Opn Payments iOS SDK

Opn Payments is a payment service provider operating in Thailand, Japan, and Singapore. Opn Payments provides a set of APIs that help merchants of any size accept payments online.

The Opn Payments iOS SDK provides bindings for tokenizing credit cards and accepting non-credit-card payments using the Opn Payments API, allowing developers to safely and easily accept payments within apps.

If you run into any issues regarding this SDK and the functionality it provides, consult the frequently asked questions in our comprehensive support documents. If you can't find an answer there, feel free to email our support team.

Security Warning

Please do NOT use Omise iOS SDK versions less than 3.2.0, as they are outdated and have security vulnerabilities.

Requirements

• Opn Payments API public key. Register for an Opn Payments account to obtain your API keys.
• iOS 10 or higher deployment target.
• Xcode 14.0 or higher (Xcode 15 is recommended)
• Swift 5.0 or higher (Swift 5.3 is recommended)

Merchant compliance

Card data should never transit through your server. We recommend that you follow our guide on how to safely collect credit information.

To be authorized to create tokens on your server, you must have a currently valid PCI-DSS Attestation of Compliance (AoC) delivered by a certified QSA Auditor. This SDK provides the means to tokenize card data through the end user's mobile phone without this data having to go through your server.

Installation

To integrate the Opn Payments SDK into your Xcode project using the Swift Package Manager, proceed with the following steps:

1. In Xcode, select File > Swift Packages > Add Package Dependency...
2. Enter the URL for this repository https://github.com/omise/omise-ios.git
3. Choose a minimum semantic version of v5.0.0
4. Select your target, go to Frameworks, Libraries, and Embedded Content, and set OmiseSDK to Embed & Sign

Usage

The Opn Payments iOS SDK provides an easy-to-use library for calling the Opn Payments API and presenting UI forms.

The main class and protocol for the Opn Payments iOS SDK are OmiseSDK and ClientProtocol through which all requests to the Opn Payments API will be sent.

To start working with OmiseSDK, you must create a new instance of the OmiseSDK class with an Opn Payments public key.

import OmiseSDK

let omiseSDK = OmiseSDK(publicKey: "omise_public_key")

You can also set up and use a shared instance of OmiseSDK in your code:

OmiseSDK.shared = omiseSDK

If you cloned this project to your local hard drive, you can check out ExampleApp.xcodeproj.

Opn Payments API

The SDK currently supports two main categories of requests: Tokenizing a Card and Creating a Payment Source.

Creating a card token

Normally, merchants must not send credit or debit card data to their own servers. To collect a card payment from a customer, merchants must first tokenize the card data using the Opn Payments API and then use the generated token in place of the card data. You can tokenize card data by creating and initializing a CreateTokenPayload.Card as follows:

let createTokenPayload = CreateTokenPayload.Card(
    name: "JOHN DOE",
    number: "4242424242424242",
    expirationMonth: 11,
    expirationYear: 2022,
    securityCode: "123"
)

let createTokenPayloadWithAddress = CreateTokenPayload.Card(
    name: "JOHN DOE",
    number: "4242424242424242",
    expirationMonth: 11,
    expirationYear: 2022,
    securityCode: "123",
    phoneNumber: "0123456789",
    countryCode: "TH",
    city: "Bangkok",
    state: "Bangkok",
    street1: "Sukhumvit",
    street2: "",
    postalCode: "10110"
)

Creating a payment source

Opn Payments supports many payment methods other than cards. You may request a payment with one of those supported payment methods from a customer by calling the CreateSource API. You need to specify the parameters (e.g., payment amount and currency) of the source you want to create by creating and initializing a CreateSourcePayload with the Payment Information object:

let createSourcePayload = CreateSourcePayload(
    amount: amount,
    currency: currency,
    details: .sourceType(.internetBankingBBL) // Bangkok Bank Internet Banking payment method
)

After creating the token or the payment source, create the completion handler, as follows:

Creating the completion handler

A simple completion handler for a token, for example, is as follows:

func tokenCompletionHandler(tokenResult: Result<Token, Error>) -> Void {
    switch tokenResult {
    case .success(let token):
        // do something with Token id
        print(token.id)
    case .failure(let error):
        print(error)
    }
}

Now, send the request:

Sending the request

Whether you are charging a source or a card, sending the request is the same. Use the ClientProtocol to perform one-off API calls with the completion handler block.

let client = omiseSDK.client
client.createToken(payload: createTokenPayload, tokenCompletionHandler)
client.createSource(payload: createSourcePayload, sourceCompletionHandler)
client.capability(capabilityCompletionHandler)
client.token(tokenID: "tokenID", tokenInfoCompletionHandler)
client.observeChargeStatus(chargeStatusCompletionHandler)

Using built-in forms

Opn Payments iOS SDK provides easy-to-use drop-in UI forms for both Tokenizing a Card and Creating a Payment Source, which you can easily integrate into your application.

