Migrate API to ASP.NET Core Auth services + refactor

PluralKit.API/Authentication/AuthExt.cs

@@ -0,0 +1,32 @@
+using System;
+using System.Security.Claims;
+
+using PluralKit.Core;
+
+namespace PluralKit.API
+{
+    public static class AuthExt
+    {
+        public static SystemId CurrentSystem(this ClaimsPrincipal user)
+        {
+            var claim = user.FindFirst(PKClaims.SystemId);
+            if (claim == null) throw new ArgumentException("User is unauthorized");
+            
+            if (int.TryParse(claim.Value, out var id))
+                return new SystemId(id);
+            throw new ArgumentException("User has non-integer system ID claim");
+        }
+        
+        public static LookupContext ContextFor(this ClaimsPrincipal user, PKSystem system)
+        {
+            if (!user.Identity.IsAuthenticated) return LookupContext.API;
+            return system.Id == user.CurrentSystem() ? LookupContext.ByOwner : LookupContext.API;
+        }
+
+        public static LookupContext ContextFor(this ClaimsPrincipal user, PKMember member)
+        {
+            if (!user.Identity.IsAuthenticated) return LookupContext.API;
+            return member.System == user.CurrentSystem() ? LookupContext.ByOwner : LookupContext.API;
+        }
+    }
+}

PluralKit.API/Authentication/PKClaims.cs

@@ -0,0 +1,7 @@
+namespace PluralKit.API
+{
+    public class PKClaims
+    {
+        public const string SystemId = "PluralKit:SystemId";
+    }
+}

PluralKit.API/Authentication/SystemTokenAuthenticationHandler.cs

@@ -0,0 +1,49 @@
+using System;
+using System.Linq;
+using System.Security.Claims;
+using System.Text.Encodings.Web;
+using System.Threading.Tasks;
+
+using Dapper;
+
+using Microsoft.AspNetCore.Authentication;
+using Microsoft.Extensions.Logging;
+using Microsoft.Extensions.Options;
+
+using PluralKit.Core;
+
+namespace PluralKit.API
+{
+    public class SystemTokenAuthenticationHandler: AuthenticationHandler<SystemTokenAuthenticationHandler.Opts>
+    {
+        private readonly IDatabase _db;
+        
+        public SystemTokenAuthenticationHandler(IOptionsMonitor<Opts> options, ILoggerFactory logger, UrlEncoder encoder, ISystemClock clock, IDatabase db): base(options, logger, encoder, clock)
+        {
+            _db = db;
+        }
+
+        protected override async Task<AuthenticateResult> HandleAuthenticateAsync()
+        {
+            if (!Request.Headers.ContainsKey("Authorization"))
+                return AuthenticateResult.NoResult();
+
+            var token = Request.Headers["Authorization"].FirstOrDefault();
+            var systemId = await _db.Execute(c => c.QuerySingleOrDefaultAsync<SystemId?>("select id from systems where token = @token", new { token }));
+            if (systemId == null) return AuthenticateResult.Fail("Invalid system token");
+
+            var claims = new[] {new Claim(PKClaims.SystemId, systemId.Value.Value.ToString())};
+            var identity = new ClaimsIdentity(claims, Scheme.Name);
+            var principal = new ClaimsPrincipal(identity);
+            var ticket = new AuthenticationTicket(principal, Scheme.Name);
+            ticket.Properties.IsPersistent = false;
+            ticket.Properties.AllowRefresh = false;
+            return AuthenticateResult.Success(ticket);
+        }
+
+        public class Opts: AuthenticationSchemeOptions
+        {
+            
+        }
+    }
+}

PluralKit.API/Authorization/MemberOwnerHandler.cs

@@ -0,0 +1,19 @@
+using System.Threading.Tasks;
+
+using Microsoft.AspNetCore.Authorization;
+
+using PluralKit.Core;
+
+namespace PluralKit.API
+{
+    public class MemberOwnerHandler: AuthorizationHandler<OwnSystemRequirement, PKMember> {
+        protected override Task HandleRequirementAsync(AuthorizationHandlerContext context,
+                                                       OwnSystemRequirement requirement, PKMember resource)
+        {
+            if (!context.User.Identity.IsAuthenticated) return Task.CompletedTask;
+            if (resource.System == context.User.CurrentSystem())
+                context.Succeed(requirement);
+            return Task.CompletedTask;
+        }
+    }
+}

