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

• An active 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).

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

Step-by-Step Instructions

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

Using .NET Framework

Install the required NuGet packages

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

var rpcHandler = new EthereumRpcHandler("

Use the GetBlockNumberAsync method to retrieve block numbers

await rpcHandler.GetBlockNumberAsync();

Using .NET Core

Install the required NuGet packages

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

var rpcHandler = new EthereumRpcHandler("

Use the GetBlockNumberAsync method to retrieve block numbers

await rpcHandler.GetBlockNumberAsync();

Error Handling

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

For example:

„`csharp

try

{

await rpcHandler.

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