Use Twitter 1.1 OAuth for Twitter onebox

lib/oneboxer/twitter_onebox.rb

@@ -1,33 +1,29 @@
-# TODO implement per: http://meta.discourse.org/t/twitter-oneboxes-are-bust/7410/3
 require_dependency 'oneboxer/handlebars_onebox'
 
 module Oneboxer
   class TwitterOnebox < HandlebarsOnebox
+    BASE_URL = 'https://api.twitter.com'.freeze
 
-    REGEX = /^https?:\/\/(?:www\.)?twitter.com\/(?<user>[^\/]+)\/status\/(?<id>\d+)$/
-    # matcher REGEX
+    REGEX =
+      /^https?:\/\/(?:www\.)?twitter.com\/(?<user>[^\/]+)\/status\/(?<id>\d+)$/
+
+    matcher REGEX
 
     # TODO: use zocial instead
     favicon 'twitter.png'
 
     def fetch_html
-      m = @url.match(REGEX)
+      raise Discourse::SiteSettingMissing if twitter_credentials_missing?
 
-      if SiteSetting.twitter_consumer_key.present? && SiteSetting.twitter_consumer_secret.present?
-        token = prepare_access_token(SiteSetting.twitter_consumer_key, SiteSetting.twitter_consumer_secret)
-        token.request(:get, "https://api.twitter.com/1.1/statuses/show/#{URI::encode(m[:id])}.json")
-      else
-        # perhaps?
-        raise Discourse::SiteSettingMissing
-      end
+      tweet_for @url.match(REGEX)[:id]
     end
 
     def parse(data)
       result = JSON.parse(data)
 
-      result["created_at"] = Time.parse(result["created_at"]).strftime("%I:%M%p - %d %b %y")
+      result['created_at'] =
+        Time.parse(result['created_at']).strftime("%I:%M%p - %d %b %y")
 
-      # Hyperlink URLs
       URI.extract(result['text'], %w(http https)).each do |url|
         result['text'].gsub!(url, "<a href='#{url}' target='_blank'>#{url}</a>")
       end
@@ -35,13 +31,61 @@ module Oneboxer
       result
     end
 
-    protected
+    private
 
-    def get_message_json(consumer_key, consumer_secret)
-      raise "NOT IMPLEMENTED"
-      # implement per http://meta.discourse.org/t/twitter-oneboxes-are-bust/7410/3
+    def tweet_for(id)
+      request = Net::HTTP::Get.new(tweet_uri_for id)
+
+      request.add_field 'Authorization', "Bearer #{bearer_token}"
+
+      http(tweet_uri_for id).request(request).body
     end
 
+    def authorization
+      request = Net::HTTP::Post.new(auth_uri)
 
+      request.add_field 'Authorization',
+        "Basic #{bearer_token_credentials}"
+      request.add_field 'Content-Type',
+        'application/x-www-form-urlencoded;charset=UTF-8'
+
+      request.set_form_data 'grant_type' => 'client_credentials'
+
+      http(auth_uri).request(request).body
+    end
+
+    def bearer_token
+      @access_token ||= JSON.parse(authorization).fetch('access_token')
+    end
+
+    def bearer_token_credentials
+      Base64.strict_encode64(
+        "#{URI::encode(consumer_key)}:#{URI::encode(consumer_secret)}"
+      )
+    end
+
+    def auth_uri
+      URI.parse "#{BASE_URL}/oauth2/token"
+    end
+
+    def tweet_uri_for(id)
+      URI.parse "#{BASE_URL}/1.1/statuses/show.json?id=#{id}"
+    end
+
+    def http(uri)
+      Net::HTTP.new(uri.host, uri.port).tap { |http| http.use_ssl = true }
+    end
+
+    def consumer_key
+      SiteSetting.twitter_consumer_key
+    end
+
+    def consumer_secret
+      SiteSetting.twitter_consumer_secret
+    end
+
+    def twitter_credentials_missing?
+      consumer_key.blank? || consumer_secret.blank?
+    end
   end
 end