The Question Mark - blog by Mark Volkmann

Overview

It is possible to determine a lot of information about an app from its bundle and from the App Store (for released apps).

AppInfo struct

The following code gathers information about an app and makes it available through computed properties.

import Foundation

struct AppInfo {
    static let infoDict = Bundle.main.infoDictionary!

    var json: [String: Any] = [:]

    private init(json: [String: Any]) {
        // print("json =", json)
        self.json = json
    }

    static func create() async throws -> Self {
        let urlPrefix = "https://itunes.apple.com/lookup?bundleId="
        let identifier = infoDict["CFBundleIdentifier"] as? String ?? ""
        let url = URL(string: "\(urlPrefix)\(identifier)&country=US")
        guard let url else {
            throw "AppStoreService: bad URL \(String(describing: url))"
        }

        // Using the ephemeral configuration avoids caching.
        let session = URLSession(configuration: .ephemeral)
        let (data, _) = try await session.data(from: url)
        guard let json = try JSONSerialization.jsonObject(
            with: data,
            options: [.allowFragments]
        ) as? [String: Any] else {
            throw "AppStoreService: bad JSON"
        }

        guard let results =
            (json["results"] as? [Any])?.first as? [String: Any] else {
            throw "AppStoreService: JSON missing results"
        }

        return Self(json: results)
    }

    private func date(_ key: String) -> Date {
        json[key] as? Date ?? Date()
    }

    private func double(_ key: String) -> Double {
        json[key] as? Double ?? 1.2 // 0
    }

    private func info(_ key: String) -> String {
        Self.infoDict[key] as? String ?? ""
    }

    private func int(_ key: String) -> Int {
        json[key] as? Int ?? 0
    }

    private func string(_ key: String) -> String {
        json[key] as? String ?? ""
    }

    var appId: Int { int("trackId") }
    var appURL: String { string("trackViewUrl") }
    var author: String { string("sellerName") }
    var bundleId: String { string("bundleId") }
    var description: String { string("description") }
    var iconURL: String { string("artworkUrl100") }
    var supportURL: String { string("sellerUrl") }

    var haveLatestVersion: Bool {
        let order = storeVersion.compare(installedVersion, options: .numeric)
        return order != .orderedDescending
    }

    var installedVersion: String { info("CFBundleShortVersionString") }
    var identifier: String { info("CFBundleIdentifier") }
    var minimumOsVersion: String { string("minimumOsVersion") }
    var name: String { string("trackName") }
    // "Promotional Text" is not present in the App Store JSON.
    var price: Double { double("price") }
    var releaseDate: Date { date("currentVersionReleaseDate") }
    var releaseNotes: String { string("releaseNotes") }
    var storeVersion: String { string("version") }
}

Creating Instance

The following code gets an instance of AppInfo in a SwiftUI view:

@State private var appInfo: AppInfo?

...

.task {
    do {
        appInfo = try await AppInfo.create()
    } catch {
        print("Error getting AppInfo:", error)
    }
}

Link to Help

The following code uses AppInfo to add a help button to the navigation bar. Tapping this opens the app support page in Safari.

.toolbar {
    ToolbarItem(placement: .navigationBarTrailing) {
        if let appInfo {
            Link(destination: URL(string: appInfo.supportURL)!) {
                Image(systemName: "questionmark.circle")
            }
        }
    }
}

Link to App Store

The following code uses AppInfo to inform users when a newer version of the app is available in App Store and provides a link that directs them to the App Store so it can be installed.

if let appInfo,
    !appInfo.haveLatestVersion,
    let url = URL(string: appInfo.appURL) {
    Link("Update Available", destination: url)
}