Built-In Attributes

CommandsNext has a variety of built-in attributes to enhance your commands and provide some access control. The majority of these attributes can be applied to your command methods and command groups.

• AliasesAttribute
• CooldownAttribute
• DescriptionAttribute
• CategoryAttribute
• DontInjectAttribute
• HiddenAttribute
• ModuleLifespanAttribute
• PriorityAttribute
• RemainingTextAttribute
• RequireBotPermissionsAttribute
• RequireDirectMessageAttribute
• RequireGuildAttribute
• RequireNsfwAttribute
• RequireOwnerAttribute
• RequirePermissionsAttribute
• RequirePrefixesAttribute
• RequireRolesAttribute
• RequireUserPermissionsAttribute

Custom Attributes

If the above attributes don't meet your needs, CommandsNext also gives you the option of writing your own! Simply create a new class which inherits from CheckBaseAttribute and implement the required method.

Our example below will only allow a command to be ran during a specified year.

public class RequireYearAttribute : CheckBaseAttribute
{
    public int AllowedYear { get; private set; }

    public RequireYearAttribute(int year)
    {
        AllowedYear = year;
    }

    public override Task<bool> ExecuteCheckAsync(CommandContext ctx, bool help)
    {
        return Task.FromResult(AllowedYear == DateTime.Now.Year);
    }
}

You'll also need to apply the AttributeUsage attribute to your attribute. For our example attribute, we'll set it to only be usable once on methods.

[AttributeUsage(AttributeTargets.Method, AllowMultiple = false)]
public class RequireYearAttribute : CheckBaseAttribute
{
    // ...
}

You can provide feedback to the user using the CommandErrored event.

private async Task Main(string[] args)
{
    var discord = new DiscordClient();
    var commands = discord.UseCommandsNext();

    commands.CommandErrored += CmdErroredHandler;
}

private async Task CmdErroredHandler(CommandsNextExtension _, CommandErrorEventArgs e)
{
    var failedChecks = ((ChecksFailedException)e.Exception).FailedChecks;
    foreach (var failedCheck in failedChecks)
    {
        if (failedCheck is RequireYearAttribute)
        {
            var yearAttribute = (RequireYearAttribute)failedCheck;
            await e.Context.RespondAsync($"Only usable during year {yearAttribute.AllowedYear}.");
        }
    }
}

Once you've got all of that completed, you'll be able to use it on a command!

[Command("generic"), RequireYear(2030)]
public async Task GenericCommand(CommandContext ctx, string generic)
{
    await ctx.RespondAsync("Generic response.");
}