Signaling Sample App

The Signaling app is a very simple application meant to get a new developer started using the signaling features of OpenTok iOS SDK.

Quick Start

To use this application:

1. Follow the instructions in the Quick Start section of the main README file for this repository.

   Among other things, you need to set values for the kApiKey, kSessionId, and kToken constants. See Obtaining OpenTok Credentials in the main README file for the repository.

2. When you run the application, an OpenTok session is created . Signaling only needs OTConnection(s).

3. Run the app on a second client. You can do this by deploying the app to an iOS device and testing it in the simulator at the same time.

Application Notes

• Signals are meant to transmit basic text data between participants in a session.

• Signals don't have extensive chat like features (like emoji's etc).

• Sending an signal using an session object as follows:

 session.signal(withType: type , string: data, connection:c.getOTConnection(), error: nil)

or

session.signal(withType: type , string: data, connection:c.getOTConnection(), retryAfterReconnect: retryAfterConnect, error: nil)

retryAfterReconnect default value is true in the first call. The error case fails silently.

• Receiving a signal is done using OTSessionDelegate callback as follows:

func session(_ session: OTSession, receivedSignalType type: String?, from connection: OTConnection?, with string: String?) {
   ..
}

You just need to implement the above calls in your app.

• Valid Characters in a signal data is limited to [^a-zA-Z0-9-_~\\s]. If a non valid character is used , signal is not send. To get around this you can encode signal data with base64 and decode it on other side. This way you can send emoji's for example. A sample code which extends String is provided below for reference:

extension String {
    func fromBase64() -> String? {
            guard let data = Data(base64Encoded: self) else {
                return nil
            }

            return String(data: data, encoding: .ascii)
        }

        func toBase64() -> String {
            return Data(self.utf8).base64EncodedString()
        }
        func isValidSignal() -> Bool {
            return self.count <= 128 && self.range(of: "[^a-zA-Z0-9-_~\\s]", options: .regularExpression) == nil
        }
 ...
 }       

Screen shot (SwiftUI based)

Starting screen:

1. Tap on "Hello !!" sends a "Hello World" message to all connections.
2. Tap on the Pen image leads to Form View (as shown below)

Starting screen with Scrollable Messages:

Signal Form view: