Detect tel, sms, mailto tags in WKWebView

WKWebView_tel_sms_mailto_tags_and_appstore_connection.swift

    func webView(webView: WKWebView, decidePolicyForNavigationAction navigationAction: WKNavigationAction, decisionHandler: (WKNavigationActionPolicy) -> Void) {
        
        
        let url = navigationAction.request.URL?.absoluteString
        
        let hostAddress = navigationAction.request.URL?.host
        
        // To connnect app store
        if hostAddress == "itunes.apple.com" {
            if UIApplication.sharedApplication().canOpenURL(navigationAction.request.URL!) {
                UIApplication.sharedApplication().openURL(navigationAction.request.URL!)
                decisionHandler(.Cancel)
                return
            }
        }
        
        
        #if DEBUG
            
            print("url = \(url), host = \(hostAddress)")
            
        #endif
        
        let url_elements = url!.componentsSeparatedByString(":")
        
        switch url_elements[0] {
            
            case "tel":
                #if DEBUG
                    
                    print("this is phone number")
                    
                #endif
                
                openCustomApp("telprompt://", additional_info: url_elements[1])
                decisionHandler(.Cancel)
                
            case "sms":
                #if DEBUG
                    
                    print("this is sms")
                    
                #endif
                
                openCustomApp("sms://", additional_info: url_elements[1])
                decisionHandler(.Cancel)
                
            case "mailto":
                #if DEBUG
                    
                    print("this is mail")
                    
                #endif
                
                openCustomApp("mailto://", additional_info: url_elements[1])
                decisionHandler(.Cancel)
                
            default:
                #if DEBUG
                    
                    print("normal http request")
                    
                #endif
        }
        
        decisionHandler(.Allow)
        
    }
    
    /**
     open custom app with urlScheme : telprompt, sms, mailto
     
     - parameter urlScheme: telpromt, sms, mailto
     - parameter additional_info: additional info related to urlScheme
     */
    func openCustomApp(urlScheme:String, additional_info:String){
        
        if let requestUrl:NSURL = NSURL(string:"\(urlScheme)"+"\(additional_info)") {
            let application:UIApplication = UIApplication.sharedApplication()
            if application.canOpenURL(requestUrl) {
                application.openURL(requestUrl)
            }
        }
    }