TweetFollow Us on Twitter

Providing Progress Feedback During Script Execution

Volume Number: 22 (2006)
Issue Number: 1
Column Tag: Programming

AppleScript Essentials

Providing Progress Feedback During Script Execution

by Benjamin S. Waldie

Many AppleScripts do not provide progress updates to the user during processing. Most of the time, when a script is run, it simply performs the appropriate tasks "behind the scenes," so to speak. If run as an application, a script may appear in the Dock when launched. However, this hardly provides detailed information to the user about what is actually occurring. Sometimes, a script may not need to provide progress updates to the user. However, there are situations when providing such feedback is a good idea.

In this month's column, we will walk through the process of creating a script that will provide visual progress information to the user during processing. The script we will create will save selected email messages in Mail as text files into a user-specified output folder. Since the script will have the ability to process multiple selected email messages, we will write our code to provide a visual indication to the user of which message is currently being processed. Once you learn how to provide this type of feedback, then you can begin integrating this same technique into your other scripts, making them more user friendly.

If you followed along with some of my past AppleScript Essentials columns, then you are probably familiar with AppleScript Studio, a feature set of Xcode and Interface Builder, the Mac OS X developer tools that come with OS X. AppleScript Studio provides a way for developers to build AppleScript-based applications, complete with robust interfaces. In this month's column, we will use AppleScript Studio to add a progress interface to our script, complete with text feedback and a progress bar.

Displaying a Basic Progress Interface with AppleScript

Before we get started with AppleScript Studio, let's discuss how to provide progress information to the user in a non-AppleScript Studio-based script.

In some cases, taking the time to construct an AppleScript Studio application may not be the best solution. For example, your script may be very simple, or it may be an existing script that is too complex to warrant conversion to AppleScript Studio at this time. You may just want a quick and easy way to provide feedback to the user. In these types of situations, the easiest method is to make use of the display dialog command, which can be found in the User Interaction suite of the Standard Additions scripting addition that is installed with Mac OS X.

Using the display dialog command, you can configure a script to display text messages in a no-frills dialog window at various times during script execution. The following example code demonstrates how a display dialog command can be used to provide such feedback.

set theOutputFolder to (choose folder with prompt "Select an output folder:") as string
tell application "Mail"
   set theSelectedMessages to selection
   set theMessageCount to count theSelectedMessages
   repeat with a from 1 to theMessageCount
      display dialog "Processing message " & a & " of " & theMessageCount giving up after 
         1 with icon note
      set theMessageContent to content of item a of theSelectedMessages
      set theArchivePath to theOutputFolder & "Archived Message " & a & ".txt" as string
      set theArchiveFile to open for access theArchivePath with write permission
      set eof of theArchiveFile to 0
      write theMessageContent to theArchiveFile
      close access theArchiveFile
   end repeat
end tell

In the previous code, the first line of the script will prompt the user to select an output folder. Next, the script will retrieve a list of selected email messages in Mail. The script will then proceed to loop through each of these messages. During each repeat loop cycle, the script will retrieve the content of the current message, and save it into a file in the output folder chosen by the user.

As you can see, in order to provide visual feedback to the user during processing, I have made use of a display dialog command within the script's repeat loop. This will cause the script to display a message to the user each time the script begins processing one of the selected email messages. I have configured the display dialog command to indicate the current message count, as well as the total count of selected messages. See figure 1.


Figure 1. A Basic Script Progress Dialog

I have also configured the display dialog command to automatically dismiss the dialog after it has been displayed for 1 second. This will ensure that the script can proceed automatically with further execution, without the user being required to actually click a button in order to proceed.

Upon the successful execution of the previous code, the output folder specified by the user should contain text files containing the contents of the selected email messages. See figure 2.


Figure 2. Archived Email Messages

The display dialog command can also be used independently, rather than within a repeat loop to indicate various tasks that are being performed by the script.

Now that we have discussed providing basic progress information to the user, let's move on to AppleScript Studio. In the remainder of this month's column, we will walk through the process of creating a script that will perform the exact same function as the previous code, only with a more robust interface.

Building the AppleScript Studio Project

You may recall that the first step in building an AppleScript Studio project is to create a new project in Xcode. Begin by launching Xcode.

    Please note that the AppleScript Studio project covered in this article was developed using Mac OS X 10.4.2 and Xcode 2.1. Please be aware that new software versions often result in changes in AppleScript terminology. Therefore, if you are using software versions other than those that I have specified, your required terminology may differ slightly from that which I am using in this article.

