从iOS应用访问Google日历

这次，我想通过Google Calenear API从iOS应用访问Google日历。

环境：Xcode 12.0，Swift 5

准备

首先，转到Google Cloud Platform并启用Google Calendar API。
接下来，获取用于OAuth身份验证的OAuth客户端ID。
请按照以下文章中的"注册客户端ID"中所述的过程来申请客户端ID。

我尝试使用Swift 4击中Google Calendar API

使用的外部库

Google API本身是REST API，但是很难直接调用它，因此我将使用一个外部库。
这次，我们将使用以下库。

？Google身份验证
AppAuth
GTMAppAuth

？使用Google日历访问
GoogleAPIClientForREST /日历

以上所有库都可以与CocoaPods一起安装。
如下所示编写Podfile并执行pod install进行安装。

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platform :ios, '14.0'

target 'GoogleCalendarSample' do
use_frameworks!

pod 'AppAuth'
pod 'GTMAppAuth'
pod 'GoogleAPIClientForREST/Calendar'

end

验证

实现使用AppAuth和GTMAppAuth执行Google身份验证的过程。

首先，将OIDExternalUserAgentSession类添加到AppDelegate。

AppDelegate.swift

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import UIKit
import AppAuth
import GTMAppAuth

@main
class AppDelegate: UIResponder, UIApplicationDelegate {
var currentAuthorizationFlow: OIDExternalUserAgentSession?

---------------- (以下略) ----------------

然后在屏幕上描述用于Google身份验证的以下过程。

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import UIKit
import AppAuth
import GTMAppAuth
import GoogleAPIClientForREST

---------------- (中略) ----------------

private var authorization: GTMAppAuthFetcherAuthorization?
private let clientID = "xxxxxxxxxxxxxxxxxxxx"
private let reverseClientID = "xxxxxxxxxxxxxxxxxxxx"
typealias showAuthorizationDialogCallBack = ((Error?) -> Void)

private func showAuthorizationDialog(callBack: @escaping showAuthorizationDialogCallBack) {
let scopes = ["https://www.googleapis.com/auth/calendar","https://www.googleapis.com/auth/calendar.readonly","https://www.googleapis.com/auth/calendar.events","https://www.googleapis.com/auth/calendar.events.readonly"]

let configuration = GTMAppAuthFetcherAuthorization.configurationForGoogle()
let redirectURL = URL.init(string: reverseClientID + ":/oauthredirect")

let request = OIDAuthorizationRequest.init(configuration: configuration,
clientId: clientID,
scopes: scopes,
redirectURL: redirectURL!,
responseType: OIDResponseTypeCode,
additionalParameters: nil)

let appDelegate: AppDelegate = UIApplication.shared.delegate as! AppDelegate
appDelegate.currentAuthorizationFlow = OIDAuthState.authState(
byPresenting: request,
presenting: self,
callback: { (authState, error) in
if let error = error {
NSLog("\(error)")
} else {
if let authState = authState {
self.authorization = GTMAppAuthFetcherAuthorization.init(authState: authState)
GTMAppAuthFetcherAuthorization.save(self.authorization!, toKeychainForName: "authorization")
}
}
callBack(error)
})
}

以下变量描述了获得OAuth客户端ID时获得的ID。
在clientID中输入OAuth 2.0客户端ID，在reverseClientID中输入反向客户端ID。

1 2	private let clientID = "xxxxxxxxxxxxxxxxxxxx" private let reverseClientID = "xxxxxxxxxxxxxxxxxxxx"

这次将所需权限设置为数组作用域。这次，我们正在请求搜索和更改Google日历的权限。

1	let scopes = ["https://www.googleapis.com/auth/calendar","https://www.googleapis.com/auth/calendar.readonly","https://www.googleapis.com/auth/calendar.events","https://www.googleapis.com/auth/calendar.events.readonly"]

当执行OIDAuthState类的authState方法时，将显示以下Google身份验证对话框。
Google認証ダイアログ
如果用户在对话框中正确输入了gmail地址和密码，并且身份验证完成，则authState方法的回调函数将生成并保存GTMAppAuthFetcherAuthorization类。
在保留此GTMAppAuthFetcherAuthorization类的同时，无需重新显示身份验证对话框。

