Add system and member privacy support

PluralKit.API/Controllers/AccountController.cs

@@ -11,10 +11,12 @@ namespace PluralKit.API.Controllers
     public class AccountController: ControllerBase
     {
         private IDataStore _data;
+        private TokenAuthService _auth;
 
-        public AccountController(IDataStore data)
+        public AccountController(IDataStore data, TokenAuthService auth)
         {
             _data = data;
+            _auth = auth;
         }
 
         [HttpGet("{aid}")]
@@ -23,7 +25,7 @@ namespace PluralKit.API.Controllers
             var system = await _data.GetSystemByAccount(aid);
             if (system == null) return NotFound("Account not found.");
             
-            return Ok(system.ToJson());
+            return Ok(system.ToJson(_auth.ContextFor(system)));
         }
     }
 }

PluralKit.API/Controllers/MemberController.cs

@@ -28,7 +28,7 @@ namespace PluralKit.API.Controllers
             var member = await _data.GetMemberByHid(hid);
             if (member == null) return NotFound("Member not found.");
 
-            return Ok(member.ToJson());
+            return Ok(member.ToJson(_auth.ContextFor(member)));
         }
 
         [HttpPost]
@@ -41,7 +41,7 @@ namespace PluralKit.API.Controllers
                 return BadRequest("Member name must be specified.");
 
             // Enforce per-system member limit
-            var memberCount = await _data.GetSystemMemberCount(system);
+            var memberCount = await _data.GetSystemMemberCount(system, true);
             if (memberCount >= Limits.MaxMemberCount)
                 return BadRequest($"Member limit reached ({memberCount} / {Limits.MaxMemberCount}).");
 
@@ -56,7 +56,7 @@ namespace PluralKit.API.Controllers
             }
             
             await _data.SaveMember(member);
-            return Ok(member.ToJson());
+            return Ok(member.ToJson(_auth.ContextFor(member)));
         }
 
         [HttpPatch("{hid}")]
@@ -78,7 +78,7 @@ namespace PluralKit.API.Controllers
             }
             
             await _data.SaveMember(member);
-            return Ok(member.ToJson());
+            return Ok(member.ToJson(_auth.ContextFor(member)));
         }
         
         [HttpDelete("{hid}")]

PluralKit.API/Controllers/MessageController.cs

@@ -25,10 +25,12 @@ namespace PluralKit.API.Controllers
     public class MessageController: ControllerBase
     {
         private IDataStore _data;
+        private TokenAuthService _auth;
 
-        public MessageController(IDataStore _data)
+        public MessageController(IDataStore _data, TokenAuthService auth)
         {
             this._data = _data;
+            _auth = auth;
         }
 
         [HttpGet("{mid}")]
@@ -43,8 +45,8 @@ namespace PluralKit.API.Controllers
                 Id = msg.Message.Mid.ToString(),
                 Channel = msg.Message.Channel.ToString(),
                 Sender = msg.Message.Sender.ToString(),
-                Member = msg.Member.ToJson(),
-                System = msg.System.ToJson(),
+                Member = msg.Member.ToJson(_auth.ContextFor(msg.System)),
+                System = msg.System.ToJson(_auth.ContextFor(msg.System)),
                 Original = msg.Message.OriginalMid?.ToString()
             };
         } 

PluralKit.API/Controllers/SystemController.cs

@@ -2,6 +2,8 @@ using System.Collections.Generic;
 using System.Linq;
 using System.Threading.Tasks;
 using Dapper;
+
+using Microsoft.AspNetCore.Http;
 using Microsoft.AspNetCore.Mvc;
 using Newtonsoft.Json;
 using Newtonsoft.Json.Linq;
@@ -48,7 +50,7 @@ namespace PluralKit.API.Controllers
         [RequiresSystem]
         public Task<ActionResult<JObject>> GetOwnSystem()
         {
-            return Task.FromResult<ActionResult<JObject>>(Ok(_auth.CurrentSystem.ToJson()));
+            return Task.FromResult<ActionResult<JObject>>(Ok(_auth.CurrentSystem.ToJson(_auth.ContextFor(_auth.CurrentSystem))));
         }
 
         [HttpGet("{hid}")]
@@ -56,7 +58,7 @@ namespace PluralKit.API.Controllers
         {
             var system = await _data.GetSystemByHid(hid);
             if (system == null) return NotFound("System not found.");
-            return Ok(system.ToJson());
+            return Ok(system.ToJson(_auth.ContextFor(system)));
         }
 
         [HttpGet("{hid}/members")]
@@ -65,8 +67,13 @@ namespace PluralKit.API.Controllers
             var system = await _data.GetSystemByHid(hid);
             if (system == null) return NotFound("System not found.");
 
+            if (!system.MemberListPrivacy.CanAccess(_auth.ContextFor(system)))
+                return StatusCode(StatusCodes.Status403Forbidden, "Unauthorized to view member list.");
+
             var members = await _data.GetSystemMembers(system);
-            return Ok(members.Select(m => m.ToJson()));
+            return Ok(members
+                .Where(m => m.MemberPrivacy.CanAccess(_auth.ContextFor(system)))
+                .Select(m => m.ToJson(_auth.ContextFor(system))));
         }
 
         [HttpGet("{hid}/switches")]
@@ -76,6 +83,9 @@ namespace PluralKit.API.Controllers
             
             var system = await _data.GetSystemByHid(hid);
             if (system == null) return NotFound("System not found.");
+            
+            if (!system.FrontHistoryPrivacy.CanAccess(_auth.ContextFor(system)))
+                return StatusCode(StatusCodes.Status403Forbidden, "Unauthorized to view front history.");
 
             using (var conn = await _conn.Obtain())
             {
@@ -97,6 +107,9 @@ namespace PluralKit.API.Controllers
             var system = await _data.GetSystemByHid(hid);
             if (system == null) return NotFound("System not found.");
             