    Create a new project by selecting New Project... from the File menu in Xcode. When prompted, select a project type of AppleScript Application from the list of available project templates, enter a project name of Archive Selected Messages, and specify an output folder for the project. Xcode will duplicate the AppleScript Application project template into the specified output folder, and open it for you. See figure 3.


Figure 3. Archive Selected Messages Project Window

Building the Interface

Next, we will create an interface for providing progress information during processing. Double click on the MainMenu.nib file within your Xcode project window. This will open the project's default view in the Interface Builder application.

Designing the Window

By default, the project's interface should already contain an empty window view. This window will be the basis for our interface. Click on the window, and give the window a name by entering Archive Selected Messages Progress into the Window Title field in the Inspector palette. See figure 4. If the Inspector palette is not visible, select Show Inspector from the Tools menu in Interface Builder.


Figure 4. Preparing the Progress Window

Once you have specified the title for the window, de-select the Visible at launch time checkbox in the Inspector palette. This will cause the window to be hidden when the project is first launched.

You may want to make some other adjustments to the window configuration at this time, as well. For example, you may want to disable the ability for the user to close or zoom the window. Refer to figure 4 for the settings that I have specified for my progress window.

Next, click on the Cocoa Controls and Indicators tab in the toolbar of the Palettes window. If the Palettes window is not visible, select Palettes > Show Palettes from the Tools menu. Next, locate an NSProgressIndicator progress bar interface element in the Palettes window, and drag it into your project's window. See figure 5.


Figure 5. Adding an NSProgressIndicator

Next, click on the Cocoa Text Controls button in the toolbar of the Palette window, and drag an NSTextField into your interface window. Enter some default text, such as Waiting to process... into the text field's contents.

Continue to arrange and design the interface, making sure to adhere to Apple's standards for human user interface guidelines, which can be found in the ADC Reference Library, both online and in Xcode's documentation. See figure 6 for an example of my completed interface design.


Figure 6. Example Progress Interface Design

Preparing the Interface for AppleScript Interaction

Once you have finished designing your progress interface, the elements that make up the interface must be prepared to interact with the AppleScript code within your project. To do this, you must assign AppleScript names to various interface elements, as well as configure certain elements of the interface to respond to event handlers.

First, we will assign an AppleScript name to the main window itself. To do this, click on the window to select it. Next, choose AppleScript from the popup button at the top of the Inspector palette, and enter the name Progress Window into the Name field. See figure 7. The process of assigning AppleScript names to the other interface elements will be the same.


Figure 7. Assigning an AppleScript Name to the Progress Window

Select the progress indicator bar and text field in the window, and assign AppleScript names of Progress Bar and Progress Text, respectively.

As the last step in configuring the progress interface, we must configure the solution to run our AppleScript code when launched. This will be done by enabling an event handler. To do this, first select File's Owner in the MainMenu.nib window. A list of available event handlers will be visible on the Inspector palette, beneath the Name field. Enable the launched event handler by selecting its checkbox in the list of event handlers. Next, link the event handler to the AppleScript code in your project by selecting the checkbox next to Archive Selected Messages.applescript in the Script area at the bottom of the Inspector palette, beneath the event handler list. See figure 8.


Figure 8. Enabling the Launched Event Handler

Adding the AppleScript code

Now that you have configured your interface, it is time to begin adding the AppleScript code into your project. Return to Xcode, and double click on Archive Selected Messages.applescript file in your project to begin editing the AppleScript code.

Preparing the Launched Event Handler

Since we configured our interface to respond to the launched event handler, we will need to add this handler to our project's code. If you saved your project's interface in Interface Builder, then this code may have been automatically inserted for you within your main project script in Xcode. If it does not exist, enter it as follows:

on launched theObject

end launched

Any code that is entered into this launched handler will be executed when our project application is launched. As we proceed, enter all code below within the launched handler.

Get the Output Folder

It is now time to begin adding the processing code to our project. Begin by entering the following code, which will prompt the user to select an output folder. Take note that this code is identical to that used in our non-AppleScript Studio example.

set theOutputFolder to (choose folder with prompt "Select an output folder:") as string

Get the Selected Messages

Next, add the following code, which will retrieve a list of any selected email messages in Mail, and will then count the detected messages.

tell application "Mail"
   set theSelectedMessages to selection
end tell
set theMessageCount to count theSelectedMessages

Show the Progress Window

You may recall that we configured our progress window to not be visible on launch. The following code will now make this window visible to the user.

set visible of window "Progress Window" to true

Prepare the Progress Bar

We are now ready to begin preparing the progress bar within our window. First, we will set the maximum value property of the progress bar to the number of detected email messages.

