Revised and refactored OutputFormatter

- OutputFormatter is now renamed to CommandHandler
CommandHandler now supports full command management
  - Dynamically generates command list (for "help")
  - Added Command class which specifies the structure of a command
  - Added struct specifying the structure of a command parameter
Added exception handling to networking
Moved shared layout resource to Common layout file

Client/Context/NetContext.cs

@@ -57,8 +57,17 @@ namespace Client
                         return;
                     }
                     */
-                    
+
-                    Promise verify = Promise.AwaitPromise(ita.CheckIdentity(new RSA(Resources.e_0x100, Resources.n_0x100), provider.NextUShort()));
+                    Promise verify;
+                    try
+                    {
+                        verify = Promise.AwaitPromise(ita.CheckIdentity(new RSA(Resources.e_0x100, Resources.n_0x100), provider.NextUShort()));
+                    }
+                    catch
+                    {
+                        Show("ConnectionError"); 
+                        return;
+                    }
                     verify.Subscribe =
                         p =>
                         {

Client/Context/WelcomeContext.cs

@@ -44,7 +44,16 @@ namespace Client
                 {
                     // Authenticate against server here
                     Show("AuthWait");
-                    promise = Promise.AwaitPromise(interactor.Authenticate(i.Inputs[0].Text, i.Inputs[1].Text));
+                    try
+                    {
+                        promise = Promise.AwaitPromise(interactor.Authenticate(i.Inputs[0].Text, i.Inputs[1].Text));
+                    }
+                    catch
+                    {
+                        Hide("AuthWait");
+                        Show("ConnectionError");
+                        return;
+                    }
                     //promise = prom.Result;
                     promise.Subscribe =
                     response =>
@@ -90,12 +99,21 @@ namespace Client
                     void a()
                     {
                         Show("RegWait");
-                        promise = Promise.AwaitPromise(interactor.Register(i.Inputs[0].Text, i.Inputs[1].Text));
+                        try
+                        {
+                            promise = Promise.AwaitPromise(interactor.Register(i.Inputs[0].Text, i.Inputs[1].Text));
+                        }
+                        catch
+                        {
+                            Hide("RegWait");
+                            Show("ConnectionError");
+                            return;
+                        }
                         promise.Subscribe =
                         response =>
                         {
                             Hide("RegWait");
-                            if (response.Value.Equals("ERROR"))
+                            if (response.Value.StartsWith("ERROR"))
                                 Show("DuplicateAccountError");
                             else
                             {

Client/Resources/Layout/Common.xml

@@ -10,4 +10,16 @@
     </Options>
     <Text>@string/ERR_empty</Text>
   </DialogView>
+
+  <DialogView id="ConnectionError"
+    padding_left="2"
+    padding_right="2"
+    padding_top="1"
+    padding_bottom="1"
+             border="4">
+    <Options>
+      <Option>@string/GENERIC_accept</Option>
+    </Options>
+    <Text>@string/NC_connerr</Text>
+  </DialogView>
 </Resources>

Client/Resources/Layout/Networking.xml

@@ -69,16 +69,4 @@
     </Options>
     <Text>@string/NC_porterr</Text>
   </DialogView>
-
-  <DialogView id="ConnectionError"
-    padding_left="2"
-    padding_right="2"
-    padding_top="1"
-    padding_bottom="1"
-             border="4">
-    <Options>
-      <Option>@string/GENERIC_accept</Option>
-    </Options>
-    <Text>@string/NC_connerr</Text>
-  </DialogView>
 </Elements>

