Class: RecordCache::Strategy::UniqueIndexCache

Inherits:
Base
  • Object
show all
Defined in:
lib/record_cache/strategy/unique_index_cache.rb

Class Method Summary collapse

Instance Method Summary collapse

Methods inherited from Base

#attribute, #fetch, #invalidate

Constructor Details

#initialize(base, attribute, record_store, options, type) ⇒ UniqueIndexCache

Returns a new instance of UniqueIndexCache.



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# File 'lib/record_cache/strategy/unique_index_cache.rb', line 27

def initialize(base, attribute, record_store, options, type)
  super(base, attribute, record_store, options)
  # remember the attributes with a unique index
  UniqueIndexCache.attributes(base) << attribute
  # for unique indexes that are not on the :id column, use key: rc/<key or model name>/<attribute>:
  @cache_key_prefix << "#{attribute}:" unless attribute == :id
  @type = type
end

Class Method Details

.attributes(base) ⇒ Object

All attributes with a unique index for the given model



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# File 'lib/record_cache/strategy/unique_index_cache.rb', line 6

def self.attributes(base)
  (@attributes ||= {})[base.name] ||= []
end

.parse(base, record_store, options) ⇒ Object

parse the options and return (an array of) instances of this strategy



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# File 'lib/record_cache/strategy/unique_index_cache.rb', line 11

def self.parse(base, record_store, options)
  return nil unless base.table_exists?
  
  attributes = [options[:unique_index]].flatten.compact
  # add unique index for :id by default
  attributes << :id if base.columns_hash['id'] unless base.record_cache[:id]
  attributes.uniq! # in development mode, do not keep adding 'id' to the list of unique index attributes
  return nil if attributes.empty?
  attributes.map do |attribute|
    type = base.columns_hash[attribute.to_s].try(:type)
    raise "No column found for unique index '#{index}' on #{base.name}." unless type
    raise "Incorrect type (expected string or integer, found #{type}) for unique index '#{attribute}' on #{base.name}." unless type == :string || type == :integer
    UniqueIndexCache.new(base, attribute, record_store, options, type)
  end
end

Instance Method Details

#cacheable?(query) ⇒ Boolean

Can the cache retrieve the records based on this query?

Returns:

  • (Boolean) 


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# File 'lib/record_cache/strategy/unique_index_cache.rb', line 37

def cacheable?(query)
  values = query.where_values(@attribute, @type)
  values && (query.limit.nil? || (query.limit == 1 && values.size == 1))
end

#record_change(record, action) ⇒ Object

Update the version store and the record store



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# File 'lib/record_cache/strategy/unique_index_cache.rb', line 43

def record_change(record, action)
  key = cache_key(record.send(@attribute))
  if action == :destroy
    version_store.delete(key)
  else
    # update the version store and add the record to the cache
    new_version = version_store.renew(key, version_opts)
    record_store.write(versioned_key(key, new_version), Util.serialize(record))
  end
end