set maximum value of progress indicator "Progress Bar" of window 
   "Progress Window" to theMessageCount

Next, in order to ensure that our progress bar will display incremental progress, we will set the indeterminate property of the progress bar to a value of false. A progress bar with an indeterminate property value of true will appear as a blue and white striped bar, as can be seen in figure 6, and this is not desirable for providing incremental progress.

set indeterminate of progress indicator "Progress Bar" of window 
   "Progress Window" to false

Looping Through the Selected Messages

We will now add code to loop through the selected email messages. Enter the following code into the script:

repeat with a from 1 to theMessageCount

end repeat

Updating the Progress Text

The following code should be added immediately within the repeat statement. It will update the text field in our interface to indicate the current message being processed. As in our non-AppleScript Studio example, this text will tell the user the current message count, as well as the total message count.

set contents of text field "Progress Text" of window "Progress Window" to 
   "Processing message " & a & " of " & theMessageCount

Getting the Current Message's Contents

Next, add the code below, which will retrieve the content of the current email message.

tell application "Mail"
      set theMessageContent to content of item a of theSelectedMessages
end tell

Saving the Contents to a File

Again, using the exact code from our non-AppleScript Studio example, add the following to your script. This code will write the content of the current message to a text file in the specified output folder.

set theArchivePath to theOutputFolder & "Archived Message " & a & ".txt" as string
set theArchiveFile to open for access theArchivePath with write permission
set eof of theArchiveFile to 0
write theMessageContent to theArchiveFile
close access theArchiveFile

Updating the Progress Bar

Finally, for the last section of code within the repeat loop, add the following code. This code will set the content of the progress bar to the current repeat loop increment, thus increasing the progress bar's display to accurately reflect the current number of messages processed.

set content of progress indicator "Progress Bar" of window "Progress Window" to a
update window "Progress Window"

Please note that the last line in the preceding code will update the window, ensuring that the progress bar's interface is refreshed each time its content value is changed.

Completing the Code

To complete the handler, add a quit command at the end of the handler, just outside of the repeat statement. This will ensure that the application quits, once processing is complete.

quit

Next, wrap all of the code within the handler inside of a try statement, configured as follows:

try

on error theErrorMessage number theErrorNumber
   if theErrorNumber = -128 then quit
   error theErrorMessage number theErrorNumber
end try

This try statement will trap for a user cancelled error, error number -128, which would occur if the user clicks the Cancel button when prompted to select an output folder.

Now that your script is complete, the following example code shows how the completed launched handler should appear within your main project script.

on launched theObject
   try
      set theOutputFolder to (choose folder with prompt "Select an 
         output folder:") as string
      tell application "Mail"
         set theSelectedMessages to selection
      end tell
      set theMessageCount to count theSelectedMessages
      set visible of window "Progress Window" to true
      set maximum value of progress indicator "Progress Bar" of window 
         "Progress Window" to theMessageCount
      set indeterminate of progress indicator "Progress Bar" of window 
         "Progress Window" to false
      repeat with a from 1 to theMessageCount
         set contents of text field "Progress Text" of window "Progress Window" 
            to "Processing message " & a & " of " & theMessageCount
         tell application "Mail"
            set theMessageContent to content of item a of theSelectedMessages
         end tell
         set theArchivePath to theOutputFolder & "Archived Message " & a & ".txt" as string
         set theArchiveFile to open for access theArchivePath with write permission
         set eof of theArchiveFile to 0
         write theMessageContent to theArchiveFile
         close access theArchiveFile
         set content of progress indicator "Progress Bar" of window "Progress Window" to a
         update window "Progress Window"
      end repeat
      quit
   on error theErrorMessage number theErrorNumber
      if theErrorNumber = -128 then quit
      error theErrorMessage number theErrorNumber
   end try
end launched

Testing the Project

Now that our project is complete, it is ready for testing. To test the project, first launch Mail, and select multiple email messages. For best results, you may want to select a large number of messages, in order to ensure that the progress bar will increment properly. Next, select Build and Run from the Build menu in Xcode. If everything works as expected, your solution should launch, and you should be prompted to select an output folder. After choosing a folder, the project's interface should be displayed, and the selected messages should be processed and saved into the specified output folder.


Figure 9. The Completed Progress Interface

Other Options

In AppleScript Studio, a progress indicator may be displayed as a bar, as we have seen. However, a progress indicator may also be displayed as a spinner. See figure 10.


Figure 10. Example of a Progress Spinner

A progress spinner may be useful in situations where your code does not warrant providing incremental feedback to the user, yet you still wish to indicate that processing is occurring.