Server/Command.cs

@@ -0,0 +1,166 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+using Tofvesson.Crypto;
+
+namespace Server
+{
+    public sealed class Command
+    {
+        public string Name { get; }
+        public Action<Command, List<Tuple<string, Parameter>>> OnInvoke { get; set; }
+        private List<Parameter> parameters = new List<Parameter>();
+
+        public string CommandString
+        {
+            get
+            {
+                StringBuilder builder = new StringBuilder(Name);
+                foreach (var p in parameters)
+                {
+                    builder.Append(' ');
+                    if (p.optional) builder.Append('{');
+                    builder.Append('-').Append(p.flag);
+                    if (p.type != Parameter.ParamType.NONE) builder.Append(' ').Append(p.name);
+                    if (p.optional) builder.Append('}');
+                }
+                return builder.ToString();
+            }
+        }
+
+
+        public Command(string name) => Name = name;
+
+        public Command WithParameter(string pName, char flag, Parameter.ParamType type, bool optional = false)
+        {
+            if (GetByFlag(flag) != null) throw new Exception("Cannot have two parameters with the same flag");
+            parameters.Add(new Parameter(pName, flag, type, optional));
+            return this;
+        }
+
+        public Command WithParameter(Parameter parameter)
+        {
+            if (GetByFlag(parameter.flag) != null) throw new Exception("Cannot have two parameters with the same flag");
+            parameters.Add(parameter);
+            return this;
+        }
+
+        public Command SetAction(Action<Command, List<Tuple<string, Parameter>>> action)
+        {
+            OnInvoke = action;
+            return this;
+        }
+        public Command SetAction(Action a) => SetAction((_, __) => a?.Invoke());
+
+        public bool Matches(string cmd) => cmd.Split(' ')[0].EqualsIgnoreCase(Name);
+
+        public Parameter? GetByFlag(char flag)
+        {
+            foreach (var param in parameters)
+                if (param.flag == flag)
+                    return param;
+            return null;
+        }
+
+        public bool Invoke(string cmd)
+        {
+            if (!Matches(cmd)) return false;
+            string[] parts = cmd.Split(' ');
+            List<Tuple<string, Parameter>> p = new List<Tuple<string, Parameter>>();
+            StringBuilder reconstruct = new StringBuilder();
+            Parameter? p1 = null;
+            bool wasFlag = true;
+            for (int i = 1; i<parts.Length; ++i)
+            {
+                if (parts[i].StartsWith("-") && parts[i].Length==2)
+                {
+                    if (reconstruct.Length != 0)
+                    {
+                        if (
+                            p1 == null ||
+                            (p1.Value.type == Parameter.ParamType.NUMBER && !double.TryParse(reconstruct.ToString(), out double _)) ||
+                            (p1.Value.type == Parameter.ParamType.BOOLEAN && !bool.TryParse(reconstruct.ToString(), out bool _))
+                            )
+                        {
+                            ShowError();
+                            return true;
+                        }
+                        p.Add(new Tuple<string, Parameter>(reconstruct.ToString(), p1.Value));
+                        reconstruct.Length = 0;
+                        wasFlag = true;
+                    }
+                    if((p1 = GetByFlag(parts[i][1])) == null)
+                    {
+                        ShowError();
+                        return false;
+                    }
+                }
+                else
+                {
+                    if(p1!=null && p1.Value.type == Parameter.ParamType.NONE)
+                    {
+                        ShowError();
+                        return false;
+                    }
+                    if (!wasFlag) reconstruct.Append(' ');
+                    reconstruct.Append(parts[i]);
+                    wasFlag = false;
+                }
+            }
+
+            if (reconstruct.Length != 0 || (p1 != null && !p.HasFlag(p1.Value.flag)))
+            {
+                if (
+                    p1 == null ||
+                    (p1.Value.type == Parameter.ParamType.NUMBER && !double.TryParse(reconstruct.ToString(), out double _)) ||
+                    (p1.Value.type == Parameter.ParamType.BOOLEAN && !bool.TryParse(reconstruct.ToString(), out bool _))
+                    )
+                {
+                    ShowError();
+                    return true;
+                }
+                p.Add(new Tuple<string, Parameter>(reconstruct.ToString(), p1.Value));
+                reconstruct.Length = 0;
+            }
+
+            foreach (var check in parameters)
+                if (check.optional) continue;
+                else
+                {
+                    foreach (var check1 in p)
+                        if (check1.Item2.Equals(check))
+                            goto found;
+                    // Could not find a match for a required parameter
+                    ShowError();
+                    return false;
+
+                    found: { }
+                }
+            OnInvoke?.Invoke(this, p);
+            return true;
+        }
+
+        public void ShowError() => Output.Error($"Usage: {CommandString}");
+    }
+
+    public static class Commands
+    {
+        public static string GetFlag(this List<Tuple<string, Parameter>> l, char flag)
+        {
+            foreach (var flagcheck in l)
+                if (flagcheck.Item2.flag == flag)
+                    return flagcheck.Item1;
+            return null;
+        }
+
+        public static bool HasFlag(this List<Tuple<string, Parameter>> l, char flag)
+        {
+            foreach (var flagcheck in l)
+                if (flagcheck.Item2.flag == flag)
+                    return true;
+            return false;
+        }
+    }
+}

