TweetFollow Us on Twitter

Becoming More Efficient through Folder Watching

Volume Number: 20 (2004)
Issue Number: 7
Column Tag: Programming

AppleScript Essentials

by Benjamin S. Waldie

Becoming More Efficient through Folder Watching

For the past several months, we have explored various aspects of AppleScripting in Mac OS X. We have discussed some basic Finder scripting, adding repeat loops and if/then statements to our scripts, and more. This month, we will explore a topic of frequent interest to those who want to automate various aspects of their workflow - folder watching.

Folder Watching

Folder watching is a common automation technique that can be used to make virtually any workflow more efficient. By configuring AppleScripts to monitor folders for new items to arrive, users are able to set up watched folders to automatically process incoming items.

Folder watching can be extremely useful in a variety of situations. For example, let's say that a user in your office copies files into a drop box on your computer at various times throughout the day. Whenever these files arrive, they need to be processed. Since you have other work to do too, you may not be able to monitor the drop box for new files on a regular basis. To assist with the process, you could create an AppleScript that monitors this drop box for you, and then notifies you whenever a new item is detected. Once notified, you could manually process the detected files. Or, you could write additional AppleScript code to process the files for you, completely removing all aspects of manual processing.

In some cases, you need to configure a large number of watched folders for multiple workflows. A common technique for dealing with this type of situation is to set up an AppleScript server. In other words, any dedicated Mac whose primary purpose is to watch these folders for new items, and then process the detected items. By integrating a dedicated folder watching machine into a workflow, users are able to hand off their files for processing, freeing them to work on other less time consuming and repetitive tasks.

In this article, we will discuss some basic ways to create a folder watching script. Then, you can expand these techniques in order to create more complex automated systems.

Idle Folder Watching

One method for writing a script that will watch a folder is to create an AppleScript that has been saved as a stay open application and makes use of AppleScript's idle handler. A stay open application is a script that, when launched, will remain open until manually quit by the user, or told to quit by the script itself, or by another script.

on idle
   -- Add code here to watch the folder
end idle

Handlers are an important, yet fairly complex topic. I will explain handlers in detail in a future article. In the meantime, this tech-note provides a very brief overview of a handler.

A handler is a group of AppleScript statements that may be executed with a single command. There are two types of handlers in AppleScript - subroutine handlers and command handlers. Subroutine handlers are groups of statements, which are defined by the developer, and called throughout a script, or from another script. A command handler is a group of statements that is triggered by an event, such as when a script is run, opened, quit, or idle. The idle handler is considered to be a command handler.

An idle handler will always begin with an on idle line and end with an end idle line. Any AppleScript code in-between these two lines will trigger whenever the script becomes idle. In a stay open script, by default, the idle handler will trigger every 30 seconds. However, you may optionally customize this delay period by adding a line to the end of the idle handler that returns a number of seconds to delay before becoming idle again. In the code below, the script would wait 1 second between executions of the idle handler.

on idle
   -- Add code here to watch the folder
   return 1 -- The number of seconds the script should delay before being idle again
end idle

Once you have a shell for your idle handler, it is time to begin adding some folder watching code. The following example represents a very basic folder watching script. In this example, the script will monitor a user specified folder for items. Whenever items are detected in the folder, they will be moved immediately to the desktop, and the user will be notified that items were detected and moved. The idle handler in this example will trigger once every second. Of course, this example could be expanded to have much greater functionality. For example, you could write code to process only new images that are placed in the folder. The script could be written to open those images in Photoshop, perform various image manipulations, and then save the images into an output folder.

global theWatchedFolder
set theWatchedFolder to choose folder
on idle
   tell application "Finder"
      set theDetectedItems to every item of theWatchedFolder
      repeat with aDetectedItem in theDetectedItems
         move aDetectedItem to the desktop
      end repeat
   end tell
   if theDetectedItems <> {} then
      activate
      display dialog "New items were detected and moved to your desktop."
   end if
   return 1
end idle

In the example above, the first line of code indicates that the variable theWatchedFolder will be a global variable. In other words, once assigned, this variable will be available to all areas of the script, at all times. The second line of code prompts the user to choose a folder, and assigns a reference to the chosen folder to the global variable theWatchedFolder. Because these first two lines of code do not fall within the idle handler, they will only be executed when the script is initially launched.

The code within the idle handler executes after the initial code has finished running. Once executed, it determines whether any items exist in the chosen folder. If items are detected in the folder, the script moves them to the desktop, and then notifies the user that items were detected and moved.

By moving items out of the watched folder, the script ensures that the same items are not detected and reprocessed during the next idle period. If necessary, the script could instead be expanded to keep track of the items in the folder, and only process when new items are added. However, this would require quite a bit more development. Therefore, it is common practice to move files from a watched folder into an output folder once processing is complete.