+            if (!system.FrontPrivacy.CanAccess(_auth.ContextFor(system)))
+                return StatusCode(StatusCodes.Status403Forbidden, "Unauthorized to view fronter.");
+            
             var sw = await _data.GetLatestSwitch(system);
             if (sw == null) return NotFound("System has no registered switches."); 
                 
@@ -104,7 +117,7 @@ namespace PluralKit.API.Controllers
             return Ok(new FrontersReturn
             {
                 Timestamp = sw.Timestamp,
-                Members = members.Select(m => m.ToJson())
+                Members = members.Select(m => m.ToJson(_auth.ContextFor(system)))
             });
         }
 
@@ -124,7 +137,7 @@ namespace PluralKit.API.Controllers
             }
 
             await _data.SaveSystem(system);
-            return Ok(system.ToJson());
+            return Ok(system.ToJson(_auth.ContextFor(system)));
         }
 
         [HttpPost("switches")]

PluralKit.API/Startup.cs

@@ -26,6 +26,7 @@ namespace PluralKit.API
 
             services
                 .AddTransient<IDataStore, PostgresDataStore>()
+                .AddSingleton<SchemaService>()
 
                 .AddSingleton(svc => InitUtils.InitMetrics(svc.GetRequiredService<CoreConfig>(), "API"))
 
@@ -41,6 +42,8 @@ namespace PluralKit.API
         // This method gets called by the runtime. Use this method to configure the HTTP request pipeline.
         public void Configure(IApplicationBuilder app, IWebHostEnvironment env)
         {
+            SchemaService.Initialize();
+
             if (env.IsDevelopment())
             {
                 app.UseDeveloperExceptionPage();

PluralKit.API/TokenAuthService.cs

@@ -26,5 +26,11 @@ namespace PluralKit.API
             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.Bot/Bot.cs

@@ -48,6 +48,8 @@ namespace PluralKit.Bot
             
             using (var services = BuildServiceProvider())
             {
+                SchemaService.Initialize();
+                
                 var logger = services.GetRequiredService<ILogger>().ForContext<Initialize>();
                 var coreConfig = services.GetRequiredService<CoreConfig>();
                 var botConfig = services.GetRequiredService<BotConfig>();

PluralKit.Bot/CommandSystem/Context.cs

@@ -57,13 +57,13 @@ namespace PluralKit.Bot.CommandSystem
         /// <summary>
         /// Checks if the next parameter is equal to one of the given keywords. Case-insensitive.
         /// </summary>
-        public bool Match(params string[] potentialMatches)
+        public bool Match(ref string used, params string[] potentialMatches)
         {
             foreach (var match in potentialMatches)
             {
                 if (PeekArgument().Equals(match, StringComparison.InvariantCultureIgnoreCase))
                 {
-                    PopArgument();
+                    used = PopArgument();
                     return true;
                 }
             }
@@ -71,6 +71,15 @@ namespace PluralKit.Bot.CommandSystem
             return false;
         }
 
+        /// <summary>
+        /// Checks if the next parameter is equal to one of the given keywords. Case-insensitive.
+        /// </summary>
+        public bool Match(params string[] potentialMatches)
+        {
+            string used = null; // Unused and unreturned, we just yeet it
+            return Match(ref used, potentialMatches);
+        }
+        
         public async Task Execute<T>(Command commandDef, Func<T, Task> handler)
         {
             _currentCommand = commandDef;
@@ -237,6 +246,15 @@ namespace PluralKit.Bot.CommandSystem
             throw new PKError("This command can not be run in a DM.");
         }
 
+        public LookupContext LookupContextFor(PKSystem target) => 
+            System?.Id == target.Id ? LookupContext.ByOwner : LookupContext.ByNonOwner;
+
+        public Context CheckSystemPrivacy(PKSystem target, PrivacyLevel level)
+        {
+            if (level.CanAccess(LookupContextFor(target))) return this;
+            throw new PKError("You do not have permission to access this information.");
+        }
+
         public ITextChannel MatchChannel()
         {
             if (!MentionUtils.TryParseChannel(PeekArgument(), out var channel)) return null;

PluralKit.Bot/Commands/CommandTree.cs

@@ -22,6 +22,7 @@ namespace PluralKit.Bot.Commands
         public static Command SystemFronter = new Command("system fronter", "system [system] fronter", "Shows a system's fronter(s)");
         public static Command SystemFrontHistory = new Command("system fronthistory", "system [system] fronthistory", "Shows a system's front history");
         public static Command SystemFrontPercent = new Command("system frontpercent", "system [system] frontpercent [timespan]", "Shows a system's front breakdown");
+        public static Command SystemPrivacy = new Command("system privacy", "system [system] privacy <description|members|fronter|fronthistory> <public|private>", "Changes your system's privacy settings");
         public static Command MemberInfo = new Command("member", "member <member>", "Looks up information about a member");
         public static Command MemberNew = new Command("member new", "member new <name>", "Creates a new member");
         public static Command MemberRename = new Command("member rename", "member <member> rename <new name>", "Renames a member");
@@ -36,6 +37,7 @@ namespace PluralKit.Bot.Commands
         public static Command MemberServerName = new Command("member servername", "member <member> servername [server name]", "Changes a member's display name in the current server");
         public static Command MemberKeepProxy = new Command("member keepproxy", "member <member> keepproxy [on|off]", "Sets whether to include a member's proxy tags when proxying");
         public static Command MemberRandom = new Command("random", "random", "Gets a random member from your system");
+        public static Command MemberPrivacy = new Command("member privacy", "member <member> privacy [on|off]", "Sets whether a member is private or public");
         public static Command Switch = new Command("switch", "switch <member> [member 2] [member 3...]", "Registers a switch");
         public static Command SwitchOut = new Command("switch out", "switch out", "Registers a switch with no members");
         public static Command SwitchMove = new Command("switch move", "switch move <date/time>", "Moves the latest switch in time");
@@ -58,7 +60,7 @@ namespace PluralKit.Bot.Commands
 