Server/CommandHandler.cs

@@ -6,15 +6,15 @@ using System.Threading.Tasks;
 
 namespace Server
 {
-    public sealed class OutputFormatter
+    public sealed class CommandHandler
     {
-        private readonly List<Tuple<string, string>> lines = new List<Tuple<string, string>>();
+        private readonly List<Tuple<Command, string>> commands = new List<Tuple<Command, string>>();
         private int leftLen = 0;
         private readonly int minPad;
         private readonly string prepend, delimiter, postpad, trail;
 
 
-        public OutputFormatter(int minPad = 1, string prepend = "", string delimiter = "", string postpad = "", string trail = "")
+        public CommandHandler(int minPad = 1, string prepend = "", string delimiter = "", string postpad = "", string trail = "")
         {
             this.prepend = prepend;
             this.delimiter = delimiter;
@@ -23,27 +23,36 @@ namespace Server
             this.minPad = Math.Abs(minPad);
         }
 
-        public OutputFormatter Append(string key, string value)
+        public CommandHandler Append(Command c, string description)
         {
-            lines.Add(new Tuple<string, string>(key, value));
+            commands.Add(new Tuple<Command, string>(c, description));
-            leftLen = Math.Max(key.Length + minPad, leftLen);
+            leftLen = Math.Max(c.CommandString.Length + minPad, leftLen);
             return this;
         }
 
+        public bool HandleCommand(string cmd)
+        {
+            foreach (var command in commands)
+                if (command.Item1.Invoke(cmd))
+                    return true;
+            return false;
+        }
+
         public string GetString()
         {
             StringBuilder builder = new StringBuilder();
-            foreach (var line in lines)
+            string cache;
+            foreach (var command in commands)
                 builder
                     .Append(prepend)
-                    .Append(line.Item1)
+                    .Append(cache = command.Item1.CommandString)
                     .Append(delimiter)
-                    .Append(Pad(line.Item1, leftLen))
+                    .Append(Pad(cache, leftLen))
                     .Append(postpad)
-                    .Append(line.Item2)
+                    .Append(command.Item2)
                     .Append(trail)
                     .Append('\n');
-            builder.Length -= 1;
+            if(commands.Count > 0) builder.Length -= 1;
             return builder.ToString();
         }
 

Server/Parameter.cs

@@ -0,0 +1,22 @@
+namespace Server
+{
+    public struct Parameter
+    {
+        public enum ParamType { STRING, NUMBER, BOOLEAN, NONE }
+        public readonly ParamType type;
+        public readonly string name;
+        public readonly char flag;
+        public readonly bool optional;
+
+        public Parameter(string name, char flag, ParamType type, bool optional = false)
+        {
+            this.name = name;
+            this.flag = flag;
+            this.type = type;
+            this.optional = optional;
+        }
+
+        // Easy shortcut to create parameterless flags
+        public static Parameter Flag(char flagChar, bool optional = true) => new Parameter("", flagChar, ParamType.NONE, optional);
+    }
+}

Server/Program.cs

@@ -104,6 +104,7 @@ namespace Server
             }
 
             string GenerateResponse(long id, dynamic d) => id + ":" + d.ToString();
+            string ErrorResponse(long id, string i18n = null) => GenerateResponse(id, $"ERROR{(i18n==null?"":":"+VERBOSE_RESPONSE)}{i18n??""}");
 
             bool GetUser(string sid, out Database.User user)
             {
@@ -133,13 +134,13 @@ namespace Server
                                 if(!ParseDataPair(cmd[1], out string user, out string pass))
                                 {
                                     Output.Error($"Recieved problematic username or password! (User: \"{user}\")");
-                                    return GenerateResponse(id, "ERROR");
+                                    return ErrorResponse(id);
                                 }
                                 Database.User usr = db.GetUser(user);
                                 if (usr == null || !usr.Authenticate(pass))
                                 {
                                     Output.Error("Authentcation failure for user: "+user);
-                                    return GenerateResponse(id, "ERROR");
+                                    return ErrorResponse(id);
                                 }
 
                                 string sess = manager.GetSession(usr, "ERROR");
@@ -173,7 +174,7 @@ namespace Server
                                 {
                                     // Don't print input data to output in case sensitive information was included
                                     Output.Error($"Recieved problematic session id or account name!");
-                                    return GenerateResponse(id, "ERROR");
+                                    return ErrorResponse(id);
                                 }
                                 user.accounts.Add(new Database.Account(user, 0, name));
                                 db.UpdateUser(user); // Notify database of the update
@@ -215,7 +216,7 @@ namespace Server
                                 {
                                     // Don't print input data to output in case sensitive information was included
                                     Output.Error($"Recieved problematic transaction data ({error}): {data?.ToList().ToString() ?? "Data could not be parsed"}");
-                                    return GenerateResponse(id, $"ERROR:{error}");
+                                    return ErrorResponse(id, error);
                                 }
                                 // At this point, we know that all parsed variables above were successfully parsed and valid, therefore: no NREs
                                 // Parsed vars: 'user', 'account', 'tUser', 'tAccount', 'amount'
@@ -243,7 +244,7 @@ namespace Server
                                     Output.Error($"Recieved problematic session id or account name!");
 
