Building Cocoa Applications: A Step by Step Guide

Creating Your Own Service

Services advertisements, such as the one we listed earlier for the Stickies application, are stored in the application’s Info.plist file, an XML-encoded file stored inside the .app wrapper. When Mac OS X registers a new application, it opens up the Info.plist file and looks for the application’s application icon, its document icons, and its Services advertisement (if it exists). This information is cached to improve performance.

Table 20-4 lists all of the fields allowed in the Services advertisement.

Table 20-4. Services advertisement fields

Field	Meaning
Message	Name of the message to be sent.
NSExecutable	Name of the application’s executable.
NSKeyEquivalent	Key equivalent, if any, that the Services menu item should have.
NSMenuItem	Name that should appear in the Services menu. If you want to have a submenu, use the forward slash (/). For example, to have “equation” be a submenu of “graph”, you would use the string “graph/equation”.
NSMessage	Actual message that is sent to your application to cause the service to be executed. Messages are implemented with the Cocoa distributed object system.
NSPortName	Name of the Mach port where the message should be sent. Normally, this will be the name of your application’s “Identifier,” defined in the Application Settings tab in PB.
NSReturnTypes	Pasteboard types that the method can return.
NSSendTypes	Pasteboard types that the method can send.
NSTimeout	Numerical string that is the time, ...