Section 15.4.3: Experimenting with LinkJumbler middleware

ticketee/config/application.rb

@@ -22,5 +22,8 @@ class Application < Rails::Application
 
     # Do not swallow errors in after_commit/after_rollback callbacks.
     config.active_record.raise_in_transactional_callbacks = true
+
+    #require "link_jumbler"
+    #config.middleware.use LinkJumbler, { "e" => "a" }
   end
 end

ticketee/lib/link_jumbler.rb

@@ -0,0 +1,24 @@
+require "nokogiri"
+
+class LinkJumbler
+  def initialize(app, letters)
+    @app = app
+    @letters = letters
+  end
+
+  def call(env)
+    status, headers, response = @app.call(env)
+    if headers['Content-Type'].include?("text/html")
+      body = Nokogiri::HTML(response.body)
+      body.css("a").each do |a|
+        @letters.each do |find, replace|
+          a.content = a.content.gsub(find.to_s, replace.to_s)
+        end
+      end
+    else
+      body = response.body
+    end
+
+    [status, headers, Rack::Response.new(body.to_s)]
+  end
+end