iOS Share Extension - Mobile clipper

ShareViewController.swift

//
//  ShareViewController.swift
//  Stample-clipper
//
//  Created by Sébastien Lorber on 15/10/2015.
//
//

import UIKit
import Social
import MobileCoreServices

@available(iOSApplicationExtension 8.0, *)
class ShareViewController: SLComposeServiceViewController {
    
    // We don't want to show the view actually
    // as we directly open our app!
    override func viewWillAppear(animated: Bool) {
        self.view.hidden = true
        self.cancel()
        self.doClipping()
    }
    
    // We directly forward all the values retrieved from Action.js to our app
    private func doClipping() {
        self.loadJsExtensionValues { dict in
            let url = "stample://mobileclipper?" + self.dictionaryToQueryString(dict)
            self.doOpenUrl(url)
        }
    }
    
    ///////////////////////////////////////////////////////////////////////////////////////////////
    ///////////////////////////////////////////////////////////////////////////////////////////////
    ///////////////////////////////////////////////////////////////////////////////////////////////
    
    private func dictionaryToQueryString(dict: Dictionary<String,String>) -> String {
        return dict.map({ entry in
            let value = entry.1
            let valueEncoded = value.stringByAddingPercentEncodingWithAllowedCharacters(.URLHostAllowedCharacterSet())
            return entry.0 + "=" + valueEncoded!
        }).joinWithSeparator("&")
    }
    
    // See https://github.com/extendedmind/extendedmind/blob/master/frontend/cordova/app/platforms/ios/extmd-share/ShareViewController.swift
    private func loadJsExtensionValues(f: Dictionary<String,String> -> Void) {
        let content = extensionContext!.inputItems[0] as! NSExtensionItem
        let contentType = kUTTypePropertyList as String
        for attachment in content.attachments as! [NSItemProvider] {
            if attachment.hasItemConformingToTypeIdentifier(contentType) {
                attachment.loadItemForTypeIdentifier(contentType, options: nil) { data, error in
                    if ( error == nil && data != nil ) {
                        let jsDict = data as! NSDictionary
                        if let jsPreprocessingResults = jsDict[NSExtensionJavaScriptPreprocessingResultsKey] {
                            let values = jsPreprocessingResults as! Dictionary<String,String>
                            f(values)
                        }
                    }
                }
            }
        }
    }
    
    // See http://stackoverflow.com/a/28037297/82609
    // Works fine for iOS 8.x and 9.0 but may not work anymore in the future :(
    private func doOpenUrl(url: String) {
        let urlNS = NSURL(string: url)!
        var responder = self as UIResponder?
        while (responder != nil){
            if responder!.respondsToSelector(Selector("openURL:")) == true{
                responder!.callSelector(Selector("openURL:"), object: urlNS, delay: 0)
            }
            responder = responder!.nextResponder()
        }
    }
}

// See http://stackoverflow.com/a/28037297/82609
extension NSObject {
    func callSelector(selector: Selector, object: AnyObject?, delay: NSTimeInterval) {
        let delay = delay * Double(NSEC_PER_SEC)
        let time = dispatch_time(DISPATCH_TIME_NOW, Int64(delay))
        dispatch_after(time, dispatch_get_main_queue(), {
            NSThread.detachNewThreadSelector(selector, toTarget:self, withObject: object)
        })
    }
}