利用iTunes接口检查是否有更新

CheckVersion.swift

 func isLatest(id: String, callback: @escaping (Bool?, Error?) -> Void) {
        var components = URLComponents(string: "http://itunes.apple.com/lookup")
        components?.queryItems = [URLQueryItem(name: "id", value: id)]
        var request = URLRequest(url: (components?.url!)!)
        request.httpMethod = "POST"
        let task = URLSession.shared.dataTask(with: request) { (data, _, error) in
            guard error == nil else {
                callback(nil, error)
                return
            }
            do {
                let resp = try JSONSerialization.jsonObject(with: data!, options: .allowFragments) as? [String:Any]
                let results = resp?["results"] as? [[String : Any]]
                if let version = results?.first?["version"] as? String,
                    let currentVersion = Bundle.main.infoDictionary?["CFBundleShortVersionString"] as? String {
                    var component: Int = 0
                    let currComponents = currentVersion.components(separatedBy: ".")
                    let remoteComponents = version.components(separatedBy: ".")
                    var ret = false
                    for (index, digit) in remoteComponents.enumerated() {
                        if index < currComponents.count - 1 {
                            let cur = currComponents[index]
                            if digit > cur {
                                ret = true
                                break
                            }
                        }
                    }
                    callback(ret, nil)
                } else {
                    callback(false, nil)
                }
            } catch(let e) {
                callback(nil, e)
            }
        }
        task.resume()
    }