feat: Add Stripe as First Payment Gateway (#11)

Add all necessary logic and changes to make payment processing using Stripe including Protocols, Factories and Models to deal with the StripePayments pod. Unit tests are included.

OSPaymentsLib/Error/OSPMTError.swift

@@ -11,6 +11,10 @@ public enum OSPMTError: Int, CustomNSError, LocalizedError {
     case paymentTriggerPresentationFailed = 10
     case paymentCancelled = 11
 
+    case gatewaySetFailed = 12
+    case stripePaymentMethodCreation = 13
+    case paymentIssue = 14
+
     /// Textual description
     public var errorDescription: String? {
         switch self {
@@ -30,6 +34,13 @@ public enum OSPMTError: Int, CustomNSError, LocalizedError {
             return "Couldn't present the Apple Pay screen."
         case .paymentCancelled:
             return "Payment was cancelled by the user."
+
+        case .gatewaySetFailed:
+            return "Couldn't set payment service provider."
+        case .stripePaymentMethodCreation:
+            return "Couldn't obtain the PaymentMethod from Stripe."
+        case .paymentIssue:
+            return "Couldn't process payment."
         }
     }
 }

OSPaymentsLib/Extensions/PKPayment+Adapter.swift

@@ -2,23 +2,24 @@ import PassKit
 
 extension PKPayment {
     /// Converts a `PKPayment` object into a `OSPMTScopeModel` one. Returns `nil` if it can't.
+    /// - Parameter paymentGatewayModel: model that contains the payment gateway information resulting from completing a payment process.
     /// - Returns: The corresponding `OSPMTScopeModel` object. Can also return `nil` if the conversion fails.
-    func createScopeModel() -> OSPMTScopeModel? {
-        var result: [String: Any] = [OSPMTScopeModel.CodingKeys.paymentData.rawValue: self.createTokenDataData()]
+    func createScopeModel(for paymentGatewayModel: OSPMTServiceProviderInfoModel? = nil) -> OSPMTScopeModel? {
+        var result: [String: Any] = [OSPMTScopeModel.CodingKeys.paymentData.rawValue: self.createTokenDataData(for: paymentGatewayModel)]
         if let shippingContact = self.shippingContact {
             result[OSPMTScopeModel.CodingKeys.shippingInfo.rawValue] = self.createContactInfoData(for: shippingContact)
         }
 
-        guard
-            let scopeData = try? JSONSerialization.data(withJSONObject: result),
+        guard let scopeData = try? JSONSerialization.data(withJSONObject: result),
             let scopeModel = try? JSONDecoder().decode(OSPMTScopeModel.self, from: scopeData)
         else { return nil }
         return scopeModel
     }
 
     /// Converts a `PKPayment` object into a dictionary that relates to an `OSPMTDataModel` object.
+    /// - Parameter paymentGatewayModel: model that contains the payment gateway information resulting from completing a payment process.
     /// - Returns: The corresponding `OSPMTDataModel` dictionary object.
-    private func createTokenDataData() -> [String: Any] {
+    private func createTokenDataData(for paymentGatewayModel: OSPMTServiceProviderInfoModel?) -> [String: Any] {
         var result: [String: Any] = [
             OSPMTDataModel.CodingKeys.tokenData.rawValue: self.createTokenData(for: self.token.paymentData)
         ]
@@ -32,6 +33,11 @@ extension PKPayment {
                 result[OSPMTDataModel.CodingKeys.cardNetwork.rawValue] = cardNetwork
             }
         }
+        if let paymentGatewayModel = paymentGatewayModel,
+            let paymentGatewayData = try? JSONEncoder().encode(paymentGatewayModel),
+            let paymentGatewayDict = try? JSONSerialization.jsonObject(with: paymentGatewayData) as? [String: String] {
+            result[OSPMTDataModel.CodingKeys.paymentServiceProviderData.rawValue] = paymentGatewayDict
+        }
 
         return result
     }
@@ -40,7 +46,6 @@ extension PKPayment {
     /// - Parameter paymentData: `Data` type object that contains information related to a payment token.
     /// - Returns: The corresponding `OSPMTTokenInfoModel` dictionary object.
     private func createTokenData(for paymentData: Data) -> [String: String] {
-        // TODO: The type passed here will probably be changed into the Payment Service Provider's name when this is implemented.
         var result = [OSPMTTokenInfoModel.CodingKeys.type.rawValue: "Apple Pay"]
 
         if let token = String(data: paymentData, encoding: .utf8) {

OSPaymentsLib/Gateways/OSPMTGateway.swift

@@ -0,0 +1,14 @@
+/// Payment Service Provider enum object
+enum OSPMTGateway: String {
+    case stripe = "Stripe"
+}
+
+extension OSPMTGateway {
+
+    /// Converts a string into a `OSPMTGateway` object.
+    /// - Parameter text: Text to convert.
+    /// - Returns: A `OSPMTGateway` enum object if successful. `nil` is returned in case of error.
+    static func convert(from text: String) -> OSPMTGateway? {
+        return text.lowercased() == "stripe" ? .stripe : nil
+    }
+}

