func searchForExistingCertificateIdInBundle()

in IoT-Sample/Swift/IoTSampleSwift/ConnectionViewController.swift [144:187]
31 lines of code
2 McCabe index (conditional complexity)

    func searchForExistingCertificateIdInBundle() -> String? {
        let defaults = UserDefaults.standard
        // No certificate ID has been stored in the user defaults; check to see if any .p12 files
        // exist in the bundle.
        let myBundle = Bundle.main
        let myImages = myBundle.paths(forResourcesOfType: "p12" as String, inDirectory:nil)
        let uuid = UUID().uuidString

        guard let certId = myImages.first else {
            let certificateId = defaults.string(forKey: "certificateId")
            return certificateId
        }
        
        // A PKCS12 file may exist in the bundle.  Attempt to load the first one
        // into the keychain (the others are ignored), and set the certificate ID in the
        // user defaults as the filename.  If the PKCS12 file requires a passphrase,
        // you'll need to provide that here; this code is written to expect that the
        // PKCS12 file will not have a passphrase.
        guard let data = try? Data(contentsOf: URL(fileURLWithPath: certId)) else {
            print("[ERROR] Found PKCS12 File in bundle, but unable to use it")
            let certificateId = defaults.string( forKey: "certificateId")
            return certificateId
        }
        
        DispatchQueue.main.async {
            self.logTextView.text = "found identity \(certId), importing..."
        }
        if AWSIoTManager.importIdentity( fromPKCS12Data: data, passPhrase:"", certificateId:certId) {
            // Set the certificate ID and ARN values to indicate that we have imported
            // our identity from the PKCS12 file in the bundle.
            defaults.set(certId, forKey:"certificateId")
            defaults.set("from-bundle", forKey:"certificateArn")
            DispatchQueue.main.async {
                self.logTextView.text = "Using certificate: \(certId))"
                self.iotDataManager.connect( withClientId: uuid,
                                             cleanSession:true,
                                             certificateId:certId,
                                             statusCallback: self.mqttEventCallback)
            }
        }
        
        let certificateId = defaults.string( forKey: "certificateId")
        return certificateId
    }