addition of post action attribute

src/Discord.Net.Commands/Attributes/PostActionAttribute.cs

@@ -0,0 +1,11 @@
+using System;
+using System.Threading.Tasks;
+
+namespace Discord.Commands
+{
+    [AttributeUsage(AttributeTargets.Method | AttributeTargets.Class, AllowMultiple = true, Inherited = true)]
+    public abstract class PostActionAttribute : Attribute
+    {
+        public abstract Task ExecuteAsync(ICommandContext context, CommandInfo command, IResult result, IServiceProvider services);
+    }
+}

src/Discord.Net.Commands/Builders/CommandBuilder.cs

@@ -1,4 +1,4 @@
-using System;
+using System;
 using System.Linq;
 using System.Threading.Tasks;
 using System.Collections.Generic;
@@ -9,6 +9,7 @@ namespace Discord.Commands.Builders
     public class CommandBuilder
     {
         private readonly List<PreconditionAttribute> _preconditions;
+        private readonly List<PostActionAttribute> _postActions;
         private readonly List<ParameterBuilder> _parameters;
         private readonly List<Attribute> _attributes;
         private readonly List<string> _aliases;
@@ -24,6 +25,7 @@ namespace Discord.Commands.Builders
         public int Priority { get; set; }
 
         public IReadOnlyList<PreconditionAttribute> Preconditions => _preconditions;
+        public IReadOnlyList<PostActionAttribute> PostActions => _postActions;
         public IReadOnlyList<ParameterBuilder> Parameters => _parameters;
         public IReadOnlyList<Attribute> Attributes => _attributes;
         public IReadOnlyList<string> Aliases => _aliases;
@@ -34,6 +36,7 @@ namespace Discord.Commands.Builders
             Module = module;
 
             _preconditions = new List<PreconditionAttribute>();
+            _postActions = new List<PostActionAttribute>();
             _parameters = new List<ParameterBuilder>();
             _attributes = new List<Attribute>();
             _aliases = new List<string>();
@@ -96,6 +99,11 @@ namespace Discord.Commands.Builders
             _preconditions.Add(precondition);
             return this;
         }
+        public CommandBuilder AddPostAction(PostActionAttribute postAction)
+        {
+            _postActions.Add(postAction);
+            return this;
+        }
         public CommandBuilder AddParameter<T>(string name, Action<ParameterBuilder> createFunc)
         {
             var param = new ParameterBuilder(this, name, typeof(T));
@@ -140,4 +148,4 @@ namespace Discord.Commands.Builders
             return new CommandInfo(this, info, service);
         }
     }
-}
+}

src/Discord.Net.Commands/Builders/ModuleBuilder.cs

@@ -1,4 +1,4 @@
-using System;
+using System;
 using System.Collections.Generic;
 using System.Threading.Tasks;
 using Microsoft.Extensions.DependencyInjection;
@@ -10,6 +10,7 @@ namespace Discord.Commands.Builders
         private readonly List<CommandBuilder> _commands;
         private readonly List<ModuleBuilder> _submodules;
         private readonly List<PreconditionAttribute> _preconditions;
+        private readonly List<PostActionAttribute> _postActions;
         private readonly List<Attribute> _attributes;
         private readonly List<string> _aliases;
 
@@ -22,6 +23,7 @@ namespace Discord.Commands.Builders
         public IReadOnlyList<CommandBuilder> Commands => _commands;
         public IReadOnlyList<ModuleBuilder> Modules => _submodules;
         public IReadOnlyList<PreconditionAttribute> Preconditions => _preconditions;
+        public IReadOnlyList<PostActionAttribute> PostActions => _postActions;
         public IReadOnlyList<Attribute> Attributes => _attributes;
         public IReadOnlyList<string> Aliases => _aliases;
 
@@ -34,6 +36,7 @@ namespace Discord.Commands.Builders
             _commands = new List<CommandBuilder>();
             _submodules = new List<ModuleBuilder>();
             _preconditions = new List<PreconditionAttribute>();
+            _postActions = new List<PostActionAttribute>();
             _attributes = new List<Attribute>();
             _aliases = new List<string>();
         }
@@ -82,6 +85,11 @@ namespace Discord.Commands.Builders
             _preconditions.Add(precondition);
             return this;
         }
+        public ModuleBuilder AddPostAction(PostActionAttribute postAction)
+        {
+            _postActions.Add(postAction);
+            return this;
+        }
         public ModuleBuilder AddCommand(string primaryAlias, Func<ICommandContext, object[], IServiceProvider, CommandInfo, Task> callback, Action<CommandBuilder> createFunc)
         {
             var builder = new CommandBuilder(this, primaryAlias, callback);

src/Discord.Net.Commands/Builders/ModuleClassBuilder.cs

@@ -122,6 +122,9 @@ namespace Discord.Commands
                     case PreconditionAttribute precondition:
                         builder.AddPrecondition(precondition);
                         break;
+                    case PostActionAttribute postAction:
+                        builder.AddPostAction(postAction);
+                        break;
                     default:
                         builder.AddAttributes(attribute);
                         break;
@@ -176,6 +179,9 @@ namespace Discord.Commands
                     case PreconditionAttribute precondition:
                         builder.AddPrecondition(precondition);
                         break;
+                    case PostActionAttribute postAction:
+                        builder.AddPostAction(postAction);
+                        break;
                     default:
                         builder.AddAttributes(attribute);
                         break;

