Run a Node locally

Web3j interacts with Ethereum client nodes. If you don't want to connect to one of the existing networks, you have different options to start a local node.

Use Geth, Besu or OpenEthereum¶

Geth:

$ geth --rpcapi personal,db,eth,net,web3 --rpc --testnet

Hyperledger Besu:

$ besu ----network=dev

The dev network uses has some handy default parameters.

OpenEthereum:

$ openethereum --chain testnet

Instructions on obtaining Ether to transact on the network can be found in the testnet section of the docs.

Use Epirus Local¶

Epirus-local is a local ethereum client, similar to what Ganache provides, written in Kotlin.

This project relies on web3-evm to execute user requests.

Features¶

Allows json-rpc interactions with a local ethereum blockchain.
Generates a default genesis file containing 10 ethereum accounts or lets you use your own genesis.
Provides a CLI to run the client.
Handles these operations:
- eth_blockNumber
- eth_getTransactionCount
- eth_getBalance
- eth_sendTransaction
- eth_sendRawTransaction
- eth_estimateGas
- eth_getBlockTransactionCountByHash
- eth_getBlockTransactionCountByNumber
- eth_getTransactionReceipt
- eth_getCode
- eth_call

Getting started¶

git clone https://github.com/epirus-io/epirus-local && cd epirus-local

./gradlew installDist

Run in Linux:¶

build/install/epirus-local/bin/epirus-local [command]

Run in Windows¶

build\install\epirus-local\bin\epirus-local.bat [command]

Start the client¶

epirus-local start -d=/path/to/directory -p=9090

This command generates a new genesis file with 10 accounts filled with 100 ether.

start command

Load from previous configuration¶

epirus-local load -g=/path/to/genesis

This command loads a pre-existing genesis-file from a certain path.

load command

Send requests¶

Example of a request¶

curl -X POST --data '{"jsonrpc":"2.0","method":"eth_sendTransaction","params":[{
  "from": "0x8f496c16955a7bb9b5e1ea0383d01f87372ab520",
  "to": "0xd46e8dd67c5d32be8058bb8eb970870f07244567",
  "gas": "0x76c0", 
  "gasPrice": "0x9184e72a000", 
  "value": "0x9184e72a",
  "nonce": "0x1"
}],"id":1}' host:port

Example of a response¶

{"id" : 1, "jsonrpc" : "2.0", "result" : "0xc631caa67cab48ead77a58321bbb0c76f4060751a4bb3d5b45b99c4a68b1a7b7"}

For more information about the requests, check out the Ethereum json-rpc api.