         public static Command[] SystemCommands = {
             SystemInfo, SystemNew, SystemRename, SystemTag, SystemDesc, SystemAvatar, SystemDelete, SystemTimezone,
-            SystemList, SystemFronter, SystemFrontHistory, SystemFrontPercent
+            SystemList, SystemFronter, SystemFrontHistory, SystemFrontPercent, SystemPrivacy
         };
 
         public static Command[] MemberCommands = {
@@ -185,6 +187,8 @@ namespace PluralKit.Bot.Commands
                 await ctx.Execute<SystemCommands>(SystemFrontHistory, m => m.SystemFrontHistory(ctx, ctx.System));
             else if (ctx.Match("fp", "frontpercent", "front%", "frontbreakdown"))
                 await ctx.Execute<SystemCommands>(SystemFrontPercent, m => m.SystemFrontPercent(ctx, ctx.System));
+            else if (ctx.Match("privacy"))
+                await ctx.Execute<SystemCommands>(SystemPrivacy, m => m.SystemPrivacy(ctx));
             else if (ctx.Match("commands", "help"))
                 await PrintCommandList(ctx, "systems", SystemCommands);
             else if (!ctx.HasNext()) // Bare command
@@ -272,6 +276,8 @@ namespace PluralKit.Bot.Commands
                 await ctx.Execute<MemberCommands>(MemberServerName, m => m.MemberServerName(ctx, target));
             else if (ctx.Match("keepproxy", "keeptags", "showtags"))
                 await ctx.Execute<MemberCommands>(MemberKeepProxy, m => m.MemberKeepProxy(ctx, target));
+            else if (ctx.Match("private", "privacy", "hidden"))
+                await ctx.Execute<MemberCommands>(MemberPrivacy, m => m.MemberPrivacy(ctx, target));
             else if (!ctx.HasNext()) // Bare command
                 await ctx.Execute<MemberCommands>(MemberInfo, m => m.ViewMember(ctx, target));
             else 

PluralKit.Bot/Commands/MemberCommands.cs

@@ -38,7 +38,7 @@ namespace PluralKit.Bot.Commands
             }
 
             // Enforce per-system member limit
-            var memberCount = await _data.GetSystemMemberCount(ctx.System);
+            var memberCount = await _data.GetSystemMemberCount(ctx.System, true);
             if (memberCount >= Limits.MaxMemberCount)
                 throw Errors.MemberLimitReachedError;
 
@@ -69,7 +69,7 @@ namespace PluralKit.Bot.Commands
             if (members == null || !members.Any())
                 throw Errors.NoMembersError;
             var randInt = randGen.Next(members.Count);
-            await ctx.Reply(embed: await _embeds.CreateMemberEmbed(ctx.System, members[randInt], ctx.Guild));
+            await ctx.Reply(embed: await _embeds.CreateMemberEmbed(ctx.System, members[randInt], ctx.Guild, ctx.LookupContextFor(ctx.System)));
 
         }
 
@@ -429,11 +429,31 @@ namespace PluralKit.Bot.Commands
                 await ctx.Reply($"{Emojis.Success} Member proxy tags will now not be included in the resulting message when proxying.");
             await _proxyCache.InvalidateResultsForSystem(ctx.System);
         }
-        
+
+        public async Task MemberPrivacy(Context ctx, PKMember target)
+        {
+            if (ctx.System == null) throw Errors.NoSystemError;
+            if (target.System != ctx.System.Id) throw Errors.NotOwnMemberError;
+
+            bool newValue;
+            if (ctx.Match("private", "hide", "hidden", "on", "enable", "yes")) newValue = true;
+            else if (ctx.Match("public", "show", "shown", "displayed", "off", "disable", "no")) newValue = false;
+            else if (ctx.HasNext()) throw new PKSyntaxError("You must pass either \"private\" or \"public\".");
+            else newValue = target.MemberPrivacy != PrivacyLevel.Private;
+
+            target.MemberPrivacy = newValue ? PrivacyLevel.Private : PrivacyLevel.Public;
+            await _data.SaveMember(target);
+
+            if (newValue)
+                await ctx.Reply($"{Emojis.Success} Member privacy set to **private**. This member will no longer show up in member lists and will return limited information when queried by other accounts.");
+            else
+                await ctx.Reply($"{Emojis.Success} Member privacy set to **public**. This member will now show up in member lists and will return all information when queried by other accounts.");
+        }
+
         public async Task ViewMember(Context ctx, PKMember target)
         {
             var system = await _data.GetSystemById(target.System);
-            await ctx.Reply(embed: await _embeds.CreateMemberEmbed(system, target, ctx.Guild));
+            await ctx.Reply(embed: await _embeds.CreateMemberEmbed(system, target, ctx.Guild, ctx.LookupContextFor(system)));
         }
     }
 }

PluralKit.Bot/Commands/SystemCommands.cs

@@ -29,7 +29,7 @@ namespace PluralKit.Bot.Commands
         public async Task Query(Context ctx, PKSystem system) {
             if (system == null) throw Errors.NoSystemError;
 
