eth-multirpc: Reliable Ethereum Interactions with Multiple RPCs

eth-multirpc is a robust library designed to interact with Ethereum smart contracts using multiple RPC endpoints. This ensures reliability and availability by distributing the load across various endpoints and retrying operations on failure. The library provides both asynchronous (AsyncMultiRpc) and synchronous (MultiRpc) interfaces to suit different use cases.

Features

• Multiple RPC Support: Seamlessly switch between different RPCs to ensure uninterrupted interactions.
• Gas Management: Fetch gas prices from multiple sources to ensure transactions are sent with an appropriate fee.
• Robust Error Handling: Designed to handle failures gracefully, increasing the reliability of your applications.
• Easy-to-use API: Interact with Ethereum smart contracts using a simple and intuitive API.

Installation

Install eth-multirpc using pip:

pip install eth-multirpc

Quick Start

Here's a quick example to get you started:

Asynchronous Usage

Below is an example of how to use the AsyncMultiRpc class for asynchronous operations:

import asyncio
import json
from eth_multirpc.utils import NestedDict
from eth_multirpc import AsyncMultiRpc


async def main():
    rpcs = NestedDict({
        "view": {
            1: ['https://1rpc.io/ftm', 'https://rpcapi.fantom.network', 'https://rpc3.fantom.network'],
            2: ['https://rpc.fantom.network', 'https://rpc2.fantom.network', ],
            3: ['https://rpc.ankr.com/fantom'],
        },
        "transaction": {
            1: ['https://1rpc.io/ftm', 'https://rpcapi.fantom.network', 'https://rpc3.fantom.network'],
            2: ['https://rpc.fantom.network', 'https://rpc2.fantom.network', ],
            3: ['https://rpc.ankr.com/fantom'],
        }
    })
    with open("abi.json", "r") as f:
        abi = json.load(f)
    multi_rpc = AsyncMultiRpc(rpcs, 'YOUR_CONTRACT_ADDRESS', contract_abi=abi, enable_estimate_gas_limit=True)
    multi_rpc.set_account("YOUR_PUBLIC_ADDRESS", "YOUR_PRIVATE_KEY")

    result = await multi_rpc.functions.YOUR_FUNCTION().call()
    print(result)


asyncio.run(main())

Synchronous Usage

Below is an example of how to use the MultiRpc class for synchronous operations:

from eth_multirpc import MultiRpc


def main():
    multi_rpc = MultiRpc(rpcs, 'YOUR_CONTRACT_ADDRESS', contract_abi=abi, enable_estimate_gas_limit=True)
    multi_rpc.set_account("YOUR_PUBLIC_ADDRESS", "YOUR_PRIVATE_KEY")

    result = multi_rpc.functions.YOUR_FUNCTION().call()
    print(result)


main()

Replace placeholders like YOUR_CONTRACT_ADDRESS, YOUR_PUBLIC_ADDRESS, YOUR_PRIVATE_KEY, and YOUR_FUNCTION with appropriate values.

Documentation

Initialization

Initialize the MultiRpc class with your RPC URLs, contract address, and contract ABI:

multi_rpc = MultiRpc(rpcs, contract_address='YOUR_CONTRACT_ADDRESS', contract_abi=abi)

• enable_estimate_gas_limit=True will check if tx can be done successfully without paying fee, and also calculate gas limit for tx
• You can pass a list of RPCs to rpcs_supporting_tx_trace=[] to identify which of the provided RPCs (rpcs) support tx_trace. Then, when a transaction fails, you can retrieve the trace of the transaction.

Setting Account

Set the Ethereum account details (address and private key) for sending transactions:

multi_rpc.set_account("YOUR_PUBLIC_ADDRESS", "YOUR_PRIVATE_KEY")

Calling Contract Functions

Call a function from your contract:

result = await multi_rpc.functions.YOUR_FUNCTION().call()

By default we return tx_receipt(wait for 90 second). if you don't want to return tx_receipt, pass wait_for_receipt=0 to call()

Calling Contract with another Private Key

You can call a transaction function with a different private key by passing the private_key, address parameter to the call() method. Here’s an example:

result = await multi_rpc.functions.YOUR_FUNCTION().call(address=PublicKey, private_key=PrivateKey)

Using Block Identifier in Calls

You can specify a block identifier when calling view functions to get the state of the contract at a specific block. Here's an example:

Note that the majority of free RPCs only support querying blocks up to 10 minutes earlier.

# You can use 'latest', 'earliest', or a specific block number
result = multi_rpc.functions.yourViewFunction().call(block_identifier='latest')  

Using multicall for view function Calls

you can also use mutlicall() for calling a view function multiple time with different parameters. Here's an example:

results = multi_rpc.functions.yourViewFunction([(param1, params2), (param1, params2)]).multicall()  

Passing View Policy

You can specify a view policy to determine how view function calls are handled. The available view policies are MostUpdated and FirstSuccess. Here’s an example:

multi_rpc = MultiRpc(rpc_urls, contract_address, contract_abi, view_policy=ViewPolicy.FirstSuccess)

Passing Gas Estimation to MultiRpc

You can pass a GasEstimation object to the MultiRpc or AsyncMultiRpc class to configure how gas prices are estimated. Here is an example of how to do this:

from eth_multirpc import MultiRpc
from eth_multirpc.gas_estimation import GasEstimation
from eth_multirpc.constants import GasEstimationMethod

gas_estimation = GasEstimation(
    chain_id=1,  # Mainnet
    providers=[],  # List of AsyncWeb3 providers
    default_method=GasEstimationMethod.GAS_API_PROVIDER,
    gas_api_provider='https://gasstation-mainnet.matic.network'  # Replace with your API provider
)

# Pass the GasEstimation object to MultiRpc
multi_rpc = MultiRpc(rpc_urls, contract_address, contract_abi, gas_estimation=gas_estimation)

The GasEstimation class allows you to implement a custom gas estimation method. You need to extend the GasEstimation class and override the _custom_gas_estimation method with your custom logic. Here is an example:

from web3 import Web3
from eth_multirpc.gas_estimation import GasEstimation
from eth_multirpc.utils import TxPriority
from eth_multirpc.constants import GasEstimationMethod


class CustomGasEstimation(GasEstimation):

    async def _custom_gas_estimation(self, priority: TxPriority, gas_upper_bound: float) -> dict:
        # Your custom gas estimation logic here
        custom_gas_price = 50  # Replace with your custom logic
        if custom_gas_price > gas_upper_bound:
            raise OutOfRangeTransactionFee(f"Custom gas price {custom_gas_price} exceeds upper bound {gas_upper_bound}")
        return {
            "gasPrice": Web3.to_wei(custom_gas_price, 'gwei')
        }


# Create an instance of your custom gas estimation
custom_gas_estimation = CustomGasEstimation(
    chain_id=1,
    providers=[],
    default_method=GasEstimationMethod.CUSTOM,
)

# Use it with MultiRpc
multi_rpc = MultiRpc(rpc_urls, contract_address, contract_abi, gas_estimation=custom_gas_estimation)

You can specify which gas estimation method in call() method. Here's an example:

tx_hash = multi_rpc.functions.yourTransactionFunction().call(
    gas_estimation_method=GasEstimationMethod.RPC,  # Specify the gas estimation method
)

By default, we check all possible ways(api, rpc, fixed, custom) to get gasPrice. but, if you pass method we only use passed method

Contributing

Contributions are welcome! Please open an issue or submit a pull request on our GitHub repository.