在MailKit中使用GMail OAuth2.0进行身份验证的正确方法是什么？

Question

我正在尝试使用Mailkit从我的Gmail中获取电子邮件：

private readonly string[] Scopes = { GmailService.Scope.GmailReadonly };
    private UserCredential GetGmailCredential()
    {
        UserCredential credential;
        using (var stream = new FileStream("client_id.json", FileMode.Open, FileAccess.Read))
        {
            // The file token.json stores the user's access and refresh tokens, and is created
            // automatically when the authorization flow completes for the first time.
            string credPath = "token.json";
            credential = GoogleWebAuthorizationBroker.AuthorizeAsync(
                GoogleClientSecrets.Load(stream).Secrets,
                Scopes,
                "user",
                CancellationToken.None,
                new FileDataStore(credPath, true),
                new LocalServerCodeReceiver()).Result;
            Console.WriteLine($"Credential file saved to: {credPath}");
        }

        return credential;
    }

    [HttpGet("check")]
    public string GetD()
    {
        using (var client = new ImapClient())
        {
            client.Connect("imap.gmail.com", 993, SecureSocketOptions.SslOnConnect);
            UserCredential credential = GetGmailCredential();
            //var oauth2 = new SaslMechanismOAuth2("[email protected]", credential.Token.AccessToken);
            var oauth2 = new SaslMechanismOAuth2("myaccount008",credential.Token.AccessToken);
            client.Authenticate(oauth2);
            client.Inbox.Open(FolderAccess.ReadOnly);

            var uids = client.Inbox.Search(SearchQuery.FromContains("bill"));
            string subjects = string.Empty;

            foreach (var uid in uids)
            {
                var message = client.Inbox.GetMessage(uid);
                subjects += message.Subject + Environment.NewLine;
                // write the message to a file
                message.WriteTo(string.Format("{0}.eml", uid));
            }

            client.Disconnect(true);
            return subjects;
        }
    }

行：client.Authenticate（oauth2）;抛出异常->

MailKit.Security.AuthenticationException

我遵循此answer来设置我的Gmail API，但随后出现“身份验证失败”问题。

更新1

这里是日志：

已连接至imaps：//imap.gmail.com：993 / S：* OK已准备好Gimap来自122.199.45.135的请求d3mb920463124pjs C：A00000000功能S：*功能IMAP4rev1取消选择空闲名称空间配额ID XLIST儿童X-GM-EXT-1 XYZZY SASL-IR AUTH = XOAUTH2 AUTH = PLAINAUTH = PLAIN-CLIENTTOKEN AUTH = OAUTHBEARER AUTH = XOAUTH S：A00000000 OK那就是她写的全部！ d3mb920463124pjs C：A00000001认证XOAUTH2dXNlcj1mcmFudmEwMDhAZ21haWwuY29tAWF1dGg9QmVhcmVyIHlhMjkuYTBBZHcxeGVWZDNSWWwzcVZlblZwVm1MbDBRRVVyWkdxd05veEd0QWpcLVhHNjRBaF90eWM0NWhwSFprZHA0d3dPWlpGMVZwbGM3dGo1Tm80eVMwc2lPNE1VYmhHV1I1WE9sdWtLUGY4TF9QU0dpZjhrSWM2UXNUbTQwYjlweDNBeXE4bVYtOTM2akEtSHdXekNQVFdGMGk0NGozX2FOTmhEYk5rAQE =S：+eyJzdGF0dXMiOiI0MDAiLCJzY2hlbWVzIjoPQmVhcmVyIiwic2NvcGUiOiJodHRwczovL21haWwuZ29vZ2xlLmNvbS8ifQ ==C：S：A00000001否[AUTHENTICATIONFAILED]无效的凭据（失败）

作用域，我使用：GmailService.Scope.GmailReadonly因为我只需要检索电子邮件。

更新2

将我的范围更新为：

private readonly string[] Scopes = { GmailService.Scope.MailGoogleCom };

已连接至imaps：//imap.gmail.com：993 /S：* OK Gimap准备接受来自122.199.45.135的请求s90mb321411106pjcC：A00000000功能。S：*功能IMAP4rev1取消选择空闲名称空间配额ID XLIST儿童X-GM-EXT-1 XYZZY SASL-IR AUTH = XOAUTH2 AUTH = PLAIN AUTH = PLAIN-CLIENTTOKEN AUTH = OAUTHBEARER AUTH = XOAUTHS：A00000000好，那就是她写的全部！ s90mb321411106pjcC：A00000001 AUTHENTICATE XOAUTH2 dXNlcj1mcmFudmEwMDhAZ21haWwuY29tAWF1dGg9QmVhcmVyIHlhMjkuYTBBZHcxeGVWZDNSWWwzcVZlblZwVm1MbDBRRVVyWkdxd05veEd0QWpXLVhHNjRBaF90eWM0NWhwSFprZHA0d3dPWlpGMVZwbGM3dGo1Tm80eVMwc2lPNE1VYmhHV1I1WE9sdWtLUGY4TF9QU0dpZjhrSWM2UXNUbTQwYjlweDNBeXE4bVYtOTM2akEtSHdXekNQVFdGMGk0NGozX2FPTmhEYk5rAQE =S：+eyJzdGF0dXMiOiI0MDAiLCJzY2hlbWVzIjoiSmVhcmVyIiwic2NvcGUiOiJodHRwczovL21haWwuZ29vZ2xlLmNvbS8ifQ ==C：S：A00000001否[AUTHENTICATIONFAILED]无效的凭据（失败）

更新3

我将所有内容保持不变，还尝试使用GmailService.Scope.ReadOnly然后将ImapClient替换为以下代码，现在可以使用。

      // Create Gmail API service.
        service = new GmailService(new BaseClientService.Initializer()
        {
            HttpClientInitializer = credential,
            ApplicationName = ApplicationName,
        });

这段代码来自Gmail Api。如果可以使用Mailkit进行身份验证，那就太好了。

Answer 1

部分问题是您使用了错误的示波器。您需要使用GoogleService.Scope.MailGoogleCom。

您正在使用的范围不适用于IMAP或POP3访问，仅适用于Google的网络请求API。

以下代码对我有用：

const string GMailAccount = "[email protected]";

var clientSecrets = new ClientSecrets {
    ClientId = "XXX.apps.googleusercontent.com",
    ClientSecret = "XXX"
};

var codeFlow = new GoogleAuthorizationCodeFlow (new GoogleAuthorizationCodeFlow.Initializer {
    DataStore = new FileDataStore ("CredentialCacheFolder", false),
    Scopes = new [] { "https://mail.google.com/" },
    ClientSecrets = clientSecrets
});

var codeReceiver = new LocalServerCodeReceiver ();
var authCode = new AuthorizationCodeInstalledApp (codeFlow, codeReceiver);
var credential = await authCode.AuthorizeAsync (GMailAccount, CancellationToken.None);

if (authCode.ShouldRequestAuthorizationCode (credential.Token))
    await credential.RefreshTokenAsync (CancellationToken.None);

var oauth2 = new SaslMechanismOAuth2 (credential.UserId, credential.Token.AccessToken);

using (var client = new ImapClient ()) {
    await client.ConnectAsync ("imap.gmail.com", 993, SecureSocketOptions.SslOnConnect);
    await client.AuthenticateAsync (oauth2);
    await client.DisconnectAsync (true);
}