from json to a ruby hash?

Question

I can go one way using

require 'json'  def saveUserLib(user_lib)     File.open("/Users/name/Documents/user_lib.json","w") do |f|     f.write($user_lib.to_json)     end end  uname = gets.chomp $user_lib["_uname"] = uname saveUserLib($user_lib) 

but how do i get it back again as my user_lib?

Answer 1

You want JSON.parse or JSON.load:

def load_user_lib( filename )   JSON.parse( IO.read(filename) ) end 

The key here is to use IO.read as a simple way to load the JSON string from disk, so that it can be parsed. Or, if you have UTF-8 data in your file:

  my_object = JSON.parse( IO.read(filename, encoding:'utf-8') ) 

I've linked to the JSON documentation above, so you should go read that for more details. But in summary:

• json = my_object.to_json — method on the specific object to create a JSON string.
• json = JSON.generate(my_object) — create JSON string from object.
• JSON.dump(my_object, someIO) — create a JSON string and write to a file.
• my_object = JSON.parse(json) — create a Ruby object from a JSON string.
• my_object = JSON.load(someIO) — create a Ruby object from a file.

Alternatively:

def load_user_lib( filename )   File.open( filename, "r" ) do |f|     JSON.load( f )   end end 

Note: I have used a "snake_case" name for the method corresponding to your "camelCase" saveUserLib as this is the Ruby convention.