As previously mentioned, idle handlers are used in scripts that have been saved as stay open applications. Therefore, in order to test the code above, you will need to save the script as a stay open application. To save a script as a stay open application, save the script as an application and select the Stay Open checkbox in Script Editor's save dialog, as shown in Figure 1.


Figure 1. Stay Open Application Save Option

You are now ready to test your script. Launch it from the Finder and select a folder. Next, try moving or copying items into the selected folder, and they should be moved to the desktop.

Folder Actions

Another method of creating a folder watching script is to make use of Mac OS X's built-in Folder Actions support. Folder Actions offer a more robust way to configure watched folders, with less coding needed.

What is a Folder Action?

A Folder Action is a specially written AppleScript, which may be attached to a folder. Folder Actions may be configured to trigger when specific types of action are taken on the folder they are attached to. Folder Actions may be written to trigger whenever:

  • A folder is opened

  • A folder's opened window is moved

  • A folder's opened window is closed

  • Items are added or removed from a folder

Information about Folder Actions, including sample code for configuring each type of Folder Action can be found on Apple Computer's web site at <http://www.apple.com/applescript/folderactions>.

Creating a Folder Action

To create a Folder Action, much like the idle handler, you add a specific handler into your script, indicating the type of action that will trigger the script. Different types of Folder Action handlers exist, and the one that you will need to use will depend on the type of action that you want to trigger your AppleScript code. A list of available Folder Action handlers can be found in the Folder Actions suite in the Standard Additions scripting addition that is installed with Mac OS X.


Figure 2. Folder Actions in the Standard Additions Scripting Addition

As you can see in Figure 2, there are several different types of Folder Action handlers that you may include in your script. Since this article specifically talks about folder watching, we will only discuss the adding folder items to Folder Action handler, which is used to process items added to a folder. However, I encourage you to try out the other types of Folder Action handlers as well.

To create a Folder Action that will process items that are moved or copied into an attached folder, add the adding folder items to Folder Action handler into your script.

on adding folder items to theWatchedFolder after receiving theDetectedItems

-- Add processing code here

end adding folder items to

In the example above, the first line of the handler contains two labeled parameters, theWatchedFolder and theDetectedItems. These parameters will pass dynamically assigned values to the script whenever the script is triggered. The parameter theWatchedFolder will contain an AppleScript alias reference to the folder that the script is attached to. The parameter theDetectedItems will contain a list of AppleScript alias references to the items that were added to the attached folder.

The on adding folder items to handler will only trigger when new items are added to the attached folder, providing to the script a list of only the newly added items. Therefore, unlike the script we created using the idle handler, we could choose to process the newly detected items, without moving them out of the watched folder.

Since, when the script is triggered, it will already have a list of newly added items, there is no need to write code to determine which items were detected. Instead, we only need to add code to process the detected items. The following example code, just like our idle handler, will move newly added items to the desktop, and then notify the user.

on adding folder items to theWatchedFolder after receiving theDetectedItems
   tell application "Finder"
      move theDetectedItems to the desktop
   end tell
   activate
   display dialog "New items were detected and moved to your desktop."
end adding folder items to

Once you have written your Folder Action script, you need to save it as a compiled script.


Figure 3. Saving a Folder Action Script

Place the saved Folder Action script into the Library > Scripts > Folder Action Scripts folder on your computer. Next, you need to actually attach the script to the folder you want to watch.

Configuring a Folder Action

To attach a Folder Action script to a folder, launch the Folder Actions Setup application, which is located in the Applications > AppleScript folder in Mac OS X 10.3 and higher. Once launched, verify that the Enable Folder Actions checkbox is selected. You must enable Folder Actions in order for them to function.


Figure 4. Enabling Folder Actions

Click the + button under the Folders with Actions field, and you will be prompted to select a folder. Make your selection, and click the Open button in the folder selection dialog window. You will then be prompted to select a Folder Action script to attach to the specified folder. Select the desired Folder Action script, and click the Attach button.


Figure 5. Selecting a Folder Action Script

As the Folder Actions Setup application interface will indicate, your Folder Action script is now attached to the folder that you specified.


Figure 6. A Configured Folder Action

Now that configuration is complete, quit the Folder Actions Setup application, and test your Folder Action script by copying or moving items into the attached folder. If everything has been properly configured, then your Folder Action script should process the items placed in the attached folder.

Please note that it is also possible to configure Folder Actions through the contextual menu in the Finder. To display the contextual menu, control click on the desired folder in the Finder.


Figure 7. Folder Action Contextual Menus

In Closing

While the idle handler method of folder watching can be useful at times, Folder Actions offer a very useful way to configure watched folders without a lot of extra coding. I strongly urge you to begin exploring Folder Actions in more detail. As you begin using them, you will wonder how you ever got along without them.

