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Adding documentation regarding lazy_load_hooks

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commit 3c3ff1377d17b584dd14d85c7cecab59ddff2679 1 parent a506d5a
@neerajdotname neerajdotname authored
Showing with 20 additions and 1 deletion.
  1. +20 −1 activesupport/lib/active_support/lazy_load_hooks.rb
21 activesupport/lib/active_support/lazy_load_hooks.rb
@@ -1,3 +1,22 @@
+# lazy_load_hooks allows rails to lazily load a lot of components and thus making the app boot faster. Because of
+# this feature now there is no need to require <tt>ActiveRecord::Base</tt> at boot time purely to apply configuration. Instead
+# a hook is registered that applies configuration once <tt>ActiveRecord::Base</tt> is loaded. Here <tt>ActiveRecord::Base</tt> is used
+# as example but this feature can be applied elsewhere too.
+# Here is an example where +on_load+ method is called to register a hook.
+# initializer "active_record.initialize_timezone" do
+# ActiveSupport.on_load(:active_record) do
+# self.time_zone_aware_attributes = true
+# self.default_timezone = :utc
+# end
+# end
+# When the entirety of +activerecord/lib/active_record/base.rb+ has been evaluated then +run_load_hooks+ is invoked.
+# The very last line of +activerecord/lib/active_record/base.rb+ is:
+# ActiveSupport.run_load_hooks(:active_record, ActiveRecord::Base)
module ActiveSupport
@load_hooks = {|h,k| h[k] = [] }
@loaded = {}
@@ -24,4 +43,4 @@ def self.run_load_hooks(name, base = Object)
execute_hook(base, options, hook)
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