[LRUG] [Bulk] Best practice for reports

[Daniel Lucraft]

Hi Paul,

It may help you to know that what you are calling a 'report' is called a 
'Presenter' in the rails world, which should help you with googling. 
Kudos for independently inventing a design pattern. :)

If you google for "ruby rails presenter" the top two articles by Jay 
Fields do exactly what you do, and he seems to think it's a good idea. 
Other people have talked about Presenters in the context of rails best 
practice.

Personally I would only go this far if (1) I was extremely serious about 
doing things right and testing properly or (2) the complexity/size of 
the code made it look like a good idea.

Other people with more experience may feel different.

best,
Dan

Paul Doerwald wrote:
> Hi everyone,
> 
> I'm asking this question in the interests of separating business logic 
> from presentation. I have a standard reporting problem — I have a bunch 
> of data in a database, and I want to dig through it, sort it, sum it, 
> frob it, average it, and display it.
> 
> The easiest way to do it is in the view:
> 
> <th><%= f.name</th><td><%= Foo.count(:conditions => "blah") %></td>
> 
> but then I've committed the heinous sin of putting the business 
> (reporting!) logic into the view. I could avoid that by stuffing it into 
> the controller, essentially mimicking the table structure, but in a hash 
> of some sort:
> 
> report = Hash.new
> report["Baz"] = { :name => f.name, :sum => Foo.count(:conditions => 
> "blah") }
> 
> But I'm not convinced that I'm winning anything here.... plus the 
> "Rails" way of doing things is to move the logic out of the controller 
> into the model... but then what if I'm pulling data from half a dozen 
> different tables? Presumably then I need to create a new 
> (non-ActiveRecord) model, perhaps:
> 
> class Report
>   class self.main_report
>     # create the hash here
>   end
> end
> 
> But that is just indirection another step away, so what I really should 
> do is:
> 
> class Report
> end
> 
> class MainReport < Report
>   attr_accessor :title, ...all the other fields I might want to use...
> 
>   def frob
>     # prepare the report
>   end
> end
> 
> and then in the controller, instantiate the MainReport, and do the 
> looping in the view... but now I've created a whole lot of work for 
> myself to simply do what I could do with much less effort in the first 
> instance.
> 
> I suspect the last option is probably the best — at least of the ones 
> I've presented — but I'm more interested in what others have read about 
> or done which they feel is the "best practice" for reporting.
> 
> Along this thread, has anyone used http://rubyreports.org/ ? Is it 
> appropriate for me? I haven't looked closely yet, but am about to.
> 
> Thanks,
> Paul.
> 
> 
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