iOS Share Extension NSPredicate trick

gistfile1.txt

//After way, way, way too much trial and error, I finally found a way to create the Share Extension for documents that I was seeking. 
// It's not obvious what the NSPredicate should be, but then harder was a lack of example of how to actually use the predicate
// within the Info.plist file of an iOS (8.2+) share extension

	<key>NSExtension</key>
	<dict>
		<key>NSExtensionAttributes</key>
		<dict>
			<key>NSExtensionActivationRule</key>
			<string>SUBQUERY (
                    extensionItems,
                    $extensionItem,
                    SUBQUERY (
                    $extensionItem.attachments,
                    $attachment,
                    (
                    ANY $attachment.registeredTypeIdentifiers UTI-CONFORMS-TO "com.adobe.pdf"
                    || ANY $attachment.registeredTypeIdentifiers UTI-CONFORMS-TO "public.url"
                    || ANY $attachment.registeredTypeIdentifiers UTI-CONFORMS-TO "public.file-url"
                    || ANY $attachment.registeredTypeIdentifiers UTI-CONFORMS-TO "public.plain-text"
                    )
                    ).@count == $extensionItem.attachments.@count
                    ).@count == 1</string>
		</dict>
		<key>NSExtensionMainStoryboard</key>
		<string>MainInterface</string>
		<key>NSExtensionPointIdentifier</key>
		<string>com.apple.share-services</string>
	</dict>

can you please explain what exactly having these lines on the info.plist does for your extension? thanks in advance.

when both "public.url" and "com.adobe.pdf" included-> it only supports one. Any different approach to fix this

Is there a way to get the public.url value in the subquery? I would like to filter out irrelevant sites... Has anyone managed to do it or I must use the using the code to handle this? I'm using cordova so I have limited access to the objective-c/swift code...