PluralKit.API/Authorization/MemberPrivacyHandler.cs

@@ -0,0 +1,21 @@
+using System.Threading.Tasks;
+
+using Microsoft.AspNetCore.Authorization;
+
+using PluralKit.Core;
+
+namespace PluralKit.API
+{
+    public class MemberPrivacyHandler: AuthorizationHandler<PrivacyRequirement<PKMember>, PKMember>
+    {
+        protected override Task HandleRequirementAsync(AuthorizationHandlerContext context,
+                                                       PrivacyRequirement<PKMember> requirement, PKMember resource)
+        {
+            var level = requirement.Mapper(resource);
+            var ctx = context.User.ContextFor(resource);
+            if (level.CanAccess(ctx))
+                context.Succeed(requirement);
+            return Task.CompletedTask;
+        }
+    }
+}

PluralKit.API/Authorization/OwnSystemRequirement.cs

@@ -0,0 +1,6 @@
+using Microsoft.AspNetCore.Authorization;
+
+namespace PluralKit.API
+{
+    public class OwnSystemRequirement: IAuthorizationRequirement { }
+}

PluralKit.API/Authorization/PrivacyRequirement.cs

@@ -0,0 +1,18 @@
+using System;
+
+using Microsoft.AspNetCore.Authorization;
+
+using PluralKit.Core;
+
+namespace PluralKit.API
+{
+    public class PrivacyRequirement<T>: IAuthorizationRequirement
+    {
+        public readonly Func<T, PrivacyLevel> Mapper;
+        
+        public PrivacyRequirement(Func<T, PrivacyLevel> mapper)
+        {
+            Mapper = mapper;
+        }
+    }
+}

PluralKit.API/Authorization/SystemOwnerHandler.cs

@@ -0,0 +1,20 @@
+using System.Threading.Tasks;
+
+using Microsoft.AspNetCore.Authorization;
+
+using PluralKit.Core;
+
+namespace PluralKit.API
+{
+    public class SystemOwnerHandler: AuthorizationHandler<OwnSystemRequirement, PKSystem>
+    {
+        protected override Task HandleRequirementAsync(AuthorizationHandlerContext context,
+                                                       OwnSystemRequirement requirement, PKSystem resource)
+        {
+            if (!context.User.Identity.IsAuthenticated) return Task.CompletedTask;
+            if (resource.Id == context.User.CurrentSystem()) 
+                context.Succeed(requirement);
+            return Task.CompletedTask;
+        }
+    }
+}

PluralKit.API/Authorization/SystemPrivacyHandler.cs

@@ -0,0 +1,21 @@
+using System.Threading.Tasks;
+
+using Microsoft.AspNetCore.Authorization;
+
+using PluralKit.Core;
+
+namespace PluralKit.API
+{
+    public class SystemPrivacyHandler: AuthorizationHandler<PrivacyRequirement<PKSystem>, PKSystem>
+    {
+        protected override Task HandleRequirementAsync(AuthorizationHandlerContext context,
+                                                       PrivacyRequirement<PKSystem> requirement, PKSystem resource)
+        {
+            var level = requirement.Mapper(resource);
+            var ctx = context.User.ContextFor(resource);
+            if (level.CanAccess(ctx))
+                context.Succeed(requirement);
+            return Task.CompletedTask;
+        }
+    }
+}

PluralKit.API/Controllers/v1/AccountController.cs

@@ -15,12 +15,10 @@ namespace PluralKit.API
     public class AccountController: ControllerBase
     {
         private IDataStore _data;
-        private TokenAuthService _auth;
 
-        public AccountController(IDataStore data, TokenAuthService auth)
+        public AccountController(IDataStore data)
         {
             _data = data;
-            _auth = auth;
         }
 
         [HttpGet("{aid}")]
@@ -29,7 +27,7 @@ namespace PluralKit.API
             var system = await _data.GetSystemByAccount(aid);
             if (system == null) return NotFound("Account not found.");
             
-            return Ok(system.ToJson(_auth.ContextFor(system)));
+            return Ok(system.ToJson(User.ContextFor(system)));
         }
     }
 }

PluralKit.API/Controllers/v1/MemberController.cs

@@ -1,5 +1,6 @@
 using System.Threading.Tasks;
 
+using Microsoft.AspNetCore.Authorization;
 using Microsoft.AspNetCore.Mvc;
 
 using Newtonsoft.Json.Linq;
@@ -15,9 +16,9 @@ namespace PluralKit.API
     public class MemberController: ControllerBase
     {
         private IDataStore _data;
-        private TokenAuthService _auth;
+        private IAuthorizationService _auth;
 
-        public MemberController(IDataStore data, TokenAuthService auth)
+        public MemberController(IDataStore data, IAuthorizationService auth)
         {
             _data = data;
             _auth = auth;
@@ -29,14 +30,14 @@ namespace PluralKit.API
             var member = await _data.GetMemberByHid(hid);
             if (member == null) return NotFound("Member not found.");
 