Until next time, keep scripting!


Benjamin Waldie is president of Automated Workflows, LLC, a firm specializing in AppleScript and workflow automation consulting. In addition to his role as a consultant, Benjamin is an evangelist of AppleScript, and can frequently be seen presenting at Macintosh User Groups, Seybold Seminars, and MacWorld. For additional information about Benjamin, please visit http://www.automatedworkflows.com, or email Benjamin at applescriptguru@mac.com.

 

Community Search:
MacTech Search:

Software Updates via MacUpdate

Backblaze 4.2.0.966 - Online backup serv...
Backblaze is an online backup service designed from the ground-up for the Mac. With unlimited storage available for $5 per month, as well as a free 15-day trial, peace of mind is within reach with... Read more
Tunnelblick 3.6.7beta02 - GUI for OpenVP...
Tunnelblick is a free, open source graphic user interface for OpenVPN on OS X. It provides easy control of OpenVPN client and/or server connections. It comes as a ready-to-use application with all... Read more
calibre 2.65.1 - Complete e-book library...
Calibre is a complete e-book library manager. Organize your collection, convert your books to multiple formats, and sync with all of your devices. Let Calibre be your multi-tasking digital librarian... Read more
jAlbum Pro 13.4 - Organize your digital...
jAlbum Pro has all the features you love in jAlbum, but comes with a commercial license. You can create gorgeous custom photo galleries for the Web without writing a line of code! Beginner-friendly... Read more
jAlbum 13.4 - Create custom photo galler...
With jAlbum, you can create gorgeous custom photo galleries for the Web without writing a line of code! Beginner-friendly, with pro results - Simply drag and drop photos into groups, choose a design... Read more
Parallels Desktop 12.0.0 - Run Windows a...
Parallels allows you to run Windows and Mac applications side by side. Choose your view to make Windows invisible while still using its applications, or keep the familiar Windows background and... Read more
Firefox 48.0.2 - Fast, safe Web browser.
Firefox offers a fast, safe Web browsing experience. Browse quickly, securely, and effortlessly. With its industry-leading features, Firefox is the choice of Web development professionals and casual... Read more
Apple iOS 9.3.5 - The latest version of...
iOS is the world’s most advanced mobile operating system, and it’s the foundation of iPhone, iPad, and iPod touch. It comes with a collection of apps and features that let you do the everyday things... Read more
Spotify 1.0.36.124. - Stream music, crea...
Spotify is a streaming music service that gives you on-demand access to millions of songs. Whether you like driving rock, silky R&B, or grandiose classical music, Spotify's massive catalogue puts... Read more
Apple iOS 9.3.5 - The latest version of...
iOS is the world’s most advanced mobile operating system, and it’s the foundation of iPhone, iPad, and iPod touch. It comes with a collection of apps and features that let you do the everyday things... Read more

Clean Text (Productivity)
Clean Text 1.0 Device: iOS Universal Category: Productivity Price: $3.99, Version: 1.0 (iTunes) Description: | Read more »
Gemini - A Journey of Two Stars (Games)
Gemini - A Journey of Two Stars 1.0.1 Device: iOS Universal Category: Games Price: $2.99, Version: 1.0.1 (iTunes) Description: *** SPECIAL LAUNCH SALE: $2.99 (25% off) *** "A mesmerizing and unexpectedly emotional journey." -- Los... | Read more »
How to get four NFL superstars for your...
Even though you're probably well on your way to building a top notch squad for the new season in Madden NFL Mobile, let's say you could beef it up by adding Rob Gronkowski, Antonio Brown, Von Miller, and Todd Gurley to your roster. That's... | Read more »
Cartoon Network Superstar Soccer: Goal!!...
Cartoon Network Superstar Soccer: Goal!!! – Multiplayer Sports Game Starring Your Favorite Characters 1.0 Device: iOS Universal Category: Games Price: $2.99, Version: 1.0 (iTunes) Description: Become a soccer superstar with your... | Read more »
NFL Huddle: What's new in Topps NFL...
Can you smell that? It's the scent of pigskin in the air, which either means that cliches be damned, pigs are flying in your neck of the woods, or the new NFL season is right around the corner. [Read more] | Read more »
FarmVille: Tropic Escape tips, tricks, a...
Maybe farming is passé in mobile games now. Ah, but farming -- and doing a lot of a other things too -- in an island paradise might be a little different. At least you can work on your tan and sip some pina coladas while tending to your crops. [... | Read more »
Become the King of Avalon in FunPlus’ la...
King Arthur is dead. Considering the legend dates back to the 5th century, it would be surprising if he wasn’t. But in the context of real-time MMO game King of Avalon: Dragon Warfare, Arthur’s death plunges the kingdom into chaos. Evil sorceress... | Read more »
Nightgate (Games)
Nightgate 1.0 Device: iOS Universal Category: Games Price: $2.99, Version: 1.0 (iTunes) Description: *** Launch Sale: 25% OFF for a limited time! *** In the year 2398, after a great war, a network of intelligent computers known as... | Read more »
3 best fantasy football apps to get you...
Last season didn't go the way you wanted it to in fantasy football. You were super happy following your drafts or auctions, convinced you had outsmarted everyone. You were all set to hustle on the waiver wire, work out some sweet trades, and make... | Read more »
Pokemon GO update: Take me to your leade...
The Team Leaders in Pokemon GO have had it pretty easy up until now. They show up when players reach level 5, make their cases for joining their respective teams, and that's pretty much it. Light work, as Floyd Mayweather might say. [Read more] | Read more »

