Python library for Uniswap, Aave, ChainLink, Enzyme and other protocols on BNB Chain, Polygon, Ethereum and other blockchains
Web-Ethereum-DeFi (eth_defi) Python package provides high level modules for smart
contracts, with prepackaged ABI files for DeFi protocol integration,
wallet management, JSON-RPC providers and automated test suites. The
package aims for robustness, high quality of the code and documentation.
Use cases for this package include
Features include e.g.
Web3-Ethereum-Defi supports
Read the full API documentation). For code examples please see below.
To use this package you need to
With pip:
pip install "web3-ethereum-defi[data]"
With poetry:
# Poetry version
poetry add -E data web3-ethereum-defi
With poetry - master Git branch:
git clone git@github.com:tradingstrategy-ai/web3-ethereum-defi.git
cd web3-ethereum-defi
poetry shell
poetry install --all-extras
See the tutorials section in the documentation for full code examples.
This example shows how to read the live trades of PancakeSwap, and other Uniswap v2 compatible forks on BNB Smart Chain
See the instructions and full example source code in Tutorials
import os
import time
from functools import lru_cache
from web3 import HTTPProvider, Web3
from eth_defi.abi import get_contract
from eth_defi.chain import install_chain_middleware
from eth_defi.event_reader.filter import Filter
from eth_defi.event_reader.logresult import decode_log
from eth_defi.event_reader.reader import read_events, LogResult
from eth_defi.uniswap_v2.pair import fetch_pair_details, PairDetails
QUOTE_TOKENS = ["BUSD", "USDC", "USDT"]
@lru_cache(maxsize=100)
def fetch_pair_details_cached(web3: Web3, pair_address: str) -> PairDetails:
return fetch_pair_details(web3, pair_address)
def main():
json_rpc_url = os.environ.get("JSON_RPC_BINANCE", "https://bsc-dataseed.binance.org/")
web3 = Web3(HTTPProvider(json_rpc_url))
web3.middleware_onion.clear()
install_chain_middleware(web3)
# Read the prepackaged ABI files and set up event filter
# for any Uniswap v2 like pool on BNB Smart Chain (not just PancakeSwap).
#
# We use ABI files distributed by SushiSwap project.
#
Pair = get_contract(web3, "sushi/UniswapV2Pair.json")
filter = Filter.create_filter(address=None, event_types=[Pair.events.Swap])
latest_block = web3.eth.block_number
# Keep reading events as they land
while True:
start = latest_block
end = web3.eth.block_number
evt: LogResult
for evt in read_events(
web3,
start_block=start,
end_block=end,
filter=filter,
):
decoded = decode_log(evt)
# Swap() events are generated by UniswapV2Pool contracts
pair = fetch_pair_details_cached(web3, decoded["address"])
token0 = pair.token0
token1 = pair.token1
block_number = evt["blockNumber"]
# Determine the human-readable order of token tickers
if token0.symbol in QUOTE_TOKENS:
base = token1 # token
quote = token0 # stablecoin/BNB
base_amount = decoded["args"]["amount1Out"] - decoded["args"]["amount1In"]
quote_amount = decoded["args"]["amount0Out"] - decoded["args"]["amount0In"]
else:
base = token0 # stablecoin/BNB
quote = token1 # token
base_amount = decoded["args"]["amount0Out"] - decoded["args"]["amount0Out"]
quote_amount = decoded["args"]["amount1Out"] - decoded["args"]["amount1Out"]
# Calculate the price in Python Decimal class
if base_amount and quote_amount:
human_base_amount = base.convert_to_decimals(base_amount)
human_quote_amount = quote.convert_to_decimals(quote_amount)
price = human_quote_amount / human_base_amount
if human_quote_amount > 0:
# We define selling when the stablecoin amount increases
# in the swap
direction = "sell"
else:
direction = "buy"
price = abs(price)
print(f"Swap block:{block_number:,} tx:{evt['transactionHash']} {direction} price:{price:,.8f} {base.symbol}/{quote.symbol}")
else:
# Swap() event from DEX that is not Uniswap v2 compatible
# print(f"Swap block:{block_number:,} tx:{evt['transactionHash']} could not decode")
pass
else:
# No event detected between these blocks
print(".")
latest_block = end
time.sleep(1)
if __name__ == "__main__":
main()
Add web3-ethereum-defi as a development dependency:
Using Poetry:
# Data optional dependencies include pandas and gql, needed to fetch Uniswap v3 data
poetry add -D "web3-ethereum-defi[data]"
MIT.
FAQs
Python library for Uniswap, Aave, ChainLink, Enzyme and other protocols on BNB Chain, Polygon, Ethereum and other blockchains
We found that web3-ethereum-defi demonstrated a healthy version release cadence and project activity because the last version was released less than a year ago. It has 1 open source maintainer collaborating on the project.
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