-            return Ok(member.ToJson(_auth.ContextFor(member)));
+            return Ok(member.ToJson(User.ContextFor(member)));
         }
 
         [HttpPost]
-        [RequiresSystem]
+        [Authorize]
         public async Task<ActionResult<JObject>> PostMember([FromBody] JObject properties)
         {
-            var system = _auth.CurrentSystem;
+            var system = User.CurrentSystem();
             
             if (!properties.ContainsKey("name"))
                 return BadRequest("Member name must be specified.");
@@ -57,17 +58,18 @@ namespace PluralKit.API
             }
             
             await _data.SaveMember(member);
-            return Ok(member.ToJson(_auth.ContextFor(member)));
+            return Ok(member.ToJson(User.ContextFor(member)));
         }
 
         [HttpPatch("{hid}")]
-        [RequiresSystem]
+        [Authorize]
         public async Task<ActionResult<JObject>> PatchMember(string hid, [FromBody] JObject changes)
         {
             var member = await _data.GetMemberByHid(hid);
             if (member == null) return NotFound("Member not found.");
             
-            if (member.System != _auth.CurrentSystem.Id) return Unauthorized($"Member '{hid}' is not part of your system.");
+            var res = await _auth.AuthorizeAsync(User, member, "EditMember");
+            if (!res.Succeeded) return Unauthorized($"Member '{hid}' is not part of your system.");
 
             try
             {
@@ -79,17 +81,18 @@ namespace PluralKit.API
             }
             
             await _data.SaveMember(member);
-            return Ok(member.ToJson(_auth.ContextFor(member)));
+            return Ok(member.ToJson(User.ContextFor(member)));
         }
         
         [HttpDelete("{hid}")]
-        [RequiresSystem]
+        [Authorize]
         public async Task<ActionResult> DeleteMember(string hid)
         {
             var member = await _data.GetMemberByHid(hid);
             if (member == null) return NotFound("Member not found.");
             
-            if (member.System != _auth.CurrentSystem.Id) return Unauthorized($"Member '{hid}' is not part of your system.");
+            var res = await _auth.AuthorizeAsync(User, member, "EditMember");
+            if (!res.Succeeded) return Unauthorized($"Member '{hid}' is not part of your system.");
             
             await _data.DeleteMember(member);
             return Ok();

PluralKit.API/Controllers/v1/MessageController.cs

@@ -30,12 +30,10 @@ namespace PluralKit.API
     public class MessageController: ControllerBase
     {
         private IDataStore _data;
-        private TokenAuthService _auth;
 
-        public MessageController(IDataStore _data, TokenAuthService auth)
+        public MessageController(IDataStore _data)
         {
             this._data = _data;
-            _auth = auth;
         }
 
         [HttpGet("{mid}")]
@@ -50,8 +48,8 @@ namespace PluralKit.API
                 Id = msg.Message.Mid.ToString(),
                 Channel = msg.Message.Channel.ToString(),
                 Sender = msg.Message.Sender.ToString(),
-                Member = msg.Member.ToJson(_auth.ContextFor(msg.System)),
+                Member = msg.Member.ToJson(User.ContextFor(msg.System)),
-                System = msg.System.ToJson(_auth.ContextFor(msg.System)),
+                System = msg.System.ToJson(User.ContextFor(msg.System)),
                 Original = msg.Message.OriginalMid?.ToString()
             };
         } 

PluralKit.API/Controllers/v1/SystemController.cs

@@ -4,6 +4,7 @@ using System.Threading.Tasks;
 
 using Dapper;
 
+using Microsoft.AspNetCore.Authorization;
 using Microsoft.AspNetCore.Http;
 using Microsoft.AspNetCore.Mvc;
 
@@ -41,9 +42,9 @@ namespace PluralKit.API
     {
         private IDataStore _data;
         private IDatabase _conn;
-        private TokenAuthService _auth;
+        private IAuthorizationService _auth;
 
-        public SystemController(IDataStore data, IDatabase conn, TokenAuthService auth)
+        public SystemController(IDataStore data, IDatabase conn, IAuthorizationService auth)
         {
             _data = data;
             _conn = conn;
@@ -51,10 +52,11 @@ namespace PluralKit.API
         }
 