src/Discord.Net.Commands/CommandMatch.cs

@@ -1,4 +1,4 @@
-using System;
+using System;
 using System.Collections.Generic;
 using System.Threading.Tasks;
 using Microsoft.Extensions.DependencyInjection;
@@ -18,6 +18,8 @@ namespace Discord.Commands
 
         public Task<PreconditionResult> CheckPreconditionsAsync(ICommandContext context, IServiceProvider services = null)
             => Command.CheckPreconditionsAsync(context, services);
+        public Task ExecutePostActionsAsync(ICommandContext context, IResult result, IServiceProvider services = null)
+            => Command.ExecutePostActionsAsync(context, result, services);
         public Task<ParseResult> ParseAsync(ICommandContext context, SearchResult searchResult, PreconditionResult preconditionResult = null, IServiceProvider services = null)
             => Command.ParseAsync(context, Alias.Length, searchResult, preconditionResult, services);
         public Task<IResult> ExecuteAsync(ICommandContext context, IEnumerable<object> argList, IEnumerable<object> paramList, IServiceProvider services)

src/Discord.Net.Commands/CommandService.cs

@@ -1,4 +1,4 @@
-using Discord.Commands.Builders;
+using Discord.Commands.Builders;
 using Discord.Logging;
 using System;
 using System.Collections.Concurrent;
@@ -362,7 +362,11 @@ namespace Discord.Commands
 
             //If we get this far, at least one parse was successful. Execute the most likely overload.
             var chosenOverload = successfulParses[0];
-            return await chosenOverload.Key.ExecuteAsync(context, chosenOverload.Value, services).ConfigureAwait(false);
+            var result = await chosenOverload.Key.ExecuteAsync(context, chosenOverload.Value, services).ConfigureAwait(false);
+
+            await chosenOverload.Key.ExecutePostActionsAsync(context, result, services).ConfigureAwait(false);
+
+            return result;
         }
     }
 }

src/Discord.Net.Commands/Info/CommandInfo.cs

@@ -32,6 +32,7 @@ namespace Discord.Commands
         public IReadOnlyList<string> Aliases { get; }
         public IReadOnlyList<ParameterInfo> Parameters { get; }
         public IReadOnlyList<PreconditionAttribute> Preconditions { get; }
+        public IReadOnlyList<PostActionAttribute> PostActions { get; }
         public IReadOnlyList<Attribute> Attributes { get; }
 
         internal CommandInfo(CommandBuilder builder, ModuleInfo module, CommandService service)
@@ -59,6 +60,7 @@ namespace Discord.Commands
                 .ToImmutableArray();
 
             Preconditions = builder.Preconditions.ToImmutableArray();
+            PostActions = builder.PostActions.ToImmutableArray();
             Attributes = builder.Attributes.ToImmutableArray();
 
             Parameters = builder.Parameters.Select(x => x.Build(this)).ToImmutableArray();
@@ -109,6 +111,16 @@ namespace Discord.Commands
             return PreconditionResult.FromSuccess();
         }
 
+        public async Task ExecutePostActionsAsync(ICommandContext context, IResult result, IServiceProvider services = null)
+        {
+            services = services ?? EmptyServiceProvider.Instance;
+
+            foreach (var postAction in Enumerable.Concat(PostActions, Module.PostActions))
+            {
+                await postAction.ExecuteAsync(context, this, result, services).ConfigureAwait(false);
+            }
+        }
+
         public async Task<ParseResult> ParseAsync(ICommandContext context, int startIndex, SearchResult searchResult, PreconditionResult preconditionResult = null, IServiceProvider services = null)
         {
             services = services ?? EmptyServiceProvider.Instance;

src/Discord.Net.Commands/Info/ModuleInfo.cs

@@ -17,6 +17,7 @@ namespace Discord.Commands
         public IReadOnlyList<string> Aliases { get; }
         public IReadOnlyList<CommandInfo> Commands { get; }
         public IReadOnlyList<PreconditionAttribute> Preconditions { get; }
+        public IReadOnlyList<PostActionAttribute> PostActions { get; }
         public IReadOnlyList<Attribute> Attributes { get; }
         public IReadOnlyList<ModuleInfo> Submodules { get; }
         public ModuleInfo Parent { get; }
@@ -34,6 +35,7 @@ namespace Discord.Commands
             Aliases = BuildAliases(builder, service).ToImmutableArray();
             Commands = builder.Commands.Select(x => x.Build(this, service)).ToImmutableArray();
             Preconditions = BuildPreconditions(builder).ToImmutableArray();
+            PostActions = BuildPostActions(builder).ToImmutableArray();
             Attributes = BuildAttributes(builder).ToImmutableArray();
 
             Submodules = BuildSubmodules(builder, service).ToImmutableArray();
@@ -90,6 +92,20 @@ namespace Discord.Commands
             return result;
         }
 
+        private static List<PostActionAttribute> BuildPostActions(ModuleBuilder builder)
+        {
+            var result = new List<PostActionAttribute>();
+
+            ModuleBuilder parent = builder;
+            while (parent != null)
+            {
+                result.AddRange(parent.PostActions);
+                parent = parent.Parent;
+            }
+
+            return result;
+        }
+
         private static List<Attribute> BuildAttributes(ModuleBuilder builder)
         {
             var result = new List<Attribute>();

src/Discord.Net.Commands/Results/PreconditionResult.cs

@@ -1,4 +1,4 @@
-using System.Diagnostics;
+using System.Diagnostics;
 
 namespace Discord.Commands
 {