From: Joe Van Dyk <joevandyk@...>
Date: 2006-01-26T02:08:49+09:00
Subject: Re: DRb and ActiveRecord

On 1/25/06, Ezra Zygmuntowicz <ezmobius@gmail.com> wrote:
> Friends-
>
>         I am trying to make a drb server publish an ActiveRecord model so it
> can be used by remote clients. It looks like I am getting close but
> no cigar. Can some kind soul enlighten me as to how to make this
> work? It seems like it is communicating with the remote AR model. And
> I am able to create records and find records. But I am unable to
> display the contents of the records on the client side. It seems like
> drb is not unmarshaling them correctly. Do I need to use DRbUndumped
> or something similar? Any help is greatly appreciated!
>
>         Here is my code and irb session:
> # server.rb
>
> #!/usr/local/bin/ruby
> require 'rubygems'
> require 'drb/drb'
> require_gem 'activerecord'
>
> ActiveRecord::Base.establish_connection(
>      :adapter  => "mysql",
>      :username => "root",
>      :host     => "localhost",
>      :password => "reversal",
>      :database => "switchboard_development"
> )
>
> class RemoteRecord < ActiveRecord::Base
> end
>
> DRb.start_service("druby://:3500", RemoteRecord)
> puts DRb.uri
> DRb.thread.join
> --------------------------------------
> And my irb session trying to access the remote model.
>
> ezra:~ ez$ irb
> irb(main):001:0> require 'rubygems'
> => true
> irb(main):002:0> require 'drb/drb'
> => true
> irb(main):003:0> require_gem 'activerecord'
> => true
> irb(main):005:0* DRb.start_service
> => #<DRb::DRbServer:0x137d3b0 @uri="druby://ezra.local:61668",
> @idconv=#<DRb::DRbIdConv:0x410d88>, @front=nil, @config=
> {:idconv=>#<DRb::DRbIdConv:
> 0x410d88>, :argc_limit=>256, :verbose=>false, :tcp_acl=>nil, :load_limit
> =>26214400}, @thread=#<Thread:0x137d324 sleep>, @grp=#<ThreadGroup:
> 0x137d374>, @protocol=#<DRb::DRbTCPSocket:0x137d02c @uri="druby://
> ezra.local:61668", @acl=nil, @config={:idconv=>#<DRb::DRbIdConv:
> 0x410d88>, :argc_limit=>256, :verbose=>false, :tcp_acl=>nil, :load_limit
> =>26214400}, @msg=#<DRb::DRbMessage:0x137d004 @argc_limit=256,
> @load_limit=26214400>, @socket=#<TCPServer:0x137d0a4>>>
>
> irb(main):006:0> test = DRbObject.new(nil, 'druby://ezra.local:3500')
> => #<DRb::DRbObject:0x1379990 @ref=nil, @uri="druby://ezra.local:3500">
>
> irb(main):009:0> test.create(:title => 'Foo', :desc => 'Bar')
> => #<DRb::DRbUnknown:0x13727f8 @buf="\004\010o:\021RemoteRecord\010:
> \020@new_recordF:\f@errorso:\031ActiveRecord::Errors\a;\a{\000:
> \n@base@\000:\020@attributes{\010\"\ntitle\"\010Foo\"\aidi\010\"\tdesc
> \"\010Bar", @name="RemoteRecord">
>
> irb(main):011:0> a = test.find :first
> => #<DRb::DRbUnknown:0x136dce4 @buf="\004\010o:\021RemoteRecord\006:
> \020@attributes{\010\"\ntitle\"\010foo\"\aid\"\0061\"\tdesc
> \"\010bar", @name="RemoteRecord">
>
> irb(main):012:0> p a
> #<DRb::DRbUnknown:0x136dce4 @buf="\004\010o:\021RemoteRecord\006:
> \020@attributes{\010\"\ntitle\"\010foo\"\aid\"\0061\"\tdesc
> \"\010bar", @name="RemoteRecord">
> => nil
>
> irb(main):013:0> a.title
> NoMethodError: undefined method `title' for #<DRb::DRbUnknown:0x136dce4>
>          from (irb):13
>
>
> So you can see it is almost working! title and desc are columns in
> the database table. The records do get created fine in the db and it
> seems to get the right records when I run a find on the model. I just
> can't figure out how to use the found object like a normal active
> record. I mean I need to be able to display the attributes of the
> record after I do a find and thats the part that is not working for me.

Just a shot in the dark:  does
    a.send :title
work?