feat: initial working discord authentication

Foxnouns.Backend/Controllers/Authentication/AuthController.cs

@@ -1,4 +1,5 @@
 using System.Web;
+using Foxnouns.Backend.Extensions;
 using Foxnouns.Backend.Services;
 using Microsoft.AspNetCore.Mvc;
 using NodaTime;
@@ -34,11 +35,19 @@ public class AuthController(Config config, KeyCacheService keyCacheSvc, ILogger
         string? Tumblr
     );
 
-    internal record AuthResponse(
+    public record AuthResponse(
         UserRendererService.UserResponse User,
         string Token,
         Instant ExpiresAt
     );
 
+    public record CallbackResponse(
+        bool HasAccount, // If true, user has an account, but it's deleted
+        string Ticket,
+        string? RemoteUsername
+    );
+
+    public record OauthRegisterRequest(string Ticket, string Username);
+
     public record CallbackRequest(string Code, string State);
 }

Foxnouns.Backend/Controllers/Authentication/DiscordAuthController.cs

@@ -1,7 +1,10 @@
 using Foxnouns.Backend.Database;
 using Foxnouns.Backend.Database.Models;
+using Foxnouns.Backend.Extensions;
 using Foxnouns.Backend.Services;
+using Foxnouns.Backend.Utils;
 using Microsoft.AspNetCore.Mvc;
+using Microsoft.EntityFrameworkCore;
 using NodaTime;
 
 namespace Foxnouns.Backend.Controllers.Authentication;
@@ -18,6 +21,10 @@ public class DiscordAuthController(
     UserRendererService userRendererSvc) : ApiControllerBase
 {
     [HttpPost("callback")]
+    // TODO: duplicating attribute doesn't work, find another way to mark both as possible response
+    // leaving it here for documentation purposes
+    [ProducesResponseType<AuthController.AuthResponse>(StatusCodes.Status200OK)]
+    [ProducesResponseType<AuthController.CallbackResponse>(StatusCodes.Status200OK)]
     public async Task<IActionResult> CallbackAsync([FromBody] AuthController.CallbackRequest req)
     {
         CheckRequirements();
@@ -30,7 +37,29 @@ public class DiscordAuthController(
         logger.Debug("Discord user {Username} ({Id}) authenticated with no local account", remoteUser.Username,
             remoteUser.Id);
 
-        throw new NotImplementedException();
+        var ticket = OauthUtils.RandomToken();
+        await keyCacheSvc.SetKeyAsync($"discord:{ticket}", remoteUser, Duration.FromMinutes(20));
+
+        return Ok(new AuthController.CallbackResponse(false, ticket, remoteUser.Username));
+    }
+
+    [HttpPost("register")]
+    [ProducesResponseType<AuthController.AuthResponse>(StatusCodes.Status200OK)]
+    public async Task<IActionResult> RegisterAsync([FromBody] AuthController.OauthRegisterRequest req)
+    {
+        var remoteUser = await keyCacheSvc.GetKeyAsync<RemoteAuthService.RemoteUser>($"discord:{req.Ticket}");
+        if (remoteUser == null) throw new ApiError.BadRequest("Invalid ticket");
+        if (await db.AuthMethods.AnyAsync(a => a.AuthType == AuthType.Discord && a.RemoteId == remoteUser.Id))
+        {
+            logger.Error("Discord user {Id} has valid ticket but is already linked to an existing account",
+                remoteUser.Id);
+            throw new FoxnounsError("Discord ticket was issued for user with existing link");
+        }
+
+        var user = await authSvc.CreateUserWithRemoteAuthAsync(req.Username, AuthType.Discord, remoteUser.Id,
+            remoteUser.Username);
+
+        return Ok(await GenerateUserTokenAsync(user));
     }
 
     private async Task<AuthController.AuthResponse> GenerateUserTokenAsync(User user)

