Compute the LP Address of a token pair using web3.py

Question

I managed to have this code run after few hours of searches but unfortunately, this does not produce the output I wanted which is to get the LP Pool Address in (TOKEN/BNB LP).

Given the Token Address: 0xe56842ed550ff2794f010738554db45e60730371

I wanted to get the BIN/BNB Pool Address: 0xe432afB7283A08Be24E9038C30CA6336A7cC8218.

Any ideas what could be the problem?

from web3 import Web3
from eth_abi.packed import encode_abi_packed
from eth_abi import encode_abi
import eth_abi

"""
Contract: 0xe56842ed550ff2794f010738554db45e60730371
BIN/BNB Address: 0xe432afB7283A08Be24E9038C30CA6336A7cC8218
BIN/BNB LP URL: https://bscscan.com/token/0xe432afB7283A08Be24E9038C30CA6336A7cC8218#balances
"""

CONTRACTS = {"CONTRACT": "0xe56842ed550ff2794f010738554db45e60730371",}

PANCAKE_SWAP_FACTORY = "0xcA143Ce32Fe78f1f7019d7d551a6402fC5350c73"
PANCAKE_SWAP_ROUTER  = "0x10ED43C718714eb63d5aA57B78B54704E256024E"
WBNB_ADDRESS = "0xbb4CdB9CBd36B01bD1cBaEBF2De08d9173bc095c"

hexadem_= '0x96e8ac4277198ff8b6f785478aa9a39f403cb768dd02cbee326c3e7da348845f'
factory = PANCAKE_SWAP_FACTORY
abiEncoded_1 = encode_abi_packed(['address', 'address'], (CONTRACTS['CONTRACT'], WBNB_ADDRESS))
salt_ = Web3.solidityKeccak(['bytes'], ['0x' +abiEncoded_1.hex()])
abiEncoded_2 = encode_abi_packed([ 'address', 'bytes32'], ( factory, salt_))
resPair = Web3.solidityKeccak(['bytes','bytes'], ['0xff' + abiEncoded_2.hex(), hexadem_])[12:]

# resPair is the address for the pancakeswap CONTRACT /WBNB pair
print("Token Contract: ", CONTRACTS)
print("BNB-LP Address: ", resPair.hex())    #-- expecting to get  0xe432afB7283A08Be24E9038C30CA6336A7cC8218

Current Output:

BNB-LP Address:  0xde173b8a63b9641a531de0fbb1c5c9eee3b4bc0c

Expected Output:

Token Contract:  0xe56842ed550ff2794f010738554db45e60730371
BNB-LP Address:  0xe432afB7283A08Be24E9038C30CA6336A7cC8218   #-- correct LP Address

Asked By: rbutrnz

||

Source

Answer 1

You need to enter the two coins in alphabetical order.

pair_traded = [token_a, token_b] #token_a, token_b are the address's
pair_traded.sort()

hexadem_1 = 0xff
abiEncoded_1 = encode_abi_packed(['address', 'address'], (token_list[0], token_list[1] ))
salt_ = w3.solidityKeccak(['bytes'], ['0x' +abiEncoded_1.hex()])
abiEncoded_2 = encode_abi_packed([ 'address', 'bytes32'], ( factory, salt_))
pair_address = w3.solidityKeccak(['bytes','bytes'], ['0xff' + abiEncoded_2.hex(), pair_code_hash])[12:]

Answered By: prij_naidu

Answer 2

For Pancake Swap the hexadem_ should be like this I think:

hexadem_= '0x00fb7f630766e6a796048ea87d01acd3068e8ff67d078148a3fa3f4a84f69bd5'  ## Pancake SWAP

The one in your code is for UniSwap

Answered By: Oruk Kai

Answer 3

hexadem_ = '0x00fb7f630766e6a796048ea87d01acd3068e8ff67d078148a3fa3f4a84f69bd5' # This is pancake right hex。
factory = PANCAKE_SWAP_FACTORY
abiEncoded_1 = encode_abi_packed(['address', 'address'], (CONTRACTS['CONTRACT'], WBNB_ADDRESS))
salt_ = Web3.solidityKeccak(['bytes'], ['0x' +abiEncoded_1.hex()])
abiEncoded_2 = encode_abi_packed([ 'address', 'bytes32'], ( factory, salt_))
resPair = Web3.solidityKeccak(['bytes','bytes'], ['0xff' + abiEncoded_2.hex(), hexadem_])[12:]

But the value I output is different from yours, my output value:

Token Contract:  {'CONTRACT': '0xe56842ed550ff2794f010738554db45e60730371'}
BNB-LP Address:  0xdbb161367d9a2a852ebeef3cbfcbf2c43b85064b

Answered By: 苏昌海

Answer 4

I figured out you need to make sure both addresses are all lowercase or all uppercase. This makes a difference when sorting. This works for me:

def compute_pool_address(self, token_address_a, token_address_b):
    pair_traded = [token_address_a.lower(), token_address_b.lower()]
    pair_traded.sort()
    hexadem = '0x00fb7f630766e6a796048ea87d01acd3068e8ff67d078148a3fa3f4a84f69bd5'
    abiEncoded_1 = encode_abi_packed(['address', 'address'], (pair_traded[0], pair_traded[1]))
    salt_ = self.web3.solidityKeccak(['bytes'], ['0x' + abiEncoded_1.hex()])
    abiEncoded_2 = encode_abi_packed(['address', 'bytes32'], (PANCAKE_FACTORY_ADDRESS, salt_))
    return self.web3.toChecksumAddress(self.web3.solidityKeccak(['bytes', 'bytes'], ['0xff' + abiEncoded_2.hex(), hexadem])[12:])

(self.web3 is a web3.py Web3 instance)

Answered By: Quint

Compute the LP Address of a token pair using web3.py

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