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On-chain price feeds

Intro

In order to simulate the order book from centralized exchanges without sacrificing capital efficiency, WOOFi created a custom on-chain price fee which works along side with the sPMM algorithm. This price feed considers multiple parameters including mid-price
pp
, spread
ss
, and liquidity coefficient
kk
.
WOOFi's on-chain price feeds are deployed on multiple blockchains. Users can call price to get priceNow and feasible of token. If feasible is false, do not use priceNow value. All prices are USDT/USDC-based, and the decimal of priceNow is 18 - base_decimal + quote_decimal.
While the price feed is on-chain and permissionless, and tradeable by any user on WOOFi, we DO NOT garanutee the availability or accuracy of it. The price feed may become unavailable when the centralized liquidity source is in maintenance or any time the operator deems necessary. In no case, WOOFi is liable for any loss that might be caused by using the price feed by any third party.

Code Example

Contract ABI

[
{
"inputs": [
{
"internalType": "address",
"name": "base",
"type": "address"
}
],
"name": "price",
"outputs": [
{
"internalType": "uint256",
"name": "priceNow",
"type": "uint256"
},
{
"internalType": "bool",
"name": "feasible",
"type": "bool"
}
],
"stateMutability": "view",
"type": "function"
}
]

Python Example (python 3.8)

  • Query price
import web3
import json
web3_provider = f'your-web3-provider'
w3 = web3.Web3(web3.Web3.HTTPProvider(web3_provider))
abi_str = '[{"inputs": [{"internalType": "address","name": "base","type": "address"}],"name": "price","outputs": [{"internalType": "uint256","name": "priceNow","type": "uint256"},{"internalType": "bool","name": "feasible","type": "bool"}],"stateMutability": "view","type": "function"}]'
abi = json.loads(abi_str)
oracle_addr = '0x6b6fBEc7934b104e81b2046D24A990e03e17afDC'
contract = w3.eth.contract(address=oracle_addr, abi=abi)
# query WOO/USDT pair quoting price
woo_addr = '0x4691937a7508860F876c9c0a2a617E7d9E945D4B'
contract.functions.price(woo_addr).call()
  • Response
# return [priceNow, feasible]
>> [841915000000000000, True]