Card form

The omiseSDK.presentCreditCardPayment() provides a pre-made card form that will automatically tokenize card information for you.

Use Opn Payments card form

To use the controller in your application, modify your view controller with the following additions:

import OmiseSDK

class ViewController: UIViewController {
  private let omiseSDK = OmiseSDK("pkey_test_123")

  @IBAction func displayCreditCardPayment() {
    omiseSDK.presentCreditCardPayment(from: self, delegate: self)
  }
}

You can provide extra parameters:

• countryCode to preselect the country in the UI form
• handleErrors to process and display errors (by default, is true); if false, then the delegate method choosePaymentMethodDidComplete(with error: Error) will be called instead.

omiseSDK.presentCreditCardPayment(
  from: self,
  countryCode: "TH", // if `nil` it will use country from Capability API 
  handleErrors: true,  // by default `true`
  delegate: self
)

Then implement the delegate to receive the Token object after the user has entered the card data:

extension ViewController: ChoosePaymentMethodDelegate {
  func choosePaymentMethodDidComplete(with token: Token) {
    // Send `Token` to your server to create a charge or a customer object.
    print(token.id) // prints Token ID
  }

  func choosePaymentMethodDidComplete(with error: Error) {
    // Only called if we set `handleErrors = false`.
    // You can send errors to a logging service or display them here to the user.
  }
}

You can call OmiseSDK.dismiss(animated:completion:) to close UI form presented by OmiseSDK:

  func choosePaymentMethodDidComplete(with token: Token) {
    omiseSDK.dismiss {
      // present another screen 
    }
  }

Creating a custom card form

You can create your card form, but please remember you must not send the card information to your server. Opn Payments iOS SDK provides the following built-in card UI components to make it easier to create your card form:

• CardNumberTextField - Provides basic number grouping as the user types.
• CardNameTextField - Cardholder name field.
• CardExpiryDateTextField - Provides card expiration date input and styling
• CardExpiryDatePicker - UIPickerView implementation with a month and year column.
• CardCVVTextField - CVV number field.

Additionally, fields automatically turn red if their content fails basic validation (e.g., alphabetic characters in the number field, content with wrong length), and come in two supported styles: plain and border.

Built-in Choose Payment Methods controller

The presentChoosePaymentMethod function of OmiseSDK presents a pre-made form that lets customers choose how they want to make a payment. Please note that the presented controller is designed to be used as-is, and you should not push your view controllers into its navigation controller stack. You can configure it to display either specified payment method options or a default list based on your country.

Use Choose Payment Methods controller

To use the controller in your application, call presentChoosePaymentMethod.

omiseSDK.presentChoosePaymentMethod(
    from: self,
    amount: paymentAmount,
    currency: paymentCurrencyCode,
    delegate: self
)

You can provide extra parameters:

• allowedPaymentMethods to display given payment methods (if presented in Capability API)
• forcePaymentMethods to override payment methods from Capability and display only allowedPaymentMethods
• isCardPaymentAllowed to display or hide the Credit Card payment method
• handleErrors to process and display errors (by default, is true); if false, then the delegate method choosePaymentMethodDidComplete(with error: Error) will be called instead.

let allowedPaymentMethods = SourceType.availableByDefaultInThailand
omiseSDK.presentChoosePaymentMethod(
    from: self,
    amount: paymentAmount,
    currency: paymentCurrencyCode,
    allowedPaymentMethods: allowedPaymentMethods,
    forcePaymentMethods: true,
    isCardPaymentAllowed: true, 
    handleErrors: true,
    delegate: self
)

