Module: Serega::SeregaPlugins::Batch

Defined in:
lib/serega/plugins/batch/batch.rb,
lib/serega/plugins/batch/lib/loader.rb,
lib/serega/plugins/batch/lib/loaders.rb,
lib/serega/plugins/batch/lib/plugins_extensions/preloads.rb,
lib/serega/plugins/batch/lib/validations/check_opt_batch.rb,
lib/serega/plugins/batch/lib/plugins_extensions/formatters.rb,
lib/serega/plugins/batch/lib/validations/check_batch_opt_key.rb,
lib/serega/plugins/batch/lib/validations/check_batch_opt_loader.rb,
lib/serega/plugins/batch/lib/plugins_extensions/activerecord_preloads.rb

Overview

Plugin ‘:batch`

Adds ability to load nested attributes values in batches.

It can be used to find value for attributes in optimal way:

  • load associations for multiple objects

  • load counters for multiple objects

  • make any heavy calculations for multiple objects only once

After including plugin, attributes gain new ‘:batch` option.

‘:batch` option must be a hash with this keys:

  • ‘key` (required) [Symbol, Proc, callable] - Defines current object identifier. Later `loader` will accept array of `keys` to find `values`.

  • ‘loader` (required) [Symbol, Proc, callable] - Defines how to fetch values for batch of keys. Receives 3 parameters: keys, context, plan_point.

  • ‘default` (optional) - Default value for attribute. By default it is `nil` or `[]` when attribute has option `many: true`

If ‘:loader` was defined using name (as Symbol) then batch loader must be defined in serializer config: `config.batch.define(:loader_name) { … }` method.

*Result of this ‘:loader` callable must be a Hash where*:

  • keys - provided keys

  • values - values for according keys

‘Batch` plugin can be defined with two specific attributes:

  • ‘auto_hide: true` - Marks attributes with defined :batch as hidden, so it will not be serialized by default

  • ‘default_key: :id` - Set default object key (in this case :id) that will be used for all attributes with :batch option specified.

This options (‘auto_hide`, `default_key`) also can be set as config options in any nested serializer.

Examples:

class PostSerializer < Serega
  plugin :batch, auto_hide: true, default_key: :id

  # Define batch loader via callable class, it must accept three args (keys, context, plan_point)
  attribute :comments_count, batch: { loader: PostCommentsCountBatchLoader, default: 0}

  # Define batch loader via Symbol, later we should define this loader via config.batch.define(:posts_comments_counter) { ... }
  attribute :comments_count, batch: { loader: :posts_comments_counter, default: 0}

  # Define batch loader with serializer
  attribute :comments, serializer: CommentSerializer, batch: { loader: :posts_comments, default: []}

  # Resulted block must return hash like { key => value(s) }
  config.batch.define(:posts_comments_counter) do |keys|
    Comment.group(:post_id).where(post_id: keys).count
  end

  # We can return objects that will be automatically serialized if attribute defined with :serializer
  # Parameter `context` can be used when loading batch
  # Parameter `plan_point` can be used to find nested attributes that will be serialized (`plan_point.preloads`)
  config.batch.define(:posts_comments) do |keys, context, plan_point|
    Comment.where(post_id: keys).where(is_spam: false).group_by(&:post_id)
  end
end

Defined Under Namespace

Modules: AttributeInstanceMethods, AttributeNormalizerInstanceMethods, CheckAttributeParamsInstanceMethods, ClassMethods, ConfigInstanceMethods, InstanceMethods, PlanPointInstanceMethods, PluginsExtensions, SeregaObjectSerializerInstanceMethods Classes: BatchConfig, CheckBatchOptKey, CheckBatchOptLoader, CheckOptBatch, SeregaBatchLoader, SeregaBatchLoaders

Class Method Summary collapse

Class Method Details

.after_load_plugin(serializer_class, **opts) ⇒ void

This method returns an undefined value.

Runs callbacks after plugin was attached

Parameters:

  • serializer_class (Class<Serega>) —

    Current serializer class

  • opts (Hash) —

    loaded plugins opts



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# File 'lib/serega/plugins/batch/batch.rb', line 105

def self.after_load_plugin(serializer_class, **opts)
  serializer_class::SeregaConfig.include(ConfigInstanceMethods)

  batch_loaders_class = Class.new(SeregaBatchLoaders)
  batch_loaders_class.serializer_class = serializer_class
  serializer_class.const_set(:SeregaBatchLoaders, batch_loaders_class)

  batch_loader_class = Class.new(SeregaBatchLoader)
  batch_loader_class.serializer_class = serializer_class
  serializer_class.const_set(:SeregaBatchLoader, batch_loader_class)

  if serializer_class.plugin_used?(:activerecord_preloads)
    require_relative "./lib/plugins_extensions/activerecord_preloads"
    serializer_class::SeregaBatchLoader.include(PluginsExtensions::ActiveRecordPreloads::BatchLoaderInstanceMethods)
  end

  if serializer_class.plugin_used?(:formatters)
    require_relative "./lib/plugins_extensions/formatters"
    serializer_class::SeregaBatchLoader.include(PluginsExtensions::Formatters::BatchLoaderInstanceMethods)
    serializer_class::SeregaAttribute.include(PluginsExtensions::Formatters::SeregaAttributeInstanceMethods)
  end

  if serializer_class.plugin_used?(:preloads)
    require_relative "./lib/plugins_extensions/preloads"
    serializer_class::SeregaAttributeNormalizer.include(PluginsExtensions::Preloads::AttributeNormalizerInstanceMethods)
  end

  config = serializer_class.config
  config.attribute_keys << :batch
  config.opts[:batch] = {loaders: {}, default_key: nil, auto_hide: false}
  config.batch.auto_hide = opts[:auto_hide] if opts.key?(:auto_hide)
end

.load_plugin(serializer_class, **_opts) ⇒ void

This method returns an undefined value.

Applies plugin code to specific serializer

Parameters:

  • serializer_class (Class<Serega>) —

    Current serializer class

  • _opts (Hash) —

    Loaded plugins options



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# File 'lib/serega/plugins/batch/batch.rb', line 81

def self.load_plugin(serializer_class, **_opts)
  require_relative "./lib/loader"
  require_relative "./lib/loaders"
  require_relative "./lib/validations/check_batch_opt_key"
  require_relative "./lib/validations/check_batch_opt_loader"
  require_relative "./lib/validations/check_opt_batch"

  serializer_class.extend(ClassMethods)
  serializer_class.include(InstanceMethods)
  serializer_class::CheckAttributeParams.include(CheckAttributeParamsInstanceMethods)
  serializer_class::SeregaAttribute.include(AttributeInstanceMethods)
  serializer_class::SeregaAttributeNormalizer.include(AttributeNormalizerInstanceMethods)
  serializer_class::SeregaPlanPoint.include(PlanPointInstanceMethods)
  serializer_class::SeregaObjectSerializer.include(SeregaObjectSerializerInstanceMethods)
end

.plugin_name ⇒ Symbol

Returns plugin name

Returns:

  • (Symbol) —

    Plugin name



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# File 'lib/serega/plugins/batch/batch.rb', line 69

def self.plugin_name
  :batch
end