搜索事件

在

中，我想继续使用GoogleAPIClientForREST访问Google日历。
首先，我将描述从Google日历获取现有事件的过程。
如果将开始日期和时间以及结束日期和时间传递给get方法，则该程序会从Google日历中搜索开始日期和时间以及结束日期和时间之间的事件。

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import UIKit
import AppAuth
import GTMAppAuth
import GoogleAPIClientForREST

---------------- (中略) ----------------

private var authorization: GTMAppAuthFetcherAuthorization?
private let clientID = "xxxxxxxxxxxxxxxxxxxx"
private let reverseClientID = "xxxxxxxxxxxxxxxxxxxx"
typealias showAuthorizationDialogCallBack = ((Error?) -> Void)
struct GoogleCalendaraEvent {
var id: String
var name: String
var startDate: Date?
var endDate: Date?
}
private var googleCalendarEventList: [GoogleCalendaraEvent] = []

private func showAuthorizationDialog(callBack: @escaping showAuthorizationDialogCallBack) {
---------------- (中略) ----------------
}

private func get(startDateTime: Date, endDateTime: Date) {
if GTMAppAuthFetcherAuthorization(fromKeychainForName: "authorization") != nil {
self.authorization = GTMAppAuthFetcherAuthorization(fromKeychainForName: "authorization")!
}

if self.authorization == nil {
showAuthorizationDialog(callBack: {(error) -> Void in
if error == nil {
self.getCalendarEvents(startDateTime: startDateTime, endDateTime: endDateTime)
}
})
} else {
self.getCalendarEvents(startDateTime: startDateTime, endDateTime: endDateTime)
}
}

private func getCalendarEvents(startDateTime: Date, endDateTime: Date) {
let calendarService = GTLRCalendarService()
calendarService.authorizer = self.authorization
calendarService.shouldFetchNextPages = true

let query = GTLRCalendarQuery_EventsList.query(withCalendarId: "primary")
query.timeMin = GTLRDateTime(date: startDateTime)
query.timeMax = GTLRDateTime(date: endDateTime)

calendarService.executeQuery(query, completionHandler: { (ticket, event, error) -> Void in
if let error = error {
NSLog("\(error)")
} else {
if let event = event as? GTLRCalendar_Events, let items = event.items {
self.googleCalendarEventList.removeAll()
for item in items {
let id: String = item.identifier ?? ""
let name: String = item.summary ?? ""
let startDate: Date? = item.start?.dateTime?.date
let endDate: Date? = item.end?.dateTime?.date
self.googleCalendarEventList.append(GoogleCalendaraEvent(id: id, name: name, startDate: startDate, endDate: endDate))
}
}
}
})
}

首先，检查Goole身份验证是否完成。
检查是否已保存GTMAppAuthFetcherAuthorization类，如果未保存，请调用先前创建的showAuthorizationDialog函数以显示Google身份验证对话框并获取GTMAppAuthFetcherAuthorization类。
如果保存了GTMAppAuthFetcherAuthorization类，请按原样使用它。

然后使用GoogleAPIClientForREST从Googl日历获取事件。
首先，生成GTLRCalendarService类以访问Goole日历，并在authorizer属性中设置GTMAppAuthFetcherAuthorization类。

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let calendarService = GTLRCalendarService()
calendarService.authorizer = self.authorization
calendarService.shouldFetchNextPages = true

接下来，生成GTLRCalendarQuery_EventsList类以从Google日历中搜索事件，并将开始日期和时间以及结束日期和时间设置为搜索条件。

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let query = GTLRCalendarQuery_EventsList.query(withCalendarId: "primary")
query.timeMin = GTLRDateTime(date: startDateTime)
query.timeMax = GTLRDateTime(date: endDateTime)

然后，以该GTLRCalendarQuery_EventsList类作为参数，执行GTLRCalendarService类的executeQuery方法以从Google日历获取事件。
当可以获取事件时，executeQuery方法的Callback函数将返回GTLRCalendar_Events类，因此将从此处获取事件信息。

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if let event = event as? GTLRCalendar_Events, let items = event.items {
self.googleCalendarEventList.removeAll()
for item in items {
let id: String = item.identifier ?? ""
let name: String = item.summary ?? ""
let startDate: Date? = item.start?.dateTime?.date
let endDate: Date? = item.end?.dateTime?.date
self.googleCalendarEventList.append(GoogleCalendaraEvent(id: id, name: name, startDate: startDate, endDate: endDate))
}
}

