From fd49e7e4ea10256e7d159efc999f6b11a5e5d9a6 Mon Sep 17 00:00:00 2001
From: spiral <spiral@spiral.sh>
Date: Wed, 13 Oct 2021 09:08:17 -0400
Subject: [PATCH] refactor(apiv2): rename APIErrors to Errors, move IsUserError
 to helper method

---
 PluralKit.API/Controllers/PKControllerBase.cs |  2 +-
 .../Controllers/v2/GroupControllerV2.cs       | 10 +--
 .../Controllers/v2/GroupMemberControllerV2.cs | 62 +++++++++----------
 .../Controllers/v2/GuildControllerV2.cs       | 22 +++----
 .../Controllers/v2/MemberControllerV2.cs      | 10 +--
 .../Controllers/v2/MiscControllerV2.cs        |  2 +-
 .../Controllers/v2/SwitchControllerV2.cs      | 50 +++++++--------
 PluralKit.API/Errors.cs                       | 19 +++++-
 PluralKit.API/Startup.cs                      |  5 +-
 9 files changed, 98 insertions(+), 84 deletions(-)

diff --git a/PluralKit.API/Controllers/PKControllerBase.cs b/PluralKit.API/Controllers/PKControllerBase.cs
index 50172df7..0e97e0a9 100644
--- a/PluralKit.API/Controllers/PKControllerBase.cs
+++ b/PluralKit.API/Controllers/PKControllerBase.cs
@@ -36,7 +36,7 @@ namespace PluralKit.API
             {
                 HttpContext.Items.TryGetValue("SystemId", out var systemId);
                 if (systemId == null)
-                    throw APIErrors.GenericAuthError;
+                    throw Errors.GenericAuthError;
                 return _repo.GetSystem((SystemId)systemId);
             }
 
diff --git a/PluralKit.API/Controllers/v2/GroupControllerV2.cs b/PluralKit.API/Controllers/v2/GroupControllerV2.cs
index d29a31f9..3604ceaa 100644
--- a/PluralKit.API/Controllers/v2/GroupControllerV2.cs
+++ b/PluralKit.API/Controllers/v2/GroupControllerV2.cs
@@ -22,12 +22,12 @@ namespace PluralKit.API
         {
             var system = await ResolveSystem(systemRef);
             if (system == null)
-                throw APIErrors.SystemNotFound;
+                throw Errors.SystemNotFound;
 
             var ctx = this.ContextFor(system);
 
             if (!system.GroupListPrivacy.CanAccess(User.ContextFor(system)))
-                throw APIErrors.UnauthorizedGroupList;
+                throw Errors.UnauthorizedGroupList;
 
             var groups = _repo.GetSystemGroups(system.Id);
             return Ok(await groups
@@ -50,7 +50,7 @@ namespace PluralKit.API
         {
             var group = await ResolveGroup(groupRef);
             if (group == null)
-                throw APIErrors.GroupNotFound;
+                throw Errors.GroupNotFound;
 
             var system = await _repo.GetSystem(group.System);
 
@@ -71,11 +71,11 @@ namespace PluralKit.API
         {
             var group = await ResolveGroup(groupRef);
             if (group == null)
-                throw APIErrors.GroupNotFound;
+                throw Errors.GroupNotFound;
 
             var system = await ResolveSystem("@me");
             if (system.Id != group.System)
-                throw APIErrors.NotOwnGroupError;
+                throw Errors.NotOwnGroupError;
 
             await _repo.DeleteGroup(group.Id);
 
diff --git a/PluralKit.API/Controllers/v2/GroupMemberControllerV2.cs b/PluralKit.API/Controllers/v2/GroupMemberControllerV2.cs
index 48cf7787..dd3da730 100644
--- a/PluralKit.API/Controllers/v2/GroupMemberControllerV2.cs
+++ b/PluralKit.API/Controllers/v2/GroupMemberControllerV2.cs
@@ -25,12 +25,12 @@ namespace PluralKit.API
         {
             var group = await ResolveGroup(groupRef);
             if (group == null)
-                throw APIErrors.GroupNotFound;
+                throw Errors.GroupNotFound;
 
             var ctx = this.ContextFor(group);
 
             if (!group.ListPrivacy.CanAccess(ctx))
-                throw APIErrors.UnauthorizedGroupMemberList;
+                throw Errors.UnauthorizedGroupMemberList;
 
             var members = _repo.GetGroupMembers(group.Id).Where(m => m.MemberVisibility.CanAccess(ctx));
 
