Module: IdentityCache::QueryAPI::ClassMethods

Defined in:
lib/identity_cache/query_api.rb

Instance Method Summary collapse

Instance Method Details

#exists_with_identity_cache?(id) ⇒ Boolean

Similar to ActiveRecord::Base#exists? will return true if the id can be found in the cache or in the DB.

Returns:

  • (Boolean)

Raises:

  • (NotImplementedError) 


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# File 'lib/identity_cache/query_api.rb', line 15

def exists_with_identity_cache?(id)
  raise NotImplementedError, "exists_with_identity_cache? needs the primary index enabled" unless primary_cache_index_enabled
  !!fetch_by_id(id)
end

#fetch(id) ⇒ Object

Default fetcher added to the model on inclusion, it behaves like ActiveRecord::Base.find, will raise ActiveRecord::RecordNotFound exception if id is not in the cache or the db.



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# File 'lib/identity_cache/query_api.rb', line 43

def fetch(id)
  fetch_by_id(id) or raise(ActiveRecord::RecordNotFound, "Couldn't find #{self.name} with ID=#{id}")
end

#fetch_by_id(id) ⇒ Object

Default fetcher added to the model on inclusion, it behaves like ActiveRecord::Base.where(id: id).first

Raises:

  • (NotImplementedError) 


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# File 'lib/identity_cache/query_api.rb', line 22

def fetch_by_id(id)
  return unless id
  raise NotImplementedError, "fetching needs the primary index enabled" unless primary_cache_index_enabled
  if IdentityCache.should_use_cache?

    require_if_necessary do
      object = nil
      coder = IdentityCache.fetch(rails_cache_key(id)){ coder_from_record(object = resolve_cache_miss(id)) }
      object ||= record_from_coder(coder)
      IdentityCache.logger.error "[IDC id mismatch] fetch_by_id_requested=#{id} fetch_by_id_got=#{object.id} for #{object.inspect[(0..100)]} " if object && object.id != id.to_i
      object
    end

  else
    self.reorder(nil).where(primary_key => id).first
  end
end

#fetch_multi(*ids) ⇒ Object

Default fetcher added to the model on inclusion, if behaves like ActiveRecord::Base.find_all_by_id

Raises:

  • (NotImplementedError) 


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# File 'lib/identity_cache/query_api.rb', line 49

def fetch_multi(*ids)
  raise NotImplementedError, "fetching needs the primary index enabled" unless primary_cache_index_enabled
  options = ids.extract_options!
  ids.flatten!(1)
  records = if IdentityCache.should_use_cache?
    require_if_necessary do
      cache_keys = ids.map {|id| rails_cache_key(id) }
      key_to_id_map = Hash[ cache_keys.zip(ids) ]
      key_to_record_map = {}

      coders_by_key = IdentityCache.fetch_multi(cache_keys) do |unresolved_keys|
        ids = unresolved_keys.map {|key| key_to_id_map[key] }
        records = find_batch(ids)
        found_records = records.compact
        found_records.each{ |record| record.send(:populate_association_caches) }
        key_to_record_map = found_records.index_by{ |record| rails_cache_key(record.id) }
        records.map {|record| coder_from_record(record) }
      end

      cache_keys.map{ |key| key_to_record_map[key] || record_from_coder(coders_by_key[key]) }
    end
  else
    find_batch(ids)
  end
  records.compact!
  prefetch_associations(options[:includes], records) if options[:includes]
  records
end