Rails datatables server side processing impossible to sort/find - ruby-on-rails

Question

If i change the processing from client-side to server-side, i will get all information for the table, but I can't search and sort the columns. But its possible to go to the next page. I have only 2 columns for searching and sorting to test it. Hopefully you can help me.
Database:
t.text "comment"
t.datetime "created_at", :null => false
t.datetime "updated_at", :null => false
t.integer "source_stock_id"
t.integer "destination_stock_id"
t.integer "order_id"
js.coffee-Code:
jQuery ->
$("#product_relocates_table").dataTable
bProcessing: true
bServerSide: true
sAjaxSource: $('#product_relocates_table').data('source')
"aaSorting": [[ 0, "desc" ]]
Datatable-Code:
class ProductRelocatesDatatable
delegate :params, :h, :link_to, to: :#view
def initialize(view)
#view = view
end
def as_json(options = {})
{
sEcho: params[:sEcho].to_i,
iTotalRecords: ProductRelocate.count,
iTotalDisplayRecords: product_relocates.total_count,
aaData: data
}
end
private
def data
product_relocates.map do |product_relocate|
[
h(product_relocate.created_at),
h(product_relocate.comment),
h(product_relocate.source_stock),
h(product_relocate.destination_stock),
h(product_relocate.quantity),
link_to('Show', [:admin, product_relocate])
]
end
end
def product_relocates
#product_relocates ||= fetch_product_relocates
end
def fetch_product_relocates
product_relocates = ProductRelocate.order("#{sort_column} #{sort_direction}")
product_relocates = product_relocates.page(page).per(per)
if params[:sSearch].present?
search_string = search_columns.map do |search_column|
"#{search_column} like :search"
end.join(" OR ")
product_relocates = product_relocates.where(search_string, search: "%#{params[:sSearch]}%")
end
product_relocates
end
def page
params[:iDisplayStart].to_i/per + 1
end
def per
params[:iDisplayLength].to_i > 0 ? params[:iDisplayLength].to_i : 10
end
def search_columns
%w[product_relocates.created_at product_relocates.comment]
end
def sort_columns
%w[product_relocates.created_at product_relocates.comment]
end
def sort_column
sort_columns[params[:iSortCol_0].to_i]
end
def sort_direction
params[:sSortDir_0] == "desc" ? "desc" : "asc"
end
end

Answer 1

I refactored a superclass that handles server side multi-column searching and sorting:
https://gist.github.com/2936095
which is derived from:
http://railscasts.com/episodes/340-datatables
class Datatable
delegate :params, :h, :raw, :link_to, :number_to_currency, to: :#view
def initialize(klass,view)
#klass = klass
#view = view
end
def as_json(options = {})
{
sEcho: params[:sEcho].to_i,
iTotalRecords: #klass.count,
iTotalDisplayRecords: items.total_entries,
aaData: data
}
end
private
def data
[]
end
def items
#items ||= fetch_items
end
def fetch_items
items = filtered_list
items = selected_columns(items)
items = items.order(sort_order)
items = items.page(page).per_page(per_page)
if params[:sSearch].present?
items = items.where(quick_search)
end
items
end
def filtered_list
#klass.all
end
def selected_columns items
items
end
def quick_search
search_for = params[:sSearch].split(' ')
terms = {}
which_one = -1
criteria = search_for.inject([]) do |criteria,atom|
which_one += 1
terms["search#{which_one}".to_sym] = "%#{atom}%"
criteria << "(#{search_cols.map{|col| "#{col} like :search#{which_one}"}.join(' or ')})"
end.join(' and ')
[criteria, terms]
end
def page
params[:iDisplayStart].to_i/per_page + 1
end
def per_page
params[:iDisplayLength].to_i > 0 ? params[:iDisplayLength].to_i : 10
end
def columns
[]
end
def sort_order
colnum = 0
sort_by = []
while true
break if !sorted?(colnum)
sort_by << "#{sort_column(colnum)} #{sort_direction(colnum)}"
colnum += 1
end
sort_by.join(", ")
end
def sorted? index=0
!params["iSortCol_#{index}"].nil?
end
def sort_column index=0
index = "iSortCol_#{index}"
columns[params[index].to_i]
end
def sort_direction index=0
index = "sSortDir_#{index}"
params[index] == "desc" ? "desc" : "asc"
end
end