Initial setup
Configuration
To proceed with testing, you’ll need environment configuration based on the following template:
USER1_FROM= # 0x...
USER1_PRIVATE_KEY= # Without prefix
USER2_FROM= # 0x...
USER2_PRIVATE_KEY= # Without prefix
ROOT_RPC=https://goerli.infura.io/v3/9aa3d95b3bc440fa88ea12eaa4456161
MATIC_RPC=https://rpc-mumbai.maticvigil.com
PROOF_API=https://apis.matic.network/api/v1/
The RPC provided can be used as-is for testnet (Mumbai - child chain, Goerli - parent chain).
To run any of test examples, you’ll need two addresses. Don’t use real addresses on testnet!
Then, to execute any transactions you’ll need some MATIC tokens. You can obtain them via the Polygon faucet (better - for both addresses, so you don’t think later how to transfer something back).
To power transactions originating from parent chain, you’ll need some Goerli ETH. You can obtain them via Goerli faucet.
Basic usage: clients
Note
You can also adjust ABI url used by this library. You can do it in any of two ways:
Set environmental variable (
export MATIC_ABI_STORE=...or via .env file, if you load it);Set value in python code directly:
from matic import services services.DEFAULT_ABI_STORE_URL = '...' # See .env.example for one of possible URLs
Warning
In order to use methods of withdraw_exit_faster family, you need to set default proof API URI. You can do it in any of two ways:
Set environmental variable (
export MATIC_PROOF_API=...or via .env file, if you load it);Set value in python code directly:
from matic import services services.DEFAULT_PROOF_API_URL = '...' # See .env.example for one of possible URLs
You can create a client to interact with blockchain like in the following snippet:
#!/usr/bin/env python
import os
from dotenv import load_dotenv
from matic import POSClient
from web3 import Web3
load_dotenv()
from_ = os.getenv('USER1_FROM')
from_pk = os.getenv('USER1_PRIVATE_KEY')
parent_contract = '0x02C869F27B0D09004107818B1150e354d38Cb189'
rpc_parent = os.getenv('ROOT_RPC', 'https://goerli.infura.io/v3/9aa3d95b3bc440fa88ea12eaa4456161')
rpc_child = os.getenv('MATIC_RPC', 'https://rpc-mumbai.maticvigil.com')
pos_client = POSClient({
'network': 'testnet',
'version': 'mumbai',
'parent': {
'provider': Web3.HTTPProvider(rpc_parent),
'default_config': {'from': from_},
},
'child': {
'provider': Web3.HTTPProvider(rpc_child),
'default_config': {'from': from_},
},
})
Obtaining tokens
If you want to experiment with dummy tokens, read the following sections on how to obtain them.
POS bridge tokens
POS ERC20
ERC20 token used in this tutorial is “Dummy ERC20 (DERC20)”.
Mapped contracts:
You can obtain them via the Polygon faucet. To avoid resolving unexpected “insufficient balance” errors in future, get this token both on Mumbai and Goerli testnets.
POS ERC721
We use “Test ERC721 (DERC721)” as a ERC721 token example.
Mapped contracts:
This is perhaps the most difficult token to obtain.
First, mint them on Goerli (you can do it directly from explorer, if you’re using browser-syncable wallet like metamask, or by interacting with contract by any convenient tool of your choice). They are not divisible, so every transaction uses 1 or more tokens, and you mint 1 at a time. Mint as many as you need.
Then, deposit these tokens to Mumbai testnet. You can use the following script to do so:
#!/usr/bin/env python
import os
from dotenv import load_dotenv
from matic import POSClient
from web3 import Web3
load_dotenv()
from_ = os.getenv('USER1_FROM')
from_pk = os.getenv('USER1_PRIVATE_KEY')
parent_contract = '0x02C869F27B0D09004107818B1150e354d38Cb189'
rpc_parent = os.getenv('ROOT_RPC', 'https://goerli.infura.io/v3/9aa3d95b3bc440fa88ea12eaa4456161')
rpc_child = os.getenv('MATIC_RPC', 'https://rpc-mumbai.maticvigil.com')
pos_client = POSClient({
'network': 'testnet',
'version': 'mumbai',
'parent': {
'provider': Web3.HTTPProvider(rpc_parent),
'default_config': {'from': from_},
},
'child': {
'provider': Web3.HTTPProvider(rpc_child),
'default_config': {'from': from_},
},
})
erc_721_parent = pos_client.erc_721(parent_contract, True)
tokens = erc_721_parent.get_all_tokens(from_)
approve_tx = erc_721_parent.approve_all(from_pk)
assert approve_tx.receipt
# You can use only some of the tokens here to preserve something on parent chain too.
deposit_tx = erc_721_parent.deposit_many(tokens, from_, from_pk)
print(deposit_tx.transaction_hash)
assert deposit_tx.receipt
You can wait for these tokens to be added with pos_client.is_deposited(transaction_hash) or just monitor your balance with your wallet or an explorer.
If you’ve spent all of the tokens, you can mint a couple more.
POS ERC1155
We use “Test ERC1155 (DERC1155)” as a ERC1155 token example.
Mapped contracts:
You can obtain tokens on both testnets via the Polygon faucet.
Plasma bridge tokens
Plasma ERC20
Mapped contracts:
You can obtain them via the Polygon faucet. To avoid resolving unexpected “insufficient balance” errors in future, get this token both on Mumbai and Goerli testnets.
Plasma ERC721
Mapped contracts:
This is another token which is difficult to obtain.
First, mint them on Goerli (you can do it directly from chain explorer, if you’re using browser-syncable wallet like metamask, or by interacting with contract by any convenient tool of your choice). They are not divisible, so every transaction uses 1 or more tokens, and you mint 1 at a time. Mint as many as you need.
Then, deposit these tokens to Mumbai testnet. You can use the following script to do so:
#!/usr/bin/env python
import os
import time
from dotenv import load_dotenv
from matic import PlasmaClient
from web3 import Web3
load_dotenv()
from_ = os.getenv('USER1_FROM')
from_pk = os.getenv('USER1_PRIVATE_KEY')
parent_contract = '0x02C869F27B0D09004107818B1150e354d38Cb189'
rpc_parent = os.getenv('ROOT_RPC', 'https://goerli.infura.io/v3/9aa3d95b3bc440fa88ea12eaa4456161')
rpc_child = os.getenv('MATIC_RPC', 'https://rpc-mumbai.maticvigil.com')
plasma_client = PlasmaClient({
'network': 'testnet',
'version': 'mumbai',
'parent': {
'provider': Web3.HTTPProvider(rpc_parent),
'default_config': {'from': from_},
},
'child': {
'provider': Web3.HTTPProvider(rpc_child),
'default_config': {'from': from_},
},
})
erc_721_parent = pos_client.erc_721(parent_contract, True)
token = erc_721_parent.get_all_tokens(from_, 1)[0]
deposit_tx = erc_721_parent.safe_deposit(
token, from_, from_pk, {'gas_limit': 300_000}
)
assert deposit_tx.receipt.status
tx_hash = deposit_tx.transaction_hash
start_time = time.time()
timeout = 60 * 60
while True:
if plasma_client.is_deposited(tx_hash):
break
elif time.time() - start_time > timeout:
print(f'Transaction {tx_hash.hex()} still not deposited')
else:
time.sleep(30)
You can wait for these tokens to be added with pos_client.is_deposited(transaction_hash) or just monitor your balance with your wallet or an explorer.
If you’ve spent all of the tokens, you can mint a couple more.