.NET Http Client Library

MClient.cs

using System.Text;
using Newtonsoft.Json;

namespace Common;

public class MClient
{
    private readonly HttpClient _httpClient;
    private readonly List<Task<HttpResponseMessage>> _requests;
    private List<MClientResponse> _responses;

    public MClient(TimeSpan timeout = default)
    {
        timeout = timeout == default ? TimeSpan.FromSeconds(30) : timeout;
        _requests = [];
        _responses = [];
        _httpClient = new HttpClient();
        _httpClient.Timeout = timeout;
    }

    public void Get(string url, Dictionary<string, string>? queryParams = null, Dictionary<string, string>? headers = null)
    {
        var requestMessage = new HttpRequestMessage(HttpMethod.Get, url);
        
        if (headers != null)
        {
            foreach (var header in headers)
            {
                requestMessage.Headers.TryAddWithoutValidation(header.Key, header.Value);
            }
        }
        
        var requestTask = _httpClient.SendAsync(requestMessage);
        _requests.Add(requestTask);
    }

    public void PostRaw(string url, StringContent? stringContent, Dictionary<string, string>? headers = null)
    {
        var requestMessage = new HttpRequestMessage(HttpMethod.Post, url)
        {
            Content = stringContent
        };

        if (headers != null)
        {
            foreach (var header in headers)
            {
                requestMessage.Headers.TryAddWithoutValidation(header.Key, header.Value);
            }
        }

        var requestTask = _httpClient.SendAsync(requestMessage);
        _requests.Add(requestTask);
    }

    public void PostData<TRequest>(string url, TRequest? body, Dictionary<string, string>? headers = null)
    {
        FormUrlEncodedContent content;
        if (body != null)
        {
            content = new FormUrlEncodedContent(
                body.GetType().GetProperties().ToDictionary(
                    prop => prop.Name,
                    prop => prop.GetValue(body)?.ToString() ?? string.Empty
                )
            );
        }
        else
        {
            content = new FormUrlEncodedContent(new Dictionary<string, string>());
        }

        var requestMessage = new HttpRequestMessage(HttpMethod.Post, url)
        {
            Content = content
        };

        if (headers != null)
        {
            foreach (var header in headers)
            {
                requestMessage.Headers.TryAddWithoutValidation(header.Key, header.Value);
            }
        }

        var requestTask = _httpClient.SendAsync(requestMessage);
        _requests.Add(requestTask);
    }

    public void PostJson<TRequest>(string url, TRequest? body, Dictionary<string, string>? headers = null)
    {
        var jsonContent = new StringContent(JsonConvert.SerializeObject(body), Encoding.UTF8, "application/json");

        var requestMessage = new HttpRequestMessage(HttpMethod.Post, url)
        {
            Content = jsonContent
        };

        if (headers != null)
        {
            foreach (var header in headers)
            {
                requestMessage.Headers.TryAddWithoutValidation(header.Key, header.Value);
            }
        }

        var requestTask = _httpClient.SendAsync(requestMessage);
        _requests.Add(requestTask);
    }

    public async Task<List<MClientResponse>> ExecuteAsync()
    {
        _responses = new List<MClientResponse>();

        var tasks = _requests.Select(async request =>
        {
            try
            {
                var response = await request;
                var responseBody = await response.Content.ReadAsStringAsync();

                _responses.Add(new MClientResponse
                {
                    Code = (int)response.StatusCode,
                    Body = responseBody,
                    Headers = response.Headers.ToDictionary(h => h.Key, h => string.Join(", ", h.Value))
                });
            }
            catch (Exception ex)
            {
                _responses.Add(new MClientResponse
                {
                    Code = 0,
                    Body = ex.Message,
                    Headers = new Dictionary<string, string>()
                });
            }
        });

        await Task.WhenAll(tasks);

        return _responses;
    }
}

public class MClientResponse
{
    public int Code { get; set; }
    public string Body { get; set; }
    public Dictionary<string, string> Headers { get; set; }

    public TResponse Json<TResponse>()
    {
        if (string.IsNullOrWhiteSpace(Body))
        {
            throw new JsonException("Body is unavailable");
        }

        var result = JsonConvert.DeserializeObject<TResponse>(Body);
        if (result == null)
        {
            throw new JsonException("Json deserialization failed");
        }
        
        return result;
    }
}