Then implement the delegate to receive the Source or Token object after the user has selected:

extension ProductDetailViewController: ChoosePaymentMethodDelegate {  
  func choosePaymentMethodDidComplete(with source: Source) {
    omiseSDK.dismiss {
      print(source.id) // prints Source ID
    }
  }
  
  func choosePaymentMethodDidComplete(with token: Token) {
    omiseSDK.dismiss {
      print(token.id) // prints Token ID
    }
  }

  func choosePaymentMethodDidComplete(with error: Error) {
    // Only called if we set `handleErrors = false`.

    let alertController = UIAlertController(title: "Error", message: error.localizedDescription, preferredStyle: .alert)
    let okAction = UIAlertAction(title: "OK", style: .cancel, handler: nil)
    alertController.addAction(okAction)

    let vc = omiseSDK.presentedViewController ?? self
    vc.present(alertController, animated: true, completion: nil)
  }
  
  func choosePaymentMethodDidCancel() {
      omiseSDK.dismiss()
  }
}

Authorizing payment

Some payment methods require the customer to authorize the payment using an authorization URL. This includes 3-D Secure verification, Internet Banking payment, Mobile Banking SCB, etc. Opn Payments iOS SDK provides a built-in class to handle the authorization.

On payment methods that require opening the external app (e.g., mobile banking app) to authorize the transaction, set the return_uri to a deep link or app link to be able to open the merchant app. Otherwise, after the cardholder authorizes the transaction on the external app, the flow redirects to the normal link in the return_uri, and opens it on the browser app, resulting in the payment not being completed. Some authorized URLs will be processed using the in-app browser flow, and others will be processed using the native flow from the SDK (3DS v2), and the SDK automatically handles all of this.

omiseSDK.presentAuthorizingPayment(
    from: self,
    authorizeURL: url,
    expectedReturnURLStrings: ["https://omise.co"],
    threeDSRequestorAppURLString: "merchantAppScheme://3ds_auth",
    threeDSUICustomization: nil
    delegate: self
)

Replace the string authorizeURL with the authorized URL that comes with the created charge and the array of string expectedReturnURLStrings with the expected pattern of redirected URLs array. Replace the string threeDSRequestorAppURLString with the url of your app to allow the external bank apps to navigate back to your app when required. Optional threeDSUICustomization parameter is used to customize the UI of the built-in 3DS SDK during the 3DS challenge flow. If you want to customize the title of the authorizing payment activity, you must use the theme customization and pass the headerText in the toolbarCustomization

let toolbarUI = ThreeDSToolbarCustomization(
    backgroundColorHex: "#FFFFFF",
    headerText: "Secure Checkout",
    buttonText: "Close",
    textFontName: "Arial-BoldMT",
    textColorHex: "#000000",
    textFontSize: 20
)

let threeDSUICustomization = ThreeDSUICustomization(toolbarCustomization: toolbarUI)

You can check out the ThreeDSUICustomization class to see customizable UI elements in the challenge flow.

After the end-user completes the payment authorization process, the delegate callback will be triggered, and you will receive varying responses based on how the transaction was processed and the flow it used. Handle it as follows:

extension ViewController: AuthorizingPaymentDelegate {
    func authorizingPaymentDidComplete(with redirectedURL: URL?) {
        print("Payment is authorized with redirect url `\(String(describing: redirectedURL))`")
        omiseSDK.dismiss()
    }
    func authorizingPaymentDidCancel() {
        print("Payment is not authorized")
        omiseSDK.dismiss()
    }
}

You can check out the sample implementation in the ProductDetailViewController class in the example app.

Observing charge status in the token

The following utility function observes the token until its charge status changes. You can use it to check the charge status after the payment authorization process is completed.

func observeTokenChargeStatusHandler(tokenResult: Result<Token, Error>) -> Void {
    switch tokenResult {
    case .success(let token):
        // do something with Token id
        print(token.id)
    case .failure(let error):
        print(error)
    }
}

let client = omiseSDK.client
client.observeChargeStatus(observeTokenChargeStatusHandler)

Authorizing payment via an external app

Some request methods allow the user to authorize the payment with an external app, for example Alipay. When a user needs to authorize the payment with an external app, OmiseSDK will automatically open an external app. However, merchant developers must handle the AuthorizingPaymentDelegate callback themselves.

Objective-C compatibility

This version of Opn Payments iOS SDK does not support Objective-C. For full Objective-C support, use this version.

Contributing

Pull requests, issues, and bug fixes are welcome!

License

MIT See the full license text