Querying via JSON-RPC

For information about Polaris Ethereum's JSON-RPC specification please see the EVM JSON-RPC section.

Querying via JSON-RPC with ethers.js

Requirements

• Node.js (opens in a new tab) (v8.9.4 or higher)
• ethers.js (opens in a new tab)(v4.0.0 or higher)

Create a new project and install ethers.js

npm install ethers

To query the latest block number of an EVM chain over JSON-RPC using ethers.js you can use the following code:

const provider = new ethers.providers.JsonRpcProvider("<JSON_RPC_ENDPOINT>");
 
const blockNumber = await provider.getBlockNumber();

blockNumber will be a number representing the latest block number.

Querying via JSON-RPC with geth

Requirements

• Golang (opens in a new tab) (v1.13 or higher)
• Geth (opens in a new tab) (v1.9.7 or higher)

Create a new project and install geth

go get -u github.com/ethereum/go-ethereum

To query the latest block number of an EVM chain over JSON-RPC using geth you can use the following code:

package main
 
import (
    "fmt"
    "log"
    "math/big"
 
    "github.com/ethereum/go-ethereum/ethclient"
)
 
func main() {
    rpcEndpoint := "http://localhost:8545" // default local node RPC Endpoint
    client, err := ethclient.Dial(rpcEndpoint)
    if err != nil {
        log.Fatal(err)
    }
 
    header, err := client.HeaderByNumber(context.Background(), nil)
    if err != nil {
        log.Fatal(err)
    }
 
    blockNumber := header.Number.String()
    fmt.Println(blockNumber) // 5671744
}

blockNumber will be a string representing the latest block number.