Question

It is easy to create ruby OS X app — create structure like this:

xxx.app
└── Contents
    ├── Info.plist
    ├── MacOS
    │   └── xxx
    └── Resources
        └── xxx.icns

and put code to execute into xxx. But launch time is noticeable, so I want this app to stay in background and run some method, when app is opened: so when I run that app first time, it executes code an stays in background, when I run another time, app is already in background, so it just runs specified method.

Minimal Info.plist:

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<plist version="1.0">
<dict>
  <key>CFBundlePackageType</key>
  <string>APPL</string>
  <key>CFBundleExecutable</key>
  <string>newTabHere</string>
  <key>CFBundleIconFile</key>
  <string>newTabHere</string>
  <key>LSUIElement</key>
  <true/><!-- hides icon from Dock -->
</dict>
</plist>

Answer 1

The slowness is due to the start up time required for the ruby interpreter. That is why it is not slow for a bash script or objective-c.

Steps to communicate with background ruby program:

• Make your ruby program use the daemons gem.(optional, but makes running in background easier)
• Write a bash script to telnet to a port when run.
• Have your ruby program run eventmachine(avaliable via Rubygems) or another socket server that supports telnet.
• When the ruby socket server receives the message over telnet have the program run the method you want.
• Package the bash script in an application like you describe in your question.

The bash script has to:

1. Launch the ruby program or start the daemon if it is not already running in the background.
2. Connect with telnet to localhost on the port specified in the ruby program
3. Send a message to run the method.
4. Save or print the result.

Advantages to this solution

• Easy to implement.
• Telnet is automatically installed on all macs.
• Bash scripts are easy to learn to use.
• Ruby has good socket gems and libraries that are easy to implement.

Warning

This has the cost of constantly using up the computer’s memory with the ruby interpreter. So, it is not a user friendly solution.

To create a true app with a graphical interface in ruby you have to use macruby with rubycocoa.

Or use the Titanium Desktop from Appcelerator, you will have to write the interface code in javascript but you can do the rest with ruby. This method also has the advantage of being cross-platform. see http://developer.appcelerator.com/doc/desktop/ruby