In Closing

The project discussed in this month's column should give you some basic ways to implement progress feedback in your scripts. Now, it is up to you to begin making your scripts more user friendly by providing such feedback to your users.

If you have difficulty getting any of the specified code to work, or if you prefer to review the actual project files, you may wish to download the example code. I have made the sample project discussed in this article available for download from my web site at the following URL:

http://www.automatedworkflows.com/files/demos/MacTECH.01.06.Example.zip

Until next time, keep scripting!


Ben Waldie is author of the best selling books "AppleScripting the Finder" and the "Mac OS X Technology Guide to Automator", available from http://www.spiderworks.com. Ben is also president of Automated Workflows, LLC, a firm specializing in AppleScript and workflow automation consulting. For years, Ben has developed professional AppleScript-based solutions for businesses including Adobe, Apple, NASA, PC World, and TV Guide. For more information about Ben, please visit http://www.automatedworkflows.com, or email Ben at applescriptguru@mac.com.

 

Community Search:
MacTech Search:

Software Updates via MacUpdate

Firefox 37.0 - 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
Arq 4.11 - Online backup to Google Drive...
Arq is super-easy online backup for the Mac. Back up to your own Google Drive storage (15GB free storage), your own Amazon Glacier ($.01/GB per month storage) or S3, or any SFTP server. Arq backs up... Read more
MacFamilyTree 7.3.4 - Create and explore...
MacFamilyTree gives genealogy a facelift: it's modern, interactive, incredibly fast, and easy to use. We're convinced that generations of chroniclers would have loved to trade in their genealogy... Read more
Yummy FTP 1.10.2 - FTP/SFTP/FTPS client...
Yummy FTP is an FTP + SFTP + FTPS file transfer client which focuses on speed, reliability and productivity. Whether you need to transfer a few files or a few thousand, schedule automatic backups, or... Read more
VueScan 9.5.08 - Scanner software with a...
VueScan is a scanning program that works with most high-quality flatbed and film scanners to produce scans that have excellent color fidelity and color balance. VueScan is easy to use, and has... Read more
Iridient Developer 3.0.1 - Powerful imag...
Iridient Developer (was RAW Developer) is a powerful image conversion application designed specifically for OS X. Iridient Developer gives advanced photographers total control over every aspect of... Read more
Air Video Server HD 2.1.0 - Stream video...
Air Video Server HD streams videos instantly from your computer on your iPhone, iPad, iPod touch or Apple TV. No need to worry about converting or transferring files. We took everything that was... Read more
Duplicate Annihilator 5.7.5 - Find and d...
Duplicate Annihilator takes on the time-consuming task of comparing the images in your iPhoto library using effective algorithms to make sure that no duplicate escapes. Duplicate Annihilator... Read more
BusyContacts 1.0.2 - Fast, efficient con...
BusyContacts is a contact manager for OS X that makes creating, finding, and managing contacts faster and more efficient. It brings to contact management the same power, flexibility, and sharing... Read more
Capture One Pro 8.2.0.82 - RAW workflow...
Capture One Pro 8 is a professional RAW converter offering you ultimate image quality with accurate colors and incredible detail from more than 300 high-end cameras -- straight out of the box. It... Read more

2K Announces WWE 2K, Mobile's First...
It seems like this month has been pretty big for wrestling. First Wrestlemania, then 2K has announces that they're releasing  WWE 2K for iOS. It's a simulation-based WWE game where you'll get to play with several WWE superstars such as John Cena, ... | Read more »
How the Apple Watch Could Change the Fac...
The Apple Watch is still a ways out, but my previous musings on the wearable’s various features got me thinking: what might it be like a year after launch? Two years? Five years? What if it becomes a symbiotic part of the iOS framework to the point... | Read more »
Pie In The Sky: A Pizza Odyssey (Games)
Pie In The Sky: A Pizza Odyssey 1.0 Device: iOS Universal Category: Games Price: $2.99, Version: 1.0 (iTunes) Description: A game about delivering pizza. In space. | Read more »
Chosen Gives Hopeful Singers, Songwriter...
If YouTube videos and reality TV shows like The Voice have taught us one thing, it’s that there are a lot of people out there who are anxious to show the world their talents. And if they’ve taught us a second thing, it’s that there’s an almost... | Read more »
Android's Popular OfficeSuite Now A...
Once only available for Android devices, OfficeSuite has finally landed on the app store. The Mobile Systems app lets you view, edit, create, and share Word, Excel, and PowerPoint documents as well as convert them to/from PDFs. It's touted as being... | Read more »
Warhammer: Arcane Magic is Coming Soon,...
Turbo Tape Games has announced that they're joining forces with Games Workshop to bring the turn-based strategy board game, Warhammer: Arcane Magic, to life on the iOS. | Read more »
Fast & Furious: Legacy's Creati...
| Read more »
N-Fusion and 505's Ember is Totally...
| Read more »
These are All the Apple Watch Apps and G...
The Apple Watch is less than a month from hitting store shelves, and once you get your hands on it you're probably going to want some apps and games to install. Fear not! We've compiled a list of all the Apple Watch apps and games we've been able to... | Read more »
Appy to Have Known You - Lee Hamlet Look...
Being at 148Apps these past 2 years has been an awesome experience that has taught me a great deal, and working with such a great team has been a privilege. Thank you to Rob Rich, and to both Rob LeFebvre and Jeff Scott before him, for helping me... | Read more »

