Реализован вход в систему в IntersvyazClient.

src/Intersvyaz.Net/IntersvyazClient.cs

@@ -0,0 +1,67 @@
+using System;
+using System.Linq;
+using System.Net.Http;
+using System.Net.Http.Headers;
+using System.Threading.Tasks;
+using Intersvyaz.Net.Models;
+using Newtonsoft.Json;
+
+namespace Intersvyaz.Net
+{
+    public class IntersvyazClient
+    {
+        private readonly Uri BASE_ADDRESS = new Uri("https://api.is74.ru");
+
+        private HttpClient httpClient;
+
+        public IntersvyazClient()
+        {
+            httpClient = new HttpClient()
+            {
+                BaseAddress = BASE_ADDRESS,
+            };
+
+            // TODO: Добавить здесь ссылку на репозитории.
+            httpClient.DefaultRequestHeaders.UserAgent.Add(
+                new ProductInfoHeaderValue("Intersvyaz.Net", "1.0"));
+        }
+
+        public IntersvyazClient(string token) : base()
+        {
+            httpClient.DefaultRequestHeaders.Authorization
+                = new AuthenticationHeaderValue("Bearer", token);
+        }
+
+        public async Task<LoginResponseDto> Login(string username, string password)
+        {
+            var content = new JsonContent(new LoginRequestDto()
+            {
+                Username = username,
+                Password = password,
+            });
+
+            using (var message = await httpClient.PostAsync("/auth/mobile", content))
+            {
+                var data = await message.Content.ReadAsStringAsync();
+
+                if ((int)message.StatusCode == 422) // NOTE: Data Validation Error
+                {
+                    var errors = JsonConvert.DeserializeObject<ValidationErrorDto[]>(data);
+                    throw new InvalidOperationException(string.Join("; ", errors.Select(e => e.Message)));
+                }
+
+                if (!message.IsSuccessStatusCode)
+                {
+                    throw new InvalidOperationException("Неизвестная ошибка сервера");
+                }
+
+                var result = JsonConvert.DeserializeObject<LoginResponseDto>(data);
+
+                httpClient.DefaultRequestHeaders.Authorization =
+                    new AuthenticationHeaderValue("Bearer", result.Token);
+
+                return result;
+            }
+        }
+    }
+}