share-extension

# Share Extension ## Overview The share extension receives content (URLs, text, images) from other apps via the system share sheet. It runs as a separate process with limited memory and no direct access to the main app's data unless App Groups are configured. ## Setup Requires a separate extension target configured as `kind: "share"` in the plan extensions array. ## Principal View Controller Implement `SLComposeServiceViewController` to handle shared content: ```swift import Social import UniformTypeIdentifiers class ShareViewController: SLComposeServiceViewController { override func isContentValid() -> Bool { return contentText.count > 0 } override func didSelectPost() { guard let item = extensionContext?.inputItems.first as? NSExtensionItem, let provider = item.attachments?.first else { extensionContext?.completeRequest(returningItems: [], completionHandler: nil) return } if provider.hasItemConformingToTypeIdentifier("public.url") { provider.loadItem(forTypeIdentifier: "public.url") { [weak self] url, _ in // Process the shared URL self?.extensionContext?.completeRequest(returningItems: [], completionHandler: nil) } } } override func configurationItems() -> [Any]! { return [] // Return SLComposeSheetConfigurationItem array for extra UI rows } } ``` ## Info.plist Configuration Set these keys in the extension target's Info.plist (via XcodeGen): ``` NSExtensionPrincipalClass: $(PRODUCT_MODULE_NAME).ShareViewController NSExtensionActivationRule: NSExtensionActivationSupportsWebURLWithMaxCount: 1 NSExtensionActivationSupportsText: true ``` ## Data Sharing via App Groups Use the App Group entitlement to share data between the main app and the extension. Both targets must belong to the same App Group to access shared `UserDefaults` or a shared container directory.