class DataTable def initialize user, params @user = user @params = sanitize_params(params) @transactions = TransactionsQuery.new(@user) @table = @transactions.arel_table end def json response_json(@params[:draw], data) end def data ActiveRecord::Base.connection.execute(self.query.to_sql) end def query #pred = predicates q = @transactions.query #q = q.where(pred) if pred q end def predicates [ *range_predicates(:amount), *range_predicates(:time), eq_predicate(:peer), eq_predicate(:issuer), like_predicate(:message) ].compact.inject { |l, r| l.and(r) } end def range_predicates name col = @params[:columns][name] [ (@table[:name].gteq(col[:lower]) if col[:lower]), (@table[:name].lteq(col[:upper]) if col[:upper]) ] end def eq_predicate name value = @params[:columns][:name][:value] @table[:name].eq(value) if value end def like_predicate name value = @params[:columns][:name][:value] @table[:name].matches("%#{value}%") if value end private def sanitize_params(params) # Parsing according to https://datatables.net/manual/server-side clean = { draw: params.require(:draw).to_i, start: params.require(:start).to_i, length: params.require(:length).to_i, columns: Hash.new } params.require(:columns).each do |i, column| type, value = column.require(:search)[:value].split(':') h = clean[:columns][column.require(:data).to_sym] = { name: column[:name], searchable: column[:searchable] == 'true', orderable: column[:orderable] == 'true', type: type } if type == 'number-range' h[:lower], h[:upper] = value.split('~').map &:to_i elsif type == 'date-range' h[:lower], h[:upper] = value.split('~').map &:to_datetime else h[:value] = value end end return clean end def response_json(draw, selection) { draw: draw, recordsTotal: @user.transactions.count, recordsFiltered: selection.count, #data: selection.offset(params[:start]).take(params[:length]).map { |transaction| { #time: transaction.created_at, #amount: transaction.signed_amount_for(user), #peer: transaction.peer_of(user).try(:name), #issuer: transaction.issuer.name, #message: transaction.message, #}} data: selection } end end