TweetFollow Us on Twitter

RemoteScriptRunner: Remotely execute scripts from any web browser

Volume Number: 19 (2003)
Issue Number: 12
Column Tag: Programming

RemoteScriptRunner: Remotely execute scripts from any web browser

by Joe Zobkiw


Lately I've been exploring Java and the many things that can be done with it. I will admit that for years I was turned off by Java due to my initial experiences with it in the Mac OS. When Java was first introduced on the Mac OS it was horribly slow. Most people first saw Java perform in the form of an applet or some other browser-based user interface - unfortunately this was not Java's strong suit. However, with Mac OS X, Jaguar and especially Panther, Apple has made great strides in making Java much more usable on the Mac...which caused me to give it a second look.

Java is not just for user interfaces. In fact, there are so many tributaries flowing off the Java river that it's liable to make your head spin just trying to figure out what Java is actually capable of! In fact, it's probably safe to say that Java is capable of just about any type of software development you are interested in - all you have to do is figure it out or find someone who already has. Java can be used to write clients and servers, access databases, communicate with mobile devices, run appliances, write platform-native code, etc. In this article we look at Java's server side - which arguably is a better choice than many other languages (including C) when writing a server.

RemoteScriptRunner is a proof-of-concept Java application that runs as a daemon process in the background. That is, you won't see any icons in the Dock while RSR is running - like most servers. Although Java can be platform independent, this one implements the ability to execute AppleScript format scripts, so in that regard it is platform specific to any platform that implements AppleScript. However, this mechanism can easily be changed to support other scripting architectures and is left as an exercise to the reader.

RSR is modeled after an article written by David Brown in August 1997 entitled "A Simple, Multithreaded Web Server" which can be found on the Sun Java developer web site at I recommend you look at this article for details on the server as I will not delve into the details of that here. In fact, this article takes more of a "here's what I learned" approach. The AppleScript portion of this code is modeled on a code example by Scott D.W. Rankin and is available at

20,000 Feet

At 20,000 feet, RSR functions as follows. You double-click the compiled Java application, usually in the form of a JAR file. Although you won't see it in the Dock, suffice it to say that this starts the server running and waiting for client connections on port 8080, or any port you specify. You can check to see if the server is running by typing ps ax | grep java in Terminal. If the server is running you should see a line in the result that looks something like 460 ?? S 0:00.71 java -jar /Users/zobkiw/RSR/RemoteScriptRunner.jar. At this point the server is active yet essentially idle as it awaits a connection from a web browser client.

Next, a user launches their web browser and accesses the server as they would any other HTTP URL. In our case, since we are testing things locally, we use http://localhost:8080/ but localhost can be or any other valid IP address or server/domain name. The server accepts the HTTP connection, sees that the request is in GET format and returns the HTML necessary to display a form to the user. This form contains an editable text area, a submit button and a button to quit the server. The editable text area is used to type your AppleScript.

Once an AppleScript is entered, you press the Submit button to POST the form and data to the server. This time when the browser connects to the server, the server accepts the connection and sees that the request is in POST format and parses the data in the form -- most importantly, the AppleScript. The server attempts to execute the script using the necessary AppleScript-related Java classes and returns the results as HTML to the client.

Figure 1 - RemoteScriptRunner in action

In Figure 1 we show the two "pages" created by the server. In the first page (behind) we have filled out the form to include an AppleScript that tells the Finder to get the name of every item in the desktop. After submitting this script, we see the results in the second page (front). Note that the results are simply a list of items that happened to be on my desktop at the time.

10,000 Feet

Zooming down to 10,000 feet, let's take a look at the development environment and source code. Java development tools can take you in many different directions - all have their advantages and disadvantages for any particular project. There is Project Builder for pre-10.3 users, Xcode for 10.3 users and beyond, Eclipse for anyone on just about any platform, and then BBEdit and the command line. Although I've written Java code using each of these options, for this project I chose BBEdit and the command line. When there isn't a whole lot of code to write I can do things just as easily and usually faster by using these stand-by tools.