-            await ctx.Reply(embed: await _embeds.CreateSystemEmbed(system));
+            await ctx.Reply(embed: await _embeds.CreateSystemEmbed(system, ctx.LookupContextFor(system)));
         }
         
         public async Task New(Context ctx)
@@ -149,27 +149,57 @@ namespace PluralKit.Bot.Commands
         
         public async Task MemberShortList(Context ctx, PKSystem system) {
             if (system == null) throw Errors.NoSystemError;
+            ctx.CheckSystemPrivacy(system, system.MemberListPrivacy);
+            
+            var authCtx = ctx.LookupContextFor(system);
+            var shouldShowPrivate = authCtx == LookupContext.ByOwner && ctx.Match("all", "everyone", "private");
 
-            var members = await _data.GetSystemMembers(system);
+            var members = (await _data.GetSystemMembers(system)).ToList();
             var embedTitle = system.Name != null ? $"Members of {system.Name.SanitizeMentions()} (`{system.Hid}`)" : $"Members of `{system.Hid}`";
-            await ctx.Paginate<PKMember>(
-                members.OrderBy(m => m.Name, StringComparer.InvariantCultureIgnoreCase).ToList(),
+
+            var membersToDisplay = members
+                .Where(m => m.MemberPrivacy == PrivacyLevel.Public || shouldShowPrivate)
+                .OrderBy(m => m.Name, StringComparer.InvariantCultureIgnoreCase).ToList();
+            var anyMembersHidden = members.Any(m => m.MemberPrivacy == PrivacyLevel.Private && !shouldShowPrivate);
+                
+            await ctx.Paginate(
+                membersToDisplay,
                 25,
                 embedTitle,
-                (eb, ms) => eb.Description = string.Join("\n", ms.Select((m) => {
-                    if (m.HasProxyTags) return $"[`{m.Hid}`] **{m.Name.SanitizeMentions()}** *({m.ProxyTagsString().SanitizeMentions()})*";
-                    return $"[`{m.Hid}`] **{m.Name.SanitizeMentions()}**";
-                }))
-            );
+                (eb, ms) =>
+                {
+                    eb.Description = string.Join("\n", ms.Select((m) =>
+                    {
+                        if (m.HasProxyTags)
+                            return
+                                $"[`{m.Hid}`] **{m.Name.SanitizeMentions()}** *({m.ProxyTagsString().SanitizeMentions()})*";
+                        return $"[`{m.Hid}`] **{m.Name.SanitizeMentions()}**";
+                    }));
+
+                    var footer = $"{membersToDisplay.Count} total.";
+                    if (anyMembersHidden && authCtx == LookupContext.ByOwner)
+                        footer += "Private members have been hidden. type \"pk;system list all\" to include them.";
+                    eb.WithFooter(footer);
+                });
         }
 
         public async Task MemberLongList(Context ctx, PKSystem system) {
             if (system == null) throw Errors.NoSystemError;
+            ctx.CheckSystemPrivacy(system, system.MemberListPrivacy);
+            
+            var authCtx = ctx.LookupContextFor(system);
+            var shouldShowPrivate = authCtx == LookupContext.ByOwner && ctx.Match("all", "everyone", "private");
 
-            var members = await _data.GetSystemMembers(system);
+            var members = (await _data.GetSystemMembers(system)).ToList();
             var embedTitle = system.Name != null ? $"Members of {system.Name} (`{system.Hid}`)" : $"Members of `{system.Hid}`";
-            await ctx.Paginate<PKMember>(
-                members.OrderBy(m => m.Name, StringComparer.InvariantCultureIgnoreCase).ToList(),
+            
+            var membersToDisplay = members
+                .Where(m => m.MemberPrivacy == PrivacyLevel.Public || shouldShowPrivate)
+                .OrderBy(m => m.Name, StringComparer.InvariantCultureIgnoreCase).ToList();
+            var anyMembersHidden = members.Any(m => m.MemberPrivacy == PrivacyLevel.Private && !shouldShowPrivate);
+            
+            await ctx.Paginate(
+                membersToDisplay,
                 5,
                 embedTitle,
                 (eb, ms) => {
@@ -179,8 +209,16 @@ namespace PluralKit.Bot.Commands
                         if (m.Birthday != null) profile += $"\n**Birthdate**: {m.BirthdayString}";
                         if (m.ProxyTags.Count > 0) profile += $"\n**Proxy tags:** {m.ProxyTagsString()}";
                         if (m.Description != null) profile += $"\n\n{m.Description}";
+                        if (m.MemberPrivacy == PrivacyLevel.Private)
+                            profile += "*(this member is private)*";
+                        
                         eb.AddField(m.Name, profile.Truncate(1024));
                     }
+
+                    var footer = $"{membersToDisplay.Count} total.";
+                    if (anyMembersHidden && authCtx == LookupContext.ByOwner)
+                        footer += " Private members have been hidden. type \"pk;system list full all\" to include them.";
+                    eb.WithFooter(footer);
                 }
             );
         }
@@ -188,6 +226,7 @@ namespace PluralKit.Bot.Commands
         public async Task SystemFronter(Context ctx, PKSystem system)
         {
             if (system == null) throw Errors.NoSystemError;
+            ctx.CheckSystemPrivacy(system, system.FrontPrivacy);
             
             var sw = await _data.GetLatestSwitch(system);
             if (sw == null) throw Errors.NoRegisteredSwitches;
@@ -198,6 +237,7 @@ namespace PluralKit.Bot.Commands
         public async Task SystemFrontHistory(Context ctx, PKSystem system)
         {
             if (system == null) throw Errors.NoSystemError;
+            ctx.CheckSystemPrivacy(system, system.FrontHistoryPrivacy);
 
             var sws = (await _data.GetSwitches(system, 10)).ToList();
             if (sws.Count == 0) throw Errors.NoRegisteredSwitches;
@@ -208,6 +248,7 @@ namespace PluralKit.Bot.Commands
         public async Task SystemFrontPercent(Context ctx, PKSystem system)
         {
             if (system == null) throw Errors.NoSystemError;
+            ctx.CheckSystemPrivacy(system, system.FrontHistoryPrivacy);
 
             string durationStr = ctx.RemainderOrNull() ?? "30d";
             