         [HttpGet]
-        [RequiresSystem]
+        [Authorize]
-        public Task<ActionResult<JObject>> GetOwnSystem()
+        public async Task<ActionResult<JObject>> GetOwnSystem()
         {
-            return Task.FromResult<ActionResult<JObject>>(Ok(_auth.CurrentSystem.ToJson(_auth.ContextFor(_auth.CurrentSystem))));
+            var system = await _conn.Execute(c => c.QuerySystem(User.CurrentSystem()));
+            return system.ToJson(User.ContextFor(system));
         }
 
         [HttpGet("{hid}")]
@@ -62,7 +64,7 @@ namespace PluralKit.API
         {
             var system = await _data.GetSystemByHid(hid);
             if (system == null) return NotFound("System not found.");
-            return Ok(system.ToJson(_auth.ContextFor(system)));
+            return Ok(system.ToJson(User.ContextFor(system)));
         }
 
         [HttpGet("{hid}/members")]
@@ -71,13 +73,13 @@ namespace PluralKit.API
             var system = await _data.GetSystemByHid(hid);
             if (system == null) return NotFound("System not found.");
 
-            if (!system.MemberListPrivacy.CanAccess(_auth.ContextFor(system)))
+            if (!system.MemberListPrivacy.CanAccess(User.ContextFor(system)))
                 return StatusCode(StatusCodes.Status403Forbidden, "Unauthorized to view member list.");
 
             var members = _data.GetSystemMembers(system);
             return Ok(await members
-                .Where(m => m.MemberPrivacy.CanAccess(_auth.ContextFor(system)))
+                .Where(m => m.MemberPrivacy.CanAccess(User.ContextFor(system)))
-                .Select(m => m.ToJson(_auth.ContextFor(system)))
+                .Select(m => m.ToJson(User.ContextFor(system)))
                 .ToListAsync());
         }
 
@@ -89,8 +91,8 @@ namespace PluralKit.API
             var system = await _data.GetSystemByHid(hid);
             if (system == null) return NotFound("System not found.");
 
-            if (!system.FrontHistoryPrivacy.CanAccess(_auth.ContextFor(system)))
+            var auth = await _auth.AuthorizeAsync(User, system, "ViewFrontHistory");
-                return StatusCode(StatusCodes.Status403Forbidden, "Unauthorized to view front history.");
+            if (!auth.Succeeded) return StatusCode(StatusCodes.Status403Forbidden, "Unauthorized to view front history.");
 
             using (var conn = await _conn.Obtain())
             {
@@ -112,26 +114,25 @@ namespace PluralKit.API
             var system = await _data.GetSystemByHid(hid);
             if (system == null) return NotFound("System not found.");
             
-            if (!system.FrontPrivacy.CanAccess(_auth.ContextFor(system)))
+            var auth = await _auth.AuthorizeAsync(User, system, "ViewFront");
-                return StatusCode(StatusCodes.Status403Forbidden, "Unauthorized to view fronter.");
+            if (!auth.Succeeded) return StatusCode(StatusCodes.Status403Forbidden, "Unauthorized to view fronter.");
             
-            var sw = await _data.GetLatestSwitch(system);
+            var sw = await _data.GetLatestSwitch(system.Id);
             if (sw == null) return NotFound("System has no registered switches."); 
                 
             var members = _data.GetSwitchMembers(sw);
             return Ok(new FrontersReturn
             {
                 Timestamp = sw.Timestamp,
-                Members = await members.Select(m => m.ToJson(_auth.ContextFor(system))).ToListAsync()
+                Members = await members.Select(m => m.ToJson(User.ContextFor(system))).ToListAsync()
             });
         }
 
         [HttpPatch]
-        [RequiresSystem]
+        [Authorize]
         public async Task<ActionResult<JObject>> EditSystem([FromBody] JObject changes)
         {
-            var system = _auth.CurrentSystem;
+            var system = await _conn.Execute(c => c.QuerySystem(User.CurrentSystem()));
-
             try
             {
                 system.ApplyJson(changes);
@@ -142,18 +143,18 @@ namespace PluralKit.API
             }
 
             await _data.SaveSystem(system);
-            return Ok(system.ToJson(_auth.ContextFor(system)));
+            return Ok(system.ToJson(User.ContextFor(system)));
         }
 
         [HttpPost("switches")]
-        [RequiresSystem]
+        [Authorize]
         public async Task<IActionResult> PostSwitch([FromBody] PostSwitchParams param)
         {
-            if (param.Members.Distinct().Count() != param.Members.Count())
+            if (param.Members.Distinct().Count() != param.Members.Count)
                 return BadRequest("Duplicate members in member list.");
             