OSPaymentsLib/Gateways/OSPMTGatewayFactory.swift

@@ -0,0 +1,18 @@
+import Foundation
+
+/// Structure responsible for creating a Wrapper for the configured Gateway.
+struct OSPMTGatewayFactory {
+    /// Creates the correct wrapper for the gateway the user has configured.
+    /// - Parameter configuration: Model with the gateway configuration information.
+    /// - Returns: The wrapper object is everything is correctly configured. `nil` is returned otherwise.
+    static func createWrapper(for configuration: OSPMTGatewayModel) -> OSPMTGatewayDelegate? {
+        guard let gateway = configuration.gatewayEnum, let url = URL(string: configuration.requestURL) else { return nil }
+        let urlRequest = URLRequest(url: url)
+
+        switch gateway {
+        case .stripe:
+            guard let publishableKey = configuration.publishableKey else { return nil }
+            return OSPMTStripeWrapper(urlRequest: urlRequest, publishableKey: publishableKey)
+        }
+    }
+}

OSPaymentsLib/Gateways/Stripe/OSPMTStripeAPIDelegate.swift

@@ -0,0 +1,37 @@
+import PassKit
+import StripePayments
+
+/// Delegate class containing the required calls for Stripe's SDK to process.
+protocol OSPMTStripeAPIDelegate: AnyObject {
+    /// Sets the required publishable key, required to trigger payments through Stripe
+    /// - Parameter publishableKey: Key obtained via Stripe's Dashboard.
+    func set(_ publishableKey: String)
+
+    /// Retrieves Stripe's Payment Method's Identifier in exchange for Apple Pay's payment request result.
+    /// - Parameters:
+    ///   - payment: Apple Pay's payment request result.
+    ///   - completion: The exchange operation result. In case of success, it returns the Payment Method Id or an error otherwise.
+    func getPaymentMethodId(from payment: PKPayment, _ completion: @escaping (Result<String, OSPMTError>) -> Void)
+}
+
+extension STPAPIClient: OSPMTStripeAPIDelegate {
+    /// Sets the required publishable key, required to trigger payments through Stripe
+    /// - Parameter publishableKey: Key obtained via Stripe's Dashboard.
+    func set(_ publishableKey: String) {
+        self.publishableKey = publishableKey
+    }
+
+    /// Retrieves Stripe's Payment Method's Identifier in exchange for Apple Pay's payment request result.
+    /// - Parameters:
+    ///   - payment: Apple Pay's payment request result.
+    ///   - completion: The exchange operation result. In case of success, it returns the Payment Method Id or an error otherwise.
+    func getPaymentMethodId(from payment: PKPayment, _ completion: @escaping (Result<String, OSPMTError>) -> Void) {
+        self.createPaymentMethod(with: payment) { paymentMethod, _ in
+            if let paymentMethod = paymentMethod {
+                completion(.success(paymentMethod.stripeId))
+            } else {
+                completion(.failure(.stripePaymentMethodCreation))
+            }
+        }
+    }
+}

OSPaymentsLib/Gateways/Stripe/OSPMTStripeRequestParametersModel.swift

@@ -0,0 +1,40 @@
+/// Model to manage Stripe's payment process request parameters. This is based on `OSPMTRequestParametersModel`.
+final class OSPMTStripeRequestParametersModel: OSPMTRequestParametersModel {
+    let paymentMethodId: String
+    let confirm: Bool
+
+    /// Keys used to encode and decode the model.
+    enum CodingKeys: String, CodingKey {
+        case paymentMethodId = "payment_method"
+        case confirm
+    }
+
+    /// Constructor method.
+    /// - Parameters:
+    ///   - amount: Amount to charge.
+    ///   - currency: Currency to charge.
+    ///   - paymentMethodId: Stripe object that represents the customer's payment instruments.
+    ///   - confirm: Automatically confirm the triggered payment process.
+    init(amount: Int, currency: String, paymentMethodId: String, confirm: Bool = true) {
+        self.paymentMethodId = paymentMethodId
+        self.confirm = confirm
+        super.init(amount: amount, currency: currency)
+    }
+
+    /// Encodes this value into the given encoder.
+    ///
+    /// If the value fails to encode anything, `encoder` will encode an empty
+    /// keyed container in its place.
+    ///
+    /// This function throws an error if any values are invalid for the given
+    /// encoder's format.
+    ///
+    /// - Parameter encoder: The encoder to write data to.
+    override func encode(to encoder: Encoder) throws {
+        var container = encoder.container(keyedBy: CodingKeys.self)
+
+        try container.encode(paymentMethodId, forKey: .paymentMethodId)
+        try container.encode(confirm, forKey: .confirm)
+        try super.encode(to: encoder)
+    }
+}

