Faling precondition while using google Gmail api for Gsuite

Question

I am completely going mad trying to get this work. I need to use the gmail api to send mail from our domain. Every time I get this result back:

Google.Apis.Requests.RequestError
Bad Request [400]
Errors [
    Message[Bad Request] Location[ - ] Reason[failedPrecondition] Domain[global]
]

I'm going completely mad!

I've read all of this and I still did not figure it out:

How do I get this to work?

These are the steps I have done:

Created a new project in console.developers.google.com
Enabled the gmail api
Created a service account
Created a key.p12 file for the service account
Configured domain-wide authority
Enabled the gmail api in admin.google.com
Added the api scopes in security->advanced->Api acces
Added and verified my domain name

Screens:

This is my code:

public class TestMailController : Controller
    {

        static string ApplicationName = "IdiciumGmail";
        private static String serviceAccountEmail = "[email protected]";

        public IActionResult Index()
        {

            string debugMessage = "";

            var certificate = new X509Certificate2(@"key.p12", "notasecret", X509KeyStorageFlags.MachineKeySet | X509KeyStorageFlags.Exportable);

            ServiceAccountCredential credential = new ServiceAccountCredential(
                new ServiceAccountCredential.Initializer(serviceAccountEmail)
                {
                    Scopes = new[] { GmailService.Scope.MailGoogleCom }
                }.FromCertificate(certificate));

            if (credential.RequestAccessTokenAsync(CancellationToken.None).Result)
            {
                // Create Gmail API service.
                var service = new GmailService(new BaseClientService.Initializer()
                {
                    HttpClientInitializer = credential,
                    ApplicationName = ApplicationName,
                });

                /*
                var message = new MimeMessage();
                message.From.Add(new MailboxAddress("Bestuur", "[email protected]"));
                message.To.Add(new MailboxAddress("Tester", "[email protected]"));
                message.Subject = "Is this working";
                message.Body = new TextPart(TextFormat.Html)
                {
                    Text = "Ja ja als je dit krijgt werkt het.... EINDELIJK. <br><br> <b>ook html werkt</b>"
                };

                 */

                Message m = new Message();
                m.Raw = "RnJvbTogQmVzdHV1ciA8YmVzdHV1ckBpbmRpY2l1bS5odT4gClRvOiBXaWxsaWFtIExvb3NtYW4g\nPHdpbGxpYW0ud2xAbGl2ZS5ubD4gClN1YmplY3Q6IERpdCBpcyBlZW4gdGVzdAoKVGhpcyBpcyBh\nIG1lc3NhZ2UganVzdCB0byBzYXkgaGVsbG8uIFNvLCAiSGVsbG8iLg==";

                try
                {
                    //var result = service.Users.Messages.Send(m, "[email protected]").Execute();

                    var result = service.Users.Messages.List("[email protected]").Execute();

                    debugMessage += "Send email: " + result;
                }
                catch (Exception e)
                {
                    debugMessage += e.Message;
                    //throw;
                }


                debugMessage += "The END!";
            }

            return Content(debugMessage);
        }

I tested the base 64 raw string inside the api explorer and there it worked! So I guess that is not the problem. Can someone please help me with this, I'm getting desperate. BTW we use the free version of G suite for nonprofits (does this form a problem?).

Yeronimo Yeronimo · Accepted Answer · 2018-04-01T12:07:35

I was strugling with the same problems, but mine had a slightly different reason. You still need to follow the steps outlined by @botenvouwer

I had this code, which I took from the documentation, but is not working and giving the mentioned error:

            ServiceAccountCredential credential;

            using (Stream stream = new FileStream(serviceAccountCredentialFilePath, FileMode.Open, FileAccess.Read))
            {
                credential = GoogleCredential.FromStream(stream).CreateScoped(scopes).UnderlyingCredential as ServiceAccountCredential;
            }

            // Create the  Calendar service.
            return new GmailService(new BaseClientService.Initializer()
            {
                HttpClientInitializer = credential,
                ApplicationName = "isatisservice",
            });

The part I was forgetting was to specify when creating the service which user you want to use it for. You can't specify the user in your calls to the API, but you have to do it here:

            credential = GoogleCredential.FromStream(stream).CreateScoped(scopes).CreateWithUser("[email protected]").UnderlyingCredential as ServiceAccountCredential;

So it is in the CreateWithUser part. Once that was added, it started working.

Please note that the email address is the address of the domain user you want access to. So not your service account e-mail.

Faling precondition while using google Gmail api for Gsuite

2 Answers