Search/check values in YAML document with Ruby

Question

my goal:

check if yaml document include value for specific key using ypath/xpath

select value for specified key using ypath/xpath

document yaml:

app:
    name: xxx
    version: xxx
description:
    author:
        name: xxx
        surname: xxx
        email: xxx@xxx.xx

what was checked:*

google

stackoverflow

Ruby API (YAML::DBM as one of methods it provide is select)

example:

Module::Class.select('description/author/name')
Module::Class.select('*/name')
Module::Class.isset?('*/name')

score 1 · Answer 1 · edited Feb 27 '14 at 20:28

1

Use yaml:

require 'yaml'
yml = YAML.load_file('your_file.yml')

Now yml is a hash. You can use it like one. Here is a simple and ugly solution for what you try:

if !yml["description"].nil? && !yml["description"]["author"].nil? && !yml["description"]["author"]["name"].nil? && !yml["description"]["author"]["name"].empty?
  puts "An author is set!"
end

edited Feb 27 '14 at 20:28

Bradly Feeley

27
6

answered Feb 12 '13 at 09:59

Ivaylo Strandjev

69,226
18
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176

Hello, thx for response, but it's not what i meant, I've updated My Goal section in question. BR. – xyz Feb 12 '13 at 10:08
Sorry link to the wrong answer. Take a look here: http://stackoverflow.com/a/9977987/812912 – Ivaylo Strandjev Feb 12 '13 at 10:10
Yeap i saw that also, but problem is that there is no example attached in that pdf. – xyz Feb 12 '13 at 10:13
have you seen the rdoc the user refers to? – Ivaylo Strandjev Feb 12 '13 at 10:14
Of course, but unfortunately it is not well documented in manner of example (working thing). Unless somebody already worked with ypath in Ruby YAML i will have to dig more and try to find proper way... but i would rather not invent wheel from beginning :) – xyz Feb 12 '13 at 10:18

score 0 · Accepted Answer · answered Feb 12 '13 at 11:48

0

Since there are no up-to-date YPath implementations around, I would suggest to give a chance ActiveSupport and Nokogiri:

yml = LOAD_YML_WITH_YOUR_PREFERRED_YAML_ENGINE

# ActiveSupport adds a to_xml method to Hash
xml = yml.to_xml(:root => 'yaml')

doc = Nokogiri::XML(xml)
doc.xpath("description/author/name").map do |name|
  puts [name['key'], name['value']]
end

answered Feb 12 '13 at 11:48

Aleksei Matiushkin

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Yeap, w can't use YPath. I've tried to use YAML/Psych::DBM without luck. I've ended using XML instead of YAML with Nokogiri gem. Thx. – xyz Feb 13 '13 at 09:02

Search/check values in YAML document with Ruby

2 Answers2