OSPaymentsLib/Gateways/Stripe/OSPMTStripeWrapper.swift

@@ -0,0 +1,44 @@
+import PassKit
+import StripeCore
+
+/// Object responsible for making a Stripe payment process. The Wrapper deals with all calls that are required to Stripe's SDK.
+final class OSPMTStripeWrapper: OSPMTGatewayDelegate {
+    var urlRequest: URLRequest
+    var urlSession: URLSession
+    let apiDelegate: OSPMTStripeAPIDelegate
+
+    /// Constructor method.
+    /// - Parameters:
+    ///   - urlRequest: URL load request object.
+    ///   - urlSession: Coordinator object for network data transfer tasks.
+    ///   - publishableKey: Key required for Stripe's API to trigger calls.
+    ///   - apiDelegate: Object responsible for Stripe's API calls.
+    init(urlRequest: URLRequest, urlSession: URLSession = .shared, publishableKey: String, apiDelegate: OSPMTStripeAPIDelegate = STPAPIClient.shared) {
+        self.urlRequest = urlRequest
+        self.urlSession = urlSession
+
+        apiDelegate.set(publishableKey)
+        self.apiDelegate = apiDelegate
+    }
+}
+
+extension OSPMTStripeWrapper {
+    /// Triggers the process through the configured gateway.
+    /// - Parameters:
+    ///   - payment: Apple Pay's payment request result.
+    ///   - details: Payment details to trigger processing.
+    ///   - completion: Payment process result. If returns the process result in case of success or an error otherwise.
+    func process(_ payment: PKPayment, with details: OSPMTDetailsModel, _ completion: @escaping (Result<OSPMTServiceProviderInfoModel, OSPMTError>) -> Void) {
+        self.apiDelegate.getPaymentMethodId(from: payment) { result in
+            switch result {
+            case .success(let paymentMethodId):
+                let requestParametersModel = OSPMTStripeRequestParametersModel(
+                    amount: details.paymentAmount.multiplying(by: 100).intValue, currency: details.currency, paymentMethodId: paymentMethodId
+                )
+                self.processURLRequest(requestParametersModel, completion)
+            case .failure(let error):
+                completion(.failure(error))
+            }
+        }
+    }
+}

OSPaymentsLib/Models/OSPMTConfigurationModel.swift

@@ -1,6 +1,43 @@
 import PassKit
 
-/// Protocol that contains all properties needed to configure a payment service.
+/// Model that manages the Payment Service Provider's configuration.
+struct OSPMTGatewayModel: Encodable {
+    let gateway: String
+    let publishableKey: String?
+    let requestURL: String
+
+    /// Keys used to encode and decode the model.
+    enum CodingKeys: String, CodingKey {
+        case gateway
+        case publishableKey
+        case requestURL
+    }
+
+    /// Encodes this value into the given encoder.
+    ///
+    /// If the value fails to encode anything, `encoder` will encode an empty
+    /// keyed container in its place.
+    ///
+    /// This function throws an error if any values are invalid for the given
+    /// encoder's format.
+    ///
+    /// - Parameter encoder: The encoder to write data to.
+    func encode(to encoder: Encoder) throws {
+        var container = encoder.container(keyedBy: CodingKeys.self)
+
+        try container.encode(gateway, forKey: .gateway)
+        try container.encodeIfPresent(publishableKey, forKey: .publishableKey)
+        try container.encode(requestURL, forKey: .requestURL)
+    }
+}
+
+extension OSPMTGatewayModel {
+    var gatewayEnum: OSPMTGateway? {
+        return OSPMTGateway.convert(from: self.gateway)
+    }
+}
+
+/// Model that contains all properties needed to configure a payment service.
 class OSPMTConfigurationModel: Encodable {
     // MARK: Merchant Information
     var merchantID: String?
@@ -18,6 +55,9 @@ class OSPMTConfigurationModel: Encodable {
     // MARK: Billing Information
     var billingSupportedContacts: [String]?
 
