support read_multi

[LcpMarvel]

No description provided.

[bf4]

Any change to AMS.config.cache_store should be where it is set

[LcpMarvel]

I found that the ActiveModelSerializers.config.cache_store is always nil in my project.

[LcpMarvel]

Should i do extra config for ActiveModelSerializers.config.cache_store? @bf4

[bf4]

What did yoi have in mind?

B mobile phone

On Dec 13, 2015, at 7:56 PM, Michael Lyu [email protected] wrote:

In lib/active_model/serializer.rb:

@@ -116,7 +116,7 @@ def self.fragmented(serializer)
# @todo require less code comments. See
# #1249 (comment)
def self.cache(options = {})

•  self._cache = ActiveModelSerializers.config.cache_store if ActiveModelSerializers.config.perform_caching
  

•  self._cache = ActionController::Base.cache_store if ActiveModelSerializers.config.perform_caching
  

  Should i do extra config for ActiveModelSerializers.config.cache_store? @bf4

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[bf4]

@LcpMarvel Thanks for this 💯

I'll review. It will need some tests and documentation. Can you add that?

ref: #827

[bf4]

vs. compact?

[LcpMarvel]

ok.

[LcpMarvel]

require 'benchmark'

n = 100000

Benchmark.bm do |x|
  x.report do
    n.times do
      Array.new(100) { nil }.reject(&:nil?)
    end
  end

  x.report do
    n.times do
      Array.new(100) { nil }.compact
    end
  end
end

       user     system      total        real
   0.970000   0.020000   0.990000 (  0.984381)
   0.630000   0.010000   0.640000 (  0.633962)

[LcpMarvel]

initializer 'active_model_serializers.caching' do
  ActiveSupport.on_load(:action_controller) do
    binding.pry

    ActiveModelSerializers.config.cache_store     = ActionController::Base.cache_store
    ActiveModelSerializers.config.perform_caching = Rails.configuration.action_controller.perform_caching
  end
end

I found that it does not work for Rails 4.2.5.

ActionController::Base.cache_store # => nil
Rails.configuration.cache_store # => :dalli_store
Rails.configuration.action_controller.perform_caching # => true

My config is

Rails.application.configure do
  # Settings specified here will take precedence over those in config/application.rb.

  # In the development environment your application's code is reloaded on
  # every request. This slows down response time but is perfect for development
  # since you don't have to restart the web server when you make code changes.
  config.cache_classes = false

  # Do not eager load code on boot.
  config.eager_load = false

  # Show full error reports and disable caching.
  config.consider_all_requests_local       = true
  config.action_controller.perform_caching = true
  config.cache_store = :dalli_store

  # Don't care if the mailer can't send.
  config.action_mailer.raise_delivery_errors = false

  # Print deprecation notices to the Rails logger.
  config.active_support.deprecation = :log

  # Raise an error on page load if there are pending migrations.
  config.active_record.migration_error = :page_load

  # Debug mode disables concatenation and preprocessing of assets.
  # This option may cause significant delays in view rendering with a large
  # number of complex assets.
  config.assets.debug = true

  # Asset digests allow you to set far-future HTTP expiration dates on all assets,
  # yet still be able to expire them through the digest params.
  config.assets.digest = true

  # Adds additional error checking when serving assets at runtime.
  # Checks for improperly declared sprockets dependencies.
  # Raises helpful error messages.
  config.assets.raise_runtime_errors = true
end

[bf4]

I wonder why. That's a strange default

B mobile phone

On Dec 13, 2015, at 10:19 PM, Michael Lyu [email protected] wrote:

initializer 'active_model_serializers.caching' do
  ActiveSupport.on_load(:action_controller) do
    binding.pry

    ActiveModelSerializers.config.cache_store     = ActionController::Base.cache_store
    ActiveModelSerializers.config.perform_caching = Rails.configuration.action_controller.perform_caching
  end
end

I found that it does not work for Rails 4.2.5.
The ActionController::Base.cache_store is nil, but theRails.configuration.action_controller.perform_caching is true.

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[LcpMarvel]

I think we should use ActiveModelSerializers.config.cache_store = ActiveSupport::Cache.lookup_store(Rails.configuration.cache_store) to fix this problem.

