Class: ActiveSupport::FileUpdateChecker
Relationships & Source Files | |
Inherits: | Object |
Defined in: | activesupport/lib/active_support/file_update_checker.rb |
Overview
File Update Checker
FileUpdateChecker
specifies the API used by Rails to watch files and control reloading. The API depends on four methods:
-
initialize
which expects two parameters and one block as described below. -
#updated? which returns a boolean if there were updates in the filesystem or not.
-
#execute which executes the given block on initialization and updates the latest watched files and timestamp.
-
#execute_if_updated which just executes the block if it was updated.
After initialization, a call to #execute_if_updated must execute the block only if there was really a change in the filesystem.
This class is used by Rails to reload the ::I18n
framework whenever they are changed upon a new request.
i18n_reloader = ActiveSupport::FileUpdateChecker.new(paths) do
I18n.reload!
end
ActiveSupport::Reloader.to_prepare do
i18n_reloader.execute_if_updated
end
Class Method Summary
-
.new(files, dirs = {}, &block) ⇒ FileUpdateChecker
constructor
It accepts two parameters on initialization.
Instance Attribute Summary
-
#updated? ⇒ Boolean
readonly
Check if any of the entries were updated.
Instance Method Summary
-
#execute
Executes the given block and updates the latest watched files and timestamp.
-
#execute_if_updated
Execute the block given if updated.
Constructor Details
.new(files, dirs = {}, &block) ⇒ FileUpdateChecker
It accepts two parameters on initialization. The first is an array of files and the second is an optional hash of directories. The hash must have directories as keys and the value is an array of extensions to be watched under that directory.
This method must also receive a block that will be called once a path changes. The array of files and list of directories cannot be changed after FileUpdateChecker
has been initialized.
# File 'activesupport/lib/active_support/file_update_checker.rb', line 44
def initialize(files, dirs = {}, &block) unless block raise ArgumentError, "A block is required to initialize a FileUpdateChecker" end @files = files.freeze @glob = compile_glob(dirs) @block = block @watched = nil @updated_at = nil @last_watched = watched @last_update_at = updated_at(@last_watched) end
Instance Attribute Details
#updated? ⇒ Boolean
(readonly)
Check if any of the entries were updated. If so, the watched and/or updated_at values are cached until the block is executed via #execute or #execute_if_updated.
# File 'activesupport/lib/active_support/file_update_checker.rb', line 63
def updated? current_watched = watched if @last_watched.size != current_watched.size @watched = current_watched true else current_updated_at = updated_at(current_watched) if @last_update_at < current_updated_at @watched = current_watched @updated_at = current_updated_at true else false end end end
Instance Method Details
#execute
Executes the given block and updates the latest watched files and timestamp.
# File 'activesupport/lib/active_support/file_update_checker.rb', line 82
def execute @last_watched = watched @last_update_at = updated_at(@last_watched) @block.call ensure @watched = nil @updated_at = nil end
#execute_if_updated
Execute the block given if updated.