.env

HOST = ""
APP_KEY = ""
APP_SECRET = ""

REQUEST_TOKEN = ""
REQUEST_TOKEN_SECRET = ""
REQUEST_TOKEN_VERIFIER = ""

ACCESS_TOKEN = ""
ACCESS_TOKEN_SECRET = ""

oauth_request_token.rb

require 'cgi'
require 'base64'
require 'securerandom'
require 'openssl'
require 'net/http'
require 'dotenv'
Dotenv.load

##
# Assemble parameters
#

oauth_consumer_key      = ENV['APP_KEY']
oauth_nonce             = SecureRandom.hex
oauth_signature_method  = 'HMAC-SHA1'
oauth_timestamp         = Time.now.to_i.to_s
oauth_version           = '1.0'

# alphabetic params
params = {
  oauth_consumer_key:     oauth_consumer_key,
  oauth_nonce:            oauth_nonce,
  oauth_signature_method: oauth_signature_method,
  oauth_timestamp:        oauth_timestamp,
  oauth_version:          oauth_version
}
parameters = params.map{|k,v| "#{k}=#{CGI.escape(v)}"}.join("&")
puts "--> Parameters:\n#{parameters}"

##
# Generate signature
#

host = ENV['HOST']
url = "#{host}/oauth/request_token"
base_string = ['GET', CGI.escape(url), CGI.escape(parameters) ].join('&')

secret_key = "#{ENV['APP_SECRET']}&"

oauth_signature = CGI.escape(Base64.encode64("#{OpenSSL::HMAC.digest('sha1', secret_key, base_string)}").chomp)
puts "--> Signature:\n#{oauth_signature}"

##
# Make request
#

request_url = url + '?' + parameters + '&oauth_signature=' + oauth_signature
puts "--> Request URL:\n#{request_url}"

response = Net::HTTP.get URI(request_url)

readable_hash_of = ->(str){str.split('&').reduce({}){|h, s| w = s.split('='); h[w[0]] = w[1]; h} }
response_ha = readable_hash_of[response]
puts "--> Response:\n#{response_ha}"
puts "--> Authorize URL:\n#{host}/oauth/authorize_token?oauth_token=#{response_ha['oauth_token']}"