gistfile1.txt

Refactor this code: URL Matching Edition
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So I have Pages, in a nested set so that each page has parent. That allows me to have urls like:

    /foo/bar

where the Page with permalink 'foo' has a child with the permalink 'bar'. In my routes.rb I have a general catch-all route as my last route. 

    map.page '/*tree', :controller => 'pages', :action => 'show'

and the show action pretty much just passes the params array to Page.find_by_params! method.

The code could have looked as simple as:

def self.find_from_params!(params)
  find_by_permalink(params.last)
end

but I want each page to only have _one_ distinct url (i.e. when finding the page 'foo' it needs to check that it's parent is 'bar'.

The code above works, thought it is intentionally fucking ugly. Go forth and work your Ruby magic on it.

HINTS: Lambdas?

EDIT: Oh, also assume that each page's permalink is unique within it's siblings.

page.rb

class Page

  def self.parse_params(params, parent=nil)
    return parent if params.empty?
    # Exit condition: raises error if there are no permalinks
    puts page = find_by_permalink_and_parent!(params.first, parent)
    params.shift!
    
    parse_params(params, page)
  end
  
  # ActiveRecord Bug: doesn't use IS if arg is NULL.
  def self.find_by_permalink_and_parent!(permalink, parent)
    if parent
      res = first :conditions => ['parent_id = ? && permalink = ?', parent, permalink]
    else
      res = first :conditions => ['parent_id IS ? && permalink = ?', parent, permalink]
    end
    raise ActiveRecord::RecordNotFound unless res
    res
  end
  
  def self.find_from_params!(params)
    parse_params(params)
  end
  
end