+    // MARK: Payment Service Provider Information
+    var gatewayModel: OSPMTGatewayModel?
+
     /// Keys used to encode and decode the model.
     enum CodingKeys: String, CodingKey {
         case merchantID
@@ -28,6 +68,7 @@ class OSPMTConfigurationModel: Encodable {
         case paymentSupportedCardCountries
         case shippingSupportedContacts
         case billingSupportedContacts
+        case gatewayModel = "tokenization"
     }
 
     /// Constructor method.
@@ -40,7 +81,18 @@ class OSPMTConfigurationModel: Encodable {
     ///   - paymentSupportedCardCountries: Payment Support Card Countries configured
     ///   - shippingSupportedContacts: Shipping Supported Contacts configured
     ///   - billingSupportedContacts: Billing Supported Contacts configured
-    init(merchantID: String?, merchantName: String?, merchantCountryCode: String?, paymentAllowedNetworks: [String]?, paymentSupportedCapabilities: [String]?, paymentSupportedCardCountries: [String]?, shippingSupportedContacts: [String]?, billingSupportedContacts: [String]?) {
+    ///   - tokenization: Payment Service Gateway configured
+    init(
+        merchantID: String?,
+        merchantName: String?,
+        merchantCountryCode: String?,
+        paymentAllowedNetworks: [String]?,
+        paymentSupportedCapabilities: [String]?,
+        paymentSupportedCardCountries: [String]?,
+        shippingSupportedContacts: [String]?,
+        billingSupportedContacts: [String]?,
+        gatewayModel: OSPMTGatewayModel?
+    ) {
         self.merchantID = merchantID
         self.merchantName = merchantName
         self.merchantCountryCode = merchantCountryCode
@@ -49,6 +101,7 @@ class OSPMTConfigurationModel: Encodable {
         self.paymentSupportedCardCountries = paymentSupportedCardCountries
         self.shippingSupportedContacts = shippingSupportedContacts
         self.billingSupportedContacts = billingSupportedContacts
+        self.gatewayModel = gatewayModel
     }
 
     /// Encodes this value into the given encoder.
@@ -78,6 +131,9 @@ class OSPMTConfigurationModel: Encodable {
 
         // MARK: Billing Information
         try container.encodeIfPresent(billingSupportedContacts, forKey: .billingSupportedContacts)
+
+        // MARK: Payment Service Provider Information
+        try container.encodeIfPresent(gatewayModel, forKey: .gatewayModel)
     }
 }
 
@@ -97,6 +153,11 @@ class OSPMTApplePayConfiguration: OSPMTConfigurationModel {
         static let shippingSupportedContacts = "ApplePayShippingSupportedContacts"
 
         static let billingSupportedContacts = "ApplePayBillingSupportedContacts"
+
+        static let paymentGateway = "ApplePayPaymentGateway"
+        static let paymentGatewayName = "ApplePayPaymentGatewayName"
+        static let paymentRequestURL = "ApplePayRequestURL"
+        static let stripePublishableKey = "ApplePayStripePublishableKey"
     }
 
     /// Constructor method.
@@ -120,6 +181,15 @@ class OSPMTApplePayConfiguration: OSPMTConfigurationModel {
         // MARK: Billing Information
         let billingSupportedContacts: [String]? = Self.getProperty(forSource: source, andKey: ConfigurationKeys.billingSupportedContacts)
 
+        // MARK: Payment Service Provider Information
+        var gatewayModel: OSPMTGatewayModel?
+        if let providerGateway: [String: Any] = Self.getProperty(forSource: source, andKey: ConfigurationKeys.paymentGateway),
+            let providerGatewayName = providerGateway[ConfigurationKeys.paymentGatewayName] as? String,
+            let requestURL = providerGateway[ConfigurationKeys.paymentRequestURL] as? String {
+            let publishableKey = providerGateway[ConfigurationKeys.stripePublishableKey] as? String
+            gatewayModel = OSPMTGatewayModel(gateway: providerGatewayName, publishableKey: publishableKey, requestURL: requestURL)
+        }
+
         self.init(
             merchantID: merchantID,
             merchantName: merchantName,
@@ -128,7 +198,8 @@ class OSPMTApplePayConfiguration: OSPMTConfigurationModel {
             paymentSupportedCapabilities: paymentSupportedCapabilities,
             paymentSupportedCardCountries: paymentSupportedCardCountries,
             shippingSupportedContacts: shippingSupportedContacts,
-            billingSupportedContacts: billingSupportedContacts
+            billingSupportedContacts: billingSupportedContacts,
+            gatewayModel: gatewayModel
         )
     }
 }