Forum: Ruby ask bout net-ping

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437595de52cf59f7fbd847ccb94492af?d=identicon&s=25 Junior Junior wangsa (vgenjr)
on 2009-04-02 03:40
hi,

can anybody help me?
i wanna create a RoR monitoring application for my project.
i have a database with table named nodes
in that nodes i have id and ipadd.

here's my code:
#nodes_controller.rb

require 'net/ping'
include Net

class NodesController < ApplicationController
  def index
    @nodes = Node.find(:all)

    @arr_stat = Array.new
    i = 0
    for node in @nodes do

      stat = PingExternal.new(node.ipadd)

      @arr_stat[i]['ipadd'] = node.ipadd
      if stat
        @arr_stat[i]['status'] = 'online';
        puts "online"
      else
        @arr_stat[i]['status'] = 'offline';
        puts "offline"
      end
    end

    respond_to do |format|
      format.html { render :html => @arr_stat }# index.html.erb
      format.xml  { render :xml => @nodes }
    end
  end
##########################

why when i run the code it always says:

You have a nil object when you didn't expect it!
You might have expected an instance of ActiveRecord::Base.
The error occurred while evaluating nil.[]=

please help me solved this.
1bc63d01bd3fcccc36fb030a62039352?d=identicon&s=25 David Masover (Guest)
on 2009-04-02 05:31
(Received via mailing list)
On Wednesday 01 April 2009 20:40:12 Junior Junior wangsa wrote:

>       @arr_stat[i]['ipadd'] = node.ipadd
[...]
> why when i run the code it always says:
>
> You have a nil object when you didn't expect it!
> You might have expected an instance of ActiveRecord::Base.
> The error occurred while evaluating nil.[]=

I'm guessing @arr_stat[i] is nil at some point.

Also, for future reference, Rails raises that particular error quite
often.
Pasting that would be like pasting "segmentation fault" to a C
development
group. I'm sure the error included more information than that.

But you may want to take this to the Rails group.
437595de52cf59f7fbd847ccb94492af?d=identicon&s=25 Junior Junior wangsa (vgenjr)
on 2009-04-02 06:26
ups..
i post wrong place.. sorry
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