使用参数值作为轨道上的循环范围红宝石

Question

Controller return error "bad value for range" when passing param as loop range limit, following is my code

def creategroups
  require 'fileutils'
  @gcount = params[:group_count]
  for i in (1..@gcount) do
    Fileutils::mkdir_p "/groups/group_#{i}"
  end
  render json: params
end

here group_count is the number of groups to be created.

Answer 1

When you fetch a parameter from the request, the value is generally a String. Therefore, in the following line @gcount is a String, not an integer.

@gcount = params[:group_count]

You need to cast it. Moreover, in Ruby you never use the for loop, rather you use blocks.

require 'fileutils'

def creategroups
  gcount = params[:group_count].to_i
  gcount.times do |index|
    Fileutils::mkdir_p "/groups/group_#{index}"
  end
  render json: params
end

or to keep it shorter

require 'fileutils'

def creategroups
  params[:group_count].to_i.times do |index|
    Fileutils::mkdir_p "/groups/group_#{index}"
  end
  render json: params
end

Of course, you may want to validate :group_count to avoid someone passes a gigantic number that will kill your system.