OAuth1.0a認証用ヘッダーを生成する

oauth1_0a_header.rb

require 'openssl'
require 'cgi'
require 'base64'

# see https://developer.twitter.com/ja/docs/authentication/oauth-1-0a/creating-a-signature
module Oauth1_0a
  class Authorization
    attr_accessor :http_method, :url, :consumer_key, :consumer_secret, :token, :token_secret, :nonce, :timestamp

    def initialize(http_method:, url:, consumer_key:, consumer_secret:, token:, token_secret:)
      @http_method = http_method
      @url = url
      @consumer_key = consumer_key
      @consumer_secret = consumer_secret
      @token = token
      @token_secret = token_secret
      @nonce = OpenSSL::Random.random_bytes(16).unpack('H*')[0]
      @timestamp = Time.now.to_i.to_s
    end

    def signature
      Base64.encode64(
        OpenSSL::HMAC.digest(OpenSSL::Digest::SHA1.new, signature_key, signature_base)
      )
        .chomp
        .gsub(/\n/, '')
    end

    def authorization_header
      dst = {
        'oauth_consumer_key' => consumer_key,
        'oauth_nonce' => nonce,
        'oauth_signature' => signature,
        'oauth_signature_method' => 'HMAC-SHA1',
        'oauth_timestamp' => timestamp,
        'oauth_token' => token,
        'oauth_version' => '1.0'
      }.collect { |k, v| %(#{k}="#{CGI.escape(v)}") }.join(',')

      "OAuth #{dst}"
    end

    private

      def signature_base
        params = {
          'oauth_consumer_key' => consumer_key,
          'oauth_nonce' => nonce,
          'oauth_signature_method' => 'HMAC-SHA1',
          'oauth_timestamp' => timestamp,
          'oauth_token' => token,
          'oauth_version' => '1.0'
        }.collect {|p| p.collect { |v| CGI.escape(v) }  }
        .sort
        .collect { |p| p.join('=') }
        .join('&')
        
        [
          http_method,
          CGI.escape(url),
          CGI.escape(params)
        ].join('&')      
      end

      def signature_key
        CGI.escape(consumer_secret) + '&' + CGI.escape(token_secret)
      end
  end
end


pp Oauth1_0a::Authorization.new(
  http_method: 'POST',
  url: 'https://api.twitter.com/2/tweets',
  consumer_key: '',
  consumer_secret: '',
  token: '',
  token_secret: '').authorization_header if __FILE__ == $0