How/where to create a void method in CQRS pattern

Question

I am trying to implement the CQRS pattern in clean architecture.

I know If a commads/query then i need to add a folder named as commads/query in applictionLayer.

Now I want to create a void method. not a command or query it is just a void method. and I want to use this again into my queries and commands.

public void FormatSomethingHtml(Something something)
{
  something.FinePrint = _helper.FormatHtml(something.FinePrint, something.SiteCode.Name);
  // removed rest      
}

I don't know where should create this method.

If I create this method inside commandHandler, I could not reuse it. i.e:

public class UpdateSomethingCommandHandler : IRequestHandler<UpdateSomethingCommand, Something>
{   
    // removed rest
    public void FormatSomethingHtml(Something something)
    {
        something.FinePrint = _helper.FormatHtml(something.FinePrint, something.SiteCode.Name);
        // removed rest      
    }
}

In above method I can use inside UpdateSomethingCommandHandler. But I could not reuse it in another handler. ie. When I call like this new UpdateSomethingCommandHandler.FormatSomethingHtml(something); I got error.

Where can create a common method?

Answer 1

This should be a utility service and inject it in any query/handler you need.

Ex:

public interface IFormatService
{
void FormatSomethingHtml(Something something)
}

public class HtmlFormatService: IFormatService
{
public void FormatSomethingHtml(Something something)
{
  something.FinePrint = _helper.FormatHtml(something.FinePrint, something.SiteCode.Name);
  // removed rest      
}
}

In your handler, you would inject it and use it just like any other service

Also, I would consider changing the return type to either Something so you can update the object and return ot or simply accept a string and return the formatted string like this:

public string FormatSomethingHtml(string something)
{
  return _helper.FormatHtml(something.FinePrint, something.SiteCode.Name);
}

In your handler/query

var something = new Something();
something.Fingerprint = _formatter.FormatSomethingHtml(...)