So, in this project I created my file in BBEdit as well as the manifest file, Then I use Terminal to compile, run and build the JAR file. The command line to compile is javac -classpath /System/Library/Java:. The command line to run is java -classpath /System/Library/Java:. RemoteScriptRunner. The command line to build the JAR file is jar cmf RemoteScriptRunner.jar *.class. The manifest file is a text file that contains two lines, as follows:

   Main-Class: RemoteScriptRunner
   Class-Path: /System/Library/Java/ 

Because the easily accessible Brown article mentioned earlier does such a good job at explaining the multithreaded nature of the server, to which I made few changes, I won't go into the details of that here. This article will primarily discuss the handleClient method of the Worker class that is called after a connection is accepted. However, let's quickly discuss what leads up to the handleClient method being called.

First, the main program loads all program settings and creates a series of Worker objects as Threads. Because it's less "expensive" to create a few of these up-front, we do it at program initialization rather when a connection is actually established. These Worker objects are stored in a Vector and are available to handle connections as they are accepted. The server then establishes itself and loops forever, waiting for a connection. When a connection is established, the first Worker object not already busy is pulled from the Vector and passed the Socket that accepted the connection. At this point the Worker object, which was in a wait state, is notified to wake up and begin its work, ultimately calling its handleClient method.

In handleClient the first thing you want to do is create a PrintWriter on the socket's output stream for writing and a BufferedReader on the socket's input stream for reading. We also set the timeout so we don't hang the machine in the case where the socket is left open but there is nothing left to read.

   // Create a reader and writer
   PrintWriter pw = new PrintWriter(clientSocket.getOutputStream(), true);
   BufferedReader br = new BufferedReader(new 
   // We will only block in read for this many milliseconds before we fail with 
   //, at which point we will abandon the connection

Depending on what the purpose of your server is, you can very easily loop calling the readLine method of the BufferedReader repeatedly until no more data is available. This will get you (most) everything coming from the client.

   // Read the bulk of the data from the input by line
   String s;
   while (((s = br.readLine()) != null) && (s.length() != 0))
      System.out.println("> " + s);

We do just this with the addition that we also look for specific information coming from the client. In the HTTP protocol the server receives all sorts of information from the client when a connection is open. A part of this information includes the type of request. Although we can just as easily look for specific codes and values within the URL or embedded in the data, in this implementation we look for GET and POST requests specifically and base our response on that. We make use of the startsWith method of the String class for this purpose. If the string starts with "GET" then we respond by sending back the HTML containing the form. If the string starts with "POST" then we know that the form is being submitted and we extract the AppleScript from it and attempt to execute it, returning its result.

One thing to note about the readLine method used above is that in the case of a POST, readLine will not read the POSTed form data. The problem is that the form data does not end in a newline character, so readLine essentially ignores it. Given that, in the case of a POST, we have to finish reading the data character by character using the read method of the BufferedReader. As we read each character, we build a string containing all of the data.

   // Read the rest of the available data and create a string of it
   s = "";
   while (br.ready() && ((ch = != -1))
      s += (char)ch;

Once you have the string containing the form data there are a few things to do to it before you use it. First we trim the string using the trim method of the String class. Next we decode the string using the decode method of the URLDecoder class, passing "UTF-8" as the decoding scheme. Then, using the StringTokenizer class we split the string by '&' to extract the name and value pairs. Once we have each pair we use the StringTokenizer class once again to split the string by '='. This gives us the value of any particular field from the form. The getFormVariableValue method shows the use of the StringTokenizer class. It assumes a string passed in such as script=beep 3&something=this&somethingelse=that.

