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). A key feature of the EVM is the ability to communicate with external services, such as the JSON-RPC API, using C#.

Prerequisites

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

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

• A compatible C
  

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

• Microsoft.Eth NuGet package for .NET Framework and System.Runtime.CompilerServices package for .NET Core.

Step-by-step instructions

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

Using the .NET Framework

Install the required NuGet packages

Install the Microsoft.Eth package

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 EthereumRpcHandlerclass

var rpcHandler = new EthereumRpcHandler("

Use the GetBlockNumberAsync method to get the block numbers

Wait for rpcHandler.GetBlockNumberAsync();

Install-Package Microsoft.Eth

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

`csharp

Use theGetBlockNumberAsync` method to get the block number

csharp

await rpcHandler.GetBlockNumberAsync();

Error Handling
To access the JSON-RPC API, you will need to handle errors returned by the interface. You can do this by examining the response status code and content.
For example:

csharp

try

{

await rpcHandler.