Needs Microsoft.AspNetCore.WebUtilities and FluentResults nuget

smsc.cs

using FluentResults;
using Microsoft.AspNetCore.WebUtilities;
using Microsoft.Extensions.Logging;
using Microsoft.Extensions.Options;
using Newtonsoft.Json;

namespace Auth.BLL.Smsc;

public class SmscHttpClient
{
    private readonly HttpClient _client;
    private readonly SmscConfig _config;

    private readonly ILogger<SmscHttpClient> _logger;

    public SmscHttpClient(HttpClient client, IOptions<SmscConfig> config, ILogger<SmscHttpClient> logger)
    {
        _client = client;
        _logger = logger;
        _config = config.Value;
    }

    public async Task<Result<SmscResult>> SendCodeViaCall(string recipient, CancellationToken cancellationToken)
    {
        const string action = "send.php";

        var url = action;


        // fmt = 0 - OK - 1 SMS, ID - 1234
        // fmt = 1 - 1234,1,1.40,100.50 или 0,-3
        // fmt = 2 - xml
        // fmt = 3 - json

        // cost = 3 means that smsc will return the cost and new balance

        var parameters = new Dictionary<string, string?>()
        {
            {"login", _config.Login},
            {"psw", _config.Password},
            {"charset", "utf-8"},
            {"fmt", "3"},
            {"cost", "3"},
            {"phones", recipient},
            {"mes", "code"},
            {"call", "1"}
        };

        url = QueryHelpers.AddQueryString(url, parameters);

        var request = new HttpRequestMessage(
            HttpMethod.Get,
            url
        );

        var response = await _client.SendAsync(request, cancellationToken);

        if (!response.IsSuccessStatusCode)
        {
            return new SmscError(response.ReasonPhrase ?? $"Неизвестная ошибка при вызове SMSC. Status: {response.StatusCode}");
        }

        var content = await response.Content.ReadAsStringAsync(cancellationToken);

        _logger.LogInformation("Received SMSC Response: {req} {res}", url, content);

        var smscResult = JsonConvert.DeserializeObject<SmscResult>(content) ?? new SmscResult {Error = "Failed to parse response"};

        return Result.Ok(smscResult);
    }

    public async Task<Result<SmscResult>> SendCodeViaSms(string message, string recipient, CancellationToken cancellationToken)
    {
        const string action = "send.php";

        var url = action;


        // fmt = 0 - OK - 1 SMS, ID - 1234
        // fmt = 1 - 1234,1,1.40,100.50 или 0,-3
        // fmt = 2 - xml
        // fmt = 3 - json

        // cost = 3 means that smsc will return the cost and new balance

        var parameters = new Dictionary<string, string?>()
        {
            {"login", _config.Login},
            {"psw", _config.Password},
            {"charset", "utf-8"},
            {"fmt", "3"},
            {"cost", "3"},
            {"phones", recipient},
            {"mes", message}
        };

        url = QueryHelpers.AddQueryString(url, parameters);

        var request = new HttpRequestMessage(
            HttpMethod.Get,
            url
        );

        var response = await _client.SendAsync(request, cancellationToken);

        if (!response.IsSuccessStatusCode)
        {
            return new SmscError(response.ReasonPhrase ?? $"Неизвестная ошибка при вызове SMSC. Status: {response.StatusCode}");
        }

        var content = await response.Content.ReadAsStringAsync(cancellationToken);

        _logger.LogInformation("Received SMSC Response: {req} {res}", url, content);

        var smscResult = JsonConvert.DeserializeObject<SmscResult>(content) ?? new SmscResult {Error = "Failed to parse response"};

        return Result.Ok(smscResult);
    }
}