I have a desktop application to read mail using GMAIL API over REST Interface. I want to use service account so that we can download the mails using domain setting and user interaction is null. I am successfully able to create Gmail Service instance but when I try to access any Gmail API method like fetching mail list or any other I get an exception saying
Google.Apis.Auth.OAuth2.Responses.TokenResponseException: Error:"access_denied", Description:"Requested client not authorized."
I am done with all the setting at developer console and added scopes to my gapps domain.
Does Gmail API support service account? Using the same setting and service account I am able to get list of all files in Google drive using Drive service and API.
I use the following C# code for accessing Gmail from Service Account
String serviceAccountEmail =
"999999999-9nqenknknknpmdvif7onn2kvusnqct2c@developer.gserviceaccount.com";
var certificate = new X509Certificate2(
AppDomain.CurrentDomain.BaseDirectory +
"certs//fe433c710f4980a8cc3dda83e54cf7c3bb242a46-privatekey.p12",
"notasecret",
X509KeyStorageFlags.MachineKeySet | X509KeyStorageFlags.Exportable);
string userEmail = "[email protected]";
ServiceAccountCredential credential = new ServiceAccountCredential(
new ServiceAccountCredential.Initializer(serviceAccountEmail)
{
User = userEmail,
Scopes = new[] { "https://mail.google.com/" }
}.FromCertificate(certificate)
);
if (credential.RequestAccessTokenAsync(CancellationToken.None).Result)
{
GmailService gs = new GmailService(
new Google.Apis.Services.BaseClientService.Initializer()
{
ApplicationName = "iLink",
HttpClientInitializer = credential
}
);
UsersResource.MessagesResource.GetRequest gr =
gs.Users.Messages.Get(userEmail, msgId);
gr.Format = UsersResource.MessagesResource.GetRequest.FormatEnum.Raw;
Message m = gr.Execute();
if (gr.Format == UsersResource.MessagesResource.GetRequest.FormatEnum.Raw)
{
byte[] decodedByte = FromBase64ForUrlString(m.Raw);
string base64Encoded = Convert.ToString(decodedByte);
MailMessage msg = new MailMessage();
msg.LoadMessage(decodedByte);
}
}