@@ -50,7 +50,7 @@ namespace PluralKit.API
 
             var system = await _repo.GetSystem(member.System);
             if (!system.GroupListPrivacy.CanAccess(ctx))
-                throw APIErrors.UnauthorizedGroupList;
+                throw Errors.UnauthorizedGroupList;
 
             var groups = _repo.GetMemberGroups(member.Id).Where(g => g.Visibility.CanAccess(ctx));
 
@@ -69,16 +69,16 @@ namespace PluralKit.API
 
             var group = await ResolveGroup(groupRef);
             if (group == null)
-                throw APIErrors.GroupNotFound;
+                throw Errors.GroupNotFound;
             if (group.System != system.Id)
-                throw APIErrors.NotOwnGroupError;
+                throw Errors.NotOwnGroupError;
 
             var member = await ResolveMember(memberRef);
             Console.WriteLine(member);
             if (member == null)
-                throw APIErrors.MemberNotFound;
+                throw Errors.MemberNotFound;
             if (member.System != system.Id)
-                throw APIErrors.NotOwnMemberError;
+                throw Errors.NotOwnMemberError;
 
             var existingMembers = await _repo.GetGroupMembers(group.Id).Select(x => x.Id).ToListAsync();
             if (!existingMembers.Contains(member.Id))
@@ -91,15 +91,15 @@ namespace PluralKit.API
         public async Task<IActionResult> GroupMembersPut(string groupRef, [FromBody] JArray memberRefs)
         {
             if (memberRefs.Count == 0)
-                throw APIErrors.GenericBadRequest;
+                throw Errors.GenericBadRequest;
 
             var system = await ResolveSystem("@me");
 
             var group = await ResolveGroup(groupRef);
             if (group == null)
-                throw APIErrors.GroupNotFound;
+                throw Errors.GroupNotFound;
             if (group.System != system.Id)
-                throw APIErrors.NotOwnGroupError;
+                throw Errors.NotOwnGroupError;
 
             var members = new List<MemberId>();
 
@@ -109,9 +109,9 @@ namespace PluralKit.API
                 var member = await ResolveMember(memberRef);
 
                 if (member == null)
-                    throw APIErrors.MemberNotFound;
+                    throw Errors.MemberNotFound;
                 if (member.System != system.Id)
-                    throw APIErrors.NotOwnMemberErrorWithRef(memberRef);
+                    throw Errors.NotOwnMemberErrorWithRef(memberRef);
 
                 members.Add(member.Id);
             }
@@ -132,15 +132,15 @@ namespace PluralKit.API
 
             var group = await ResolveGroup(groupRef);
             if (group == null)
-                throw APIErrors.GroupNotFound;
+                throw Errors.GroupNotFound;
             if (group.System != system.Id)
-                throw APIErrors.NotOwnGroupError;
+                throw Errors.NotOwnGroupError;
 
             var member = await ResolveMember(memberRef);
             if (member == null)
-                throw APIErrors.MemberNotFound;
+                throw Errors.MemberNotFound;
             if (member.System != system.Id)
-                throw APIErrors.NotOwnMemberError;
+                throw Errors.NotOwnMemberError;
 
             await _repo.RemoveMembersFromGroup(group.Id, new List<MemberId>() { member.Id });
 
