Time-Based Trial App Licensing

Adds time-based trial and easy license verification using CocoaFob to your macOS app.

For setup instructions of your own store and app preparation with FastSpring, have a look at my book Make Money Outside the Mac App Store!

Installation

Swift Package Manager

dependencies: [
  .package(url: "https://github.com/CleanCocoa/TrialLicensing.git", .upToNextMajor(from: Version(3, 0, 0))),
]

Add package depencency via Xcode by using this URL: https://github.com/CleanCocoa/TrialLicensing.git

CocoaFob is automatically linked statically for you, no need to do anything.

Carthage

Include the Trial and TrialLicense libraries in your project.
Include the CocoaFob (Swift 5) library in your project, too. (You have to link this in the app because a library cannot embed another library.)

Usage

Create an AppLicensing instance with licenseChangeBlock and invalidLicenseInformationBlock handling change events.
Set up and start the trial.

Example:

import TrialLicense

let publicKey = [
        "-----BEGIN DSA PUBLIC KEY-----\n",
        // ...
        "-----END DSA PUBLIC KEY-----\n"
    ].join("")
let configuration = LicenseConfiguration(appName: "AmazingApp!", publicKey: publicKey)

class MyApp: AppLicensingDelegate {

    init() {

        AppLicensing.setUp(
            configuration: configuration,
            initialTrialDuration: Days(30),

            // Set up the callbacks:
            licenseChangeBlock: self.licenseDidChange(licenseInfo:),
            invalidLicenseInformationBlock: self.didEnterInvalidLicenseCode(name:licenseCode:),

            // Get notified about initial state to unlock the app immediately:
            fireInitialState: true)
    }

    func licenseDidChange(licenseInformation: LicenseInformation) {

        switch licenseInformation {
        case .onTrial(_):
            // Changing back to trial may be possible if you support unregistering
            // form the app (and the trial period is still good.)
            return

        case .registered(_):
            // For example:
            //   displayThankYouAlert()
            //   unlockApp()

        case .trialUp:
            // For example:
            //   displayTrialUpAlert()
            //   lockApp()
            //   showRegisterApp()
        }
    }

    func didEnterInvalidLicenseCode(name: String, licenseCode: String) {

        // For example:
        //   displayInvalidLicenseAlert()
        // -- or show an error label in the license window.
    }
}

let myApp = MyApp()

Privacy Manifest

The package declares usage of UserDefaults API because it ships with these mechanisms to read/write information in principle. That's it.

If you use this to store actual customer names and/or email addresses in your app, depending on the licensing scheme you use, you should check that your app has a NSPrivacyCollectedDataTypes entry with e.g. a value of NSPrivacyCollectedDataTypeEmailAddress.

Components

LicenseInformation reveals the state your app is in:

enum LicenseInformation {
    case registered(License)
    case onTrial(TrialPeriod)
    case trialUp
}

The associated types provide additional information, for example to display details in a settings window or show remaining trial days in the title bar of your app.

License represents a valid name--license code pair:

struct License {
    let name: String
    let licenseCode: String
}

TrialPeriod encapsulates the duration of the trial.

struct TrialPeriod {
    let startDate: Date
    let endDate: Date
}

TrialPeriod also provides these convenience methods:

ended() -> Bool
daysLeft() -> Days

... where Days encapsulates the remainder for easy conversion to TimeInterval and exposing userFacingAmount: Int for display.

mattrmiller/TrialLicensing