[Cleanup] Remove Cache.hash

Rails already handles long keys for us

Gemfile

@@ -14,7 +14,6 @@ gem 'draper'
 gem 'streamio-ffmpeg'
 gem 'responders'
 gem 'dtext_rb', :git => "https://github.com/e621ng/dtext_rb.git", branch: "master", :require => "dtext"
-gem 'cityhash'
 gem 'memoist'
 gem 'bootsnap'
 gem 'addressable'

Gemfile.lock

@@ -103,7 +103,6 @@ GEM
     builder (3.2.4)
     case_transform (0.2)
       activesupport
-    cityhash (0.9.0)
     concurrent-ruby (1.2.2)
     connection_pool (2.4.0)
     crack (0.4.5)
@@ -399,7 +398,6 @@ DEPENDENCIES
   addressable
   bcrypt
   bootsnap
-  cityhash
   dalli
   diff-lcs
   dotenv-rails

app/helpers/bulk_update_requests_helper.rb

@@ -73,8 +73,8 @@ module BulkUpdateRequestsHelper
   end
 
   def script_with_line_breaks(bur, with_decorations:)
-    hash = Cache.hash "#{CurrentUser.is_admin? ? "mod" : ""}#{with_decorations ? "color" : ""}#{bur.status}#{bur.script}"
-    Cache.fetch(hash, 3600) do
+    cache_key = "#{CurrentUser.is_admin? ? 'mod' : ''}#{with_decorations ? 'color' : ''}#{bur.updated_at}"
+    Cache.fetch(cache_key, 1.hour) do
       script_tokenized = BulkUpdateRequestImporter.tokenize(bur.script)
       script_tags = collect_script_tags(script_tokenized)
       script_tokenized.map do |cmd, arg1, arg2, arg3|

app/logical/cache.rb

@@ -1,6 +1,6 @@
 class Cache
   def self.read_multi(keys, prefix)
-    sanitized_key_to_key_hash = keys.index_by { |key| "#{prefix}:#{Cache.hash(key)}" }
+    sanitized_key_to_key_hash = keys.index_by { |key| "#{prefix}:#{key}" }
 
     sanitized_keys = sanitized_key_to_key_hash.keys
     sanitized_key_to_value_hash = Rails.cache.read_multi(*sanitized_keys)
@@ -24,10 +24,6 @@ class Cache
     Rails.cache.clear
   end
 
-  def self.hash(string)
-    CityHash.hash64(string).to_s(36)
-  end
-
   def self.redis
     # Using a shared variable like this here is OK
     # since unicorn spawns a new process for each worker

app/logical/tag_correction.rb

@@ -15,7 +15,7 @@ class TagCorrection
   end
 
   def category_cache
-    Cache.fetch("tc:#{Cache.hash(tag.name)}")
+    Cache.fetch("tc:#{tag.name}")
   end
 
   def fix!

app/models/post.rb

@@ -1030,7 +1030,7 @@ class Post < ApplicationRecord
       tags += " -status:deleted" if !Tag.has_metatag?(tags, "status", "-status")
       tags = Tag.normalize_query(tags)
 
-      cache_key = "pfc:#{Cache.hash(tags)}"
+      cache_key = "pfc:#{tags}"
       count = Cache.fetch(cache_key)
       if count.nil?
         count = Post.tag_match(tags).count_only

app/models/tag.rb

@@ -125,7 +125,7 @@ class Tag < ApplicationRecord
         if disable_cache
           select_category_for(tag_name)
         else
-          Cache.fetch("tc:#{Cache.hash(tag_name)}") do
+          Cache.fetch("tc:#{tag_name}") do
             select_category_for(tag_name)
           end
         end
@@ -144,7 +144,7 @@ class Tag < ApplicationRecord
           if not_found.count > 0
             # Is multi_write worth it here? Normal usage of this will be short put lists and then never touched.
             Tag.where(name: not_found).select([:id, :name, :category]).find_each do |tag|
-              Cache.write("tc:#{Cache.hash(tag.name)}", tag.category)
+              Cache.write("tc:#{tag.name}", tag.category)
               found[tag.name] = tag.category
             end
           end
@@ -181,7 +181,7 @@ class Tag < ApplicationRecord
     end
 
     def update_category_cache
-      Cache.write("tc:#{Cache.hash(name)}", category, 3.hours)
+      Cache.write("tc:#{name}", category, 3.hours)
     end
 
     def user_can_change_category?
@@ -948,11 +948,9 @@ class Tag < ApplicationRecord
     end
 
     def update_related_if_outdated
-      key = Cache.hash(name)
-
-      if Cache.fetch("urt:#{key}").nil? && should_update_related?
+      if Cache.fetch("urt:#{name}").nil? && should_update_related?
         TagUpdateRelatedJob.perform_later(id)
-        Cache.write("urt:#{key}", true, 600) # mutex to prevent redundant updates
+        Cache.write("urt:#{name}", true, 600) # mutex to prevent redundant updates
       end
     end
 

app/models/user.rb

@@ -146,13 +146,8 @@ class User < ApplicationRecord
     module ClassMethods
       def name_to_id(name)
         normalized_name = normalize_name(name)
-        Cache.fetch("uni:#{Cache.hash(normalized_name)}", 4.hours) do
-          val = select_value_sql("SELECT id FROM users WHERE lower(name) = ?", normalized_name)
-          if val.present?
-            val.to_i
-          else
-            nil
-          end
+        Cache.fetch("uni:#{normalized_name}", 4.hours) do
+          select_value_sql("SELECT id FROM users WHERE lower(name) = ?", normalized_name)&.to_i
         end
       end
 
@@ -205,7 +200,7 @@ class User < ApplicationRecord
 
     def update_cache
       Cache.write("uin:#{id}", name, 4.hours)
-      Cache.write("uni:#{Cache.hash(name)}", id, 4.hours)
+      Cache.write("uni:#{name}", id, 4.hours)
     end
   end
 

test/unit/post_test.rb

@@ -505,7 +505,7 @@ class PostTest < ActiveSupport::TestCase
         end
 
         should "1234 update the category cache of the tag" do
-          assert_equal(Tag.categories.copyright, Cache.fetch("tc:#{Cache.hash('abc')}"))
+          assert_equal(Tag.categories.copyright, Cache.fetch("tc:abc"))
         end
 
         should "update the tag counts of the posts" do

test/unit/tag_test.rb

@@ -74,10 +74,10 @@ class TagTest < ActiveSupport::TestCase
 
     should "reset its category after updating" do
       tag = create(:artist_tag)
-      assert_equal(Tag.categories.artist, Cache.fetch("tc:#{Cache.hash(tag.name)}"))
+      assert_equal(Tag.categories.artist, Cache.fetch("tc:#{tag.name}"))
 
       tag.update_attribute(:category, Tag.categories.copyright)
-      assert_equal(Tag.categories.copyright, Cache.fetch("tc:#{Cache.hash(tag.name)}"))
+      assert_equal(Tag.categories.copyright, Cache.fetch("tc:#{tag.name}"))
     end
 
     context "not be settable to an invalid category" do