fswatchr

A recursive fs.watch

npm install fswatchr
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FSWatchr

A recursive fs.watch for Node.js that recursively walks throught a directory tree, deploy fs.FSWatcher on each directory, and throws back better event reports than the original fs.watch method.

Note FSWatchr uses fs.watch method and not fs.watchFile.

fs.watchFile is not recommended beause it is slower and less reliable according to the node.js api document.

But fs.watch is not 100% platform compatible and FSWatchr doesn't have a fallback mechanism at the moment. See the availability on the node document.

Installation

sudo npm install fswatchr

Usage

# a temp directory for this example  
TMP = "#{__dirname}/tmp"

FSWatchr = require('fswatchr)

#instantiate with the root path to watch
fswatchr = new FSWatchr(TMP)

# set up some listeners
fswatchr.on('File found', (filepath, stat) ->
  console.log("File: #{filepath} is found!")
)

fswatchr.on('File changed, (filepath, stat) ->
  console.log("File: #{filepath} is changed!")
)

# start the recursive watch process
fswatchr.watch()

#stop the watch process
fswatchr.kill()

File Types

7 file types are supported and FSWatchr emits corresponding events in combination with the event types described in the next section.

Note those event names are capitalized.

File Directory BlockDevice FIFO Socket CharacterDevice SymbolicLink

Other file types will still be found and marked Unknown.

Listener functions will have filepath and stats from fs.lstat()

   fswatchr.on('File found', (filepath, stat) ->
  console.log("FilePath: #{filepath}")
  console.log("Stats: #{stats}")      
)

File Type Specific Event types

Each of 7 file types will be broadcasted on the 5 events below...

found created changed unchanged removed

So for instance, File has these 5 events.

File found File created File changed File unchanged File removed

FSWathchr reads the directory contents before it starts watching each directory. found events are emitted during that initial readdir operations, thus happens only once for each file.

unchanged will be emitted when a file is accessed, but not modified.

So there are possibly 80 different events (7 file types + Unknown multiplied by 5 event types), plus we have 7 more non-file-type-specific-events

Non File Type Specific Event types

Once again, these 5 event types are broadcasted without the file type prefixes.

found created changed unchanged removed

And the file types of each event are accessible at the third passed value to the listener function.

   fswatchr.on('created`, (filepath, stat, type) ->
  console.log("FilePath: #{filepath}")
  console.log("Stats: #{stats}")
  console.log("FileType: #{type}")      
)

You can listen to eather file-type-specific-events or non-file-type-specific-events to get the same results.

There are 2 more events.

watchstart will be emitted when FSWatchr successfully set a fs.FSWatcher to each of the directories. So if there are 3 directories inside the root directory (assume there are no third level sub directries), watchstart will be emitted 4 times including the root directory.

   fswatchr.on('watchstart`, (direpath, stats) ->
  console.log("started watching #{dirpath}")

  for filepath, stat of stats
    console.log("Stats for #{filepath}")
    console.log(stat)
  )

watchset will be emitted when FSWachr finish deploying all the fs.FSWatcheres to the entire directory tree starting from the given root. So it will initially be emitted only once.

Note if a new directory is created, FSWatchr initiates the readdir and fs.FSWatcher deploying process for that new directory. So another watchset will be emitted for the new directory.

   fswatchr.on('watchset`, (direpath, stats) ->
  console.log("finish deploying for #{dirpath}")

  # watchset returns the stats of the entire files under the watch of the FSWatchr instance
  for filepath, stat of stats
    console.log("Stats for #{filepath}")
    console.log(stat)
  )

Filter Function

A filter function can be set to ignore files and directories. If a directory is ignored, FSWatchr doesn't go into that directory, so the sub contents under the directorey are all ignored, thus events are unreported.

fswatchr.setFilter((filepath, stat) ->
  return filepath is "#{TMP}/ignore.coffee"
)

Running Tests

Run tests with mocha

make

License

FSWatchr is released under the MIT License. - see LICENSE file .

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