Module: ScopeCacheKey

Defined in:
lib/scope_cache_key.rb,
lib/scope_cache_key/version.rb

Overview

Add support for passing models and scopes as cache keys. The cache key will include the md5 digest of the ids and timestamps. Any modification to the group of records will generate a new key.

Eg.:

cache [ Community.first, Category.active ] do ...

Will use the key: communites/1/categories/0b27dac757428d88c0f3a0298eb0278f

Constant Summary collapse

VERSION = 
"0.0.1"

Instance Method Summary collapse

Instance Method Details

#cache_key ⇒ Object

Compute the cache key of a group of records.

Item.cache_key # => "0b27dac757428d88c0f3a0298eb0278f"
Item.active.cache_key # => "0b27dac757428d88c0f3a0298eb0278e"



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# File 'lib/scope_cache_key.rb', line 19

def cache_key
  scope_sql = scoped.select("#{table_name}.id, #{table_name}.updated_at").to_sql

  sql = "SELECT md5(array_agg(id || '-' || updated_at)::text) " +
        "FROM (#{scope_sql}) as query"

  md5 = connection.select_value(sql)

  key = if md5.present?
    md5
  else
    "empty"
  end

  "#{model_name.cache_key}/#{key}"
end