feat: GitHub OAuth mechanism implemented

WotBlitzStatisticsPro.GraphQl/GitHubOauth/GitHubOauthAppConfiguration.cs

@@ -0,0 +1,20 @@
+namespace WotBlitzStatisticsPro.GraphQl.GitHubOauth
+{
+    public class GitHubOauthAppConfiguration
+    {
+        /// <summary>
+        /// Github OAuth clientId
+        /// </summary>
+        public string? ClientId { get; set; }
+
+        /// <summary>
+        /// GutHub OAuth client secret
+        /// </summary>
+        public string? ClientSecret { get; set; }
+
+        /// <summary>
+        /// GutHub user, that allowed to make dictionary updates mutation
+        /// </summary>
+        public string AllowedUser { get; set; } = "DrMboga";
+    }
+}

WotBlitzStatisticsPro.GraphQl/GitHubOauth/GitHubOauthService.cs

@@ -0,0 +1,106 @@
+using System;
+using System.Collections.Generic;
+using System.IdentityModel.Tokens.Jwt;
+using System.Net.Http;
+using System.Net.Http.Headers;
+using System.Security.Claims;
+using System.Text;
+using System.Text.Json;
+using System.Text.RegularExpressions;
+using System.Threading.Tasks;
+using Microsoft.IdentityModel.Tokens;
+using WotBlitzStatisticsPro.Common.Model;
+
+namespace WotBlitzStatisticsPro.GraphQl.GitHubOauth
+{
+    public class GitHubOauthService: IGitHubOauthService
+    {
+        private readonly IHttpClientFactory _httpClientFactory;
+        private readonly GitHubOauthAppConfiguration _configuration;
+
+        public GitHubOauthService(
+            IHttpClientFactory httpClientFactory,
+            GitHubOauthAppConfiguration configuration)
+        {
+            _httpClientFactory = httpClientFactory;
+            _configuration = configuration;
+            if (_configuration.ClientId == null || _configuration.ClientSecret == null)
+            {
+                throw new ArgumentNullException(nameof(_configuration));
+            }
+        }
+
+        public async Task<GitHubUser?> GetGitHubUser(string oAuthCode)
+        {
+            var token = await GetAccessToken(oAuthCode);
+            return await GetUser(token);
+        }
+
+        public string GenerateToken(GitHubUser user)
+        {
+            var key = new SymmetricSecurityKey(Encoding.UTF8.GetBytes(_configuration.ClientSecret!));
+            var credentials = new SigningCredentials(key, SecurityAlgorithms.HmacSha256);
+
+            // generate jwt token
+            var claims = new[]
+            {
+                new Claim(ClaimTypes.Name, user.Login?? "unknown"),
+            };
+
+            var token = new JwtSecurityToken(
+                issuer: "https://WotBlitzStatisticsPro.com",
+                audience: "https://WotBlitzStatisticsPro.com",
+                claims: claims,
+                expires: DateTime.Now.AddMinutes(30),
+                signingCredentials: credentials);
+
+            return new JwtSecurityTokenHandler().WriteToken(token);
+        }
+
+        private async Task<string> GetAccessToken(string oAuthCode)
+        {
+            string url = "https://github.com/login/oauth/access_token";
+
+            var parameters = new Dictionary<string, string>
+            {
+                { "client_id", _configuration.ClientId! }, 
+                { "client_secret", _configuration.ClientSecret! },
+                { "code", oAuthCode }
+            };
+            var encodedContent = new FormUrlEncodedContent(parameters!);
+
+            var client = _httpClientFactory.CreateClient("github");
+
+            var response = await client.PostAsync(url, encodedContent).ConfigureAwait(false);
+            response.EnsureSuccessStatusCode();
+            var stringResponse = await response.Content.ReadAsStringAsync();
+
+            var regex = new Regex("access_token=(.{40})&scope=&token_type=bearer");
+            var match = regex.Match(stringResponse);
+
+            if (match.Success)
+            {
+                return match.Groups[1].Value;
+            }
+
+            throw new ApplicationException($"Can not get access_token from string '{stringResponse}'");
+        }
+
+        private async Task<GitHubUser?> GetUser(string token)
+        {
+            string url = "https://api.github.com/user";
+
+            var client = _httpClientFactory.CreateClient("github");
+            client.DefaultRequestHeaders.Authorization
+                = new AuthenticationHeaderValue("Bearer", token);
+            client.DefaultRequestHeaders.Add("User-Agent", "WotBlitzStatisticsPro");
+
+            var response = await client.GetAsync(url);
+
+            response.EnsureSuccessStatusCode();
+            
+            await using var responseStream = await response.Content.ReadAsStreamAsync();
+            return await JsonSerializer.DeserializeAsync<GitHubUser?>(responseStream);
+        }
+    }
+}

WotBlitzStatisticsPro.GraphQl/GitHubOauth/IGitHubOauthService.cs

@@ -0,0 +1,12 @@
+using System.Threading.Tasks;
+using WotBlitzStatisticsPro.Common.Model;
+
+namespace WotBlitzStatisticsPro.GraphQl.GitHubOauth
+{
+    public interface IGitHubOauthService
+    {
+        Task<GitHubUser?> GetGitHubUser(string oAuthCode);
+
+        string GenerateToken(GitHubUser user);
+    }
+}