Price Scanner via MacPrices.net

13-inch 2.4GHz Retina MacBook Pro available f...
MacMall has the 2013 13″ 2.4GHz/128GB Retina MacBook Pro available for $949.99 for a limited time. Shipping is free. Their price is $350 off original MSRP, and it’s the only sub-$1000 new Retina... Read more
Adobe Brings Powerful Layout-Design Capabilit...
Adobe today announced the availability of Adobe Comp CC, a free iPad app that enables rapid creation of layout concepts for mobile, Web and print projects. With Comp CC, designers can rough out and... Read more
13-inch 2.6GHz/256GB Retina MacBook Pro avail...
Best Buy has clearance 2014 13″ 2.6GHz/256GB Retina MacBook Pros available for $1199.99 including free shipping. Their price is $300 off original MSRP, and it’s the lowest price for this model.... Read more
Updated Mac Price Trackers
We’ve updated our Mac Price Trackers with the latest information on prices, bundles, and availability on systems from Apple’s authorized internet/catalog resellers: - 15″ MacBook Pros - 13″ MacBook... Read more
21-inch 1.4GHz iMac on sale for $999, save $1...
Best Buy has the 21″ 1.4GHz iMac on sale for $999.99 on their online store. Choose free shipping or free local store pick up. Price is for online orders only, in-store prices may vary. Their price is... Read more
2.6GHz Mac mini on sale for $649, save $50
Amazon has the 2.6GHz Mac mini on sale for $649.99 including free shipping. Their price is $50 off MSRP, and it’s the lowest price available for this model. Read more
Textkraft Professional 3.2 Powerful iPad Text...
Finally it’s springtime, at least theoretically in my neck of the woods, where we’re still navigating canyons between towering snowbanks with temperatures well below freezing in winter weather that... Read more
Apple offering refurbished 27-inch 5K iMacs f...
The Apple Store is offering Apple Certified Refurbished 27″ 3.5GHz 5K iMacs for $2119 including free shipping. Their price is $380 off the price of new models, and it’s the lowest price available for... Read more
16GB iPad mini on sale for $199, save $50
Walmart has 16GB iPad minis (1st generation) available for $199.99 on their online store, including free shipping. Their price is $50 off MSRP. Online orders only. Read more
New 128GB MacBook Airs on sale for $50 off MS...
 B&H Photo has 128GB 11″ and 13″ 2015 MacBook Airs on sale today for $50 off MSRP including free shipping plus NY sales tax only: - 11″ 1.6GHz/128GB MacBook Air (Model #MJVM2LL/A): $849 $50 off... Read more

Jobs Board

DevOps Software Engineer - *Apple* Pay, iOS...
**Job Summary** Imagine what you could do here. At Apple , great ideas have a way of becoming great products, services, and customer experiences very quickly. Bring Read more
*Apple* Retail - Multiple Positions (US) - A...
Sales Specialist - Retail Customer Service and Sales Transform Apple Store visitors into loyal Apple customers. When customers enter the store, you're also the Read more
Sr. Technical Services Consultant, *Apple*...
**Job Summary** Apple Professional Services (APS) has an opening for a senior technical position that contributes to Apple 's efforts for strategic and transactional Read more
Lead *Apple* Solutions Consultant - Retail...
**Job Summary** Job Summary The Lead ASC is an Apple employee who serves as the Apple business manager and influencer in a hyper-business critical Reseller's store Read more
*Apple* Pay - Site Reliability Engineer - Ap...
**Job Summary** Imagine what you could do here. At Apple , great ideas have a way of becoming great products, services, and customer experiences very quickly. Bring Read more
All contents are Copyright 1984-2011 by Xplain Corporation. All rights reserved. Theme designed by Icreon.