   // Get a form variable value from a list of variable name and data pairs
   String getFormVariableValue(String variables, String name)
      // Set up our first tokenizer and variables
      StringTokenizer st1 = new StringTokenizer(variables, "&");
      String s1 = "";
      String n1 = name.toLowerCase() + "=";
      // If the given name is not even in the variables then exit immediately
      if (variables.toLowerCase().indexOf(n1) == -1)
         return null;
      // Search for first token as a name and data pair (ie: variable=data)
      while (!s1.startsWith(n1) || s1.length()==0) {
         s1 = st1.nextToken();
         System.out.println("s1=" + s1);
      // Now that we have the first token, we can split it into the name and data specifics
      StringTokenizer st2 = new StringTokenizer(s1, "=");
      String s2 = "";
      String n2 = name.toLowerCase();
      while (s2.startsWith(n2) || s2.length()==0) {
         s2 = st2.nextToken();
         System.out.println("s2=" + s2);
      return s2;

At this point, by extracting the value of the "script" form variable we finally have the raw AppleScript to execute. We first create a new NSAppleScript object by passing in the script. We then create an NSMutableDictionary object to hold any errors during execution. Sending the NSAppleScript object the execute message causes the script to execute and return results in an NSAppleEventDescriptor object. The results in that object can then be extracted and displayed.

   NSAppleScript myScript = new NSAppleScript(s);
   // This dictionary holds any errors that are encountered during script execution
   NSMutableDictionary errors = new NSMutableDictionary();
   // Execute the script!
   NSAppleEventDescriptor results = myScript.execute(errors); 
   // If multiple items in the result we use this to display results
   int numberOfItems = (results == null) ? 0 : results.numberOfItems();
   for (int i = 1; i <= numberOfItems; i++) {
      NSAppleEventDescriptor subDescriptor = results.descriptorAtIndex(i);
   // If only one item in the result we can use this
   if (numberOfItems == 0) {
      String resultString = (results == null) ? "" : results.stringValue();


As mentioned, RSR is a proof-of-concept for a larger project of mine. There are many ways to improve this code and even more possible features to add. There are also other ways to remotely invoke scripts, but this was a fun project to put together that works reliably. In closing, I hope this convinces you to give Java a second chance -- you just might like it!

Joe Zobkiw is the author of Mac OS X Advanced Development Techniques and President of TripleSoft Inc., a software development and consulting company in Raleigh, NC. He can be reached at


Community Search:
MacTech Search:

Software Updates via MacUpdate

Microsoft Office 2016 16.11 - Popular pr...
Microsoft Office 2016 - Unmistakably Office, designed for Mac. The new versions of Word, Excel, PowerPoint, Outlook, and OneNote provide the best of both worlds for Mac users - the familiar Office... Read more
Adobe Photoshop CC 2018 19.1.2 - Profess...
Photoshop CC 2018 is available as part of Adobe Creative Cloud for as little as $19.99/month (or $9.99/month if you're a previous Photoshop customer). Adobe Photoshop CC 2018, the industry standard... Read more
Adobe Dreamweaver CC 2018 -...
Dreamweaver CC 2018 is available as part of Adobe Creative Cloud for as little as $19.99/month (or $9.99/month if you're a previous Dreamweaver customer). Adobe Dreamweaver CC 2018 allows you to... Read more
Adobe Flash Player - Plug-in...
Adobe Flash Player is a cross-platform, browser-based application runtime that provides uncompromised viewing of expressive applications, content, and videos across browsers and operating systems.... Read more
Drive Genius 5.2.0 - $79.00
Drive Genius features a comprehensive Malware Scan. Automate your malware protection. Protect your investment from any threat. The Malware Scan is part of the automated DrivePulse utility. DrivePulse... Read more
MegaSeg 6.0.6 - Professional DJ and radi...
MegaSeg is a complete solution for pro audio/video DJ mixing, radio automation, and music scheduling with rock-solid performance and an easy-to-use design. Mix with visual waveforms and Magic... Read more
ffWorks 1.0.7 - Convert multimedia files...
ffWorks (was iFFmpeg), focused on simplicity, brings a fresh approach to the use of FFmpeg, allowing you to create ultra-high-quality movies without the need to write a single line of code on the... Read more
Dash 4.1.5 - Instant search and offline...
Dash is an API documentation browser and code snippet manager. Dash helps you store snippets of code, as well as instantly search and browse documentation for almost any API you might use (for a full... Read more
Evernote 7.0.3 - Create searchable notes...
Evernote allows you to easily capture information in any environment using whatever device or platform you find most convenient, and makes this information accessible and searchable at anytime, from... Read more
jAlbum Pro 15.3 - 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