Price Scanner via MacPrices.net

Global Tablet Shipments Projected to Increase...
Digitimes’ Jim Hsiao reports that global tablet shipments will increase by 16.3 percent sequentially to reach nearly 47 million units in 2016′s third quarter, but that volume will still be down over... Read more
Apple’s 2016 Back to School promotion: Free B...
Purchase a new Mac or iPad using Apple’s Education Store and take up to $300 off MSRP. All teachers, students, and staff of any educational institution qualify for the discount. Shipping is free, and... Read more
Apple refurbished iPad Air 2s available start...
Apple has Certified Refurbished iPad Air 2 available starting at $339. Apple’s one-year warranty is included with each model, and shipping is free: - 128GB Wi-Fi iPad Air 2: $499 - 64GB Wi-Fi iPad... Read more
13-inch 2.5GHz MacBook Pro available for $961...
Overstock has the 13″ 2.5GHz MacBook Pro available for $961.63 including free shipping. Their price is $138 off MSRP. Read more
Clearance 12-inch Retina MacBooks, Apple refu...
Apple has Certified Refurbished 2015 12″ Retina MacBooks available starting at $929. Apple will include a standard one-year warranty with each MacBook, and shipping is free. The following... Read more
BookBook Releases SurfacePad, BookBook &...
BookBook has released three new covers just for iPad Pro: SurfacePad, BookBook and BookBook Rutledge Edition. BookBook for iPad Pro is a gorgeous leather case reminiscent of a vintage sketchbook.... Read more
Clean Text 1.0 for iOS Reduces Text Cleanup a...
Apimac today announced availability of Clean Text for iOS, a tool for webmasters, graphic designers, developers and magazine editors to reduce text cleanup and editing time, and also for any iPhone... Read more
27-inch iMacs on sale for up to $220 off MSRP
B&H Photo has 27″ Apple iMacs on sale for up to $200 off MSRP including free shipping plus NY sales tax only: - 27″ 3.3GHz iMac 5K: $2099 $200 off MSRP - 27″ 3.2GHz/1TB Fusion iMac 5K: $1899 $100... Read more
Apple refurbished 13-inch MacBook Airs availa...
Apple has Certified Refurbished 2016 and 2015 13″ MacBook Airs now available starting at $849. An Apple one-year warranty is included with each MacBook, and shipping is free: - 2016 13″ 1.6GHz/8GB/... Read more
Apple refurbished iPad mini 2s available for...
Apple is offering Certified Refurbished iPad mini 2s for up to $80 off the cost of new minis. An Apple one-year warranty is included with each model, and shipping is free: - 16GB iPad mini 2 WiFi: $... Read more

Jobs Board

*Apple* Retail - Multiple Positions (US) - A...
Job Description: Sales Specialist - Retail Customer Service and Sales Transform Apple Store visitors into loyal Apple customers. When customers enter the store, Read more
Seasonal Sales Associate - *Apple* Blossom...
Seasonal Sales Associate - Apple Blossom Mall Location:Winchester, VA, United States- Apple Blossom Mall 1850 Apple Blossom Dr Job ID:1001993 Date:August 22, Read more
*Apple* Engineer - Softthink Solutions, Inc....
Job Description:- Proven experience in administering IOS and OSX Apple devices in enterprises - Experience in administering Apple devices in Windows environments Read more
*Apple* Professional Learning Specialist - A...
# Apple Professional Learning Specialist Job Number: 51234243 Portland, Maine, Maine, United States Posted: Aug. 18, 2016 Weekly Hours: 40.00 **Job Summary** The Read more
*Apple* Mobile Master - Best Buy (United Sta...
What does a Best Buy Apple Mobile Master do? At Best Buy, our mission is to leverage the unique talents and passions of our employees to inspire, delight, and enrich Read more
All contents are Copyright 1984-2011 by Xplain Corporation. All rights reserved. Theme designed by Icreon.