             // We get the current switch, if it exists
-            var latestSwitch = await _data.GetLatestSwitch(_auth.CurrentSystem);
+            var latestSwitch = await _data.GetLatestSwitch(User.CurrentSystem());
             if (latestSwitch != null)
             {
                 var latestSwitchMembers = _data.GetSwitchMembers(latestSwitch);
@@ -169,7 +170,7 @@ namespace PluralKit.API
                 membersList = (await conn.QueryAsync<PKMember>("select * from members where hid = any(@Hids)", new {Hids = param.Members})).ToList();
             
             foreach (var member in membersList)
-                if (member.System != _auth.CurrentSystem.Id)
+                if (member.System != User.CurrentSystem())
                     return BadRequest($"Cannot switch to member '{member.Hid}' not in system.");
 
             // membersList is in DB order, and we want it in actual input order
@@ -185,7 +186,7 @@ namespace PluralKit.API
             }
 
             // Finally, log the switch (yay!)
-            await _data.AddSwitch(_auth.CurrentSystem, membersInOrder);
+            await _data.AddSwitch(User.CurrentSystem(), membersInOrder);
             return NoContent();
         }
     }

PluralKit.API/Modules.cs

@@ -6,8 +6,6 @@ namespace PluralKit.API
     {
         protected override void Load(ContainerBuilder builder)
         {
-            // Lifetime scope so the service, RequiresSystem, and handler itself all get the same value
-            builder.RegisterType<TokenAuthService>().AsSelf().InstancePerLifetimeScope();
         }
     }
 }

PluralKit.API/Services/TokenAuthService.cs

@@ -1,41 +0,0 @@
-using System.Linq;
-using System.Threading.Tasks;
-
-using Dapper;
-
-using Microsoft.AspNetCore.Http;
-
-using PluralKit.Core;
-
-namespace PluralKit.API
-{
-    public class TokenAuthService: IMiddleware
-    {
-        public PKSystem CurrentSystem { get; set; }
-
-        private readonly IDatabase _db;
-
-        public TokenAuthService(IDatabase db)
-        {
-            _db = db;
-        }
-
-        public async Task InvokeAsync(HttpContext context, RequestDelegate next)
-        {
-            var token = context.Request.Headers["Authorization"].FirstOrDefault();
-            if (token != null)
-            {
-                CurrentSystem = await _db.Execute(c => c.QueryFirstOrDefaultAsync("select * from systems where token = @token", new { token }));
-            }
-            
-            await next.Invoke(context);
-            CurrentSystem = null;
-        }
-
-        public LookupContext ContextFor(PKSystem system) => 
-            system.Id == CurrentSystem?.Id ? LookupContext.ByOwner : LookupContext.API;
-            
-        public LookupContext ContextFor(PKMember member) => 
-            member.System == CurrentSystem?.Id ? LookupContext.ByOwner : LookupContext.API;
-    }
-}

PluralKit.API/Startup.cs

@@ -4,6 +4,8 @@ using System.Reflection;
 
 using Autofac;
 
+using Microsoft.AspNetCore.Authentication;
+using Microsoft.AspNetCore.Authorization;
 using Microsoft.AspNetCore.Builder;
 using Microsoft.AspNetCore.Hosting;
 using Microsoft.AspNetCore.Mvc;
@@ -13,6 +15,7 @@ using Microsoft.Extensions.DependencyInjection;
 using Microsoft.Extensions.Hosting;
 using Microsoft.OpenApi.Models;
 
+using PluralKit.API;
 using PluralKit.Core;
 
 namespace PluralKit.API
@@ -30,6 +33,23 @@ namespace PluralKit.API
         public void ConfigureServices(IServiceCollection services)
         {
             services.AddCors();
+            services.AddAuthentication("SystemToken")
+                .AddScheme<SystemTokenAuthenticationHandler.Opts, SystemTokenAuthenticationHandler>("SystemToken", null);
+            
+            services.AddAuthorization(options =>
+            {
+                options.AddPolicy("EditSystem", p => p.RequireAuthenticatedUser().AddRequirements(new OwnSystemRequirement()));
+                options.AddPolicy("EditMember", p => p.RequireAuthenticatedUser().AddRequirements(new OwnSystemRequirement()));
+                
+                options.AddPolicy("ViewMembers", p => p.AddRequirements(new PrivacyRequirement<PKSystem>(s => s.MemberListPrivacy)));
+                options.AddPolicy("ViewFront", p => p.AddRequirements(new PrivacyRequirement<PKSystem>(s => s.FrontPrivacy)));
+                options.AddPolicy("ViewFrontHistory", p => p.AddRequirements(new PrivacyRequirement<PKSystem>(s => s.FrontHistoryPrivacy)));
+            });
+            services.AddSingleton<IAuthenticationHandler, SystemTokenAuthenticationHandler>();
+            services.AddSingleton<IAuthorizationHandler, MemberOwnerHandler>();
+            services.AddSingleton<IAuthorizationHandler, SystemOwnerHandler>();
+            services.AddSingleton<IAuthorizationHandler, SystemPrivacyHandler>();
+            
             services.AddControllers()
                 .SetCompatibilityVersion(CompatibilityVersion.Latest)
                 .AddNewtonsoftJson(); // sorry MS, this just does *more*
@@ -105,9 +125,10 @@ namespace PluralKit.API
 
