Forum: Ruby problem with YAML:load

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Df13d29fbc02d6979b4e6d3a3ccb4e4a?d=identicon&s=25 Bino Oetomo (bino)
on 2007-04-28 05:37
Dear All.

I'm learning to use yaml4r
A friend of me, give a simple script for starting point, i save it as
lyaml01

---------Start lyaml01-----
Nota = Struct.new(:nomor, :items)
Item = Struct.new(:description, :quantity, :satuan, :harga_satuan,
:total)

nota1 = Nota.new('nota-123', [])
nota1.items << Item.new('gula', 2, 'kg', 100, 2*100)
nota1.items << Item.new('kopi', 3, 'kg', 500, 3*500)

# convert to yaml string
yaml_str = nota1.to_yaml

puts '--- save to file ---'
open("/mnt/ramdisk0/yaml_file.yml", "w") do |file|
  file.write(yaml_str)
        puts '--- close the file ---'
        file.close
end

puts '--- reading yaml from file ---'
nota = YAML::load(IO.read("/mnt/ramdisk0/yaml_file.yml"))
puts '---- display it ----'
puts nota
puts '--- display part ---'
puts nota.nomor

---------Stop Lyaml01 -----

Next, I try to run that script :

---Start lyaml01 run-----


[root@kannel blajarruby]# ruby ./lyaml01
--- save to file ---
--- close the file ---
--- reading yaml from file ---
---- display it ----
#<struct Nota nomor="nota-123", items=[#<struct Item description="gula",
quantity=2, satuan="kg", harga_satuan=100, total=200>, #<struct Item
description="kopi", quantity=3, satuan="kg", harga_satuan=500,
total=1500>]>
--- display part ---
nota-123

---Stop lyaml01 run-----

hmmm look nice

And here is the result file generated by that script :

----Start /mnt/ramdisk0/yaml_file.yml ----
[root@kannel blajarruby]# more /mnt/ramdisk0/yaml_file.yml
--- !ruby/struct:Nota
nomor: nota-123
items:
- !ruby/struct:Item
  description: gula
  quantity: 2
  satuan: kg
  harga_satuan: 100
  total: 200
- !ruby/struct:Item
  description: kopi
  quantity: 3
  satuan: kg
  harga_satuan: 500
  total: 1500

----Stop /mnt/ramdisk0/yaml_file.yml ----


Next i make a copy , just specific on the  "YAML::load" part, to try
re-read the generated file via IRB :

----Start load yaml irb ------

[root@kannel blajarruby]# irb
irb(main):002:0> require 'yaml'
=> true
irb(main):003:0> nota =
YAML::load(IO.read("/mnt/ramdisk0/yaml_file.yml"))
TypeError: invalid subclass
        from /usr/local/lib/ruby/1.8/yaml.rb:133:in `transfer'
        from /usr/local/lib/ruby/1.8/yaml.rb:133:in `node_import'
        from /usr/local/lib/ruby/1.8/yaml.rb:133:in `load'
        from /usr/local/lib/ruby/1.8/yaml.rb:133:in `load'
        from (irb):3
irb(main):004:0>

----Stop load yaml irb ------

Look like there is problem on this part.

I tried to write a more simple script (i name it "lyaml02"), that will
just re read the generated file :

-----Start lyaml02 file---------
[root@kannel blajarruby]# more lyaml02
require 'yaml'
nota = YAML::load(IO.read("/mnt/ramdisk0/yaml_file.yml"))
----Start lyaml02 file---------

And try to run  lyaml02 script :

-----------Start lyaml02 run --------
[root@kannel blajarruby]# ruby ./lyaml02
/usr/local/lib/ruby/1.8/yaml.rb:133:in `transfer': invalid subclass
(TypeError)
        from /usr/local/lib/ruby/1.8/yaml.rb:133:in `node_import'
        from /usr/local/lib/ruby/1.8/yaml.rb:133:in `load'
        from /usr/local/lib/ruby/1.8/yaml.rb:133:in `load'
        from ./lyaml02:2

-----------Stop lyaml02 run --------

question :
1. Is it caused by instability of YAML::load ? or
2. Could some body point me to something wrong that I did ?

regards
-bino-
2cf8e61cc41385722472a5882ded24fb?d=identicon&s=25 Christian Surlykke (Guest)
on 2007-04-28 11:36
(Received via mailing list)
Lørdag den 28. April 2007 skrev Bino Oetomo:
> :total)
>   file.write(yaml_str)
>
> --- reading yaml from file ---
> hmmm look nice
>   quantity: 2
> ----Stop /mnt/ramdisk0/yaml_file.yml ----
> irb(main):003:0> nota =
>
>
>
> -----------Stop lyaml02 run --------
>
> question :
> 1. Is it caused by instability of YAML::load ? or
> 2. Could some body point me to something wrong that I did ?
>
> regards
> -bino-

Hi

I'm not an expert on YAML, but I think YAML has to know about the
classes Nota
and Item, if it is to load instances of them.