@@ -151,15 +151,15 @@ namespace PluralKit.API
         public async Task<IActionResult> GroupMembersDelete(string groupRef, [FromBody] JArray memberRefs)
         {
             if (memberRefs.Count == 0)
-                throw APIErrors.GenericBadRequest;
+                throw Errors.GenericBadRequest;
 
             var system = await ResolveSystem("@me");
 
             var group = await ResolveGroup(groupRef);
             if (group == null)
-                throw APIErrors.GroupNotFound;
+                throw Errors.GroupNotFound;
             if (group.System != system.Id)
-                throw APIErrors.NotOwnGroupError;
+                throw Errors.NotOwnGroupError;
 
             var members = new List<MemberId>();
 
@@ -169,9 +169,9 @@ namespace PluralKit.API
                 var member = await ResolveMember(memberRef);
 
                 if (member == null)
-                    throw APIErrors.MemberNotFound;
+                    throw Errors.MemberNotFound;
                 if (member.System != system.Id)
-                    throw APIErrors.NotOwnMemberError;
+                    throw Errors.NotOwnMemberError;
 
                 members.Add(member.Id);
             }
@@ -185,15 +185,15 @@ namespace PluralKit.API
         public async Task<IActionResult> MemberGroupsPut(string memberRef, [FromBody] JArray groupRefs)
         {
             if (groupRefs.Count == 0)
-                throw APIErrors.GenericBadRequest;
+                throw Errors.GenericBadRequest;
 
             var system = await ResolveSystem("@me");
 
             var member = await ResolveMember(memberRef);
             if (member == null)
-                throw APIErrors.MemberNotFound;
+                throw Errors.MemberNotFound;
             if (member.System != system.Id)
-                throw APIErrors.NotOwnMemberError;
+                throw Errors.NotOwnMemberError;
 
             var groups = new List<GroupId>();
 
@@ -203,9 +203,9 @@ namespace PluralKit.API
                 var group = await ResolveGroup(groupRef);
 
                 if (group == null)
-                    throw APIErrors.GroupNotFound;
+                    throw Errors.GroupNotFound;
                 if (group.System != system.Id)
-                    throw APIErrors.NotOwnGroupErrorWithRef(groupRef);
+                    throw Errors.NotOwnGroupErrorWithRef(groupRef);
 
                 groups.Add(group.Id);
             }
@@ -223,15 +223,15 @@ namespace PluralKit.API
         public async Task<IActionResult> MemberGroupsDelete(string memberRef, [FromBody] JArray groupRefs)
         {
             if (groupRefs.Count == 0)
-                throw APIErrors.GenericBadRequest;
+                throw Errors.GenericBadRequest;
 
             var system = await ResolveSystem("@me");
 
             var member = await ResolveMember(memberRef);
             if (member == null)
-                throw APIErrors.MemberNotFound;
+                throw Errors.MemberNotFound;
             if (member.System != system.Id)
-                throw APIErrors.NotOwnMemberError;
+                throw Errors.NotOwnMemberError;
 
             var groups = new List<GroupId>();
 
@@ -241,9 +241,9 @@ namespace PluralKit.API
                 var group = await ResolveGroup(groupRef);
 
                 if (group == null)
-                    throw APIErrors.GroupNotFound;
+                    throw Errors.GroupNotFound;
                 if (group.System != system.Id)
-                    throw APIErrors.NotOwnGroupErrorWithRef(groupRef);
+                    throw Errors.NotOwnGroupErrorWithRef(groupRef);
 
                 groups.Add(group.Id);
             }
diff --git a/PluralKit.API/Controllers/v2/GuildControllerV2.cs b/PluralKit.API/Controllers/v2/GuildControllerV2.cs
index 6c098eff..2f5ffc47 100644
--- a/PluralKit.API/Controllers/v2/GuildControllerV2.cs
+++ b/PluralKit.API/Controllers/v2/GuildControllerV2.cs
@@ -23,7 +23,7 @@ namespace PluralKit.API
             var system = await ResolveSystem("@me");
             var settings = await _repo.GetSystemGuild(guild_id, system.Id, defaultInsert: false);
             if (settings == null)
-                throw APIErrors.SystemGuildNotFound;
+                throw Errors.SystemGuildNotFound;
 