Foxnouns.Backend/Extensions/KeyCacheExtensions.cs

@@ -0,0 +1,21 @@
+using Foxnouns.Backend.Services;
+using Foxnouns.Backend.Utils;
+using NodaTime;
+
+namespace Foxnouns.Backend.Extensions;
+
+public static class KeyCacheExtensions
+{
+    public static async Task<string> GenerateAuthStateAsync(this KeyCacheService keyCacheSvc)
+    {
+        var state = OauthUtils.RandomToken();
+        await keyCacheSvc.SetKeyAsync($"oauth_state:{state}", "", Duration.FromMinutes(10));
+        return state;
+    }
+
+    public static async Task ValidateAuthStateAsync(this KeyCacheService keyCacheSvc, string state)
+    {
+        var val = await keyCacheSvc.GetKeyAsync($"oauth_state:{state}", delete: true);
+        if (val == null) throw new ApiError.BadRequest("Invalid OAuth state");
+    }
+}

Foxnouns.Backend/Program.cs

@@ -6,7 +6,6 @@ using Foxnouns.Backend.Services;
 using Microsoft.AspNetCore.Mvc;
 using Newtonsoft.Json;
 using Newtonsoft.Json.Serialization;
-using NodaTime;
 
 // Read version information from .version in the repository root
 await BuildInfo.ReadBuildInfo();

Foxnouns.Backend/Services/AuthService.cs

@@ -34,6 +34,37 @@ public class AuthService(ILogger logger, DatabaseContext db, ISnowflakeGenerator
 
         return user;
     }
+    
+    /// <summary>
+    /// Creates a new user with the given username and remote authentication method.
+    /// To create a user with email authentication, use <see cref="CreateUserWithPasswordAsync" />
+    /// This method does <i>not</i> save the resulting user, the caller must still call <see cref="M:Microsoft.EntityFrameworkCore.DbContext.SaveChanges" />.
+    /// </summary>
+    public async Task<User> CreateUserWithRemoteAuthAsync(string username, AuthType authType, string remoteId,
+        string remoteUsername, FediverseApplication? instance = null)
+    {
+        AssertValidAuthType(authType, instance);
+        
+        if (await db.Users.AnyAsync(u => u.Username == username))
+            throw new ApiError.BadRequest("Username is already taken");
+
+        var user = new User
+        {
+            Id = snowflakeGenerator.GenerateSnowflake(),
+            Username = username,
+            AuthMethods =
+            {
+                new AuthMethod
+                {
+                    Id = snowflakeGenerator.GenerateSnowflake(), AuthType = authType, RemoteId = remoteId,
+                    RemoteUsername = remoteUsername, FediverseApplication = instance
+                }
+            }
+        };
+
+        db.Add(user);
+        return user;
+    }
 
     /// <summary>
     /// Authenticates a user with email and password.
@@ -81,10 +112,7 @@ public class AuthService(ILogger logger, DatabaseContext db, ISnowflakeGenerator
     public async Task<User?> AuthenticateUserAsync(AuthType authType, string remoteId,
         FediverseApplication? instance = null)
     {
-        if (authType == AuthType.Fediverse && instance == null)
-            throw new FoxnounsError("Fediverse authentication requires an instance.");
-        if (authType != AuthType.Fediverse && instance != null)
-            throw new FoxnounsError("Non-Fediverse authentication does not require an instance.");
+        AssertValidAuthType(authType, instance);
 
         return await db.Users.FirstOrDefaultAsync(u =>
             u.AuthMethods.Any(a =>
@@ -115,4 +143,12 @@ public class AuthService(ILogger logger, DatabaseContext db, ISnowflakeGenerator
 
         return (token, hash);
     }
+
+    private static void AssertValidAuthType(AuthType authType, FediverseApplication? instance)
+    {
+        if (authType == AuthType.Fediverse && instance == null)
+            throw new FoxnounsError("Fediverse authentication requires an instance.");
+        if (authType != AuthType.Fediverse && instance != null)
+            throw new FoxnounsError("Non-Fediverse authentication does not require an instance.");
+    }
 }

