Class: FileSystemWatcher

Inherits:
Object
  • Object
show all
Includes:
ServiceState
Defined in:
lib/filesystemwatcher/filesystemwatcher.rb

Overview

This class will watch a directory or a set of directories and alert you of new files, modified files, deleted files. You can optionally only be alerted when a files md5 hash has been changed so you only are alerted to real changes. this of course means slower performance and higher cpu/io usage.

Constant Summary collapse

CREATED = 
0
MODIFIED = 
1
DELETED = 
2

Constants included from ServiceState

ServiceState::CONFIGURED, ServiceState::NOT_STARTED, ServiceState::STARTED, ServiceState::STOPPED

Instance Attribute Summary collapse

Attributes included from ServiceState

#endTime, #startTime

Instance Method Summary collapse

Methods included from ServiceState

#initializeState, #isConfigured?, #isStarted?, #isStopped?, #onStateChange, #setState, #stopWhen

Constructor Details

#initialize(dir = nil, expression = "**/*") ⇒ FileSystemWatcher

Returns a new instance of FileSystemWatcher.



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# File 'lib/filesystemwatcher/filesystemwatcher.rb', line 22

def initialize(dir=nil, expression="**/*")
  @sleepTime = 5
  @useMD5 = false
  @priority = 0
  @stopWhen = nil

  @directories = Array.new()
  @files = Array.new()

  @foundFiles = nil
  @firstLoad = true
  @watchThread = nil
  
  initializeState()

  if dir then
    addDirectory(dir, expression)
  end
end

Instance Attribute Details

#directories ⇒ Object

the time to wait before checking the directories again



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# File 'lib/filesystemwatcher/filesystemwatcher.rb', line 17

def directories
  @directories
end

#priority ⇒ Object

the time to wait before checking the directories again



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# File 'lib/filesystemwatcher/filesystemwatcher.rb', line 17

def priority
  @priority
end

#sleepTime ⇒ Object

the time to wait before checking the directories again



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# File 'lib/filesystemwatcher/filesystemwatcher.rb', line 17

def sleepTime
  @sleepTime
end

#useMD5 ⇒ Object

you can optionally use the file contents md5 to detect if a file has changed



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# File 'lib/filesystemwatcher/filesystemwatcher.rb', line 20

def useMD5
  @useMD5
end

Instance Method Details

#addDirectory(dir, expression = "**/*") ⇒ Object

add a directory to be watched

Parameters:

  • dir —

    the directory to watch

  • expression (defaults to: "**/*") —

    the glob pattern to search under the watched directory



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# File 'lib/filesystemwatcher/filesystemwatcher.rb', line 45

def addDirectory(dir, expression="**/*")
  if FileTest.exists?(dir) && FileTest.readable?(dir) then
    @directories << FSWatcher::Directory.new(dir, expression)
  else
    raise FSWatcher::InvalidDirectoryError, "Dir '#{dir}' either doesnt exist or isnt readable"
  end
end

#addFile(file) ⇒ Object

add a specific file to the watch list

Parameters:

  • file —

    the file to watch



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# File 'lib/filesystemwatcher/filesystemwatcher.rb', line 59

def addFile(file)
  if FileTest.exists?(file) && FileTest.readable?(file) then
    @files << file
  else
    raise FSWatcher::InvalidFileError, "File '#{file}' either doesnt exist or isnt readable"
  end
end

#join ⇒ Object

wait for the filewatcher to finish



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# File 'lib/filesystemwatcher/filesystemwatcher.rb', line 139

def join()
  @watchThread.join() if @watchThread
end

#removeDirectory(dir) ⇒ Object 



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# File 'lib/filesystemwatcher/filesystemwatcher.rb', line 53

def removeDirectory(dir)
  @directories.delete(dir)
end

#removeFile(file) ⇒ Object 



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# File 'lib/filesystemwatcher/filesystemwatcher.rb', line 67

def removeFile(file)
  @files.delete(file)
end

#start(&block) ⇒ Object

start watching the specified files/directories



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# File 'lib/filesystemwatcher/filesystemwatcher.rb', line 72

def start(&block)
  if isStarted? then
    raise RuntimeError, "already started"
  end

  setState(STARTED)

  @firstLoad = true
  @foundFiles = Hash.new()

  # we watch in a new thread
  @watchThread = Thread.new {
    # we will be stopped if someone calls stop or if someone set a stopWhen that becomes true
    while !isStopped? do
	if (!@directories.empty?) or (!@files.empty?) then	
 # this will hold the list of the files we looked at this iteration
 # allows us to not look at the same file again and also to compare
 # with the foundFile list to see if something was deleted
 alreadyExamined = Hash.new()
 
 # check the files in each watched directory
 if not @directories.empty? then
   @directories.each { |dirObj|
     examineFileList(dirObj.getFiles(), alreadyExamined, &block)
   }
 end
 
 # now examine any files the user wants to specifically watch
 examineFileList(@files, alreadyExamined, &block) if not @files.empty?
 
 # see if we have to delete files from our found list
 if not @firstLoad then
   if not @foundFiles.empty? then
     # now diff the found files and the examined files to see if
     # something has been deleted
     allFoundFiles = @foundFiles.keys()
     allExaminedFiles = alreadyExamined.keys()
     intersection = allFoundFiles - allExaminedFiles
     intersection.each { |fileName|
# callback
block.call(DELETED, fileName)
# remove deleted file from the foundFiles list
@foundFiles.delete(fileName)
     }	  
   end
 else
   @firstLoad = false
 end
	end
	
	# go to sleep
	sleep(@sleepTime)
    end
  }
  
  # set the watch thread priority
  @watchThread.priority = @priority

end

#stop ⇒ Object

kill the filewatcher thread



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# File 'lib/filesystemwatcher/filesystemwatcher.rb', line 133

def stop()
  setState(STOPPED)
  @watchThread.wakeup()
end