特别是标识符(事件的唯一ID)很重要。
更改或删除事件时，此标识符是关键。

新增活动

接下来，我想在

中向Google日历添加事件。
它是通过将事件名称，开始日期和时间以及结束日期和时间传递给add方法在Google日历中创建事件的程序。

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import UIKit
import AppAuth
import GTMAppAuth
import GoogleAPIClientForREST

---------------- (中略) ----------------

private var authorization: GTMAppAuthFetcherAuthorization?
typealias showAuthorizationDialogCallBack = ((Error?) -> Void)

private func showAuthorizationDialog(callBack: @escaping showAuthorizationDialogCallBack) {
---------------- (中略) ----------------
}

private func add(eventName: String, startDateTime: Date, endDateTime: Date) {

if GTMAppAuthFetcherAuthorization(fromKeychainForName: "authorization") != nil {
self.authorization = GTMAppAuthFetcherAuthorization(fromKeychainForName: "authorization")!
}

if self.authorization == nil {
showAuthorizationDialog(callBack: {(error) -> Void in
if error == nil {
self.addCalendarEvent(eventName: eventName, startDateTime: startDateTime, endDateTime: endDateTime)
}
})
} else {
self.addCalendarEvent(eventName: eventName, startDateTime: startDateTime, endDateTime: endDateTime)
}
}

private func addCalendarEvent(eventName: String, startDateTime: Date, endDateTime: Date) {

let calendarService = GTLRCalendarService()
calendarService.authorizer = self.authorization
calendarService.shouldFetchNextPages = true

let event = GTLRCalendar_Event()
event.summary = eventName

let gtlrDateTimeStart: GTLRDateTime = GTLRDateTime(date: startDateTime)
let startEventDateTime: GTLRCalendar_EventDateTime = GTLRCalendar_EventDateTime()
startEventDateTime.dateTime = gtlrDateTimeStart
event.start = startEventDateTime

let gtlrDateTimeEnd: GTLRDateTime = GTLRDateTime(date: endDateTime)
let endEventDateTime: GTLRCalendar_EventDateTime = GTLRCalendar_EventDateTime()
endEventDateTime.dateTime = gtlrDateTimeEnd
event.end = endEventDateTime

let query = GTLRCalendarQuery_EventsInsert.query(withObject: event, calendarId: "primary")
calendarService.executeQuery(query, completionHandler: { (ticket, event, error) -> Void in
if let error = error {
NSLog("\(error)")
}
})
}

生成GTLRCalendarService类的过程与搜索时的过程相同，因此我们将在后续部分中进行说明。
生成GTLRCalendar_Event类以设置要添加的事件的信息。
这次，设置了事件名称，开始日期和时间以及结束日期和时间，因此在GTLRCalendar_Event类的summary属性，start属性和end属性中进行了设置。

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let event = GTLRCalendar_Event()
event.summary = eventName

let gtlrDateTimeStart: GTLRDateTime = GTLRDateTime(date: startDateTime)
let startEventDateTime: GTLRCalendar_EventDateTime = GTLRCalendar_EventDateTime()
startEventDateTime.dateTime = gtlrDateTimeStart
event.start = startEventDateTime

let gtlrDateTimeEnd: GTLRDateTime = GTLRDateTime(date: endDateTime)
let endEventDateTime: GTLRCalendar_EventDateTime = GTLRCalendar_EventDateTime()
endEventDateTime.dateTime = gtlrDateTimeEnd
event.end = endEventDateTime

另外，在添加新事件的情况下，成为事件唯一ID的标识符由Google日历自动分配，因此无需在此处进行设置。

然后，以GTLRCalendar_Event类作为参数，生成一个GTLRCalendarQuery_EventsInsert类以添加到Google日历，并执行GTLRCalendarService类的executeQuery方法将一个新事件添加到Google Calendar。

活动变更

接下来，让我们更改现有事件的信息。
当将事件标识符，事件名称，开始日期和时间，结束日期和时间传递给更新方法时，该程序会更改Google日历中相应标识符的事件信息。

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import UIKit
import AppAuth
import GTMAppAuth
import GoogleAPIClientForREST