Foxnouns.Backend/Services/KeyCacheService.cs

@@ -2,6 +2,7 @@ using Foxnouns.Backend.Database;
 using Foxnouns.Backend.Database.Models;
 using Foxnouns.Backend.Utils;
 using Microsoft.EntityFrameworkCore;
+using Newtonsoft.Json;
 using NodaTime;
 
 namespace Foxnouns.Backend.Services;
@@ -42,16 +43,18 @@ public class KeyCacheService(DatabaseContext db, IClock clock, ILogger logger)
         if (count != 0) logger.Information("Removed {Count} expired keys from the database", count);
     }
 
-    public async Task<string> GenerateAuthStateAsync()
+    public Task SetKeyAsync<T>(string key, T obj, Duration expiresAt) where T : class =>
+        SetKeyAsync(key, obj, clock.GetCurrentInstant() + expiresAt);
+
+    public async Task SetKeyAsync<T>(string key, T obj, Instant expires) where T : class
     {
-        var state = OauthUtils.RandomToken();
-        await SetKeyAsync($"oauth_state:{state}", "", Duration.FromMinutes(10));
-        return state;
+        var value = JsonConvert.SerializeObject(obj);
+        await SetKeyAsync(key, value, expires);
     }
 
-    public async Task ValidateAuthStateAsync(string state)
+    public async Task<T?> GetKeyAsync<T>(string key, bool delete = false) where T : class
     {
-        var val = await GetKeyAsync($"oauth_state:{state}", delete: true);
-        if (val == null) throw new ApiError.BadRequest("Invalid OAuth state");
+        var value = await GetKeyAsync(key, delete: false);
+        return value == null ? default : JsonConvert.DeserializeObject<T>(value);
     }
 }

Foxnouns.Frontend/src/lib/api/auth.ts

@@ -0,0 +1,18 @@
+import type { User } from "./user";
+
+export type CallbackRequest = {
+	code: string;
+	state: string;
+};
+
+export type CallbackResponse = {
+	has_account: boolean;
+	ticket: string;
+	remote_username: string | null;
+};
+
+export type AuthResponse = {
+	user: User;
+	token: string;
+	expires_at: string;
+};

Foxnouns.Frontend/src/routes/+layout.server.ts

@@ -2,12 +2,12 @@ import type Meta from "$lib/api/meta";
 import type { User } from "$lib/api/user";
 import request from "$lib/request";
 
-export async function load({ fetch }) {
+export async function load({ fetch, locals }) {
 	const meta = await request<Meta>(fetch, "GET", "/meta");
 	let user: User | undefined;
 	try {
 		user = await request<User>(fetch, "GET", "/users/@me");
 	} catch {}
 
-	return { meta, user };
+	return { meta, user, token: locals.token };
 }

Foxnouns.Frontend/src/routes/auth/login/+page.svelte

@@ -9,7 +9,7 @@
 		<div class="grid">
 			<div class="cell">
 				<p class="title">Log in with email address</p>
-				<form action="?/login">
+				<form method="POST" action="?/login">
 					<div class="field">
 						<label for="email" class="label">Email address</label>
 						<div class="control">

Foxnouns.Frontend/src/routes/auth/login/discord/+page.server.ts

@@ -1,10 +1,55 @@
-import { fastRequest } from "$lib/request";
+import request from "$lib/request";
+import type { AuthResponse, CallbackResponse } from "$lib/api/auth";
 