@@ -267,6 +308,80 @@ namespace PluralKit.Bot.Commands
             await ctx.Reply($"System time zone changed to {zone.Id}.");
         }
 
+        public async Task SystemPrivacy(Context ctx)
+        {
+            ctx.CheckSystem();
+
+            if (!ctx.HasNext())
+            {
+                string PrivacyLevelString(PrivacyLevel level) => level switch
+                {
+                    PrivacyLevel.Private => "**Private** (visible only when queried by you)",
+                    PrivacyLevel.Public => "**Public** (visible to everyone)",
+                    _ => throw new ArgumentOutOfRangeException(nameof(level), level, null)
+                };
+
+                var eb = new EmbedBuilder()
+                    .WithTitle("Current privacy settings for your system")
+                    .AddField("Description", PrivacyLevelString(ctx.System.DescriptionPrivacy))
+                    .AddField("Member list", PrivacyLevelString(ctx.System.MemberListPrivacy))
+                    .AddField("Current fronter(s)", PrivacyLevelString(ctx.System.FrontPrivacy))
+                    .AddField("Front/switch history", PrivacyLevelString(ctx.System.FrontHistoryPrivacy))
+                    .WithDescription("To edit privacy settings, use the command:\n`pk;system privacy <subject> <level>`\n\n- `subject` is one of `description`, `list`, `front` or `fronthistory`\n- `level` is either `public` or `private`.");
+                await ctx.Reply(embed: eb.Build());
+                return;
+            }
+            
+            PrivacyLevel PopPrivacyLevel(string subject, out string levelStr, out string levelExplanation)
+            {
+                if (ctx.Match("public", "show", "shown", "visible"))
+                {
+                    levelStr = "public";
+                    levelExplanation = "be able to query";
+                    return PrivacyLevel.Public;
+                }
+
+                if (ctx.Match("private", "hide", "hidden"))
+                {
+                    levelStr = "private";
+                    levelExplanation = "*not* be able to query";
+                    return PrivacyLevel.Private;
+                }
+
+                if (!ctx.HasNext())
+                    throw new PKSyntaxError($"You must pass a privacy level for `{subject}` (`public` or `private`)");
+                throw new PKSyntaxError($"Invalid privacy level `{ctx.PopArgument().SanitizeMentions()}` (must be `public` or `private`).");
+            }
+
+            string levelStr, levelExplanation, subjectStr;
+            var subjectList = "`description`, `members`, `front` or `fronthistory`";
+            if (ctx.Match("description", "desc", "text", "info"))
+            {
+                subjectStr = "description";
+                ctx.System.DescriptionPrivacy = PopPrivacyLevel("description", out levelStr, out levelExplanation);
+            } 
+            else if (ctx.Match("members", "memberlist", "list", "mlist"))
+            {
+                subjectStr = "member list";
+                ctx.System.MemberListPrivacy = PopPrivacyLevel("members", out levelStr, out levelExplanation);
+            }
+            else if (ctx.Match("front", "fronter"))
+            {
+                subjectStr = "fronter(s)";
+                ctx.System.FrontPrivacy = PopPrivacyLevel("front", out levelStr, out levelExplanation);
+            } 
+            else if (ctx.Match("switch", "switches", "fronthistory", "fh"))
+            {
+                subjectStr = "front history";
+                ctx.System.FrontHistoryPrivacy = PopPrivacyLevel("fronthistory", out levelStr, out levelExplanation);
+            }
+            else
+                throw new PKSyntaxError($"Invalid privacy subject `{ctx.PopArgument().SanitizeMentions()}` (must be {subjectList}).");
+
+            await _data.SaveSystem(ctx.System);
+            await ctx.Reply($"System {subjectStr} privacy has been set to **{levelStr}**. Other accounts will now {levelExplanation} your system {subjectStr}.");
+        }
+
         public async Task<DateTimeZone> FindTimeZone(Context ctx, string zoneStr) {
             // First, if we're given a flag emoji, we extract the flag emoji code from it.
             zoneStr = PluralKit.Utils.ExtractCountryFlag(zoneStr) ?? zoneStr;

PluralKit.Bot/Services/EmbedService.cs

@@ -20,13 +20,13 @@ namespace PluralKit.Bot {
             _data = data;
         }
 
-        public async Task<Embed> CreateSystemEmbed(PKSystem system) {
+        public async Task<Embed> CreateSystemEmbed(PKSystem system, LookupContext ctx) {
             var accounts = await _data.GetSystemAccounts(system);
 
