feat: Improve command validation

Author: alex289

DockerDiscordBot/Commands/Command.cs

@@ -1,14 +1,18 @@
 using Discord.WebSocket;
+using FluentValidation.Results;
 using MediatR;
 
 namespace DockerDiscordBot.Commands;
 
 public abstract class Command : IRequest
 {
     public SocketMessage Message { get; }
+    public ValidationResult? ValidationResult { get; protected set; }
 
     protected Command(SocketMessage message)
     {
         Message = message;
     }
+    
+    public abstract bool IsValid();
 }

DockerDiscordBot/Commands/CommandHandler.cs

@@ -13,4 +13,25 @@ protected CommandHandler(ILogger<CommandHandler<T>> logger)
     }
 
     public abstract Task Handle(T request, CancellationToken cancellationToken);
+    
+    protected async ValueTask<bool> TestValidityAsync(Command command)
+    {
+        if (command.IsValid())
+        {
+            return true;
+        }
+
+        if (command.ValidationResult is null)
+        {
+            throw new InvalidOperationException("Command is invalid and should therefore have a validation result");
+        }
+
+        foreach (var error in command.ValidationResult!.Errors)
+        {
+            Logger.LogWarning("Validation error: {ErrorMessage}", error.ErrorMessage);
+            await command.Message.Channel.SendMessageAsync(error.ErrorMessage);
+        }
+
+        return false;
+    }
 }

DockerDiscordBot/Commands/CommandValidation.cs

@@ -0,0 +1,43 @@
+using FluentValidation;
+
+namespace DockerDiscordBot.Commands;
+
+public abstract class CommandValidation<T> : AbstractValidator<T> where T : Command
+{
+    protected void AddRuleForMessageContent(
+        int? parameterMinAmount = null,
+        int? parameterMaxAmount = null)
+    {
+        if (parameterMinAmount is null && parameterMaxAmount is null)
+        {
+            return;
+        }
+        
+        RuleFor(x => x.Message.Content)
+            .NotEmpty()
+            .WithMessage("Message content cannot be empty.");
+        
+        if (parameterMinAmount is not null && parameterMaxAmount is not null)
+        {
+            var message = parameterMinAmount == parameterMaxAmount
+                ? $"Message content must have exactly {parameterMinAmount} parameter(s)."
+                : $"Message content must have between {parameterMinAmount} and {parameterMaxAmount} parameter(s).";
+            
+            RuleFor(x => x.Message.Content.Split(" ", StringSplitOptions.None))
+                .Must(x => x.Length >= parameterMinAmount + 1 && x.Length <= parameterMaxAmount + 1)
+                .WithMessage(message);
+        }
+        else if (parameterMinAmount is not null)
+        {
+            RuleFor(x => x.Message.Content.Split(" ", StringSplitOptions.None))
+                .Must(x => x.Length >= parameterMinAmount + 1)
+                .WithMessage($"Message content must have at least {parameterMinAmount} parameter(s).");
+        }
+        else if (parameterMaxAmount is not null)
+        {
+            RuleFor(x => x.Message.Content.Split(" ", StringSplitOptions.None))
+                .Must(x => x.Length <= parameterMaxAmount + 1)
+                .WithMessage($"Message content must have at most {parameterMaxAmount} parameter(s).");
+        }
+    }
+}

DockerDiscordBot/Commands/CreateContainer/CreateContainerCommand.cs

@@ -4,7 +4,19 @@ namespace DockerDiscordBot.Commands.CreateContainer;
 
 public sealed class CreateContainerCommand : Command
 {
+    private static readonly CreateContainerCommandValidation s_validation = new();
+    
+    public string ImageId => Message.Content.Split(" ").ElementAtOrDefault(1) ?? string.Empty;
+    public string ContainerName => Message.Content.Split(" ").ElementAtOrDefault(2) ?? string.Empty;
+    public string Ports => Message.Content.Split(" ").ElementAtOrDefault(3) ?? string.Empty;
+    
     public CreateContainerCommand(SocketMessage message) : base(message)
     {
     }
+    
+    public override bool IsValid()
+    {
+        ValidationResult = s_validation.Validate(this);
+        return ValidationResult.IsValid;
+    }
 }

DockerDiscordBot/Commands/CreateContainer/CreateContainerCommandHandler.cs

@@ -18,28 +18,15 @@ public override async Task Handle(CreateContainerCommand request, CancellationTo
     {
         Logger.LogInformation("Executing {Command}", nameof(CreateContainerCommand));
 