-export const load = async ({ fetch, url }) => {
-	await fastRequest(fetch, "POST", "/auth/discord/callback", {
-		body: {
-			code: url.searchParams.get("code"),
-			state: url.searchParams.get("state"),
+export const load = async ({ fetch, url, cookies, parent }) => {
+	const data = await parent();
+	if (data.user) {
+		return { loggedIn: true, token: data.token, user: data.user };
+	}
+
+	const resp = await request<AuthResponse | CallbackResponse>(
+		fetch,
+		"POST",
+		"/auth/discord/callback",
+		{
+			body: {
+				code: url.searchParams.get("code"),
+				state: url.searchParams.get("state"),
+			},
 		},
-	});
+	);
+
+	console.log(JSON.stringify(resp));
+
+	if ("token" in resp) {
+		const authResp = resp as AuthResponse;
+		cookies.set("pronounscc-token", authResp.token, { path: "/" });
+		return { loggedIn: true, token: authResp.token, user: authResp.user };
+	}
+
+	const callbackResp = resp as CallbackResponse;
+	return {
+		loggedIn: false,
+		hasAccount: callbackResp.has_account,
+		ticket: resp.ticket,
+		remoteUsername: resp.remote_username,
+	};
+};
+
+export const actions = {
+	register: async ({ cookies, request: req, fetch, locals }) => {
+		const data = await req.formData();
+		const username = data.get("username");
+		const ticket = data.get("ticket");
+
+		console.log(JSON.stringify({ username, ticket }));
+
+		const resp = await request<AuthResponse>(fetch, "POST", "/auth/discord/register", {
+			body: { username, ticket },
+		});
+		cookies.set("pronounscc-token", resp.token, { path: "/" });
+		locals.token = resp.token;
+
+		return { token: resp.token, user: resp.user };
+	},
 };

Foxnouns.Frontend/src/routes/auth/login/discord/+page.svelte

@@ -1,5 +1,79 @@
 <script lang="ts">
+	import { onMount } from "svelte";
+	import { goto } from "$app/navigation";
+	import { enhance } from "$app/forms";
+	import type { PageData, ActionData } from "./$types";
+	export let data: PageData;
 
+	export let form: ActionData;
+
+	onMount(async () => {
+		if (data.user) {
+			await new Promise((r) => setTimeout(r, 3000));
+			await goto(`/@${data.user.username}`);
+		}
+	});
+
+	const redirectOnForm = async (action: ActionData) => {
+		if (form?.user) {
+			await new Promise((r) => setTimeout(r, 3000));
+			await goto(`/@${form.user.username}`);
+		}
+	};
+
+	$: redirectOnForm(form);
 </script>
 
-<p>omg its a login page</p>
+<div class="container">
+	{#if form?.user}
+		<h1 class="title">Successfully created account!</h1>
+		<p>Welcome, <strong>@{form.user.username}</strong>!</p>
+		<p>
+			You should automatically be redirected to your profile in a few seconds. If you're not
+			redirected, please press the link above.
+		</p>
+	{:else if data.loggedIn}
+		<h1 class="title">Successfully logged in!</h1>
+		<p>You are now logged in as <a href="/@{data.user?.username}">@{data.user?.username}</a>.</p>
+		<p>
+			You should automatically be redirected to your profile in a few seconds. If you're not
+			redirected, please press the link above.
+		</p>
+	{:else}
+		<h1 class="title">Finish signing up with a Discord account</h1>
+		<form method="POST" action="?/register" use:enhance>
+			<div class="field">
+				<label for="remote_username" class="label">Discord username</label>
+				<div class="control">
+					<input
+						type="text"
+						name="remote_username"
+						id="remote_username"
+						class="input"
+						value={data.remoteUsername}
+						disabled
+					/>
+				</div>
+			</div>
+			<div class="field">
+				<label for="username" class="label">Username</label>
+				<div class="control">
+					<input type="text" name="username" id="username" class="input" placeholder="Username" />
+				</div>
+			</div>
+			<input
+				type="text"
+				name="ticket"
+				id="ticket"
+				class="hidden"
+				style="display: hidden;"
+				value={data.ticket}
+			/>
+			<div class="field">
+				<div class="control">
+					<button class="button is-primary">Sign up</button>
+				</div>
+			</div>
+		</form>
+	{/if}
+</div>

Foxnouns.Frontend/svelte.config.js

@@ -15,6 +15,9 @@ const config = {
 		env: {
 			privatePrefix: "PRIVATE_",
 		},
+		csrf: {
+			checkOrigin: false,
+		},
 	},
 };