             // 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);
+            var memberCount = await _data.GetSystemMemberCount(system, false);
             var eb = new EmbedBuilder()
                 .WithColor(Color.Blue)
                 .WithTitle(system.Name ?? null)
@@ -34,7 +34,7 @@ namespace PluralKit.Bot {
                 .WithFooter($"System ID: {system.Hid} | Created on {Formats.ZonedDateTimeFormat.Format(system.Created.InZone(system.Zone))}");
  
             var latestSwitch = await _data.GetLatestSwitch(system);
-            if (latestSwitch != null)
+            if (latestSwitch != null && system.FrontPrivacy.CanAccess(ctx))
             {
                 var switchMembers = (await _data.GetSwitchMembers(latestSwitch)).ToList();
                 if (switchMembers.Count > 0)
@@ -44,9 +44,12 @@ namespace PluralKit.Bot {
 
             if (system.Tag != null) eb.AddField("Tag", system.Tag);
             eb.AddField("Linked accounts", string.Join(", ", users).Truncate(1000), true);
-            eb.AddField($"Members ({memberCount})", $"(see `pk;system {system.Hid} list` or `pk;system {system.Hid} list full`)", true);
+            
+            if (system.MemberListPrivacy.CanAccess(ctx))
+                eb.AddField($"Members ({memberCount})", $"(see `pk;system {system.Hid} list` or `pk;system {system.Hid} list full`)", true);
 
-            if (system.Description != null) eb.AddField("Description", system.Description.Truncate(1024), false);
+            if (system.Description != null && system.DescriptionPrivacy.CanAccess(ctx))
+                eb.AddField("Description", system.Description.Truncate(1024), false);
 
             return eb.Build();
         }
@@ -62,7 +65,7 @@ namespace PluralKit.Bot {
                 .Build();
         }
 
-        public async Task<Embed> CreateMemberEmbed(PKSystem system, PKMember member, IGuild guild)
+        public async Task<Embed> CreateMemberEmbed(PKSystem system, PKMember member, IGuild guild, LookupContext ctx)
         {
             var name = member.Name;
             if (system.Name != null) name = $"{member.Name} ({system.Name})";
@@ -91,19 +94,21 @@ namespace PluralKit.Bot {
             var eb = new EmbedBuilder()
                 // TODO: add URL of website when that's up
                 .WithAuthor(name, member.AvatarUrl)
-                .WithColor(color)
+                .WithColor(member.MemberPrivacy.CanAccess(ctx) ? color : Color.Default)
                 .WithFooter($"System ID: {system.Hid} | Member ID: {member.Hid} | Created on {Formats.ZonedDateTimeFormat.Format(member.Created.InZone(system.Zone))}");
 
+            if (member.MemberPrivacy == PrivacyLevel.Private) eb.WithDescription("*(this member is private)*");
+
             if (member.AvatarUrl != null) eb.WithThumbnailUrl(member.AvatarUrl);
 
             if (member.DisplayName != null) eb.AddField("Display Name", member.DisplayName.Truncate(1024), true);
             if (guild != null && guildDisplayName != null) eb.AddField($"Server Nickname (for {guild.Name})", guildDisplayName.Truncate(1024), true);
-            if (member.Birthday != null) eb.AddField("Birthdate", member.BirthdayString, true);
-            if (member.Pronouns != null) eb.AddField("Pronouns", member.Pronouns.Truncate(1024), true);
-            if (messageCount > 0) eb.AddField("Message Count", messageCount, true);
+            if (member.Birthday != null && member.MemberPrivacy.CanAccess(ctx)) eb.AddField("Birthdate", member.BirthdayString, true);
+            if (member.Pronouns != null && member.MemberPrivacy.CanAccess(ctx)) eb.AddField("Pronouns", member.Pronouns.Truncate(1024), true);
+            if (messageCount > 0 && member.MemberPrivacy.CanAccess(ctx)) eb.AddField("Message Count", messageCount, true);
             if (member.HasProxyTags) eb.AddField("Proxy Tags", string.Join('\n', proxyTagsStr).Truncate(1024), true);
-            if (member.Color != null) eb.AddField("Color", $"#{member.Color}", true);
-            if (member.Description != null) eb.AddField("Description", member.Description, false);
+            if (member.Color != null && member.MemberPrivacy.CanAccess(ctx)) eb.AddField("Color", $"#{member.Color}", true);
+            if (member.Description != null && member.MemberPrivacy.CanAccess(ctx)) eb.AddField("Description", member.Description, false);
 
             return eb.Build();
         }

PluralKit.Core/Migrations/2.sql

@@ -0,0 +1,13 @@
+-- We're doing a psuedo-enum here since Dapper is wonky with enums
+-- Still getting mapped to enums at the CLR level, though.
+-- https://github.com/StackExchange/Dapper/issues/332 (from 2015, still unsolved!)
+-- 1 = "public"
+-- 2 = "private"
+-- not doing a bool here since I want to open up for the possibliity of other privacy levels (eg. "mutuals only")
+alter table systems add column description_privacy integer check (description_privacy in (1, 2)) not null default 1;
+alter table systems add column member_list_privacy integer check (member_list_privacy in (1, 2)) not null default 1;
+alter table systems add column front_privacy integer check (front_privacy in (1, 2)) not null default 1;
+alter table systems add column front_history_privacy integer check (front_history_privacy in (1, 2)) not null default 1;
+alter table members add column member_privacy integer check (member_privacy in (1, 2)) not null default 1;
+
+update info set schema_version = 2;

