gistfile1.rb

require 'rubygems'
require 'oauth'

htt_method      = :get
endpoint        = 'http://oauth.service-provider.com/oauth/request_token'
consumer_secret = 'CONSUMER_SECRET'
token_secret    = 'ACCESS_TOKEN_SECRET'

request_params = {
  # ADD ALL PARAMETERS HERE
  # ex.) In case of OpenSocial OAuth proxy
  # :xoauth_app_url       => "http://example.com/gadget.xml",
  # :opensocial_owner_id  => "nov",
  # :opensocial_viewer_id => "nov",
  # :opensocial_app_id    => "http://example.com/gadget.xml",
  # :opensocial_app_url   => "http://example.com/gadget.xml"
}

oauth_params = {
  :oauth_consumer_key     => 'CONSUMER_KEY',
  :oauth_token            => 'REQUEST_TOKEN_OR_ACCESS_TOKEN_OR_BLANK',
  :oauth_verifier         => 'VERIFIER',
  :oauth_nonce            => 'NONCE',
  :oauth_timestamp        => 'TIMESTAMP',
  :oauth_signature_method => 'HMAC-SHA1',
  :oauth_version          => '1.0'
}

def escape(value)
  URI::escape(value.to_s, OAuth::RESERVED_CHARACTERS)
end

def signature_key(consumer_secret, token_secret)
  "#{escape consumer_secret}&#{escape token_secret}"
end

def signature_base_string(http_method, endpoint, params = {})
  sorted_params = params.sort do |a, b|
    a[0].to_s <=> b[0].to_s or a[1].to_s <=> b[1].to_s
  end
  params_string = sorted_params.collect do |key, value|
    "#{escape key}=#{escape value}"
  end.join("&")
  "#{http_method.to_s.upcase}&#{escape endpoint}&#{escape params_string}"
end

signature_key = signature_key(consumer_secret, token_secret)
signature_base_string = signature_base_string(htt_method, endpoint, oauth_params.merge(request_params))
digest = HMAC::SHA1.digest(signature_key, signature_base_string)
signature = escape Base64.encode64(digest).chomp.gsub(/\n/,'')

puts <<-EXPECTED
SIGNATURE BASE STRING 
------------------------
#{signature_base_string}

SIGNATURE KEY
------------------------
#{signature_key}

SIGNATURE
------------------------
#{signature}
EXPECTED