How I can parse JSON file by pure Ruby code without gem

Question

I Have tried many ways and googled but everywhere i getting same way out, use json gem to parse a JSON file.

JSON.parse(string)

And couple of links are also using same stackoverflow Link

I wanted to achieve it by pure Ruby code without using any gem or rails help.

Answer 1

JSON is in the stdlib, so using JSON.parse is pure ruby.

require "json"
json_from_file = File.read("myfile.json")
hash = JSON.parse(json_from_file)

or just JSON.parse("{}")

If you're looking to write your own JSON parser (good luck), but just keep in mind that it's just a string when read from a file. So, start by reading it in from your file

File.open("myfile.json") do |f|
  str = f.gets
  # start parsing
end

At this point you'll need to tokenize what you read, and start picking apart each bit. Read up on the json spec.