Latest Forum Discussions

See All

All the best games on sale for iPhone an...
It might not have been the greatest week for new releases on the App Store, but don't let that get you down, because there are some truly incredible games on sale for iPhone and iPad right now. Seriously, you could buy anything on this list and I... | Read more »
Everything You Need to Know About The Fo...
In just over a week, Epic Games has made a flurry of announcements. First, they revealed that Fortnite—their ultra-popular PUBG competitor—is coming to mobile. This was followed by brief sign-up period for interested beta testers before sending out... | Read more »
The best games that came out for iPhone...
It's not been the best week for games on the App Store. There are a few decent ones here and there, but nothing that's really going to make you throw down what you're doing and run to the nearest WiFi hotspot in order to download it. That's not to... | Read more »
Death Coming (Games)
Death Coming Device: iOS Universal Category: Games Price: $1.99, Version: (iTunes) Description: --- Background Story ---You Died. Pure and simple, but death was not the end. You have become an agent of Death: a... | Read more »
Hints, tips, and tricks for Empires and...
Empires and Puzzles is a slick match-stuff RPG that mixes in a bunch of city-building aspects to keep things fresh. And it's currently the Game of the Day over on the App Store. So, if you're picking it up for the first time today, we thought it'd... | Read more »
What You Need to Know About Sam Barlow’s...
Sam Barlow’s follow up to Her Story is #WarGames, an interactive video series that reimagines the 1983 film WarGames in a more present day context. It’s not exactly a game, but it’s definitely still interesting. Here are the top things you should... | Read more »
Pixel Plex Guide - How to Build Better T...
Pixel Plex is the latest city builder that has come to the App Store, and it takes a pretty different tact than the ones that came before it. Instead of being in charge of your own city by yourself, you have to work together with other players to... | Read more »
Fortnite Will Be Better Than PUBG on Mob...
Before last week, if you asked me which game I prefer between Fortnite Battle Royale and PlayerUnknown’s Battlegrounds (PUBG), I’d choose the latter just about 100% of the time. Now that we know that both games are primed to hit our mobile screens... | Read more »
Siege of Dragonspear (Games)
Siege of Dragonspear 2.5.12 Device: iOS Universal Category: Games Price: $9.99, Version: 2.5.12 (iTunes) Description: Experience the Siege of Dragonspear, an epic Baldur’s Gate tale, filled with with intrigue, magic, and monsters.... | Read more »
7 Wonders Guide - Should You Buy The Lea...
The fantastic mobile version of 7 Wonders just got updated with an expansion that adds Leaders to the game. This new content adds a whole layer of depth to the game, but before you spend $1.99 to buy it blindly, check out this breakdown of exactly... | Read more »

