Applies to: Reader SDK - iOS | Mobile Authorization API
Learn how to build a secure in-person payment solution for iOS devices.
The Mobile Payments SDK has launched as the successor of the Reader SDK. To take in-person payments on Square hardware, you should migrate from the Reader SDK to the Mobile Payments SDK.
To complete the following steps, you need:
The Reader SDK isn't compatible to run on custom devices from OEMs that violate Square's security rules or on devices that grant root access to the mobile device operating system code and kernel. As a result, these devices cannot connect to a Contactless and Chip Reader.
The following additional considerations apply when trying to run the SDK on custom devices:
The following steps are recommended to verify your device:
Open the Developer Console. You're prompted to sign in or create an account.
Create a Square application.
Choose the new application to open the Square application settings pages.
Open the Reader SDK page, and then choose Request Credentials to generate your Reader SDK repository password.
Download and configure the latest version of SquareReaderSDK.xcframework in your project root. The framework is installed in the current directory.
ruby <(curl https://connect.squareup.com/readersdk-installer) install \ --app-id SQUARE_READER_SDK_APPLICATION_ID \ --repo-password SQUARE_READER_SDK_REPOSITORY_PASSWORD
Optional: If you need to test or revert to a previous version of the SDK, you can also include the desired version number. If unspecified, the most recent version is installed.
--version 1.6.9
Add the Reader SDK to your project:
Open the Xcode workspace or project for your application.
On the Build Phases tab for your application target, choose the + button (at the top of the pane).
Choose New Run Script Phase.
Paste the following into the editor panel of the new run script:
FRAMEWORKS="${BUILT_PRODUCTS_DIR}/${FRAMEWORKS_FOLDER_PATH}" "${FRAMEWORKS}/SquareReaderSDK.framework/setup"
To avoid "No such file or directory" build errors, make sure that the Reader SDK Run Script phase is the last phase in the list.
The Reader SDK doesn't currently support bitcode. To disable bitcode:
If your application target is pure Objective-C and contains no Swift code, you must include the standard Swift libraries with your application.
In Xcode, open the General tab for your application target.
Make sure the Landscape Left and Landscape Right device orientations are supported, as shown:
If your application runs on iPhone, it must support portrait and landscape interface orientations so that the Reader SDK can display the signature screen during checkout.
If you want specific screens in your application to only support the portrait orientation, you can override the supportedInterfaceOrientations method in your UIViewController subclasses.
Add or update the following key-value pairs on the Info tab for your application target to explain why your application requires these device permissions. Xcode can display human-readable labels (such as Privacy - Microphone Usage Description) rather than the raw keys.
| Key | Description |
|---|---|
| NSLocationWhenInUseUsageDescription | This application integrates with Square for card processing. To protect buyers and sellers, Square requires your location to process payments. |
| NSMicrophoneUsageDescription | This application integrates with Square for card processing. To swipe magnetic cards using the headphone jack, Square requires access to the microphone. |
| NSBluetoothPeripheralUsageDescription | This application integrates with Square for card processing. Square uses Bluetooth to connect your device to compatible hardware. |
| NSCameraUsageDescription | This application integrates with Square for card processing. Upload your account logo, feature photo, and product images with the photos stored on your mobile device. |
| NSPhotoLibraryUsageDescription | This application integrates with Square for card processing. Upload your account logo, feature photo, and product images with the photos stored on your mobile device. |
| NSBluetoothAlwaysUsageDescription | This application integrates with Square for card processing. Square uses Bluetooth to connect your device to compatible hardware. |
Your application doesn't need to request Bluetooth, Camera, or Photo Library permissions to use the Reader SDK. The usage descriptions are required due to the way the Reader SDK is built.
Add code to ensure that your application has permission to use location services before starting a checkout flow. The location permission is managed by Apple's CLLocationManager class.
import CoreLocation
class YourViewController: UIViewController {
private lazy var locationManager = CLLocationManager()
func requestLocationPermission() {
switch CLLocationManager.authorizationStatus() {
case .notDetermined:
locationManager.requestWhenInUseAuthorization()
case .restricted, .denied:
print("Show UI directing the user to the iOS Settings app")
case .authorizedAlways, .authorizedWhenInUse:
print("Location services have already been authorized.")
}
}
}Add code to ensure that your application has permission to access the microphone before starting checkout. The microphone permission is managed by Apple's AVAudioSession class. You must have the record permission from AVAudioSession to use Square Magstripe Readers.
import AVFoundation
extension <#YourViewController#> {
func requestMicrophonePermission() {
// Note: The microphone permission prompt will not be displayed
// when running on the simulator
AVAudioSession.sharedInstance().requestRecordPermission { authorized in
if !authorized {
print("Show UI directing the user to the iOS Settings app")
}
}
}
}Update the application:didFinishLaunchingWithOptions: method in your application delegate to initialize the Reader SDK.
import SquareReaderSDK
func application(
_: UIApplication,
didFinishLaunchingWithOptions launchOptions:
[UIApplicationLaunchOptionsKey: Any]? = nil
) -> Bool {
SQRDReaderSDK.initialize(applicationLaunchOptions: launchOptions)
return true
}The Reader SDK requires a mobile authorization code from the Mobile Authorization API. Mobile authorization codes allow custom mobile applications to process payments on Square hardware on behalf of a specific Square account for a given location.
