Class: QueryHelper::SqlSort

Inherits:
Object
  • Object
show all
Defined in:
lib/query_helper/sql_sort.rb

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(sort_string: "", column_maps: []) ⇒ SqlSort

Returns a new instance of SqlSort.



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# File 'lib/query_helper/sql_sort.rb', line 8

def initialize(sort_string: "", column_maps: [])
  @sort_string = sort_string
  @column_maps = column_maps
  @select_strings = []
end

Instance Attribute Details

#column_maps ⇒ Object

Returns the value of attribute column_maps.



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# File 'lib/query_helper/sql_sort.rb', line 6

def column_maps
  @column_maps
end

#select_strings ⇒ Object

Returns the value of attribute select_strings.



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# File 'lib/query_helper/sql_sort.rb', line 6

def select_strings
  @select_strings
end

Instance Method Details

#parse_sort_string ⇒ Object 



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# File 'lib/query_helper/sql_sort.rb', line 14

def parse_sort_string
  sql_strings = []
  sorts = @sort_string.split(",")
  sorts.each_with_index do |sort, index|
    sort_alias = sort.split(":")[0]
    direction = sort.split(":")[1]
    modifier = sort.split(":")[2]

    begin
      sql_expression = @column_maps.find{ |m| m.alias_name == sort_alias }.sql_expression
    rescue NoMethodError => e
      raise InvalidQueryError.new("Sorting not allowed on column '#{sort_alias}'")
    end

    if direction == "desc"
      case ActiveRecord::Base.connection.adapter_name
      when "SQLite" # SQLite is used in the test suite
        direction = "desc"
      else
        direction = "desc nulls last"
      end
    else
      direction = "asc"
    end

    case modifier
    when "lowercase"
      sql_expression = "lower(#{sql_expression})"
      # When select distincts are used, the order by clause must be included in the select clause
      @select_strings << sql_expression
    end

    sql_strings << "#{sql_expression} #{direction}"
  end

  return sql_strings
end