Can't read JSON file in Ruby on Rails - json

Question

I am new in ruby on rails and I want to read data from a JSON file from a specified directory, but I constantly get an error in chap3(File name)
Errno::ENOENT in TopController#chap3. No such file or directory # rb_sysopen - links.json.
In the console, I get a message
Failed to load resource: the server responded with a status of 500 (Internal Server Error)
How I can fix that?
Code:
require "json"
class TopController < ApplicationController
def index
#message = "おはようございます！"
end
def chap3
data = File.read('links.json')
datahash = JSON.parse(data)
puts datahash.keys
end
def getName
render plain: "名前は、#{params[:name]}"
end
def database
#members = Member.all
end
end
JSON file:
{ "data": [
{"link1": "http://localhost:3000/chap3/a.html"},
{"link2": "http://localhost:3000/chap3/b.html"},
{"link3": "http://localhost:3000/chap3/c.html"},
{"link4": "http://localhost:3000/chap3/d.html"},
{"link5": "http://localhost:3000/chap3/e.html"},
{"link6": "http://localhost:3000/chap3/f.html"},
{"link7": "http://localhost:3000/chap3/g.html"}]}

Answer 1

I would change these two lines
data = File.read('links.json')
datahash = JSON.parse(data)
in the controller to
datahash = Rails.root.join('app/controllers/links.json').read
Note: I would consider moving this kind of configuration file into the /config folder and creating a simple Ruby class to handle it. Additionally, you might want to consider paths instead of URLs with a host because localhost:3000 might work in the development environment but in production, you will need to return non-localhost URLs anyway.

Answer 2

Rails use the content of file in the controller
#data = File.read("#{Rails.root}/app/controllers/links.json")