Get iTunes Artwork for Current Song with ScriptingBridge

Question

I have been trying to figure out how to get the iTunes artwork for the currently playing song with scripting bridge. I have gotten to a point where it works for some songs, but for others, I get a SIGABRT. I'm not sure what the issue could be, so any help would be greatly appreciated. Here is what I have so far:

iTunesApplication * iTunes = [SBApplication applicationWithBundleIdentifier:@"com.apple.iTunes"];
NSImage *songArtwork;
iTunesTrack *current = [iTunes currentTrack];
iTunesArtwork *artwork = (iTunesArtwork *)[[[current artworks] get] lastObject];
if(artwork != nil)
  songArtwork = [artwork data];
else
  songArtwork = [NSImage imageNamed:@"Image.tiff"];

NSMenuItem *artworkMenuItem = [[NSMenuItem alloc] initWithTitle:@"" action:NULL keyEquivalent:@""];
[songArtwork setSize:NSMakeSize(128, 128)];
[artworkMenuItem setImage:songArtwork];
[Menu insertItem:artworkMenuItem atIndex:0];

I for some songs it works, and displays the artwork nicely in the menu item, but for others I get a SIGABRT on the line:

[songArtwork setSize:NSMakeSize(128, 128)];

The output of the console is as follows:

2011-08-12 23:13:20.094 SongViewer[2146:707] -[NSAppleEventDescriptor setSize:]:     unrecognized selector sent to instance 0x102827f70
2011-08-12 23:13:20.095 SongViewer[2146:707] An uncaught exception was raised
2011-08-12 23:13:20.096 SongViewer[2146:707] -[NSAppleEventDescriptor setSize:]: unrecognized selector sent to instance 0x102827f70
2011-08-12 23:13:20.097 SongViewer[2146:707] (
0   CoreFoundation                      0x00007fff86f11986 __exceptionPreprocess + 198
1   libobjc.A.dylib                     0x00007fff8b04cd5e objc_exception_throw + 43
2   CoreFoundation                      0x00007fff86f9d5ae -[NSObject doesNotRecognizeSelector:] + 190
3   CoreFoundation                      0x00007fff86efe803 ___forwarding___ + 371
4   CoreFoundation                      0x00007fff86efe618 _CF_forwarding_prep_0 + 232
5   SongViewer                          0x0000000100002a83 -[IPMenulet awakeFromNib] + 4483
6   CoreFoundation                      0x00007fff86f089e1 -[NSObject performSelector:] + 49
7   CoreFoundation                      0x00007fff86f08962 -[NSSet makeObjectsPerformSelector:] + 274
8   AppKit                              0x00007fff8d9d9c27 -[NSIBObjectData nibInstantiateWithOwner:topLevelObjects:] + 1245
9   AppKit                              0x00007fff8d9d01b9 loadNib + 322
10  AppKit                              0x00007fff8d9cf6b6 +[NSBundle(NSNibLoading) _loadNibFile:nameTable:withZone:ownerBundle:] + 217
11  AppKit                              0x00007fff8d9cf5d1 +[NSBundle(NSNibLoading) loadNibFile:externalNameTable:withZone:] + 141
12  AppKit                              0x00007fff8d9cf514 +[NSBundle(NSNibLoading) loadNibNamed:owner:] + 364
13  AppKit                              0x00007fff8dc42355 NSApplicationMain + 398
14  SongViewer                          0x0000000100001882 main + 34
15  SongViewer                          0x0000000100001854 start + 52
)
2011-08-12 23:13:20.098 SongViewer[2146:707] *** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '-[NSAppleEventDescriptor setSize:]: unrecognized selector sent to instance 0x102827f70'
*** First throw call stack:
(
0   CoreFoundation                      0x00007fff86f11986 __exceptionPreprocess + 198
1   libobjc.A.dylib                     0x00007fff8b04cd5e objc_exception_throw + 43
2   CoreFoundation                      0x00007fff86f9d5ae -[NSObject doesNotRecognizeSelector:] + 190
3   CoreFoundation                      0x00007fff86efe803 ___forwarding___ + 371
4   CoreFoundation                      0x00007fff86efe618 _CF_forwarding_prep_0 + 232
5   SongViewer                          0x0000000100002a83 -[IPMenulet awakeFromNib] + 4483
6   CoreFoundation                      0x00007fff86f089e1 -[NSObject performSelector:] + 49
7   CoreFoundation                      0x00007fff86f08962 -[NSSet makeObjectsPerformSelector:] + 274
8   AppKit                              0x00007fff8d9d9c27 -[NSIBObjectData nibInstantiateWithOwner:topLevelObjects:] + 1245
9   AppKit                              0x00007fff8d9d01b9 loadNib + 322
10  AppKit                              0x00007fff8d9cf6b6 +[NSBundle(NSNibLoading) _loadNibFile:nameTable:withZone:ownerBundle:] + 217
11  AppKit                              0x00007fff8d9cf5d1 +[NSBundle(NSNibLoading) loadNibFile:externalNameTable:withZone:] + 141
12  AppKit                              0x00007fff8d9cf514 +[NSBundle(NSNibLoading) loadNibNamed:owner:] + 364
13  AppKit                              0x00007fff8dc42355 NSApplicationMain + 398
14  SongViewer                          0x0000000100001882 main + 34
15  SongViewer                          0x0000000100001854 start + 52
)
terminate called throwing an exception(gdb) 

If anyone has any idea what could be wrong, please let me know!!

Docia

What other console output do you see? – Cession

Hi jtbandes, thanks for your response. I've added the console output to the above question. It appears to me that for some reason the NSImage *artwork is nil (or NULL?) and that would explain the segmentation fault. The strange thing is that I thought the check to see if it was nil would check for that... I guess not... I'm not really sure how to continue. From the iTunes perspective, both songs I was playing seemed to be the same in terms of having artwork. One worked, and one didn't. Thanks for any help you can give me! :) – Docia

Ok so I've narrowed it down to the actual iTunesArtwork *artwork being invalid. But it is not nil. Is there any way to check if this artwork is valid or not? – Docia

Answer 1

Ok so I figured it out. The solution is to use the NSData raw data provided by the API rather than the NSImage. So I used:

NSImage *songArtwork = [[NSImage alloc] initWithData:[artwork rawData]];

rather than

songArtwork = [artwork data];

Docia

This really helped, thanks! You can accept your own answer as well. – Saltzman

Answer 2

I have to fetch batch of track artworks from iTunes and use ‘rawData’ too. But this way is inefficient. I found a better way (actually it decreases ‘fetch’ time about 2 times, it’s very significant when fetching artworks for many tracks using ‘valueForKey:’ according to «Improving the Performance of Scripting Bridge Code»).

So I decided to understand what’s wrong with iTunesArtwork ‘data’ property. We expect to get an NSImage object (according to iTunes.h ), but real object is kind of ‘NSAppleEventDescriptor’. And it’s easy to guess, that this object contains an image for us. So we can just use ‘data’ property to get image data. And this is really faster than getting ‘rawData’ from iTunesArtwork. But sometimes iTunes return NSImage object instead NSAppleEventDescriptor. This is an strange behavior, but it's still faster then using rawData.

Heiser