A simple Express.js OAuth provider which takes an Application ID and some authentication token which, once matched, results in a negotiated App Login based Token for ArcGIS Online.
Included is an ArcGIS Runtime for iOS Sample client.
Modify the JSON configuration in app.js to specify a Client ID and Client Secret. This sample operates on matching well known text, but in practice you would modify the service to handle some other kind of authentication.
var clientsDetails = {
"OeGPy3X6ERqWPNFS": { // <-- Client ID
"authString": "I could be a username and password.",
"secret": "<< INSERT CLIENT SECRET HERE >>" // <-- Client Secret
}
};
See this page for more details.