             //app.UseHttpsRedirection();
             app.UseCors(opts => opts.AllowAnyMethod().AllowAnyOrigin().WithHeaders("Content-Type", "Authorization"));
-            app.UseMiddleware<TokenAuthService>();
             
             app.UseRouting();
+            app.UseAuthentication();
+            app.UseAuthorization();
             app.UseEndpoints(endpoints => endpoints.MapControllers());
         }
     }

PluralKit.API/Utils/RequiresSystemAttribute.cs

@@ -1,23 +0,0 @@
-using System.Threading.Tasks;
-using Microsoft.AspNetCore.Mvc;
-using Microsoft.AspNetCore.Mvc.Filters;
-using Microsoft.Extensions.DependencyInjection;
-
-namespace PluralKit.API
-{
-    public class RequiresSystemAttribute: ActionFilterAttribute
-    {
-
-        public override async Task OnActionExecutionAsync(ActionExecutingContext context, ActionExecutionDelegate next)
-        {
-            var auth = context.HttpContext.RequestServices.GetRequiredService<TokenAuthService>();
-            if (auth.CurrentSystem == null)
-            {
-                context.Result = new UnauthorizedObjectResult("Invalid or missing token in Authorization header.");
-                return;
-            }
-
-            await base.OnActionExecutionAsync(context, next);
-        }
-    }
-}

PluralKit.Bot/Commands/Member.cs

@@ -33,12 +33,12 @@ namespace PluralKit.Bot
             }
 
             // Enforce per-system member limit
-            var memberCount = await _data.GetSystemMemberCount(ctx.System, true);
+            var memberCount = await _data.GetSystemMemberCount(ctx.System.Id, true);
             if (memberCount >= Limits.MaxMemberCount)
                 throw Errors.MemberLimitReachedError;
 
             // Create the member
-            var member = await _data.CreateMember(ctx.System, memberName);
+            var member = await _data.CreateMember(ctx.System.Id, memberName);
             memberCount++;
             
             // Send confirmation and space hint

PluralKit.Bot/Commands/Switch.cs

@@ -56,7 +56,7 @@ namespace PluralKit.Bot
             if (members.Select(m => m.Id).Distinct().Count() != members.Count) throw Errors.DuplicateSwitchMembers;
 
             // Find the last switch and its members if applicable
-            var lastSwitch = await _data.GetLatestSwitch(ctx.System);
+            var lastSwitch = await _data.GetLatestSwitch(ctx.System.Id);
             if (lastSwitch != null)
             {
                 var lastSwitchMembers = _data.GetSwitchMembers(lastSwitch);
@@ -65,7 +65,7 @@ namespace PluralKit.Bot
                     throw Errors.SameSwitch(members);
             }
 
-            await _data.AddSwitch(ctx.System, members);
+            await _data.AddSwitch(ctx.System.Id, members);
 
             if (members.Count == 0)
                 await ctx.Reply($"{Emojis.Success} Switch-out registered.");
@@ -87,7 +87,7 @@ namespace PluralKit.Bot
             if (time.ToInstant() > SystemClock.Instance.GetCurrentInstant()) throw Errors.SwitchTimeInFuture;
 
             // Fetch the last two switches for the system to do bounds checking on
-            var lastTwoSwitches = await _data.GetSwitches(ctx.System).Take(2).ToListAsync();
+            var lastTwoSwitches = await _data.GetSwitches(ctx.System.Id).Take(2).ToListAsync();
             
             // If we don't have a switch to move, don't bother
             if (lastTwoSwitches.Count == 0) throw Errors.NoRegisteredSwitches;
@@ -133,7 +133,7 @@ namespace PluralKit.Bot
             }
             
             // Fetch the last two switches for the system to do bounds checking on
-            var lastTwoSwitches = await _data.GetSwitches(ctx.System).Take(2).ToListAsync();
+            var lastTwoSwitches = await _data.GetSwitches(ctx.System.Id).Take(2).ToListAsync();
             if (lastTwoSwitches.Count == 0) throw Errors.NoRegisteredSwitches;
 
             var lastSwitchMembers = _data.GetSwitchMembers(lastTwoSwitches[0]);

