract Functions

Executable Functions	Function ID	Inputs	Input Types	Description
Supersede	0	("newIssuer")	(address)	Transfer ownership of contract
Issue	1	("tokenDescription")	(short_text)	Issue the single Token with its description
Send	2	("recipient", "tokenIndex")	(amount, int32)	Send the Token, since each NFT contract can issue multiple tokens, the tokenIndex must be specified. The first token issued will have tokenIndex 0, second will have tokenIndex 1, and so on.
Transfer	3	("sender", "recipient", "tokenIndex")	(address, address, int32)	Transfer the Token from sender to recipient
Deposit	4	("sender", "contract", "tokenIndex")	(address, contract_account, int32)	Deposit the Token into another contract
Withdraw	5	("contract", "recipient", "tokenIndex")	(contract_account, address, int32)	Withdraw the Token from another contract

Supersede the issuing rights to another address

non_fungible_token_contract_id = "<your_non_fungible_token_contract_id>"

supersede_function_id = non_fungible_contract_helper.supersede_function_index

supersede_data_stack = non_fungible_contract_helper.supersede_data_stack_generator("<your_new_issuer_address>")

sender.execute_contract(non_fungible_token_contract_id, supersede_function_id, supersede_data_stack)

Issue the non fungible token

non_fungible_token_contract_id = "<your_non_fungible_token_contract_id>"

issue_function_id = non_fungible_contract_helper.issue_function_index

issue_data_stack = non_fungible_contract_helper.issue_data_stack_generator("test NFT0")

sender.execute_contract(non_fungible_token_contract_id, issue_function_id, issue_data_stack)

# to find the token's id we can use a function in pyvsystems
token_id0 = token_id_from_contract_id(non_fungible_token_contract_id, 0)

# in fact a single non_fungible_token_contract can issue multiple tokens
issue2_data_stack = non_fungible_contract_helper.issue_data_stack_generator("test NFT1")

sender.execute_contract(non_fungible_token_contract_id, issue_function_id, issue2_data_stack)

# then the second token id can be found by index 1
token_id1 = token_id_from_contract_id(non_fungible_token_contract_id, 1)

# and a third token
issue3_data_stack = non_fungible_contract_helper.issue_data_stack_generator("test NFT2")

sender.execute_contract(non_fungible_token_contract_id, issue_function_id, issue3_data_stack)

token_id2 = token_id_from_contract_id(non_fungible_token_contract_id, 2)

Send the non fungible token

non_fungible_token_contract_id = "<your_non_fungible_token_contract_id>"

send_function_id = non_fungible_contract_helper.send_function_index

send_data_stack = non_fungible_contract_helper.send_data_stack_generator("<your_recipient_address>", 0)

sender.execute_contract(non_fungible_token_contract_id, send_function_id, send_data_stack)

Transfer the token from one account to another

non_fungible_token_contract_id = "<your_non_fungible_token_contract_id>"

transfer_function_id = non_fungible_contract_helper.transfer_function_index

transfer_data_stack = non_fungible_contract_helper.transfer_data_stack_generator(sender.address, "<your_recipient_address>", 1)

sender.execute_contract(non_fungible_token_contract_id, transfer_function_id, transfer_data_stack)

Deposit the token into a contract

# previously prepared lock contract that stores the third token from this NFT contract
lock_contract_id = "<your_lock_contract_id>"

non_fungible_token_contract_id = "<your_non_fungible_token_contract_id>"

deposit_function_id = non_fungible_contract_helper.deposit_function_index

deposit_data_stack = non_fungible_contract_helper.deposit_data_stack_generator(sender.address, lock_contract_id, 2)

sender.execute_contract(non_fungible_token_contract_id, deposit_function_id, deposit_data_stack)

Withdraw the token from a contract

# previously prepared lock contract that stores the third token from this NFT contract
lock_contract_id = "<your_lock_contract_id>"

non_fungible_token_contract_id = "<your_non_fungible_token_contract_id>"

withdraw_function_id = non_fungible_contract_helper.withdraw_function_index

withdraw_data_stack = non_fungible_contract_helper.withdraw_data_stack_generator(lock_contract_id, sender.address, 2)

sender.execute_contract(non_fungible_token_contract_id, withdraw_function_id, withdraw_data_stack)

 

Querying the contract database

In order for the contract to do anything, it has to store some information within the database. This information can be queried by using the correct database key within the full node. The contract helper objects contain the corresponding database keys for each stored variable.

State Variable	State Variable Index	Description
issuer	0	The address of the issuer of the non fungible contract
maker	1	The address of the creator of the non fungible contract

State Map	State Map Index	State Map Key	Description
N/A	N/A	N/A	N/A

Get the issuer of the non fungible token contract

non_fungible_contract_helper = NonFungibleContractHelper()

non_fungible_token_contract_id = "<your_non_fungible_token_contract_id>"

issuer_db_key = non_fungible_contract_helper.issuer_db_key_generator()

print(chain.contract_db_query(non_fungible_token_contract_id, issuer_db_key))

Get the maker of the non fungible token contract

non_fungible_contract_helper = NonFungibleContractHelper()

non_fungible_token_contract_id = "<your_non_fungible_token_contract_id>"

maker_db_key = non_fungible_contract_helper.maker_db_key_generator()

print(chain.contract_db_query(non_fungible_token_contract_id, maker_db_key))