Accessing Ethereum’s JSON-RPC API with C#

The Ethereum Virtual Machine (EVM) and its JSON-RPC interface provide a standardized way for developers to interact with smart contracts and deploy decentralized applications (dApps). One of the key features of the EVM is its ability to communicate with external services, such as the JSON-RPC API, using C#.

Prerequisites

Before learning how to access Ethereum’s JSON-RPC API in C#, you will need:

• A running Ethereum node (e.g., Ethereum Mainnet or Ropsten testnet).

• A compatible C
  

  runtime environment (e.g., .NET Framework 4.8, .NET Core 3.1, or Mono).

• The NuGet package „Microsoft.Eth” for .NET Framework and the package „System.Runtime.CompilerServices” for .NET Core.

Step-by-step instructions

To access Ethereum’s JSON-RPC API in C#, follow these steps:

Using .NET Framework

Install the required NuGet packages

Microsoft.Eth Installer Package

Create a new class to handle the RPC connection

using System;
using System.Net.Http;
using System.Threading.Tasks;
public class EthereumRpcHandler : IDisposable
{
private readonly string _rpcUrl = "
private readonly HttpClient _httpClient;
public EthereumRpcHandler(string rpcUrl)
{
_httpClient = new HttpClient();
_httpClient.DefaultRequestHeaders.Accept.Clear();
_httpClient.DefaultRequestHeaders.Add("x-eth-rpc-version", "1");
_httpClient.DefaultRequestHeaders.Add("x-eth-rpc subscription token", rpcUrl);
_rpcUrl = $"{_httpClient.DefaultRequestHeaders["x-eth-rpc-url"]}/{_rpcUrl}";
}
public asyncTask GetBlockNumberAsync()
{
var response = await _httpClient.GetAsync(_rpcUrl + "/blocknumber");
response.EnsureSuccessStatusCode();
return await response.Content.ReadAsStringAsync();
}
}

Create an instance of the EthereumRpcHandler class

var rpcHandler = new EthereumRpcHandler("

Use the GetBlockNumberAsync method to retrieve block numbers

await rpcHandler.GetBlockNumberAsync();

Using .NET Core

Install the required NuGet packages

Microsoft.Eth Installer Package

Create a new class to handle the RPC connection

using System;
using System.Net.Http;
using System.Threading.Tasks;
public class EthereumRpcHandler : IDisposable
{
private readonly string _rpcUrl = "
private readonly HttpClient _httpClient;
public EthereumRpcHandler(string rpcUrl)
{
_httpClient = new HttpClient();
_httpClient.DefaultRequestHeaders.Accept.Clear();
_httpClient.DefaultRequestHeaders.Add("x-eth-rpc-version", "1");
_httpClient.DefaultRequestHeaders.Add("x-eth-rpc subscription token", rpcUrl);
_rpcUrl = $"{_httpClient.DefaultRequestHeaders["x-eth-rpc-url"]}/{_rpcUrl}";
}
public async task GetBlockNumberAsync()
{
var response = await _httpClient.GetAsync(_rpcUrl + "/blocknumber");
response.EnsureSuccessStatusCode();
return await response.Content.ReadAsStringAsync();
}
}

Create an instance of the EthereumRpcHandler class

var rpcHandler = new EthereumRpcHandler("

Use the GetBlockNumberAsync method to retrieve block numbers

await rpcHandler.GetBlockNumberAsync();

Error Handling

To access the JSON-RPC API, you need to handle errors returned by the interface. You can do this by checking the status code and the response content.

For example:

„`csharp

try

{

await rpcHandler.