问题
I'm writing a command-line daemon to read images from iPhoto.
I can init and load an MLMediaLibrary fine from a full-blown Cocoa application, created using the Xcode project creation tools. However, when I try and do the same from a command-line tool (also created in Xcode), the following error appears in Xcode console window:
MLMediaLibrary error obtaining remote object proxy: Error Domain=NSCocoaErrorDomain Code=4097 "Couldn’t communicate with a helper application."
How can I access MLMediaLibrary from a command-line tool?
回答1:
In order to access MLMediaLibrary your application has to be sandboxed and codesigned.
Update
It seems like you also have to add some permanent read-only access entitlements to your .entitlements file.
If you want to access Photos, iPhoto or Aperture libraries:
<key>com.apple.security.assets.pictures.read-only</key>
<true/>
If you want to access iMovie and FinalCut:
<key>com.apple.security.assets.movies.read-only</key>
<true/>
If you want to access iTunes or Logic:
<key>com.apple.security.assets.music.read-only</key>
<true/>
You can read about my poor experience with a MediaLibrary framework here: https://devforums.apple.com/message/1125821
回答2:
I don't think Konstantin's statement is correct: In order to access MLMediaLibrary your application has to be sandboxed and codesigned.
Per my test, I can use MediaLibrary.framework within my application and my application is not code signed, it doesn't have an entitlements file, so it is abviously not a sandboxed app.
来源：https://stackoverflow.com/questions/29012865/xpc-error-when-using-mlmedialibrary-from-command-line-daemon