             PKMember member = null;
             if (settings.AutoproxyMember != null)
@@ -38,7 +38,7 @@ namespace PluralKit.API
             var system = await ResolveSystem("@me");
             var settings = await _repo.GetSystemGuild(guild_id, system.Id, defaultInsert: false);
             if (settings == null)
-                throw APIErrors.SystemGuildNotFound;
+                throw Errors.SystemGuildNotFound;
 
             MemberId? memberId = null;
             if (data.ContainsKey("autoproxy_member"))
@@ -47,7 +47,7 @@ namespace PluralKit.API
                 {
                     var member = await ResolveMember(data.Value<string>("autoproxy_member"));
                     if (member == null)
-                        throw APIErrors.MemberNotFound;
+                        throw Errors.MemberNotFound;
 
                     memberId = member.Id;
                 }
@@ -66,10 +66,10 @@ namespace PluralKit.API
                 if (patch.AutoproxyMode.IsPresent)
                 {
                     if (patch.AutoproxyMode.Value == AutoproxyMode.Member)
-                        throw APIErrors.MissingAutoproxyMember;
+                        throw Errors.MissingAutoproxyMember;
                 }
                 else if (settings.AutoproxyMode == AutoproxyMode.Member)
-                    throw APIErrors.MissingAutoproxyMember;
+                    throw Errors.MissingAutoproxyMember;
 
             var newSettings = await _repo.UpdateSystemGuild(system.Id, guild_id, patch);
 
@@ -85,13 +85,13 @@ namespace PluralKit.API
             var system = await ResolveSystem("@me");
             var member = await ResolveMember(memberRef);
             if (member == null)
-                throw APIErrors.MemberNotFound;
+                throw Errors.MemberNotFound;
             if (member.System != system.Id)
-                throw APIErrors.NotOwnMemberError;
+                throw Errors.NotOwnMemberError;
 
             var settings = await _repo.GetMemberGuild(guild_id, member.Id, defaultInsert: false);
             if (settings == null)
-                throw APIErrors.MemberGuildNotFound;
+                throw Errors.MemberGuildNotFound;
 
             return Ok(settings.ToJson());
         }
@@ -102,13 +102,13 @@ namespace PluralKit.API
             var system = await ResolveSystem("@me");
             var member = await ResolveMember(memberRef);
             if (member == null)
-                throw APIErrors.MemberNotFound;
+                throw Errors.MemberNotFound;
             if (member.System != system.Id)
-                throw APIErrors.NotOwnMemberError;
+                throw Errors.NotOwnMemberError;
 
             var settings = await _repo.GetMemberGuild(guild_id, member.Id, defaultInsert: false);
             if (settings == null)
-                throw APIErrors.MemberGuildNotFound;
+                throw Errors.MemberGuildNotFound;
 
             var patch = MemberGuildPatch.FromJson(data);
 
diff --git a/PluralKit.API/Controllers/v2/MemberControllerV2.cs b/PluralKit.API/Controllers/v2/MemberControllerV2.cs
index 38b958d4..2b72618c 100644
--- a/PluralKit.API/Controllers/v2/MemberControllerV2.cs
+++ b/PluralKit.API/Controllers/v2/MemberControllerV2.cs
@@ -23,12 +23,12 @@ namespace PluralKit.API
         {
             var system = await ResolveSystem(systemRef);
             if (system == null)
-                throw APIErrors.SystemNotFound;
+                throw Errors.SystemNotFound;
 
             var ctx = this.ContextFor(system);
 
             if (!system.MemberListPrivacy.CanAccess(this.ContextFor(system)))
-                throw APIErrors.UnauthorizedMemberList;
+                throw Errors.UnauthorizedMemberList;
 
             var members = _repo.GetSystemMembers(system.Id);
             return Ok(await members
@@ -51,7 +51,7 @@ namespace PluralKit.API
         {
             var member = await ResolveMember(memberRef);
             if (member == null)
-                throw APIErrors.MemberNotFound;
+                throw Errors.MemberNotFound;
 
             var system = await _repo.GetSystem(member.System);
 
