feat(backend): add skeleton discord auth controller

Foxnouns.Backend/Controllers/Authentication/DiscordAuthController.cs

@@ -0,0 +1,14 @@
+using Foxnouns.Backend.Database;
+using Microsoft.AspNetCore.Mvc;
+
+namespace Foxnouns.Backend.Controllers.Authentication;
+
+[Route("/api/v2/auth/discord")]
+public class DiscordAuthController(Config config, DatabaseContext db) : ApiControllerBase
+{
+    [HttpPost("url")]
+    public async Task<IActionResult> AuthenticationUrl()
+    {
+        throw new NotImplementedException();
+    }
+}

Foxnouns.Backend/Database/DatabaseContext.cs

@@ -17,6 +17,7 @@ public class DatabaseContext : DbContext
     public DbSet<FediverseApplication> FediverseApplications { get; set; }
     public DbSet<Token> Tokens { get; set; }
     public DbSet<Application> Applications { get; set; }
+    public DbSet<TemporaryKey> TemporaryKeys { get; set; }
 
     public DatabaseContext(Config config)
     {
@@ -47,6 +48,7 @@ public class DatabaseContext : DbContext
     {
         modelBuilder.Entity<User>().HasIndex(u => u.Username).IsUnique();
         modelBuilder.Entity<Member>().HasIndex(m => new { m.UserId, m.Name }).IsUnique();
+        modelBuilder.Entity<TemporaryKey>().HasIndex(k => k.Key).IsUnique();
 
         modelBuilder.Entity<User>()
             .OwnsOne(u => u.Fields, f => f.ToJson())

Foxnouns.Backend/Database/DatabaseQueryExtensions.cs

@@ -1,7 +1,9 @@
 using System.Security.Cryptography;
 using Foxnouns.Backend.Database.Models;
 using Foxnouns.Backend.Utils;
+using Microsoft.AspNetCore.Mvc.Formatters;
 using Microsoft.EntityFrameworkCore;
+using NodaTime;
 
 namespace Foxnouns.Backend.Database;
 
@@ -84,4 +86,33 @@ public static class DatabaseQueryExtensions
         await context.SaveChangesAsync();
         return app;
     }
+
+    public static Task SetKeyAsync(this DatabaseContext context, string key, string value, Duration expireAfter) =>
+        context.SetKeyAsync(key, value, SystemClock.Instance.GetCurrentInstant() + expireAfter);
+
+    public static async Task SetKeyAsync(this DatabaseContext context, string key, string value, Instant expires)
+    {
+        context.TemporaryKeys.Add(new TemporaryKey
+        {
+            Expires = expires,
+            Key = key,
+            Value = value,
+        });
+        await context.SaveChangesAsync();
+    }
+
+    public static async Task<string?> GetKeyAsync(this DatabaseContext context, string key,
+        bool delete = false)
+    {
+        var value = await context.TemporaryKeys.FirstOrDefaultAsync(k => k.Key == key);
+        if (value == null) return null;
+
+        if (delete)
+        {
+            await context.TemporaryKeys.Where(k => k.Key == key).ExecuteDeleteAsync();
+            await context.SaveChangesAsync();   
+        }
+
+        return value.Value;
+    }
 }

Foxnouns.Backend/Database/Models/TemporaryKey.cs

@@ -2,7 +2,7 @@ using NodaTime;
 
 namespace Foxnouns.Backend.Database.Models;
 
-public class Cache
+public class TemporaryKey
 {
     public long Id { get; init; }
     public required string Key { get; init; }