PluralKit.Core/Models.cs

@@ -17,6 +17,25 @@ namespace PluralKit
     {
         public PKParseError(string message): base(message) { }
     }
+
+    public enum PrivacyLevel
+    {
+        Public = 1,
+        Private = 2
+    }
+
+    public static class PrivacyExt
+    {
+        public static bool CanAccess(this PrivacyLevel level, LookupContext ctx) =>
+            level == PrivacyLevel.Public || ctx == LookupContext.ByOwner;
+    }
+
+    public enum LookupContext
+    {
+        ByOwner,
+        ByNonOwner,
+        API
+    }
     
     public struct ProxyTag
     {
@@ -58,14 +77,19 @@ namespace PluralKit
         [JsonIgnore] public string Token { get; set; }
         [JsonProperty("created")] public Instant Created { get; set; }
         [JsonProperty("tz")] public string UiTz { get; set; }
+        public PrivacyLevel DescriptionPrivacy { get; set; }
+        public PrivacyLevel MemberListPrivacy { get; set; }
+        public PrivacyLevel FrontPrivacy { get; set; }
+        public PrivacyLevel FrontHistoryPrivacy { get; set; }
+        
         [JsonIgnore] public DateTimeZone Zone => DateTimeZoneProviders.Tzdb.GetZoneOrNull(UiTz);
 
-        public JObject ToJson()
+        public JObject ToJson(LookupContext ctx)
         {
             var o = new JObject();
             o.Add("id", Hid);
             o.Add("name", Name);
-            o.Add("description", Description);
+            o.Add("description", DescriptionPrivacy.CanAccess(ctx) ? Description : null);
             o.Add("tag", Tag);
             o.Add("avatar_url", AvatarUrl);
             o.Add("created", Formats.TimestampExportFormat.Format(Created));
@@ -100,6 +124,8 @@ namespace PluralKit
         [JsonProperty("keep_proxy")] public bool KeepProxy { get; set; }
         [JsonProperty("created")] public Instant Created { get; set; }
 
+        public PrivacyLevel MemberPrivacy { get; set; }
+
         /// Returns a formatted string representing the member's birthday, taking into account that a year of "0001" is hidden
         [JsonIgnore] public string BirthdayString
         {
@@ -120,17 +146,17 @@ namespace PluralKit
             return $"{guildDisplayName ?? DisplayName ?? Name} {systemTag}";
         }
 
-        public JObject ToJson()
+        public JObject ToJson(LookupContext ctx)
         {
             var o = new JObject();
             o.Add("id", Hid);
             o.Add("name", Name);
-            o.Add("color", Color);
+            o.Add("color", MemberPrivacy.CanAccess(ctx) ? Color : null);
             o.Add("display_name", DisplayName);
-            o.Add("birthday", Birthday.HasValue ? Formats.DateExportFormat.Format(Birthday.Value) : null);
-            o.Add("pronouns", Pronouns);
+            o.Add("birthday", MemberPrivacy.CanAccess(ctx) && Birthday.HasValue ? Formats.DateExportFormat.Format(Birthday.Value) : null);
+            o.Add("pronouns", MemberPrivacy.CanAccess(ctx) ? Pronouns : null);
             o.Add("avatar_url", AvatarUrl);
-            o.Add("description", Description);
+            o.Add("description", MemberPrivacy.CanAccess(ctx) ? Description : null);
             
             var tagArray = new JArray();
             foreach (var tag in ProxyTags) 

PluralKit.Core/SchemaService.cs

@@ -1,5 +1,4 @@
 using System;
-using System.Data;
 using System.IO;
 using System.Threading.Tasks;
 using Dapper;
@@ -11,7 +10,7 @@ using Serilog;
 namespace PluralKit {
     public class SchemaService
     {
-        private const int TargetSchemaVersion = 1;
+        private const int TargetSchemaVersion = 2;
 
         private DbConnectionFactory _conn;
         private ILogger _logger;
@@ -22,6 +21,13 @@ namespace PluralKit {
             _logger = logger.ForContext<SchemaService>();
         }
 
+        public static void Initialize()
+        {
+            // Without these it'll still *work* but break at the first launch + probably cause other small issues
+            NpgsqlConnection.GlobalTypeMapper.MapComposite<ProxyTag>("proxy_tag");
+            NpgsqlConnection.GlobalTypeMapper.MapEnum<PrivacyLevel>("privacy_level");
+        }
+
         public async Task ApplyMigrations()
         {
             for (var version = 0; version <= TargetSchemaVersion; version++) 

PluralKit.Core/Stores.cs

@@ -116,7 +116,8 @@ namespace PluralKit {
         /// <summary>
         /// Gets the member count of a system.
         /// </summary>
-        Task<int> GetSystemMemberCount(PKSystem system);
+        /// <param name="includePrivate">Whether the returned count should include private members.</param>
+        Task<int> GetSystemMemberCount(PKSystem system, bool includePrivate);
 
         /// <summary>
         /// Gets a list of members with proxy tags that conflict with the given tags.
@@ -488,7 +489,7 @@ namespace PluralKit {
 
         public async Task SaveSystem(PKSystem system) {
             using (var conn = await _conn.Obtain())
-                await conn.ExecuteAsync("update systems set name = @Name, description = @Description, tag = @Tag, avatar_url = @AvatarUrl, token = @Token, ui_tz = @UiTz where id = @Id", system);
+                await conn.ExecuteAsync("update systems set name = @Name, description = @Description, tag = @Tag, avatar_url = @AvatarUrl, token = @Token, ui_tz = @UiTz, description_privacy = @DescriptionPrivacy, member_list_privacy = @MemberListPrivacy, front_privacy = @FrontPrivacy, front_history_privacy = @FrontHistoryPrivacy where id = @Id", system);
 
             _logger.Information("Updated system {@System}", system);
         }
@@ -590,7 +591,7 @@ namespace PluralKit {
 
         public async Task SaveMember(PKMember member) {
             using (var conn = await _conn.Obtain())
-                await conn.ExecuteAsync("update members set name = @Name, display_name = @DisplayName, description = @Description, color = @Color, avatar_url = @AvatarUrl, birthday = @Birthday, pronouns = @Pronouns, proxy_tags = @ProxyTags, keep_proxy = @KeepProxy where id = @Id", member);
+                await conn.ExecuteAsync("update members set name = @Name, display_name = @DisplayName, description = @Description, color = @Color, avatar_url = @AvatarUrl, birthday = @Birthday, pronouns = @Pronouns, proxy_tags = @ProxyTags, keep_proxy = @KeepProxy, member_privacy = @MemberPrivacy where id = @Id", member);
 