-        var parameters = request.Message.Content.Split(" ");
-
-        var image = parameters.ElementAtOrDefault(1);
-        var containerName = parameters.ElementAtOrDefault(2);
-        var ports = parameters.ElementAtOrDefault(3);
-
-        if (string.IsNullOrWhiteSpace(image))
-        {
-            await request.Message.Channel.SendMessageAsync("Please provide a container id.");
-            return;
-        }
-
-        if (string.IsNullOrWhiteSpace(containerName))
+        if (!await TestValidityAsync(request))
         {
-            await request.Message.Channel.SendMessageAsync("Please provide a container id.");
             return;
         }
 
-        var imageWithoutTag = image.Contains(":") ? image.Split(":")[0] : image;
-        var tag = image.Contains(":") ? image.Split(":")[^1] : "latest";
+        var imageWithoutTag = request.ImageId.Contains(":") ? request.ImageId.Split(":")[0] : request.ImageId;
+        var tag = request.ImageId.Contains(":") ? request.ImageId.Split(":")[^1] : "latest";
 
-        var imageExists = await _dockerService.ImageExistsAsync(image, cancellationToken);
+        var imageExists = await _dockerService.ImageExistsAsync(request.ImageId, cancellationToken);
 
         if (!imageExists)
         {
@@ -55,9 +42,9 @@ public override async Task Handle(CreateContainerCommand request, CancellationTo
 
         var portMapping = new Dictionary<string, string>();
 
-        if (!string.IsNullOrWhiteSpace(ports))
+        if (!string.IsNullOrWhiteSpace(request.Ports))
         {
-            var portPairs = ports.Split(",");
+            var portPairs = request.Ports.Split(",");
 
             foreach (var portPair in portPairs)
             {
@@ -68,13 +55,13 @@ public override async Task Handle(CreateContainerCommand request, CancellationTo
 
         var containerId = await _dockerService.CreateContainerAsync(
             imageWithoutTag + ":" + tag,
-            containerName,
+            request.ContainerName,
             portMapping,
             cancellationToken);
 
         if (containerId is null)
         {
-            await request.Message.Channel.SendMessageAsync($"Failed to create container {containerName}.");
+            await request.Message.Channel.SendMessageAsync($"Failed to create container {request.ContainerName}.");
             return;
         }
 

DockerDiscordBot/Commands/CreateContainer/CreateContainerCommandValidation.cs

@@ -0,0 +1,27 @@
+using FluentValidation;
+
+namespace DockerDiscordBot.Commands.CreateContainer;
+
+public sealed class CreateContainerCommandValidation : CommandValidation<CreateContainerCommand>
+{
+    public CreateContainerCommandValidation()
+    {
+        AddRuleForMessageContent(2, 3);
+        AddRuleForImageId();
+        AddRuleForContainerName();
+    }
+    
+    private void AddRuleForImageId()
+    {
+        RuleFor(x => x.ImageId)
+            .NotEmpty()
+            .WithMessage("Image id cannot be empty.");
+    }
+
+    private void AddRuleForContainerName()
+    {
+        RuleFor(x => x.ContainerName)
+            .NotEmpty()
+            .WithMessage("Container name cannot be empty.");
+    }
+}

DockerDiscordBot/Commands/GetContainers/GetContainersCommand.cs

@@ -7,4 +7,6 @@ public sealed class GetContainersCommand : Command
     public GetContainersCommand(SocketMessage message) : base(message)
     {
     }
+    
+    public override bool IsValid() => true;
 }

DockerDiscordBot/Commands/GetDockerInfo/GetDockerInfoCommand.cs

@@ -7,4 +7,6 @@ public sealed class GetDockerInfoCommand : Command
     public GetDockerInfoCommand(SocketMessage message) : base(message)
     {
     }
+    
+    public override bool IsValid() => true;
 }

DockerDiscordBot/Commands/GetDockerInfo/GetDockerInfoCommandHandler.cs

@@ -19,7 +19,6 @@ public override async Task Handle(GetDockerInfoCommand request, CancellationToke
     {
         Logger.LogInformation("Executing {Command}", nameof(GetDockerInfoCommand));
 
-
         var result = await _dockerService.GetDockerInfoAsync(cancellationToken);
 
         if (result is null)

DockerDiscordBot/Commands/GetImages/GetImagesCommand.cs

@@ -7,4 +7,6 @@ public sealed class GetImagesCommand : Command
     public GetImagesCommand(SocketMessage message) : base(message)
     {
     }
+    
+    public override bool IsValid() => true;
 }