Watchers

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CommandBox has a powerful utility that can be used to watch a folder of files for changes and fire arbitrary code when changes happen. The utility will block execution of the task until the user stops it with Ctrl+C. To use a watcher in your task, there is a method called watch() in the base task class that you can call. It has a nice DSL of chainable methods to configure it.

watch()
.paths( '**.cfc' )
.inDirectory( getCWD() )
.withDelay( 5000 )
.onChange( function() {
print.line( 'Something changed!' );
command( 'testbox run' )
.run();
} )
.start();

Here's a rundown of the methods used above in the DSL.

  • paths( ... ) - Receives a comma-delimtied list of globbing patterns to watch for changes. (defaults to **)

  • inDirectory( ... ) - Set the base directory that the file globs are relative to. (defaults to current working directory)

  • withDelay( ... ) - Set the number of milliseconds between polling the file system. (defaults to 500 ms)

  • onChange( ... ) - Pass a closure to be executed when a change has occurred.

  • start() - Starts the watcher. Always call this at the end of the DSL chain

onChange() Closure

If you don't care what the change was then you don't need to define any arguments to your closure. However, each time your closure is called, there is a struct of data passed to it that defines what paths were added removed and changed. The data is the format of:

{
'added':[],
'removed':[],
'changed':[]
}

The arrays will contain the corresponding file paths. For example, if the removed array is empty, it means no files were removed. There should be at least one file path in at least one of the 3 arrays.

watch()
.onChange( function( paths ) {
print
.line( '#paths.added.len()# paths were added!' )
.line( '#paths.removed.len()# paths were removed!' )
.line( '#paths.changed.len()# paths were changed!' ) ;
} )
.start();