@@ -72,11 +72,11 @@ namespace PluralKit.API
         {
             var member = await ResolveMember(memberRef);
             if (member == null)
-                throw APIErrors.MemberNotFound;
+                throw Errors.MemberNotFound;
 
             var system = await ResolveSystem("@me");
             if (system.Id != member.System)
-                throw APIErrors.NotOwnMemberError;
+                throw Errors.NotOwnMemberError;
 
             await _repo.DeleteMember(member.Id);
 
diff --git a/PluralKit.API/Controllers/v2/MiscControllerV2.cs b/PluralKit.API/Controllers/v2/MiscControllerV2.cs
index 1e015b37..3fdff9a7 100644
--- a/PluralKit.API/Controllers/v2/MiscControllerV2.cs
+++ b/PluralKit.API/Controllers/v2/MiscControllerV2.cs
@@ -35,7 +35,7 @@ namespace PluralKit.API
         {
             var msg = await _db.Execute(c => _repo.GetMessage(c, messageId));
             if (msg == null)
-                throw APIErrors.MessageNotFound;
+                throw Errors.MessageNotFound;
 
             var ctx = this.ContextFor(msg.System);
 
diff --git a/PluralKit.API/Controllers/v2/SwitchControllerV2.cs b/PluralKit.API/Controllers/v2/SwitchControllerV2.cs
index fe79760e..14f908fe 100644
--- a/PluralKit.API/Controllers/v2/SwitchControllerV2.cs
+++ b/PluralKit.API/Controllers/v2/SwitchControllerV2.cs
@@ -29,12 +29,12 @@ namespace PluralKit.API
         {
             var system = await ResolveSystem(systemRef);
             if (system == null)
-                throw APIErrors.SystemNotFound;
+                throw Errors.SystemNotFound;
 
             var ctx = this.ContextFor(system);
 
             if (!system.FrontHistoryPrivacy.CanAccess(ctx))
-                throw APIErrors.UnauthorizedFrontHistory;
+                throw Errors.UnauthorizedFrontHistory;
 
             if (before == null)
                 before = SystemClock.Instance.GetCurrentInstant();
@@ -58,12 +58,12 @@ namespace PluralKit.API
         {
             var system = await ResolveSystem(systemRef);
             if (system == null)
-                throw APIErrors.SystemNotFound;
+                throw Errors.SystemNotFound;
 
             var ctx = this.ContextFor(system);
 
             if (!system.FrontPrivacy.CanAccess(ctx))
-                throw APIErrors.UnauthorizedCurrentFronters;
+                throw Errors.UnauthorizedCurrentFronters;
 
             var sw = await _repo.GetLatestSwitch(system.Id);
             if (sw == null)
@@ -83,12 +83,12 @@ namespace PluralKit.API
         public async Task<IActionResult> SwitchCreate([FromBody] PostSwitchParams data)
         {
             if (data.Members.Distinct().Count() != data.Members.Count)
-                throw APIErrors.DuplicateMembersInList;
+                throw Errors.DuplicateMembersInList;
 
             var system = await ResolveSystem("@me");
 
             if (data.Timestamp != null && await _repo.GetSwitches(system.Id).Select(x => x.Timestamp).ContainsAsync(data.Timestamp.Value))
-                throw APIErrors.SameSwitchTimestampError;
+                throw Errors.SameSwitchTimestampError;
 
             var members = new List<PKMember>();
 
@@ -97,9 +97,9 @@ namespace PluralKit.API
                 var member = await ResolveMember(memberRef);
                 if (member == null)
                     // todo: which member
-                    throw APIErrors.MemberNotFound;
+                    throw Errors.MemberNotFound;
                 if (member.System != system.Id)
-                    throw APIErrors.NotOwnMemberErrorWithRef(memberRef);
+                    throw Errors.NotOwnMemberErrorWithRef(memberRef);
                 members.Add(member);
             }
 