---------------- (中略) ----------------

private var authorization: GTMAppAuthFetcherAuthorization?
typealias showAuthorizationDialogCallBack = ((Error?) -> Void)

private func showAuthorizationDialog(callBack: @escaping showAuthorizationDialogCallBack) {
---------------- (中略) ----------------
}

private func update(eventId: String, eventName: String, startDateTime: Date, endDateTime: Date) {

if GTMAppAuthFetcherAuthorization(fromKeychainForName: "authorization") != nil {
self.authorization = GTMAppAuthFetcherAuthorization(fromKeychainForName: "authorization")!
}

if self.authorization == nil {
showAuthorizationDialog(callBack: {(error) -> Void in
if error == nil {
self.updateCalendarEvent(eventId: eventId, eventName: eventName, startDateTime: startDateTime, endDateTime: endDateTime)
}
})
} else {
self.updateCalendarEvent(eventId: eventId, eventName: eventName, startDateTime: startDateTime, endDateTime: endDateTime)
}
}

private func updateCalendarEvent(eventId: String, eventName: String, startDateTime: Date, endDateTime: Date) {
let calendarService = GTLRCalendarService()
calendarService.authorizer = self.authorization
calendarService.shouldFetchNextPages = true

let event = GTLRCalendar_Event()
event.identifier = eventId
event.summary = eventName

let gtlrDateTimeStart: GTLRDateTime = GTLRDateTime(date: startDateTime)
let startEventDateTime: GTLRCalendar_EventDateTime = GTLRCalendar_EventDateTime()
startEventDateTime.dateTime = gtlrDateTimeStart
event.start = startEventDateTime

let gtlrDateTimeEnd: GTLRDateTime = GTLRDateTime(date: endDateTime)
let endEventDateTime: GTLRCalendar_EventDateTime = GTLRCalendar_EventDateTime()
endEventDateTime.dateTime = gtlrDateTimeEnd
event.end = endEventDateTime

let query = GTLRCalendarQuery_EventsUpdate.query(withObject: event, calendarId: "primary", eventId: eventId)
calendarService.executeQuery(query, completionHandler: { (ticket, event, error) -> Void in
if let error = error {
NSLog("\(error)")
}
})
}

对于

更新，请在GTLRCalendar_Event类的identifier属性中设置相应事件的ID。然后，将要更改的值设置为GTLRCalendar_Event类的属性。
之后，生成GTLRCalendarQuery_EventsUpdate类以GTLRCalendar_Event类作为参数来更新Google日历事件，并以GTLRCalendarService类的executeQuery方法作为参数。

删除活动

最后，删除Google日历中的事件。
当事件的标识符传递给delete方法时，该程序将从Google日历中删除相应的事件。

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import UIKit
import AppAuth
import GTMAppAuth
import GoogleAPIClientForREST

---------------- (中略) ----------------

private var authorization: GTMAppAuthFetcherAuthorization?
typealias showAuthorizationDialogCallBack = ((Error?) -> Void)

private func showAuthorizationDialog(callBack: @escaping showAuthorizationDialogCallBack) {
---------------- (中略) ----------------
}

private func delete(eventId: String) {

if GTMAppAuthFetcherAuthorization(fromKeychainForName: "authorization") != nil {
self.authorization = GTMAppAuthFetcherAuthorization(fromKeychainForName: "authorization")!
}

if self.authorization == nil {
showAuthorizationDialog(callBack: {(error) -> Void in
if error == nil {
self.deleteCalendarEvent(eventId: eventId)
}
})
} else {
self.deleteCalendarEvent(eventId: eventId)
}
}

private func deleteCalendarEvent(eventId: String) {
let calendarService = GTLRCalendarService()
calendarService.authorizer = self.authorization
calendarService.shouldFetchNextPages = true

let query = GTLRCalendarQuery_EventsDelete.query(withCalendarId: "primary", eventId: eventId)
calendarService.executeQuery(query, completionHandler: { (ticket, event, error) -> Void in
if let error = error {
NSLog("\(error)")
}
})
}

删除可以通过生成以事件标识符为参数的GTLRCalendarQuery_EventsDelete类并以GTLRCalendarService的executeQuery方法为参数来完成。

样例程序

这次创建的示例程序可在GitHub上找到。
https://github.com/naosekig/GoogleCalendarSample

参考

CocoaDocs.org --GoogleAPIClientForRest
Qiita：我尝试使用Swift 4

击中Google Calendar API