alekseyl

# DB way
Shipment.scope
        .joins(purchase: :product)
        .select(["shipments.*","sum(purchases.items_count*products.gross_weight) as gross_weight"])
        .group("shipments.id")

alekseyl

# nil means current_user is empty i.e. it's a guest
keys = [ [:user, :admin, :moderator, nil], [:ru, :en ] ]
# all combination of keys:
all_flatten_keys = keys.pop.product(*keys)
# [[:ru, :user], [:ru, :admin], [:ru, :moderator], [:ru, nil], 
#  [:en, :user], [:en, :admin], [:en, :moderator], [:en, nil]]

alekseyl

class Product <ActiveRecord::Base
 after_commit :prerender
 def prerender
  keys = [ [:user, :admin, :moderator, nil], [:ru, :en ] ]
  keys.pop.product(*keys).each do |lr|
   # lr - locale + role
   ApplicationController.render(
    assigns: {locals: {product: self, role: lr[1], locale: lr[0]} },
    inline: '<% render partial: "products/product", locals: @locals %>')
    #of course products/_product.html.slim must start with

alekseyl

proxy_cache_path /path/to/cache levels=1:2 keys_zone=my_cache:10m max_size=10g
                 inactive=60m use_temp_path=off;

server {
    ...
    location / {
        proxy_cache my_cache;
        proxy_cache_revalidate on;
        proxy_cache_min_uses 1;
        proxy_cache_use_stale error timeout updating http_500 http_502 http_503 

alekseyl

def all_files_in(dir)
  Dir[ File.join(dir, '**', '*') ].reject { |p| File.directory? p }
end

new_namespace = Digest::SHA256.hexdigest( all_files_in( 'app/views' )
  .map{|fl| Digest::SHA256.file(fl).hexdigest }
  .join )

alekseyl

#in controller:
before_action :resourceful_cache_headers
before_action :resourceless_cache_headers
before_action :skip_session

def skip_session
  # if you need to deliver flash, or authencity token, or you explicitly need session
  request.session_options[:skip] = true unless you_need_session
end

alekseyl

proxy_cache_pass /path/to/cache levels= keys_zone=rails_cache:10m max_size=10g use_temp_path=off inactive=120m;
  
  location / {
    try_files $uri @rails;
  }
  
  location @rails {
    # lets skip authorized user.
    proxy_no_cache $cookie_remember_user_token;
    proxy_cache_bypass $cookie_remember_user_token;

alekseyl

def run_async_with_rescue( airbrake_params = {} )
    backtrace = Kernel.caller
    Thread.new do
      begin
        yield
      rescue => e
        e.set_backtrace( backtrace )
        notice = Airbrake.build_notice(e, airbrake_params)
        Airbrake.notify(notice) if notice
      end

alekseyl

def send_devise_notification(notification, *args)
  # don't forget email not sended without calling deliver
  message = devise_mailer.send(notification, self, *args)

  # this is the params you want to anylise when something crashes
  add_to_airbrake_notice = attributes.slice('email', 'name', 'surname', 'cell', 'id')

  # run message delivering
  run_async_with_rescue(add_to_airbrake_notice) { message.deliver }
end

alekseyl

server {    
    set $versioned_location @version_one;
    
    if ( $cookie_condition ) {
        set $versioned_location @version_two;
    }
    
    if ( $cookie_site_version = "version_one" ) {
        set $versioned_location @version_one;
    }