PluralKit.Bot/Commands/SystemFront.cs

@@ -36,7 +36,7 @@ namespace PluralKit.Bot
             if (system == null) throw Errors.NoSystemError;
             ctx.CheckSystemPrivacy(system, system.FrontPrivacy);
             
-            var sw = await _data.GetLatestSwitch(system);
+            var sw = await _data.GetLatestSwitch(system.Id);
             if (sw == null) throw Errors.NoRegisteredSwitches;
             
             await ctx.Reply(embed: await _embeds.CreateFronterEmbed(sw, system.Zone));
@@ -47,7 +47,7 @@ namespace PluralKit.Bot
             if (system == null) throw Errors.NoSystemError;
             ctx.CheckSystemPrivacy(system, system.FrontHistoryPrivacy);
 
-            var sws = _data.GetSwitches(system)
+            var sws = _data.GetSwitches(system.Id)
                 .Scan(new FrontHistoryEntry(null, null), (lastEntry, newSwitch) => new FrontHistoryEntry(lastEntry.ThisSwitch?.Timestamp, newSwitch));
             var totalSwitches = await _data.GetSwitchCount(system);
             if (totalSwitches == 0) throw Errors.NoRegisteredSwitches;

PluralKit.Bot/Services/EmbedService.cs

@@ -32,14 +32,14 @@ namespace PluralKit.Bot {
             // Fetch/render info for all accounts simultaneously
             var users = await Task.WhenAll(accounts.Select(async uid => (await client.GetUserAsync(uid))?.NameAndMention() ?? $"(deleted account {uid})"));
 
-            var memberCount = await _data.GetSystemMemberCount(system, false);
+            var memberCount = await _data.GetSystemMemberCount(system.Id, false);
             var eb = new DiscordEmbedBuilder()
                 .WithColor(DiscordUtils.Gray)
                 .WithTitle(system.Name ?? null)
                 .WithThumbnailUrl(system.AvatarUrl)
                 .WithFooter($"System ID: {system.Hid} | Created on {DateTimeFormats.ZonedDateTimeFormat.Format(system.Created.InZone(system.Zone))}");
  
-            var latestSwitch = await _data.GetLatestSwitch(system);
+            var latestSwitch = await _data.GetLatestSwitch(system.Id);
             if (latestSwitch != null && system.FrontPrivacy.CanAccess(ctx))
             {
                 var switchMembers = await _data.GetSwitchMembers(latestSwitch).ToListAsync();

PluralKit.Core/Services/DataFileService.cs

@@ -132,7 +132,7 @@ namespace PluralKit.Core
             {
                 // Tally up the members that didn't exist before, and check member count on import
                 // If creating the unmatched members would put us over the member limit, abort before creating any members
-                var memberCountBefore = await _data.GetSystemMemberCount(system, true);
+                var memberCountBefore = await _data.GetSystemMemberCount(system.Id, true);
                 var membersToAdd = data.Members.Count(m => imp.IsNewMember(m.Id, m.Name));
                 if (memberCountBefore + membersToAdd > Limits.MaxMemberCount)
                 {

PluralKit.Core/Services/IDataStore.cs

@@ -79,7 +79,7 @@ namespace PluralKit.Core {
         /// Gets the member count of a system.
         /// </summary>
         /// <param name="includePrivate">Whether the returned count should include private members.</param>
-        Task<int> GetSystemMemberCount(PKSystem system, bool includePrivate);
+        Task<int> GetSystemMemberCount(SystemId system, bool includePrivate);
 
         /// <summary>
         /// Gets a list of members with proxy tags that conflict with the given tags.
@@ -162,7 +162,7 @@ namespace PluralKit.Core {
         /// <param name="system">The system in which to create the member.</param>
         /// <param name="name">The name of the member to create.</param>
         /// <returns>The created system model.</returns>
-        Task<PKMember> CreateMember(PKSystem system, string name);
+        Task<PKMember> CreateMember(SystemId system, string name);
         
         /// <summary>
         /// Saves the information within the given <see cref="PKMember"/> struct to the data store.
@@ -213,7 +213,7 @@ namespace PluralKit.Core {
         /// Gets switches from a system.
         /// </summary>
         /// <returns>An enumerable of the *count* latest switches in the system, in latest-first order. May contain fewer elements than requested.</returns>
-        IAsyncEnumerable<PKSwitch> GetSwitches(PKSystem system);
+        IAsyncEnumerable<PKSwitch> GetSwitches(SystemId system);
 
