Ruby Convert String to Hash - ruby

Question

I'm storing configuration data in hashes written in flat files. I want to import the hashes into my Class so that I can invoke corresponding methods.
example.rb
{
:test1 => { :url => 'http://www.google.com' },
:test2 => {
{ :title => 'This' } => {:failure => 'sendemal'}
}
}
simpleclass.rb
class Simple
def initialize(file_name)
# Parse the hash
file = File.open(file_name, "r")
#data = file.read
file.close
end
def print
#data
end
a = Simple.new("simpleexample.rb")
b = a.print
puts b.class # => String
How do I convert any "Hashified" String into an actual Hash?

Answer 1

You can use eval(#data), but really it would be better to use a safer and simpler data format like JSON.

Answer 2

You can try YAML.load method
Example:
YAML.load("{test: 't_value'}")
This will return following hash.
{"test"=>"t_value"}
You can also use eval method
Example:
eval("{test: 't_value'}")
This will also return same hash
{"test"=>"t_value"}
Hope this will help.

Answer 3

I would to this using the json gem.
In your Gemfile you use
gem 'json'
and then run bundle install.
In your program you require the gem.
require 'json'
And then you may create your "Hashfield" string by doing:
hash_as_string = hash_object.to_json
and write this to your flat file.
Finally, you may read it easily by doing:
my_hash = JSON.load(File.read('your_flat_file_name'))
This is simple and very easy to do.

Answer 4

Should it not be clear, it is only the hash that must be contained in a JSON file. Suppose that file is "simpleexample.json":
puts File.read("simpleexample.json")
# #{"test1":{"url":"http://www.google.com"},"test2":{"{:title=>\"This\"}":{"failure":"sendemal"}}}
The code can be in a normal Ruby source file, "simpleclass.rb":
puts File.read("simpleclass.rb")
# class Simple
# def initialize(example_file_name)
# #data = JSON.parse(File.read(example_file_name))
# end
# def print
# #data
# end
# end
Then we can write:
require 'json'
require_relative "simpleclass"
a = Simple.new("simpleexample.json")
#=> #<Simple:0x007ffd2189bab8 #data={"test1"=>{"url"=>"http://www.google.com"},
# "test2"=>{"{:title=>\"This\"}"=>{"failure"=>"sendemal"}}}>
a.print
#=> {"test1"=>{"url"=>"http://www.google.com"},
# "test2"=>{"{:title=>\"This\"}"=>{"failure"=>"sendemal"}}}
a.class
#=> Simple
To construct the JSON file from the hash:
h = { :test1=>{ :url=>'http://www.google.com' },
:test2=>{ { :title=>'This' }=>{:failure=>'sendemal' } } }
we write:
File.write("simpleexample.json", JSON.generate(h))
#=> 95