In other words: You should do something like:

  require 'yaml'

  Nota = Struct.new(:nomor, :items)
  Item = Struct.new(:description, :quantity, :satuan, :harga_satuan)

  nota1 = YAML::load(File.open('/mnt/ramdisk0/yaml_file.yml'))

  puts nota1.inspect

when loading the yaml file.


br. Christian Surlykke
E0d864d9677f3c1482a20152b7cac0e2?d=identicon&s=25 Robert Klemme (Guest)
on 2007-04-28 15:01
(Received via mailing list)
On 28.04.2007 05:37, Bino Oetomo wrote:
>
>         puts '--- close the file ---'
> ---------Stop Lyaml01 -----
> ---- display it ----
>
>   satuan: kg
>
> YAML::load(IO.read("/mnt/ramdisk0/yaml_file.yml"))
> Look like there is problem on this part.
> And try to run  lyaml02 script :
> -----------Stop lyaml02 run --------
>
> question :
> 1. Is it caused by instability of YAML::load ? or
> 2. Could some body point me to something wrong that I did ?
>
> regards
> -bino-
>
Without looking too deep into your issue: did you make sure that all
classes mentioned in the YAML file are defined when loading the file?

Kind regards

  robert
Df13d29fbc02d6979b4e6d3a3ccb4e4a?d=identicon&s=25 Bino Oetomo (bino)
on 2007-04-30 03:50
Dear Surlykke and all

Christian Surlykke wrote:
> Lørdag den 28. April 2007 skrev Bino Oetomo:
> In other words: You should do something like:
>
>   require 'yaml'
>
>   Nota = Struct.new(:nomor, :items)
>   Item = Struct.new(:description, :quantity, :satuan, :harga_satuan)
>
>   nota1 = YAML::load(File.open('/mnt/ramdisk0/yaml_file.yml'))
>
>   puts nota1.inspect
>
> when loading the yaml file.
Thankyou for your enlightment,
the codes above is work for me when I try to load and parse "real" YAML
file.

Actualy my code is to parse YAML contended in a string-variable received
from other "external" process.

I try to parse YAML that stored in a variable called m.body.
Actualy this is a body part of received XMPP msg (based on XMPP4R).

Part of my script that will receive XMPP msg is :

----Start----
if m.subject == "bntrans"
  puts '---> Subject is BNTRANS, Proceed'
  puts '--> Content of m.body'
  puts m.body #puts the XMPP msg body
  #Lets try struct for YAML
  Nota = Struct.new(:nomor, :items)
  Item = Struct.new(:description, :quantity, :satuan, :harga_satuan,
:total)
  puts '----> try YAML::load again m.body'
  Nota1 = YAML::load(IO.read(m.body))
  puts '-----nota----------'
end
----Stop-----

Below is the results, cutted from where it start to process the msg body
-------Start results : just plain "puts" to msg body----
--> Content of m.body
--- !ruby/struct:Nota
nomor: Nota-xyz
items:
- !ruby/struct:Item
  description: gula
  quantity: 2
  satuan: kg
  harga_satuan: 100
  total: 200
- !ruby/struct:Item
  description: kopi
  quantity: 3
  satuan: kg
  harga_satuan: 500
  total: 1500
-------Stop results : just plain "puts" to msg body----
That is the plain content of the msg body. Is it ok in a matter of
"YAML::load" ?

-----Start YAML::Load agains the m.body-------------
----> try YAML::load again m.body
08:18:52 EXCEPTION:
    Errno::ENOENT
    No such file or directory - --- !ruby/struct:Nota
    nomor: Nota-xyz
    items:
    - !ruby/struct:Item
      description: gula
      quantity: 2
      satuan: kg
      harga_satuan: 100
      total: 200
    - !ruby/struct:Item
      description: kopi
      quantity: 3
      satuan: kg
      harga_satuan: 500
      total: 1500

    ./trima06:26:in `read'
    ./trima06:26
    /usr/local/lib/ruby/site_ruby/1.8/callbacks.rb:93:in `call'
    /usr/local/lib/ruby/site_ruby/1.8/callbacks.rb:93:in `process'
    /usr/local/lib/ruby/site_ruby/1.8/callbacks.rb:92:in `each'
    /usr/local/lib/ruby/site_ruby/1.8/callbacks.rb:92:in `process'

-----Stop YAML::Load agains the m.body-------------

AFAIK, the content of m.body string is exactly the same of
/mnt/ramdisk0/yaml_file.yml
but it didn't work

Sincerely
-bino-
Df13d29fbc02d6979b4e6d3a3ccb4e4a?d=identicon&s=25 Bino Oetomo (bino)
on 2007-04-30 11:44
Bino Oetomo wrote:

> ----Start----
> if m.subject == "bntrans"
>   puts '---> Subject is BNTRANS, Proceed'
>   puts '--> Content of m.body'
>   puts m.body #puts the XMPP msg body
>   #Lets try struct for YAML
>   Nota = Struct.new(:nomor, :items)
>   Item = Struct.new(:description, :quantity, :satuan, :harga_satuan,
> :total)
>   puts '----> try YAML::load again m.body'
>   Nota1 = YAML::load(IO.read(m.body))
>   puts '-----nota----------'
> end
> ----Stop-----
>

OOppps ... my stupidity ..
I have to not using YAML::load(IO.read(m.body))
m.body is a string variable .. so no need of IO.read
I have to use YAML::load(m.body)

Thank for all the enlightment

sincerely
-bino-
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