         /// <summary>
         /// Gets the total amount of switches in a given system.
@@ -223,7 +223,7 @@ namespace PluralKit.Core {
         /// <summary>
         /// Gets the latest (temporally; closest to now) switch of a given system.
         /// </summary>
-        Task<PKSwitch> GetLatestSwitch(PKSystem system);
+        Task<PKSwitch> GetLatestSwitch(SystemId system);
 
         /// <summary>
         /// Gets the members a given switch consists of.
@@ -261,7 +261,7 @@ namespace PluralKit.Core {
         /// Registers a switch with the given members in the given system.
         /// </summary>
         /// <exception>Throws an exception (TODO: which?) if any of the members are not in the given system.</exception>
-        Task AddSwitch(PKSystem system, IEnumerable<PKMember> switchMembers);
+        Task AddSwitch(SystemId system, IEnumerable<PKMember> switchMembers);
 
         /// <summary>
         /// Updates the timestamp of a given switch. 

PluralKit.Core/Services/PostgresDataStore.cs

@@ -113,11 +113,11 @@ namespace PluralKit.Core {
                 await conn.ExecuteAsync("delete from switches where system = @Id", system);
         }
 
-        public async Task<PKMember> CreateMember(PKSystem system, string name) {
+        public async Task<PKMember> CreateMember(SystemId system, string name) {
             PKMember member;
             using (var conn = await _conn.Obtain())
                 member = await conn.QuerySingleAsync<PKMember>("insert into members (hid, system, name) values (find_free_member_hid(), @SystemId, @Name) returning *", new {
-                    SystemID = system.Id,
+                    SystemID = system,
                     Name = name
                 });
 
@@ -162,13 +162,13 @@ namespace PluralKit.Core {
             _logger.Information("Deleted member {@Member}", member);
         }
 
-        public async Task<int> GetSystemMemberCount(PKSystem system, bool includePrivate)
+        public async Task<int> GetSystemMemberCount(SystemId id, bool includePrivate)
         {
-            var query = "select count(*) from members where system = @Id";
+            var query = "select count(*) from members where system = @id";
             if (!includePrivate) query += " and member_privacy = 1"; // 1 = public
             
             using (var conn = await _conn.Obtain())
-                return await conn.ExecuteScalarAsync<int>(query, system);
+                return await conn.ExecuteScalarAsync<int>(query, new { id });
         }
 
         public async Task<ulong> GetTotalMembers()
@@ -220,7 +220,7 @@ namespace PluralKit.Core {
             }
         }
 
-        public async Task AddSwitch(PKSystem system, IEnumerable<PKMember> members)
+        public async Task AddSwitch(SystemId system, IEnumerable<PKMember> members)
         {
             // Use a transaction here since we're doing multiple executed commands in one
             await using var conn = await _conn.Obtain();
@@ -228,7 +228,7 @@ namespace PluralKit.Core {
             
             // First, we insert the switch itself
             var sw = await conn.QuerySingleAsync<PKSwitch>("insert into switches(system) values (@System) returning *",
-                new {System = system.Id});
+                new {System = system});
 
             // Then we insert each member in the switch in the switch_members table
             // TODO: can we parallelize this or send it in bulk somehow?
@@ -242,16 +242,16 @@ namespace PluralKit.Core {
             // Finally we commit the tx, since the using block will otherwise rollback it
             await tx.CommitAsync();
 
-            _logger.Information("Registered switch {Switch} in system {System} with members {@Members}", sw.Id, system.Id, members.Select(m => m.Id));
+            _logger.Information("Registered switch {Switch} in system {System} with members {@Members}", sw.Id, system, members.Select(m => m.Id));
         }
 
-        public IAsyncEnumerable<PKSwitch> GetSwitches(PKSystem system)
+        public IAsyncEnumerable<PKSwitch> GetSwitches(SystemId system)
         {
             // TODO: refactor the PKSwitch data structure to somehow include a hydrated member list
             // (maybe when we get caching in?)
             return _conn.QueryStreamAsync<PKSwitch>(
                 "select * from switches where system = @System order by timestamp desc",
-                new {System = system.Id});
+                new {System = system});
         }
 
         public async Task<int> GetSwitchCount(PKSystem system)
@@ -304,7 +304,7 @@ namespace PluralKit.Core {
                 new {Switch = sw.Id});
         }
 
-        public async Task<PKSwitch> GetLatestSwitch(PKSystem system) => 
+        public async Task<PKSwitch> GetLatestSwitch(SystemId system) => 
             await GetSwitches(system).FirstOrDefaultAsync();
 
         public async Task MoveSwitch(PKSwitch sw, Instant time)