RPC Components

The core RPC components are the building blocks for high-performance asynchronous RPC communication with RPC APIs like the Ethereum Virtual Machine (EVM) RPC API.

RPC Client

The RPC client is designed to process as many requests as quickly as is feasible with the RPC API endpoint. This is achieved by using the asynchronous nature of websocket connections to send as many simultaneous request as allowed. The client has the capability of limiting the number of requests per second and the number of simultaneous concurrent requests being processed. This ensures that crawlers can tune their throughput for RPC APIs for maximum speed.

To track and optimize performance, the RPC Client utilizes another core component in the Stats Service which tracks a number of RPC client metrics such as requests sent, responses received, total request processing time, the number of requests delayed due to exceeding the maximum number of requests or waiting for the required time for a “too many requests” response from the RPC API, the number of connection resets, and more.

The RPC Client is an async context manager and must be utilized as such. Below is an example of making an EVM RPC request to get the block height:

async def run():
    stats_service = StatsService()
    async with RpcClient(
        # Replace with actual RPC WSS endpoint
        provider_url="wss://some.rpc.provider",
        stats_service=stats_service,
        requests_per_second=100,
    ) as rpc_client:
        block_number = await rpc_client.send("eth_blockNumber")
        print("Block Number", int(block_number, 16))
        print("RPC Calls:", stats_service.get_count(RpcClient.STAT_REQUEST_SENT))
        print("RPC Call ms:", stats_service.get_count(RpcClient.STAT_REQUEST_MS))

Complete Simple Example

import asyncio

from blockcrawler.core.rpc import RpcClient
from blockcrawler.core.stats import StatsService


async def run():
    stats_service = StatsService()
    async with RpcClient(
        # Replace with actual RPC WSS endpoint
        provider_url="wss://some.rpc.provider",
        stats_service=stats_service,
        requests_per_second=100,
    ) as rpc_client:
        block_number = await rpc_client.send("eth_blockNumber")
        print("Block Number", int(block_number, 16))
        print("RPC Calls:", stats_service.get_count(RpcClient.STAT_REQUEST_SENT))
        print("RPC Call ms:", stats_service.get_count(RpcClient.STAT_REQUEST_MS))


if __name__ == "__main__":
    asyncio.run(run())

Executing the above example will result in something similar to following being displayed in the console:

Block Number 16636314

RPC Calls: 1

RPC Call ms: 184

Download the example and try it yourself.