Merging two records together by an attribute into a new object

Question

Okay.. I've been banging my head against the wall on this one for a while now.

I have two models, let's say Downloads and Rankings, both with their very own unique schema. I need to merge these records by the hour they were created at, and then send that data to my view to display in a table, which looks as follows.

 Hour    download_count     overall_ranking
 1:00    10                 115
 2:00    11                 116
 ...

I'd like to create a sort of "meta" container, which has all of the attributes from the @download and the @ranking and the hour:

• hour created at
• download_count (from Download)
• overall_ranking (from Ranking)
• ...

How do I create this meta container object?

I'm able to group by downloads and rankings by hour created, and merge them via a hash. So I have an object that looks like:

@metrics = {"Sun, 06 May 2012 00:00:00" => [<Ranking ...>, <Download ...>], ...}

But I'm not sure how to make a new object that fits my schema above.. My only solution is to create a new class and manually set each attribute I want to transfer over. This feels really cumbersome though.

(I'm using rails 3.0.10 and ruby 1.8.7)

Answer 1

It sounds to me like you want to use a presenter. That link is from 2007, but that and searching for "rails presenter pattern" should get you heading in the right direction.