Find a best way to work with redis cache on rails - ruby-on-rails

Question

I try to use Redis to cache on rails, but I get a challenge when trying to cache multi-language. Because my Redis needs to be cached with table_translations
I try with some code, but I don't think this is the best way
I have the instance variable to work with Erb template
def index
#posts = fetch_posts
#translations = fetch_translations
puts #posts
puts #translations
end
and Redis fetch like this
private
def fetch_posts
begin
posts = $redis.get "posts"
if posts.nil?
posts = []
Post.all.order("id ASC").each do |post|
posts << post
end
posts = posts.to_json
$redis.set "posts", posts
end
posts = JSON.load posts
rescue => error
puts error.inspect
posts = Post.all
end
posts
end
def fetch_translations
begin
translations = $redis.get "translations"
if translations.nil?
translations = []
Post.all.order("id ASC").each do |post|
post.translations.order("locale ASC").each do |translation|
translations << translation
end
end
translations = translations.to_json
$redis.set "translations", translations
end
translations = JSON.load translations
rescue => error
puts error.inspect
translations = Post.all
end
translations
end
I do that because I need to get all language version of a post, so I make a Redis key for translate
and my output:
{"id":1,"slug":"hello-world","thumb_url":"thumbs/null","thumb_file_name":null,"thumb_content_type":null,"thumb_file_size":null,"thumb_updated_at":null,"featured":false,"hidden":false,"created_at":"2019-04-18T07:05:09.117Z","updated_at":"2019-04-18T07:27:55.830Z"}
{"title":"Xin chao","description":"Day la bai viet dau tien, duoc viet tu rails CMS","body":"xin chao cac ban"}
{"title":"Hello World","description":"This is first post from rails CMS","body":"Hello every body"}
I find the best solution to make my output into a key, like this:
{"id":1,"slug":"hello-world","thumb_url":"thumbs/null","thumb_file_name":null,"thumb_content_type":null,"thumb_file_size":null,"thumb_updated_at":null,"featured":false,"hidden":false,"created_at":"2019-04-18T07:05:09.117Z","updated_at":"2019-04-18T07:27:55.830Z","title":"Xin chao","description":"Đay la bai viet đau tien, đuoc viet tu rails CMS","body":"xin chao cac ban"}
{"id":1,"slug":"hello-world","thumb_url":"thumbs/null","thumb_file_name":null,"thumb_content_type":null,"thumb_file_size":null,"thumb_updated_at":null,"featured":false,"hidden":false,"created_at":"2019-04-18T07:05:09.117Z","updated_at":"2019-04-18T07:27:55.830Z",title":"Hello World","description":"This is first post from rails CMS","body":"Hello every body"}
My code can work correctly, but I need your help to make it better, please help me to improve my skills
Thank for your help

Answer 1

You can use the built in Rails cache handler, this way you won't need to handle .nil? calls to cache keys.
private
def fetch_posts
posts = Rails.cache.fetch("posts") do
begin
Post.all.order("id ASC").as_json
rescue => error
puts error.inspect
Post.all
end
end
posts
end
def fetch_translations
translations = Rails.cache.fetch("translations") do
begin
Post.all.order("id ASC").map do |post|
post.translations.order("locale ASC").as_json
end.flatten
rescue => error
puts error.inspect
Post.all
end
end
translations
end

Answer 2

I found the solution by follow this stuff How do you add an array to another array in Ruby and not end up with a multi-dimensional result?
concept is flatten all attr in two array and then Hash again this into new array
def fetch_posts
posts = []
Post.all.order("id ASC").each do |post|
post.translations.each do |translation|
posts << [*post.attributes.slice('slug','thumb_url'),*JSON.parse(translation.to_json)].to_h
end
end
end
Hope this help to anyone have question same to me :)