@@ -111,7 +111,7 @@ namespace PluralKit.API
 
                 // Bail if this switch is identical to the latest one
                 if (await latestSwitchMembers.Select(m => m.Hid).SequenceEqualAsync(members.Select(m => m.Hid).ToAsyncEnumerable()))
-                    throw APIErrors.SameSwitchMembersError;
+                    throw Errors.SameSwitchMembersError;
             }
 
             var newSwitch = await _db.Execute(conn => _repo.AddSwitch(conn, system.Id, members.Select(m => m.Id).ToList()));
@@ -131,20 +131,20 @@ namespace PluralKit.API
         public async Task<IActionResult> SwitchGet(string systemRef, string switchRef)
         {
             if (!Guid.TryParse(switchRef, out var switchId))
-                throw APIErrors.InvalidSwitchId;
+                throw Errors.InvalidSwitchId;
 
             var system = await ResolveSystem(systemRef);
             if (system == null)
-                throw APIErrors.SystemNotFound;
+                throw Errors.SystemNotFound;
 
             var sw = await _repo.GetSwitchByUuid(switchId);
             if (sw == null || system.Id != sw.System)
-                throw APIErrors.SwitchNotFoundPublic;
+                throw Errors.SwitchNotFoundPublic;
 
             var ctx = this.ContextFor(system);
 
             if (!system.FrontHistoryPrivacy.CanAccess(ctx))
-                throw APIErrors.SwitchNotFoundPublic;
+                throw Errors.SwitchNotFoundPublic;
 
             var members = _db.Execute(conn => _repo.GetSwitchMembers(conn, sw.Id));
             return Ok(new FrontersReturnNew
@@ -161,25 +161,25 @@ namespace PluralKit.API
             // for now, don't need to make a PatchObject for this, since it's only one param
 
             if (!Guid.TryParse(switchRef, out var switchId))
-                throw APIErrors.InvalidSwitchId;
+                throw Errors.InvalidSwitchId;
 
             var valueStr = data.Value<string>("timestamp").NullIfEmpty();
             if (valueStr == null)
                 // todo
-                throw APIErrors.GenericBadRequest;
+                throw Errors.GenericBadRequest;
 
             var value = Instant.FromDateTimeOffset(DateTime.Parse(valueStr).ToUniversalTime());
 
             var system = await ResolveSystem("@me");
             if (system == null)
-                throw APIErrors.SystemNotFound;
+                throw Errors.SystemNotFound;
 
             var sw = await _repo.GetSwitchByUuid(switchId);
             if (sw == null || system.Id != sw.System)
-                throw APIErrors.SwitchNotFoundPublic;
+                throw Errors.SwitchNotFoundPublic;
 
             if (await _repo.GetSwitches(system.Id).Select(x => x.Timestamp).ContainsAsync(value))
-                throw APIErrors.SameSwitchTimestampError;
+                throw Errors.SameSwitchTimestampError;
 
             await _repo.MoveSwitch(sw.Id, value);
 
@@ -198,13 +198,13 @@ namespace PluralKit.API
             if (!Guid.TryParse(switchRef, out var switchId))
 
                 if (data.Distinct().Count() != data.Count)
-                    throw APIErrors.DuplicateMembersInList;
+                    throw Errors.DuplicateMembersInList;
 
             var system = await ResolveSystem("@me");
 
             var sw = await _repo.GetSwitchByUuid(switchId);
             if (sw == null)
-                throw APIErrors.SwitchNotFound;
+                throw Errors.SwitchNotFound;
 
             var members = new List<PKMember>();
 