Price Scanner via

B&H drops prices on 15″ MacBook Pros up t...
B&H Photo has dropped prices on new 2017 15″ MacBook Pros, now up to $300 off MSRP and matching Adorama’s price drop yesterday. Shipping is free, and B&H charges sales tax for NY & NJ... Read more
Apple restocks Certified Refurbished 2017 13″...
Apple has restocked Certified Refurbished 2017 13″ 2.3GHz MacBook Pros for $200-$230 off MSRP. A standard Apple one-year warranty is included with each MacBook, models receive new outer cases, and... Read more
13″ Space Gray Touch Bar MacBook Pros on sale...
Adorama has new 2017 13″ Space Gray Touch Bar MacBook Pros on sale for $150 off MSRP. Shipping is free, and Adorama charges sales tax in NY & NJ only: – 13″ 3.1GHz/256GB Space Gray MacBook Pro (... Read more
Best deal of the year on 15″ Apple MacBook Pr...
Adorama has New 2017 15″ MacBook Pros on sale for up to $300 off MSRP. Shipping is free, and Adorama charges sales tax in NJ and NY only: – 15″ 2.8GHz Touch Bar MacBook Pro Space Gray (MPTR2LL/A): $... Read more
Save $100-$150+ on 13″ Touch Bar MacBook Pros...
B&H Photo has 13″ Touch Bar MacBook Pros on sale for $100-$150 off MSRP. Shipping is free, and B&H charges sales tax for NY & NJ residents only: – 13″ 3.1GHz/256GB Space Gray MacBook Pro... Read more
Current deals on 27″ Apple iMacs, models up t...
B&H Photo has 27″ iMacs on sale for up to $150 off MSRP. Shipping is free, and B&H charges sales tax for NY & NJ residents only: – 27″ 3.8GHz iMac (MNED2LL/A): $2149 $150 off MSRP – 27″ 3... Read more
Thursday Deal: 13″ 2.3GHz MacBook Pro for $11...
B&H Photo has the 13″ 2.3GHz/128GB Space Gray MacBook Pro on sale for $100 off MSRP. Shipping is free, and B&H charges sales tax for NY & NJ residents only: – 13-inch 2.3GHz/128GB Space... Read more
How to save $100-$190 on 10″ & 12″ iPad P...
Apple is now offering Certified Refurbished 2017 10″ and 12″ iPad Pros for $100-$190 off MSRP, depending on the model. An Apple one-year warranty is included with each model, and shipping is free: –... Read more
Silver 12″ 1.3GHz MacBook on sale at B&H...
B&H Photo has the 2017 12″ 1.3GHz Silver MacBook on sale for $1399.99 including free shipping plus sales tax for NY & NJ residents only. Their price is $200 off MSRP, and it’s the lowest... Read more
Amazon offers 21″ Apple iMacs for up to $150...
Amazon 21″ iMacs on sale today for $50-$150 off MSRP, depending on the model. Shipping is free: – 21″ 3.4GHz 4K iMac (MNE02LL/A): $1349.99 $150 off MSRP – 21″ 3.0GHz iMac (MNDY2LL/A): $1199 $100 off... Read more

Jobs Board

Data Scientist, *Apple* Ecosystem (AMP Anal...
# Data Scientist, Apple Ecosystem (AMP Analytics) Job Number: 113428728 Santa Clara Valley, California, United States Posted: 24-Jan-2018 Weekly Hours: 40.00 **Job Read more
*Apple* Solutions Consultant - Apple (United...
# Apple Solutions Consultant Job Number: 113523441 Orange, CA, California, United States Posted: 21-Feb-2018 Weekly Hours: 40.00 **Job Summary** Are you passionate Read more
*Apple* Professional Learning Specialist - A...
# Apple Professional Learning Specialist Job Number: 113456892 Englewood, NJ, New Jersey, United States Posted: 02-Feb-2018 Weekly Hours: 40.00 **Job Summary** The Read more
*Apple* Retail Online, Senior Financial Anal...
# Apple Retail Online, Senior Financial Analyst Job Number: 57228835 Santa Clara Valley, California, United States Posted: 12-Feb-2018 Weekly Hours: 40.00 **Job Read more
Site Reliability Engineer, *Apple* Pay - Ap...
# Site Reliability Engineer, Apple Pay Job Number: 113356036 Santa Clara Valley, California, United States Posted: 12-Jan-2018 Weekly Hours: 40.00 **Job Summary** Read more
All contents are Copyright 1984-2011 by Xplain Corporation. All rights reserved. Theme designed by Icreon.