                                     // Possible errors: bad session id, bad account name, balance in account isn't 0
-                                    return GenerateResponse(id, $"ERROR:{VERBOSE_RESPONSE} {(user==null? "badsession" : account==null? "badacc" : "hasbal")}");
+                                    return ErrorResponse(id, (user==null? "badsession" : account==null? "badacc" : "hasbal"));
                                 }
                                 break;
                             }
@@ -253,11 +254,11 @@ namespace Server
                                 {
                                     // Don't print input data to output in case sensitive information was included
                                     Output.Error($"Recieved problematic username or password!");
-                                    return GenerateResponse(id, $"ERROR:{VERBOSE_RESPONSE}userpass");
+                                    return ErrorResponse(id, "userpass");
                                 }
 
                                 // Cannot register an account with an existing username
-                                if (db.ContainsUser(user)) return GenerateResponse(id, $"ERROR:{VERBOSE_RESPONSE}exists");
+                                if (db.ContainsUser(user)) return ErrorResponse(id, "exists");
 
                                 // Create the database user entry and generate a personal password salt
                                 Database.User u = new Database.User(user, pass, random.GetBytes(Math.Abs(random.NextShort() % 60) + 20), true);
@@ -286,11 +287,11 @@ namespace Server
                                 }
                                 catch
                                 {
-                                    return GenerateResponse(id, $"ERROR:{VERBOSE_RESPONSE}crypterr");
+                                    return ErrorResponse(id, "crypterr");
                                 }
                             }
                         default:
-                            return GenerateResponse(id, $"ERROR:{VERBOSE_RESPONSE}unwn"); // Unknown request
+                            return ErrorResponse(id, "unwn"); // Unknown request
                     }
 
                     return null;
@@ -304,81 +305,71 @@ namespace Server
             server.StartListening();
 
 
-            string commands =
+            bool running = true;
-                new OutputFormatter(4, "  ", "", "- ")
-                .Append("help", "Show this help menu")
-                .Append("stop", "Stop server")
-                .Append("sessions", "Show active client sessions")
-                .Append("list {admin}", "Show registered users. Add \"admin\" to only list admins")
-                .Append("admin [user] {true/false}", "Show or set admin status for a user")
-                .GetString();
-
-            Output.OnNewLine = () => Output.WriteOverwritable(">> ");
-            Output.OnNewLine();
-            // Server command loop
-            while (true)
-            {
-                string cmd = Output.ReadLine();
-                string[] parts = cmd.Split();
-
-                if (cmd.EqualsIgnoreCase("stop")) break;
-                else if (cmd.EqualsIgnoreCase("sessions"))
-                {
-                    StringBuilder builder = new StringBuilder();
-                    manager.Update(); // Ensure that we don't show expired sessions (artifacts exist until it is necessary to remove them)
-                    foreach (var session in manager.Sessions)
-                        builder.Append(session.user.Name).Append(" : ").Append(session.sessionID).Append('\n');
-                    if (builder.Length == 0) builder.Append("There are no active sessions at the moment");
-                    else builder.Length = builder.Length - 1;
-                    Output.Raw(builder);
-                }
-                else if (parts[0].EqualsIgnoreCase("admin"))
-                {
-                    if (parts.Length == 1) Output.Raw("Usage: admin [username] {true/false}");
-                    else if (parts.Length == 2)
-                    {
-                        Database.User user = db.GetUser(parts[1]);
-                        if (user == null) Output.RawErr($"User \"{parts[1]}\" could not be found in the databse!");
-                        else Output.Raw(user.IsAdministrator);
-                    }
-                    else if (parts.Length == 3)
-                    {
-                        Database.User user = db.GetUser(parts[1]);
-                        if (user == null) Output.RawErr($"User \"{parts[1]}\" could not be found in the databse!");
-                        else if (!bool.TryParse(parts[2].ToLower(), out bool admin)) Output.RawErr($"Could not interpret \"{parts[2]}\"");
-                        else
-                        {
-                            if (user.IsAdministrator == admin) Output.Info("The given administrator state was already set");
-                            else if (admin) Output.Raw("User is now an administrator");
-                            else Output.Raw("User is no longer an administrator");
-                            user.IsAdministrator = admin;
-                            db.AddUser(user);
-                        }
-                    }
-                    else Output.RawErr("Too many parameters!");
-                }
-                else if (parts[0].EqualsIgnoreCase("list"))
-                {
-                    if (parts.Length > 2) Output.RawErr("Too many parameters!");
-                    else
-                    {
-                        bool filter = parts.Length > 1, filterAdmin = filter && parts[1].EqualsIgnoreCase("admin");
 
