--- a/app/controllers/tweets_controller.rb	Fri Aug 03 02:12:54 2018 +0900
+++ b/app/controllers/tweets_controller.rb	Fri Aug 03 02:31:25 2018 +0900
@@ -1,34 +1,26 @@
 class TweetsController < ApplicationController
-  before_action :validate_id, :only => :show
-
   def index
-    return try_redirect if params[:id]
+    return redirect if params[:id] || params[:name]
   end
 
   def show
-    client = Tweet.new(params[:id])
+    return redirect if params[:id][/D/].present?
+
+    client = Tweet.new(params[:id].to_i)
+    @user = client.user
+
+    return redirect if @user.screen_name != params[:name]
+
     @tweets = client.timeline
-    @user = client.user
   rescue Twitter::Error::NotFound
     head :not_found
   rescue Twitter::Error::Unauthorized
     head :forbidden
   end
 
-  private
-
-  def validate_id
-    id = params[:id].split("/")[0]
-    if id[/\D/].nil?
-      params[:id] = id
-    else
-      try_redirect
-    end
-  end
-
-  def try_redirect
-    user = Tweet.new(params[:id]).user
-    redirect_to tweet_path("#{user.id}/#{user.screen_name}")
+  def redirect
+    @user ||= Tweet.new(params[:id] || params[:name]).user
+    redirect_to tweet_path(@user.id, @user.screen_name)
   rescue Twitter::Error::NotFound
     head :not_found
   rescue Twitter::Error::Unauthorized

--- a/app/models/tweet.rb	Fri Aug 03 02:12:54 2018 +0900
+++ b/app/models/tweet.rb	Fri Aug 03 02:31:25 2018 +0900
@@ -12,7 +12,7 @@
 
   def initialize(twitter_id)
     @clients = {}
-    @twitter_id = twitter_id.to_s
+    @twitter_id = twitter_id
   end
 
   def id
@@ -47,12 +47,13 @@
 
   def user
     if @user.nil?
-      raw = Rails.cache.fetch("user:v1:#{@twitter_id}", :expires_in => self.class.cache_expires_time) do
+      cache_key = "user:v1:#{@twitter_id.is_a?(Integer) ? 'id' : 'lookup'}:#{@twitter_id}"
+      raw = Rails.cache.fetch(cache_key, :expires_in => self.class.cache_expires_time) do
         client_try(:user, @twitter_id).tap do |data|
           if data[:result] == :ok
             user = data[:data]
 
-            if user.id.to_s != @twitter_id && user.screen_name != @twitter_id
+            if user.id != @twitter_id && user.screen_name.downcase != @twitter_id
               throw "Wrong user data. Requested: #{@twitter_id}, got: #{user.id} (#{user.screen_name.printable})"
             end
           end

--- a/config/routes.rb	Fri Aug 03 02:12:54 2018 +0900
+++ b/config/routes.rb	Fri Aug 03 02:31:25 2018 +0900
@@ -1,5 +1,6 @@
 Rails.application.routes.draw do
   root "tweets#index"
 
-  get "*id" => "tweets#show", :defaults => { :format => :atom }, :as => "tweet"
+  get ":id/:name" => "tweets#show", :defaults => { :format => :atom }, :as => "tweet"
+  get ":name" => "tweets#redirect"
 end