Mobile authorization codes are short lived and should be used immediately to authorize the Reader SDK. Authorization is valid until it's explicitly revoked by calling deauthorize or your application fails to take a payment within 90 days. Mobile authorization codes don't need to be manually refreshed under normal operations.
Production applications should request mobile authorization codes programmatically, but you can generate mobile authorization codes on the Reader SDK page of your application settings or manually with cURL during development.
Create a function, retrieveAuthorizationCode, to handle the work of calling your authorization service and handling the result.
import SquareReaderSDK
func retrieveAuthorizationCode() -> String {
// TODO: Add code to retrieve a mobile authorization code.
return "<Mobile Authorization Code>"
}import SquareReaderSDK
func authorizeReaderSDKIfNeeded() {
if SQRDReaderSDK.shared.isAuthorized {
print("Already authorized.")
} else {
let authCode = retrieveAuthorizationCode()
SQRDReaderSDK.shared.authorize(withCode: authCode) { _, error in
if let authError = error {
// Handle the error
print(authError)
} else {
// Proceed to the main application interface.
}
}
}
}Your view controller must conform to the SQRDCheckoutControllerDelegate protocol to handle results and errors from the checkout flow. In most cases, your view controller should implement SQRDCheckoutControllerDelegate. If you choose to implement the delegate as a separate object, make sure it's retained until the checkout flow completes.
This view controller is a good place to add a button that starts the contactless reader connect flow using the Reader SDK settings view controller. A Square contactless reader cannot be connected until the Reader SDK is authorized. Authorization is completed in step 8, which means you can now connect a reader. For information about connecting a reader, see Connect a Contactless Reader.
import SquareReaderSDK
extension <#YourViewController#>: SQRDCheckoutControllerDelegate {
func checkoutControllerDidCancel(
_: SQRDCheckoutController
) {
print("Checkout canceled.")
}
func checkoutController(
_: SQRDCheckoutController, didFailWith _: Error
) {
// TODO: Handle checkout errors
}
func checkoutController(
_: SQRDCheckoutController,
didFinishCheckoutWith _: SQRDCheckoutResult
) {
// TODO: Handle checkout success
}
}Create an SQRDCheckoutParameters object. At a minimum, you need to set the amount of money to be charged. You then start the checkout flow by instantiating a Square checkout controller (SQRDCheckoutController) and presenting it.
import SquareReaderSDK
extension <#YourViewController#> {
func startCheckout() {
// Create a money amount in the currency of the authorized Square account
let amountMoney = SQRDMoney(amount: 100)
// Create parameters to customize the behavior of the checkout flow.
let params = SQRDCheckoutParameters(amountMoney: amountMoney)
params.additionalPaymentTypes = [.cash, .manualCardEntry]
// Create a checkout controller and call present to start checkout flow.
let checkoutController = SQRDCheckoutController(
parameters: params,
delegate: self
)
checkoutController.present(from: self)
}
}Implement the success and failure delegate methods. For now, print the checkout result to the Xcode console on success and error information on failure.
The Reader SDK provides error types for all failable operations. For example, errors that occur while presenting the checkout flow are always of the SQRDCheckoutControllerError type. Error objects always contain user displayable details (error codes and descriptions) and debugging information (debug codes and debug messages).
// Success delegate method
func checkoutController(
_: SQRDCheckoutController,
didFinishCheckoutWith result: SQRDCheckoutResult
) {
// result contains details about the completed checkout
print("Checkout completed: \(result.description).")
}
// ...
// Failure delegate method
func checkoutController(
_: SQRDCheckoutController, didFailWith error: Error
) {
// Checkout controller errors are always of type SQRDCheckoutControllerError
let checkoutControllerError = error as! SQRDCheckoutControllerError
switch checkoutControllerError.code {
case .sdkNotAuthorized:
// Checkout failed because the SDK is not authorized
// with a Square merchant account.
print("Reader SDK is not authorized.")
case .usageError:
// Checkout failed due to a usage error. Inspect the userInfo
// dictionary for additional information.
if let debugMessage = checkoutControllerError.userInfo[SQRDErrorDebugMessageKey],
let debugCode = checkoutControllerError.userInfo[SQRDErrorDebugCodeKey] {
print(debugCode, debugMessage)
}
}
}The Reader SDK provides a testing module that contains additional initializers that aren't exposed in the Reader SDK framework. You can use these initializers to construct mock objects in your tests. For example, you might initialize a SQRDCard object in a unit test and use it to verify the behavior of your application.
import SquareReaderSDK.Testing // import the Testing module
func test_updateWithCard() {
let card = SQRDCard(brand: .visa, lastFour: "1111")
self.cardView.updateWithCard(card)
XCTAssertEqualObjects(self.cardView.lastFourLabel.text, "1111")
XCTAssertEqualObjects(self.cardView.brandLabel.text, "Visa")
}If you need more assistance, contact Developer and App Marketplace Support or ask for help in the Developer Forums.