Enabling PIN and Biometric using Cotter's Android SDK consists of:
Initializing Cotter
Calling functions to start PIN and Biometric Enrollment
Verify Biometric or PIN before an action
Enabling and disabling Biometric or PIN in Settings
We use Cocoapods as our SDK host. If you're using Cocoapods, add this to your Podfile
pod 'Cotter'
Otherwise please open an issue at our Github Issues page.
Then simply run pod install
You need to set allowed methods for authentication your users. To allow PIN
and BIOMETRIC
, go to https://dev.cotter.app/rules
Remember to select the correct project in the dropdown list
You will have to do import Cotter
on the file that will use Cotter. Then do initialization as follows
import Cotter...let cotter = Cotter(apiSecretKey: <your-api-secret-key>,apiKeyID: <your-api-key-id>,cotterURL: "https://www.cotter.app/api/v0",userID: <your-user-id>, // user’s id that will be created laterconfiguration: <your-cotter-config>)
example:
import Cotter...let cotter = Cotter(apiSecretKey: "<API_SECRET_KEY>",apiKeyID: "<API_KEY_ID>",cotterURL: "https://www.cotter.app/api/v0",userID: "hello@example.com",configuration: [:]);
/* https://www.cotter.app/api/v0/user/create */CotterAPIService.shared.registerUser(userID: <your-user-id>,cb: { response in// handle Result (Swift 5 enum) callback here})
Response:
{"ID": "9449e9e9-00e0-4d6b-a4b6-28c5b22b0b0f","created_at": "2020-01-21T12:40:21.200727668Z","update_at": "2020-01-21T12:40:21.200727668Z","deleted_at": null,"issuer": "<your key ID>","client_user_id": "<Your User Identifier (string)>","enrolled": [],"default_method": null}
Example:
// registerUserCb is a simple callback that handles the cases for// the API Callfunc registerUserCb(_ response: CotterResult<CotterUser>){switch response{case .success(let user):print("successfully registered the \(user)")case .failure(let err):// you can put exhaustive error handling hereswitch err{case CotterAPIError.decoding:print("this is decoding error on registering user")breakcase CotterAPIError.network:print("this is network error on registering user")breakcase CotterAPIError.status:print("this is not successful error")breakdefault:print("error registering user: \(err)")}}}// call the API using our clientCotterAPIService.shared.registerUser(userID: "hello@example.com",cb: registerUserCb)
/* https://www.cotter.app/api/v0/user/:your_user_id */CotterAPIService.shared.getUser(userID: <your-user-id>,cb: { response in// handle Result (Swift 5 enum) callback here})
Response:
{"ID": "9449e9e9-00e0-4d6b-a4b6-28c5b22b0b0f","created_at": "2020-01-21T12:40:21.200727668Z","update_at": "2020-01-21T12:40:21.200727668Z","deleted_at": null,"issuer": "<your key ID>","client_user_id": "<Your User Identifier (string)>","enrolled": ["PIN", "BIOMETRIC"],"default_method": "BIOMETRIC"}
Example:
func enrollCb(response: CotterResult<CotterUser>) {switch response {case .success(let resp):self.yourLabel.text = resp.enrolled.joined(separator: ", ")case .failure(let err):// we can handle multiple error results hereswitch err {case CotterAPIError.status(code: 500):print("internal server error")case CotterAPIError.status(code: 404):print("user not found")default:print(err.localizedDescription)}}}CotterAPIService.shared.getUser(userID:self.userID, cb:enrollCb)
For starting authentication flow, you need to have the following:
The UIViewController
you want to attach Cotter to
The UIViewController
MUST have a NavigationController
set (i.e. self.navigationController
cannot be nil
)
// initializationlet cotter = Cotter(...)cotter.PinEnrollment.startEnrollment(vc: <your-vc>,animated: true,cb: <your-callback>);
example:
class SomeUIVC: UIViewController {var cotter: Cotter?override func viewDidLoad() {super.viewDidLoad()// cotter initialization hereself.cotter = Cotter(apiSecretKey: "588d6f67-0981-4718-899b-bcd512de1aca",apiKeyID: "w4FK6Zz0XIhtGY3o5biI",userID: "hello@example.com",cotterURL: "https://www.cotter.app/api/v0",configuration: [:]);cotter.startEnrollment(vc: self,animated: true,cb: { (token: String, err: Error?) inif err != nil {// handle errorreturn}// handle success})}}
The verification flow will automatically prompt for Biometric Verification if the user's device has an enrolled biometric. Otherwise, it will fallback to entering PIN. Starting the verification flow is exactly the same as starting the Enrollment Flow on step 5.
// initializationlet cotter = Cotter(...)cotter.PinEnrollment.startTransaction(vc: <your-vc>,animated: true,cb: <your-callback>,hideClose: false, // hideClose param gives you the choice to show/hide the close buttonconfiguration: [:]);
Example:
class SomeUIVC: UIViewController {var cotter: Cotter?override func viewDidLoad() {super.viewDidLoad()// cotter initialization hereself.cotter = Cotter(apiSecretKey: "<your API_SECRET_KEY>",apiKeyID: "<your API_KEY_ID>",userID: "hello@example.com",cotterURL: "https://www.cotter.app/api/v0");cotter.startTransaction(vc: self,animated: true,cb: { (token: String, err: Error?) inif err != nil {// handle errorreturn}// handle success},hideClose: false)}}
There are 2 types of callback:
HTTP Callbacks are the ones that you pass in to the start flow functions (startEnrollment, startTransaction, startUpdateProfile).
The callback form is as such:
// FinalCallbackAuth is the general callback function declarationpublic typealias FinalAuthCallback = (_ token: String, _ error: Error?) -> Void
It takes in a token String and an optional Error object. Currently token String is not used in PIN or Biometric authentication. We're working on making the token useable.
For the FinalAuthCallback function, there are 3 types of CotterError that exist in the SDK. These include:
1. CotterError.biometricEnrollment
This error is produced when you fail to enroll your biometrics during the Enrollment flow in startEnrollment.
2. CotterError.biometricVerification
This error is produced when you fail to verify your biometrics during the Transaction flow in startTransaction.
3. CotterError.keychainError
This error is produced in all flows when the user's device is unable to attain its corresponding public/private keys.
However, you will almost always only encounter CotterError.biometricEnrollment
and CotterError.biometricVerification
errors in the resulting FinalAuthCallback
function.
Authentication Callbacks are the ones that is passed in through the CotterAPIService
. It uses the latest Result enum in Swift 5. The Authentication callback works similarly as the HTTP Callback, it can handle success and error cases as shown on the previous example.
The callback form is as such:
public typealias ResultCallback<Value> = (Result<Value, Error>) -> Void
What this definition says is that it takes a Result of a type Value, which Value can be any of the pre defined Cotter classes (such as CotterUser
, CotterEvent
, etc), and returns nothing.
When using the CotterAPIService
class to call Cotter's API endpoints, there are 5 types of Cotter errors that you might encounter:
1. CotterAPIError.encoding
An 'encoding' error refers to an error encoding the HTTP Request.
2. CotterAPIError.decoding
A 'decoding' error refers to an error decoding the HTTP Response.
3. CotterAPIError.status(code: Int)
A 'status' error refers to the response having an invalid HTTP Status Code - e.g. Status 400 (Bad Request Error)
4. CotterAPIError.server(message: String)
A 'server' error means that our API server has responded to the request with an error message.
5. CotterAPIError.network
A 'network' error means that network conditions are poor, which can be due to bad internet connection.