feat: start dashboard

Catalogger.Backend/Api/AuthController.cs

@@ -0,0 +1,85 @@
+// Copyright (C) 2021-present sam (starshines.gay)
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Affero General Public License as published
+// by the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU Affero General Public License for more details.
+//
+// You should have received a copy of the GNU Affero General Public License
+// along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+using System.Diagnostics.CodeAnalysis;
+using System.Net;
+using System.Web;
+using Catalogger.Backend.Api.Middleware;
+using Catalogger.Backend.Cache.InMemoryCache;
+using Catalogger.Backend.Database.Redis;
+using Microsoft.AspNetCore.Mvc;
+
+namespace Catalogger.Backend.Api;
+
+[Route("/api")]
+public class AuthController(
+    Config config,
+    RedisService redisService,
+    GuildCache guildCache,
+    ApiCache apiCache,
+    DiscordRequestService discordRequestService
+) : ApiControllerBase
+{
+    private static string StateKey(string state) => $"state:{state}";
+
+    [HttpGet("authorize")]
+    public async Task<IActionResult> GenerateAuthUrlAsync()
+    {
+        var state = ApiUtils.RandomToken();
+        await redisService.SetStringAsync(StateKey(state), state, TimeSpan.FromMinutes(30));
+
+        var url =
+            $"https://discord.com/oauth2/authorize?response_type=code"
+            + $"&client_id={config.Discord.ApplicationId}&scope=identify+guilds"
+            + $"&prompt=none&state={state}"
+            + $"&redirect_uri={HttpUtility.UrlEncode($"{config.Web.BaseUrl}/callback")}";
+
+        return Redirect(url);
+    }
+
+    [HttpPost("callback")]
+    [ProducesResponseType<CallbackResponse>(statusCode: StatusCodes.Status200OK)]
+    public async Task<IActionResult> CallbackAsync([FromBody] CallbackRequest req)
+    {
+        var redisState = await redisService.GetStringAsync(StateKey(req.State), delete: true);
+        if (redisState != req.State)
+            throw new ApiError(
+                HttpStatusCode.BadRequest,
+                ErrorCode.BadRequest,
+                "Invalid OAuth state"
+            );
+
+        var (token, user, guilds) = await discordRequestService.RequestDiscordTokenAsync(req.Code);
+        await apiCache.SetUserAsync(user);
+        await apiCache.SetGuildsAsync(user.Id, guilds);
+
+        return Ok(
+            new CallbackResponse(
+                new ApiUser(user),
+                guilds
+                    .Where(g => g.CanManage)
+                    .Select(g => new ApiGuild(g, guildCache.Contains(g.Id))),
+                token.DashboardToken
+            )
+        );
+    }
+
+    public record CallbackRequest(string Code, string State);
+
+    private record CallbackResponse(ApiUser User, IEnumerable<ApiGuild> Guilds, string Token);
+
+    [SuppressMessage("ReSharper", "ClassNeverInstantiated.Local")]
+    private record DiscordTokenResponse(string AccessToken, string? RefreshToken, int ExpiresIn);
+}