uniswap-universal-router-decoder 0.5.5

Decode & Encode transaction data sent to Uniswap universal router

Uniswap Universal Router Decoder & Encoder

⚠ This branch (v0.5.*) is kept for compatibility with web3 v5.31.*.

⚠ The latest version is on the master branch and uses web3 > v6.0.0

The rationale is:

• web3 v5 uses eth-account < v0.6.0
• a bug impacting EIP712 signatures for structured data with arrays has been fixed in eth-account v0.7.0 (see #175)
• web3 v6 uses eth-account > v0.8.0
• web3 v6 introduces breaking changes compared to v5

Project Information

Code Quality

Overview and Points of Attention

The object of this library is to decode & encode the transaction input sent to the Uniswap universal router (UR) (address 0xEf1c6E67703c7BD7107eed8303Fbe6EC2554BF6B on Ethereum Mainnet).

⚠ This library has not been audited, so use at your own risk !

⚠ There is no guarantee of compatibility between 2 versions: consider forcing the version in your dependency requirements.

⚠ This project is a work in progress so not all commands are decoded yet. Below the list of the already implemented ones. Also, only one command can be encoded in a single transaction input data at the moment.

Command Id	Function Name	Decode	Encode
0x00	V3_SWAP_EXACT_IN	✅	✅
0x01	V3_SWAP_EXACT_OUT	✅	✅
0x02 - 0x06		❌	❌
0x07	placeholder	N/A	N/A
0x08	V2_SWAP_EXACT_IN	✅	✅
0x09	V2_SWAP_EXACT_OUT	✅	✅
0x0a	PERMIT2_PERMIT	✅	❌
0x0b	WRAP_ETH	✅	✅
0x0c	UNWRAP_WETH	✅	❌
0x0d	PERMIT2_TRANSFER_FROM_BATCH	❌	❌
0x0e - 0x0f	placeholders	N/A	N/A
0x10 - 0x1d		❌	❌
0x1e - 0x3f	placeholders	N/A	N/A

Installation

A good practice is to use Python virtual environments, here is a tutorial.

The library can be pip installed from pypi.org as usual:

# update pip to latest version if needed
pip install -U pip

# install the decoder from pypi.org
pip install uniswap-universal-router-decoder

Usage

The library exposes a class, RouterDecoder with several public methods that can be used to decode or encode UR data.

How to decode a transaction input

To decode a transaction input, use the decode_function_input method as follow:

from uniswap_universal_router_decoder.router_decoder import RouterDecoder

trx_input = "0x3593564c000000000000000000 ... 90095b5c4e9f5845bba"  # the trx input to decode
decoder = RouterDecoder()
decoded_trx_input = decoder.decode_function_input(trx_input)

How to decode a transaction

It's also possible to decode the whole transaction, given its hash and providing the decoder has been built with either a valid Web3 instance or the link to a rpc endpoint:

# Using a web3 instance
from web3 import Web3
from uniswap_universal_router_decoder.router_decoder import RouterDecoder
w3 = Web3(...)  # your web3 instance
decoder = RouterDecoder(w3=w3)

# Using a rpc endpoint
from web3 import Web3
from uniswap_universal_router_decoder.router_decoder import RouterDecoder
rpc_link = "https://..."  # your rpc endpoint
decoder = RouterDecoder(rpc_endpoint=rpc_link)

And then the decoder will get the transaction from the blockchain and decode it, along with its input data:

trx_hash = "0x52e63b7 ... 11b979dd9"
decoded_transaction = decoder.decode_transaction(trx_hash)

How to decode an Uniswap V3 swap path

The RouterDecoder class exposes also the static method decode_v3_path which can be used to decode a given Uniswap V3 path.

from uniswap_universal_router_decoder.router_decoder import RouterDecoder

uniswap_v3_path = b"\xc0*\xaa9\xb2#\xfe\x8d\n\x0e ... \xd7\x89"  # bytes or str hex
fn_name = "V3_SWAP_EXACT_IN"  # Or V3_SWAP_EXACT_OUT
decoded_path = RouterDecoder.decode_v3_path(fn_name, uniswap_v3_path)

The result is a tuple, starting with the "in-token" and ending with the "out-token", with the pool fees between each pair.

How to encode a call to the function WRAP_ETH

This function can be used to convert eth to weth using the UR.

from uniswap_universal_router_decoder.router_decoder import RouterDecoder

decoder = RouterDecoder()
encoded_data = decoder.encode_data_for_wrap_eth(amount_in_wei)  # to convert amount_in_wei eth to weth

# then in your transaction dict:
transaction["data"] = encoded_data

# you can now sign and send the transaction to the UR

How to encode a call to the function V2_SWAP_EXACT_IN

This function can be used to swap tokens on a V2 pool. Correct allowances must have been set before using sending such transaction.

from uniswap_universal_router_decoder.router_decoder import RouterDecoder

decoder = RouterDecoder()
encoded_data = decoder.encode_data_for_v2_swap_exact_in(
        amount_in,  # in Wei
        min_amount_out,  # in Wei
        [
            in_token_address,
            out_token_address,
        ],
        timestamp,  # unix timestamp after which the trx will not be valid any more
    )

# then in your transaction dict:
transaction["data"] = encoded_data

# you can now sign and send the transaction to the UR

How to encode a call to the function V2_SWAP_EXACT_OUT

This function can be used to swap tokens on a V2 pool. Correct allowances must have been set before using sending such transaction.

from uniswap_universal_router_decoder.router_decoder import RouterDecoder

decoder = RouterDecoder()
encoded_data = decoder.encode_data_for_v2_swap_exact_out(
        amount_out,  # in Wei
        max_amount_in,  # in Wei
        [
            in_token_address,
            out_token_address,
        ],
        timestamp,  # unix timestamp after which the trx will not be valid any more
    )

# then in your transaction dict:
transaction["data"] = encoded_data

# you can now sign and send the transaction to the UR

How to encode a call to the function V3_SWAP_EXACT_IN

This function can be used to swap tokens on a V3 pool. Correct allowances must have been set before using sending such transaction.

from uniswap_universal_router_decoder.router_decoder import RouterDecoder

decoder = RouterDecoder()
encoded_data = decoder.encode_data_for_v3_swap_exact_in(
        amount_in,  # in Wei
        min_amount_out,  # in Wei
        [
            in_token_address,
            pool_fee,
            out_token_address,
        ],
        timestamp,  # unix timestamp after which the trx will not be valid any more
    )

# then in your transaction dict:
transaction["data"] = encoded_data

# you can now sign and send the transaction to the UR

How to encode a call to the function V3_SWAP_EXACT_OUT

This function can be used to swap tokens on a V3 pool. Correct allowances must have been set before using sending such transaction.

from uniswap_universal_router_decoder.router_decoder import RouterDecoder

decoder = RouterDecoder()
encoded_data = decoder.encode_data_for_v3_swap_exact_out(
        amount_out,  # in Wei
        max_amount_in,  # in Wei
        [
            in_token_address,
            pool_fee,
            out_token_address,
        ],
        timestamp,  # unix timestamp after which the trx will not be valid any more
    )

# then in your transaction dict:
transaction["data"] = encoded_data

# you can now sign and send the transaction to the UR

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