+            // Create the command manager
+            CommandHandler commands = null;
+            commands =
+                new CommandHandler(4, "  ", "", "- ")
+                .Append(new Command("help").SetAction(() => Output.Raw("Available commands:\n" + commands.GetString())), "Show this help menu")
+                .Append(new Command("stop").SetAction(() => running = false), "Stop server")
+                .Append(new Command("sess").SetAction(
+                    (c, l) => {
                         StringBuilder builder = new StringBuilder();
-                        foreach (var user in db.Users(u => !filter || (filterAdmin && u.IsAdministrator)))
+                        manager.Update(); // Ensure that we don't show expired sessions (artifacts exist until it is necessary to remove them)
+                        foreach (var session in manager.Sessions)
+                            builder.Append(session.user.Name).Append(" : ").Append(session.sessionID).Append('\n');
+                        if (builder.Length == 0) builder.Append("There are no active sessions at the moment");
+                        else builder.Length = builder.Length - 1;
+                        Output.Raw(builder);
+                    }), "Show active client sessions")
+                .Append(new Command("list").WithParameter(Parameter.Flag('a')).SetAction(
+                    (c, l) => {
+                        bool filter = l.HasFlag('a');
+                        StringBuilder builder = new StringBuilder();
+                        foreach (var user in db.Users(u => !filter || (filter && u.IsAdministrator)))
                             builder.Append(user.Name).Append('\n');
                         if (builder.Length != 0)
                         {
                             builder.Length = builder.Length - 1;
                             Output.Raw(builder);
                         }
-                    }
+                    }), "Show registered users. Add \"-a\" to only list admins")
-                }
+                .Append(new Command("admin")
-                else if (cmd.EqualsIgnoreCase("help"))
+                    .WithParameter("username", 'u', Parameter.ParamType.STRING) // Guaranteed to appear in the list passed in the action
-                {
+                    .WithParameter("true/false", 's', Parameter.ParamType.BOOLEAN, true) // Might show up
-                    Output.Raw("Available commands:\n" + commands);
+                    .SetAction(
-                }
+                        (c, l) =>
-                else if (cmd.Length != 0) Output.RawErr("Unknown command. Use command \"help\" to view available commands");
+                        {
+                            bool set = l.HasFlag('s');
+                            string username = l.GetFlag('u');
+                            Database.User user = db.GetUser(username);
+                            if (user == null) {
+                                Output.RawErr($"User \"{username}\" could not be found in the databse!");
+                                return;
+                            }
+                            if (set)
+                            {
+                                bool admin = bool.Parse(l.GetFlag('s'));
+                                if (user.IsAdministrator == admin) Output.Info("The given administrator state was already set");
+                                else if (admin) Output.Raw("User is now an administrator");
+                                else Output.Raw("User is no longer an administrator");
+                                user.IsAdministrator = admin;
+                                db.AddUser(user);
+                            }
+                            else Output.Raw(user.IsAdministrator);
+                        }), "Show or set admin status for a user");
+
+            // Set up a persistent terminal-esque input design
+            Output.OnNewLine = () => Output.WriteOverwritable(">> ");
+            Output.OnNewLine();
+
+            // Server command loop
+            while (running)
+            {
+                // Handle command input
+                if (!commands.HandleCommand(Output.ReadLine()))
+                    Output.Error("Unknown command. Enter 'help' for a list of supported commands.", true, false);
             }
 
             server.StopRunning();

Server/Server.csproj

@@ -43,9 +43,11 @@
     <Reference Include="System.Xml" />
   </ItemGroup>
   <ItemGroup>
+    <Compile Include="Command.cs" />
     <Compile Include="Database.cs" />
     <Compile Include="Output.cs" />
-    <Compile Include="OutputFormatter.cs" />
+    <Compile Include="CommandHandler.cs" />
+    <Compile Include="Parameter.cs" />
     <Compile Include="Program.cs" />
     <Compile Include="Properties\AssemblyInfo.cs" />
     <Compile Include="Properties\Resources.Designer.cs">