feat(backend): limit total members per user

Foxnouns.Backend/Controllers/MembersController.cs

@@ -41,6 +41,8 @@ public class MembersController(
         return Ok(memberRenderer.RenderMember(member, CurrentToken));
     }
 
+    public const int MaxMemberCount = 500;
+
     [HttpPost("/api/v2/users/@me/members")]
     [ProducesResponseType<MemberRendererService.MemberResponse>(StatusCodes.Status200OK)]
     [Authorize("member.create")]
@@ -58,6 +60,10 @@ public class MembersController(
             .. ValidationUtils.ValidateLinks(req.Links)
         ]);
 
+        var memberCount = await db.Members.CountAsync(m => m.UserId == CurrentUser.Id, ct);
+        if (memberCount >= MaxMemberCount)
+            throw new ApiError.BadRequest("Maximum number of members reached");
+
         var member = new Member
         {
             Id = snowflakeGenerator.GenerateSnowflake(),

Foxnouns.Backend/Controllers/MetaController.cs

@@ -1,3 +1,4 @@
+using Foxnouns.Backend.Utils;
 using Microsoft.AspNetCore.Mvc;
 
 namespace Foxnouns.Backend.Controllers;
@@ -18,14 +19,22 @@ public class MetaController : ApiControllerBase
                 (int)FoxnounsMetrics.UsersActiveMonthCount.Value,
                 (int)FoxnounsMetrics.UsersActiveWeekCount.Value,
                 (int)FoxnounsMetrics.UsersActiveDayCount.Value
-            ))
+            ),
+            new Limits(
+                MemberCount: MembersController.MaxMemberCount,
+                BioLength: ValidationUtils.MaxBioLength))
         );
     }
 
     [HttpGet("/api/v2/coffee")]
     public IActionResult BrewCoffee() => Problem("Sorry, I'm a teapot!", statusCode: StatusCodes.Status418ImATeapot);
 
-    private record MetaResponse(string Repository, string Version, string Hash, int Members, UserInfo Users);
+    private record MetaResponse(string Repository, string Version, string Hash, int Members, UserInfo Users, Limits Limits);
 
     private record UserInfo(int Total, int ActiveMonth, int ActiveWeek, int ActiveDay);
+
+    // All limits that the frontend should know about (for UI purposes)
+    private record Limits(
+        int MemberCount,
+        int BioLength);
 }

Foxnouns.Backend/Utils/ValidationUtils.cs

@@ -127,12 +127,14 @@ public static class ValidationUtils
         return errors;
     }
 
+    public const int MaxBioLength = 1024;
+    
     public static ValidationError? ValidateBio(string? bio)
     {
         return bio?.Length switch
         {
-            0 => ValidationError.LengthError("Bio is too short", 1, 1024, bio.Length),
+            0 => ValidationError.LengthError("Bio is too short", 1, MaxBioLength, bio.Length),
-            > 1024 => ValidationError.LengthError("Bio is too long", 1, 1024, bio.Length),
+            > MaxBioLength => ValidationError.LengthError("Bio is too long", 1, MaxBioLength, bio.Length),
             _ => null
         };
     }