Paint the Tiger, Carve the Swan

Christoph asked me for some advice on how to get notification on iTunes track changes in a comment, I said I would write a bit of a tutorial on how I got it to work.

First thing was to create an AppleScript Studio program - you will need to have the Developer Tools installed for this.

Now, open the main.m file. It should look something like the following:

#import <mach-o/dyld.h>

extern int NSApplicationMain(int argc, const char *argv[]);

int main(int argc, const char *argv[])
{
    if (NSIsSymbolNameDefined("_ASKInitialize"))
    {
    NSSymbol *symbol = NSLookupAndBindSymbol("_ASKInitialize");
    if (symbol)
    {
    void (*initializeASKFunc)(void) = NSAddressOfSymbol(symbol);
        if (initializeASKFunc)
    {
    initializeASKFunc();
    }
    }
    }

return NSApplicationMain(argc, argv);
}

The file needs to have the following elements.

At the start, the following imports are required:

#import <Foundation/NSDistributedNotificationCenter.h>
#import <Foundation/NSString.h>
#import <AppKit/NSAppleScriptExtensions.h>

This should be all of the imports that are required - although I also had stdio.h for a while for testing.

After the declaration of the NSApplicationMain, I put the following in:

@interface iTunesConnection : NSObject
 - (id) init;
@end

@implementation iTunesConnection
 - (id) init {
    NSDistributedNotificationCenter *nc = [NSDistributedNotificationCenter defaultCenter];
    [nc addObserver:self
           selector:@selector(updateNow:)
               name:@"com.apple.iTunes.playerInfo"
             object:nil];

    return self;
}

 - (void) updateNow:(NSNotification *)notification {
    NSString *updateScript = [NSString stringWithFormat:@"tell application \nend tell"];
    NSAppleScript *as = [[[NSAppleScript alloc] initWithSource:updateScript] autorelease];
    [as executeAndReturnError:nil];
}
@end

Copy and paste the stuff above - there is some that goes over the line in my browser, but it’s all there if you drag out the selection.

You may need to change a couple of things depending on what you want to do. For instance, the @"tell application \nend tell" section needs to be the applescript code that is run whenever a new iTunes track is started, or iTunes is paused. You could fit the entire application into this place, but what I did was have a hidden button that this script “presses”, triggering the update process.

Finally, I added the following declaration just after the first brace in the main function declaration:

iTunesConnection *connection;
connection = [[iTunesConnection alloc] init];

This gets everything running.

I would suggest putting the following into the applescript string to test it and see that it works:

@"tell application \"Finder\"\ndisplay dialog \"iTunes Changed\"\nend tell"

You need to have \" whenever your script would have a ", and \n wherever it would have a newline.

 

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