[bf4]

@LcpMarvel Thanks for looking into this. I'm learning more about this part of the Rails stack.

It looks to me like we are safest getting the 'Rails' cache store via ActiveSupport::Cache.lookup_store(ActionController::Base.cache_store || Rails.cache) since that won't blow up in the absence of a Rails app (i.e. Rails.configuration.cache_store won't raise undefined method 'config' on nil). Otherwise, we can append the condition Rails.application && Rails.configuration.cache_store (i.e. Rails.application.config.cache_store). Then, the default for nil cache_store would be the Memory cache.

I also noticed in the ActionController::Cache code that there's a caching_enabled? check that combines perform_caching with the presence of config.cache_store. I like that idea. In that case, we probably wouldn't want to default to the memory store when no store is set.

Any reason you're using read_multi over fetch_multi? fetch_multi calls read_multi.

• https://github.com/rails/rails/blob/4-0-stable/railties/lib/rails/application/bootstrap.rb#L59-L68
• https://github.com/rails/rails/blob/4-0-stable/actionpack/lib/action_controller/caching.rb#L35-L47
• https://github.com/rails/rails/blob/4-0-stable/activesupport/lib/active_support/cache.rb#L54-L65
• https://github.com/rails/rails/blob/4-0-stable/activesupport/test/caching_test.rb
• https://github.com/rails/rails/blob/4-0-stable/railties/lib/rails.rb#L28

[LcpMarvel]

Yes, here we have no necessary for calling block because of the cache_check method.

[LcpMarvel]

👍

[LcpMarvel]

I wonder know how to set cache key by current_user.id because i have to handle the response by user.

My solution is

def attributes(requested_attrs = nil)
  attrs = super

  self.class.cache key: "#{scope.id}/#{scope.updated_at.to_i}"
  # business logic

  attrs
end

Can you give some suggestions?

[bf4]

@LcpMarvel

I wonder know how to set cache key by current_user.id because i have to handle the response by user.

see https://github.com/rails-api/active_model_serializers/pull/1371/files#diff-683b15b4d7c82f436aaeada1733d9eecR97 https://github.com/bf4/active_model_serializers/blob/1b2324bd021b7e9adc5be11c123dd90286f3541b/docs/general/serializers.md#cache_key

# Uses a custom non-time-based cache key
def cache_key
  "#{self.class.name.downcase}/#{self.id}"
end

Do you use scope? If so, I could use some help documenting it #1252

[LcpMarvel]

Yes, I think we can use any variables from the instance_options.

[bf4]

batch_cache is a purely internal serialization option?

[LcpMarvel]

@bf4 I think it's free to users. haha.
Users can pass in batch_cache: { disable: true } for preventing batch_cache.

[LcpMarvel]

@bf4 I have refactored

[bf4]

simpler to follow if the logic is something like think below?

def serializable_hash_for_collection(options)
+   cache_attributes(options)
  serializer.map { |s| Attributes.new(s, instance_options).serializable_hash(options) }
end

and

def cache_attributes(options)
  options[:cached_attributes] ||=
    begin
      if ActiveModelSerializers.config.cache_store.nil?
        {}
      else
        keys = CachedSerializer.object_cache_keys(serializer, @include_tree)
        if keys.any?
          ActiveModelSerializers.config.cache_store.read_multi(*keys)
        else
          {}
        end
      end
    end
end

def cached_attributes(cache_key)
  options[:cached_attributes].fetch(cache_key) do
    block_given? ? yield : raise(KeyError, "No key #{cache_key}. Keys are #{options[:cached_attributes].keys}")
  end
end

then

         def resource_object_for(options)
 -          cache_check(serializer) do
+          cached_serializer = CachedSerializer.new(serializer)
+          cached_attributes(cached_serializer.cache_key) do
+            cached_serializer.cache_check(self) do
                serializer.attributes(options[:fields])
              end
            end
          end

[bf4]

@LcpMarvel Thanks for this. I don't recall why we didn't merge it. I added a changelog entry in b45f7b4

[bf4]

I don't recall why we removed the cache_check method here