Pitfalls

The missing attributes

The missing select statement

The most trap i step on is when i forget to select attributes, that are used during rendering. Here is a quick example.

A User model has the attributes first_name and last_name and a method full_name that combines the two:

class User < ActiveRecord::Base
  def full_name
    "#{first_name} #{last_name}"
  end
end

Now when i define a fancygrid to show the full name only, it will not work

def index
  fancygrid_for :users do |g|
    g.columns :full_name
    g.find
  end
end

The problem is that the attributes first_name and last_name are not selected in the sql query and the records are returned without them. So the solution is to select both attributes in the find block

def index
  fancygrid_for :users do |g|
    g.columns :full_name
    g.find do |query|
      query.select :first_name, :last_name
    end
  end
end

Another solution is to disable the query optimization. However, this is not recommended for large data.

def index
  fancygrid_for :users do |g|
    g.columns :full_name
    g.select = false
    g.find
  end
end

The missing else case

If you add a block to the fancygrid render method, then you are able to format column values. Inside that block you usually have a switch statement to handle each column. If the else case is missing on the end of the statement, unformatted columns will appear with no content.

This is bad

= fancygrid :users do |column, record, value|
  - case column.name
  - when :email
    = mail_to value

This is good

= fancygrid :users do |column, record, value|
  - case column.name
  - when :email
    = mail_to value
  - else
    = value