@@ -215,9 +215,9 @@ namespace PluralKit.API
                 var member = await ResolveMember(memberRef);
                 if (member == null)
                     // todo: which member
-                    throw APIErrors.MemberNotFound;
+                    throw Errors.MemberNotFound;
                 if (member.System != system.Id)
-                    throw APIErrors.NotOwnMemberErrorWithRef(memberRef);
+                    throw Errors.NotOwnMemberErrorWithRef(memberRef);
 
                 members.Add(member);
             }
@@ -225,7 +225,7 @@ namespace PluralKit.API
             var latestSwitchMembers = _db.Execute(conn => _repo.GetSwitchMembers(conn, sw.Id));
 
             if (await latestSwitchMembers.Select(m => m.Hid).SequenceEqualAsync(members.Select(m => m.Hid).ToAsyncEnumerable()))
-                throw APIErrors.SameSwitchMembersError;
+                throw Errors.SameSwitchMembersError;
 
             await _db.Execute(conn => _repo.EditSwitch(conn, sw.Id, members.Select(x => x.Id).ToList()));
             return Ok(new FrontersReturnNew
@@ -240,12 +240,12 @@ namespace PluralKit.API
         public async Task<IActionResult> SwitchDelete(string switchRef)
         {
             if (!Guid.TryParse(switchRef, out var switchId))
-                throw APIErrors.InvalidSwitchId;
+                throw Errors.InvalidSwitchId;
 
             var system = await ResolveSystem("@me");
             var sw = await _repo.GetSwitchByUuid(switchId);
             if (sw == null || system.Id != sw.System)
-                throw APIErrors.SwitchNotFoundPublic;
+                throw Errors.SwitchNotFoundPublic;
 
             await _repo.DeleteSwitch(sw.Id);
 
diff --git a/PluralKit.API/Errors.cs b/PluralKit.API/Errors.cs
index a2cfe8bb..d1045a00 100644
--- a/PluralKit.API/Errors.cs
+++ b/PluralKit.API/Errors.cs
@@ -75,7 +75,7 @@ namespace PluralKit.API
         }
     }
 
-    public static class APIErrors
+    public static class Errors
     {
         public static PKError GenericBadRequest = new(400, 0, "400: Bad Request");
         public static PKError GenericAuthError = new(401, 0, "401: Missing or invalid Authorization header");
@@ -104,4 +104,21 @@ namespace PluralKit.API
         public static PKError InvalidSwitchId = new(400, 40006, "Invalid switch ID.");
         public static PKError Unimplemented = new(501, 50001, "Unimplemented");
     }
+
+    public static class APIErrorHandlerExt
+    {
+        public static bool IsUserError(this Exception exc)
+        {
+            // caused by users sending an incorrect JSON type (array where an object is expected, etc)
+            if (exc is InvalidCastException && exc.Message.Contains("Newtonsoft.Json"))
+                return true;
+
+            // Hacky parsing of timestamps results in hacky error handling. Probably fix this one at some point.
+            if (exc is FormatException && exc.Message.Contains("was not recognized as a valid DateTime"))
+                return true;
+
+            // This may expanded at some point.
+            return false;
+        }
+    }
 }
\ No newline at end of file
diff --git a/PluralKit.API/Startup.cs b/PluralKit.API/Startup.cs
index c21b5a64..df292497 100644
--- a/PluralKit.API/Startup.cs
+++ b/PluralKit.API/Startup.cs
@@ -140,10 +140,7 @@ namespace PluralKit.API
                 var exc = ctx.Features.Get<IExceptionHandlerPathFeature>();
 
                 // handle common ISEs that are generated by invalid user input
-                if (
-                       (exc.Error is InvalidCastException && exc.Error.Message.Contains("Newtonsoft.Json"))
-                    || (exc.Error is FormatException && exc.Error.Message.Contains("was not recognized as a valid DateTime"))
-                )
+                if (exc.Error.IsUserError())
                 {
                     ctx.Response.StatusCode = 400;
                     await ctx.Response.WriteAsync("{\"message\":\"400: Bad Request\",\"code\":0}");