             _logger.Information("Updated member {@Member}", member);
         }
@@ -637,10 +638,13 @@ namespace PluralKit {
                     new { System = system.Id });
         }
 
-        public async Task<int> GetSystemMemberCount(PKSystem system)
+        public async Task<int> GetSystemMemberCount(PKSystem system, bool includePrivate)
         {
+            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>("select count(*) from members where system = @Id", system);
+                return await conn.ExecuteScalarAsync<int>(query, system);
         }
 
         public async Task<ulong> GetTotalMembers()

docs/3-api-documentation.md

@@ -18,6 +18,11 @@ Authentication is done with a simple "system token". You can get your system tok
 Discord bot, either in a channel with the bot or in DMs. Then, pass this token in the `Authorization` HTTP header
 on requests that require it. Failure to do so on endpoints that require authentication will return a `401 Unauthorized`.
 
+Some endpoints show information that a given system may have set to private. If this is a specific field
+(eg. description), the field will simply contain `null` rather than the true value. If this applies to entire endpoint
+responses (eg. fronter, switches, member list), the entire request will return `403 Forbidden`. Authenticating with the
+system's token (as described above) will override these privacy settings and show the full information. 
+
 ## Models
 The following three models (usually represented in JSON format) represent the various objects in PluralKit's API. A `?` after the column type indicates an optional (nullable) parameter.
 
@@ -99,6 +104,7 @@ Returns information about your own system.
 
 ### GET /s/\<id>
 Queries a system by its 5-character ID, and returns information about it. If the system doesn't exist, returns `404 Not Found`.
+Some fields may be set to `null` if unauthenticated and the system has chosen to make those fields private.
 
 #### Example request
     GET https://api.pluralkit.me/v1/s/abcde
@@ -118,6 +124,8 @@ Queries a system by its 5-character ID, and returns information about it. If the
 
 ### GET /s/\<id>/members
 Queries a system's member list by its 5-character ID. If the system doesn't exist, returns `404 Not Found`.
+If the system has chosen to hide its member list, this will return `403 Forbidden`, unless the request is authenticated with the system's token.
+If the request is not authenticated with the system's token, members marked as private will *not* be returned.
 
 #### Example request
     GET https://api.pluralkit.me/v1/s/abcde/members
@@ -145,6 +153,8 @@ Returns a system's switch history in newest-first chronological order, with a ma
 Optionally takes a `?before=` query parameter with an ISO-8601-formatted timestamp, and will only return switches
 that happen before that timestamp.
 
+If the system has chosen to hide its switch history, this will return `403 Forbidden`, unless the request is authenticated with the system's token.
+
 #### Example request
     GET https://api.pluralkit.me/v1/s/abcde/switches?before=2019-03-01T14:00:00Z
 
@@ -168,6 +178,7 @@ that happen before that timestamp.
 
 ### GET /s/\<id>/fronters
 Returns a system's current fronter(s), with fully hydrated member objects. If the system doesn't exist, *or* the system has no registered switches, returns `404 Not Found`.
+If the system has chosen to hide its current fronters, this will return `403 Forbidden`, unless the request is authenticated with the system's token. If a returned member is private, and the request isn't properly authenticated, some fields may be null.
 
 #### Example request
     GET https://api.pluralkit.me/v1/s/abcde/fronters
@@ -243,6 +254,7 @@ Registers a new switch to your own system given a list of member IDs.
 
 ### GET /m/\<id>
 Queries a member's information by its 5-character member ID. If the member does not exist, will return `404 Not Found`.
+If this member is marked private, and the request isn't authenticated with the member's system's token, some fields (currently only `description`) will contain `null` rather than the true value.
 
 #### Example request
     GET https://api.pluralkit.me/v1/m/qwert
@@ -354,6 +366,7 @@ Deletes a member from the database. Be careful as there is no confirmation and t
 
 ### GET /a/\<id>
 Queries a system by its linked Discord account ID (17/18-digit numeric snowflake). Returns `404 Not Found` if the account doesn't have a system linked.
+Some fields may be set to `null` if unauthenticated and the system has chosen to make those fields private.
 
 #### Example request
     GET https://api.pluralkit.me/v1/a/466378653216014359
@@ -375,6 +388,8 @@ Queries a system by its linked Discord account ID (17/18-digit numeric snowflake
 Looks up a proxied message by its message ID. Returns `404 Not Found` if the message ID is invalid or wasn't found (eg. was deleted or not proxied by PK).
 You can also look messages up by their *trigger* message ID (useful for, say, logging bot integration).
 
+The returned system and member's privacy settings will be respected, and as such, some fields may be set to null without the proper authentication.
+
 #### Example request
     GET https://api.pluralkit.me/v1/msg/601014599386398700
 
@@ -411,6 +426,8 @@ You can also look messages up by their *trigger* message ID (useful for, say, lo
 ```
 
 ## Version history
+* 2020-01-08
+  * Added privacy support, meaning some responses will now lack information or return 403s, depending on the specific system and member's privacy settings.
 * 2019-12-28
   * Changed behaviour of missing fields in PATCH responses, will now preserve the old value instead of clearing
   * This is technically a breaking change, but not *significantly* so, so I won't bump the version number.