LINE Notify を iOS から使ってみる

ViewController.swift

//
//  ViewController.swift
//

import UIKit

class ViewController: UIViewController {
    typealias VC = ViewController
    private static let MyHost = "https://example.com"
    private static let BotHost = "https://notify-bot.line.me"
    private static let ApiHost = "https://notify-api.line.me"
    private static let TokenPath = "/oauth/token"
    private static let GrantType = "authorization_code"
    private static let RedirectUri = "\(MyHost)/callback/"
    private static let ClientId = "YourClientId"
    private static let ClientSecret = "YourClientSecret"
    private static let GetAccessTokenUrlFormat = "\(VC.BotHost)\(VC.TokenPath)?grant_type=\(VC.GrantType)&code=%@&redirect_uri=\(VC.RedirectUri)&client_id=\(VC.ClientId)&client_secret=\(VC.ClientSecret)"
    private static let NotifyPath = "/api/notify"
    private static let PostMessageUrlFormat = "\(VC.ApiHost)\(VC.NotifyPath)?message=%@"

    @IBOutlet weak var button: PrimaryButton!
    private var accessToken: String? = nil {
        didSet {
            let title = accessToken == nil ? "WebViewを開く" : "テストメッセージ送信"
            button.setTitle(title, for: .normal)
        }
    }
    
    override func viewDidLoad() {
        super.viewDidLoad()
        title = "Gome"
        accessToken = UserDefaults.standard.string(forKey: "AccessToken")
    }

    /**
     ボタンタップ
     */
    @IBAction func didTapButton(_ sender: Any) {
        if let accessToken = accessToken {
            presentPostMessageAlert(accessToken)
        } else {
            openWebView()
        }
    }
    
    /**
     WebViewを開く
     */
    private func openWebView() {
        let webVC = WebViewController(VC.MyHost) { [weak self] url, vc in
            guard url.contains(VC.RedirectUri + "?code=") else { return }
            vc.dismissViewController()
            guard let comp = NSURLComponents(string: url) else { return }
            let c = comp.queryItems?.filter { $0.name == "code" }.first?.value
            guard let code = c else { NSLog("code is nil."); return }
            self?.getAccessToken(code) { token in
                guard let token = token else { NSLog("token is nil."); return }
                self?.presentAlertViewController("アクセストークンの取得に成功しました。")
                self?.accessToken = token
                UserDefaults.standard.set(token, forKey: "AccessToken")
            }
        }
        present(webVC.withNavigationController(true, "Login"), animated: true, completion: nil)
    }
    
    /**
     メッセージ送信用アラートを表示
     */
    private func presentPostMessageAlert(_ accessToken: String) {
        presentAlertViewController("メッセージを送信します。", nil, okHandler: { [weak self] textFiled in
            guard let message = textFiled?.text else {
                self?.presentErrorAlertViewController("メッセージが入力されていません")
                return
            }
            guard let msg = message.addingPercentEncoding(withAllowedCharacters: CharacterSet.urlQueryAllowed) else {
                return
            }
            self?.postMessage(accessToken, msg) { [weak self] e in e == nil ? self?.presentAlertViewController("メッセージの送信に成功") : NSLog("error=\(e)") }
        })
    }
    
    /**
     AccessToken を取得します
     */
    private func getAccessToken(_ code: String, _ callback: @escaping ((String?) -> ())) {
        let url = NSString(format: VC.GetAccessTokenUrlFormat as NSString, code) as String
        post(url, nil) { d, r, e in
            if let e = e { NSLog("error=\(e)"); callback(nil); return }
            guard let d = d else { callback(nil); return }
            let result = NSString(data: d, encoding: String.Encoding.utf8.rawValue)!
            NSLog("result=\(result)")
            guard let data = result.data(using: String.Encoding.utf8.rawValue) else { callback(nil); return }
            guard let json = try? JSONSerialization.jsonObject(with: data) as? [String: Any] else { callback(nil); return }
            guard let accessToken = json?["access_token"] as? String else { NSLog("access_token is nil."); callback(nil); return }
            callback(accessToken)
        }
    }

    /**
     Message を送信します
     */
    private func postMessage(_ accessToken: String, _ message: String, callback: @escaping (Error?) -> ()) {
        let url = NSString(format: VC.PostMessageUrlFormat as NSString, message) as String
        let header = ["Authorization": "Bearer \(accessToken)"]
        post(url, header) { d, r, e in
            print("d=\(d), e=\(e), e=\(e)")
            callback(e)
        }
    }
    
    /**
     POST リクエストを送信します
     */
    private func post(_ url: String, _ headers: [String: String]?, completionHandler: @escaping (Data?, URLResponse?, Error?) -> ()) {
        let request = NSMutableURLRequest(url: URL(string: url)!)
        headers?.forEach { request.addValue($0.value, forHTTPHeaderField: $0.key) }
        request.httpMethod = "POST"
        let task = URLSession.shared.dataTask(with: request as URLRequest) { data, responce, error in
            DispatchQueue.main.async() { completionHandler(data, responce, error) }
        }
        task.resume()
    }
}