如何从Rails Controller中删除代码块

Question

I am trying to remove a code section from my controller so that it looks clean and thin. In one of my controller I have to use many conditions and that is making my controller look very heavy. I just want to remove just that code block in other file and want to include it into my controller. My controller code

Here you can see I am using some logic like:

   if search == 'Primary'
    if rain_fall_type == "Agriculture, Forestry and Fishing"

      if compare == "None"
        search = "None"
        rain_fall_type
      elsif compare == "All"
        rain_fall_type = compare
        data = [
          "Crops",
          "Livestock",
          "Forestry and Logging",
          "Fishing and Aquaculture",
        ]
      else
        search = "None"
        rain_fall_type = compare
      end

    elsif rain_fall_type == "None"
      rain_fall_type

      data = [
        "Primary",
      ]

    else
      data = [
        "Agriculture, Forestry and Fishing",
        "Mining and Quarrying",
      ]
    end
    ......

I want this section to be in some other files and want to call it as it is. I can write a function and a method and return values. My question is can I call this code block as it is without returning function or anything. For example I need to do something like this:

  a = if test == "a"
       #my code
    end

   #and in my controller 

  def test
     a 
  end

Can we do this in ruby put all code block in one file and call that value in my controller.

Answer 1

To give you a short answer, so you can start right away you can do something like this:

if search == 'Primary'
  data, search = RainFallSearcher.call(rain_fall_type, compare)
end

class RainFallSearcher
  def call(rain_fall_type, compare)
    if rain_fall_type == "Agriculture, Forestry and Fishing"
      if compare == "None"
        search = "None"
        rain_fall_type
      elsif compare == "All"
        rain_fall_type = compare
        data = [
          "Crops",
          "Livestock",
          "Forestry and Logging",
          "Fishing and Aquaculture",
        ]
      else
        search = "None"
        rain_fall_type = compare
      end
    elsif rain_fall_type == "None"
      data = [
        "Primary",
      ]
    else
      data = [
        "Agriculture, Forestry and Fishing",
        "Mining and Quarrying",
      ]
    end

    return data, search
  end
end

You can then have RainFallSearcher in a location that's loaded by Rails (I would choose app/services .

You are not forced to have all your logic in the controllers or the models, it's actually recommended to have them quite thin, and create simple (or complex) Ruby objects to deal with the logic.

One of the "patterns" I like in Rails is "Service Object" (there are various discussion and naming convention), so google that and you can get more information.

This article is quite explanatory: https://www.engineyard.com/blog/keeping-your-rails-controllers-dry-with-services