Michael Ash wrote:
On Tue, Mar 31, 2009 at 3:57 PM, Luca C. <luca.pazzere...@gmail.com>
wrote:
2009/3/31 Ammar Ibrahim <ammar.ibra...@gmail.com>
If I want to add a track to iTunes, I need to make sure iTunes is
responsive.
Are you sure it is that important? Actually, if you run an AS
script wich,
say, opens with the Finder some mp3 files whilst iTunes has dialog
windows
opened, the command will be automatically enqueued. Â In other
words, your
tracks will be added after the user closes the dialog window.
 Run the script in a separate thread so it won't block your
application's
interface in any case.
No, don't do this. AppleScript is not safe to use outside the main
thread. If you must run AppleScript asynchronously, either spawn a
subprocess to run it or, better yet, don't use AS at all but send
Apple Events in some other way, such as with ScriptingBridge.
Scripting Bridge apparently isn't thread-safe either:
http://www.dribin.org/dave/blog/archives/2009/02/01/main_thread_apis/
ObjC-appscript is almost entirely thread-safe. You'll need to watch
when using methods that rely on the Carbon Process Manager (some
initializers, -isRunning) as the PM APIs don't appear to be thread-
safe itself, but the main query builder and event dispatch methods
should work fine on any thread (e.g. I use Python appscript in a
background thread without problems).
For example:
tell application "iTunes"
set newPlaylist to make new playlist with properties {name:"Rock-
n-Roll", shuffle:true}
duplicate (every track of library playlist 1 whose artist is
"Chuck Berry") to newPlaylist
end tell
#import "ITGlue/ITGlue.h"
int main (int argc, const char * argv[]) {
NSAutoreleasePool * pool = [[NSAutoreleasePool alloc] init];
int err = 0;
// create a new application object
ITApplication *itunes = [ITApplication applicationWithBundleID:
@"com.apple.itunes"];
// create a new playlist
ITMakeCommand *cmd = [[[itunes make] new_: [ITConstant playlist]]
withProperties: [NSDictionary
dictionaryWithObjectsAndKeys:
ASTrue, [ITConstant
shuffle],
@"Rock-n-Roll",
[ITConstant name],
nil]];
ITReference *newPlaylist = [cmd send];
// duplicate all tracks that match the given criteria to the new
playlist
ITReference *ref = [[[[itunes libraryPlaylists] at: 1] tracks]
byTest: [[ITIts
artist] equals: @"Chuck Berry"]];
NSError *error;
NSArray *tracks = [[[ref duplicate] to: newPlaylist]
sendWithError: &error];
if (!tracks) {
// check for errors
NSLog(@"%@", [error localizedDescription]);
err = [error code];
} else
// display result
NSLog(@"%@", tracks);
[pool drain];
return err;
}
The ASDictionary application on the appscript site has options for
exporting application dictionaries in both human-readable HTML format
and as ObjC glue files.
Not surprisingly, the ObjC code's a bit more verbose, but
straightforward enough to construct once you understand the general
principles behind Apple event-based IPC. Appscript respects the
original Apple event semantics and doesn't obfuscate them under piles
of fake Cocoa-isms, so if you already know how to do it in AppleScript
then it's pretty much a straight translation: there's even a free
tool, ASTranslate, that will help you with that.
Apple event IPC is kinda weird and very different to Cocoa/OOP (a
rough analogy would be to using XPath queries over XML-RPC) but is
usually serviceable once you get your head around it. Apple docs do a
lousy job of explaining how it all works, but there's an introduction
to the basic concepts in the appscript manual and links on the
appscript site to further information.
Oh, and as for checking if an application is responsive - I'd suggest
just sending an event and seeing if it times out (timeouts may be
reported as either error -609 or -1712, depending on what sort of mood
AESendMessage is in at the time). The launch event (ascr/noop) is
basically a no-op that will return error -1708 if 'successfully'
handled; handy if you don't want to send a 'work' event.
HTH
has
--
Control AppleScriptable applications from Python, Ruby and ObjC:
http://appscript.sourceforge.net
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