Google Apps Email Settings API using .Net and OAuth 2.0

Question

I want to use the email settings API, but can not find any documentation how to use this api with the oAuth2 authentication

1. Am I using the correct API?
2. Am I using the latest API? (Google.GData.Apps.dll Version 2.2.0)
3. How can I use this DLl with an google console project with p12 file and serviceaccount?

According to the Google documentation this is the latest api voor email settings: https://developers.google.com/admin-sdk/email-settings/

I can not find any documentation on this page how to use it in .Net with Oauth, but in the example I see this:

using Google.GData.Apps;
using Google.GData.Apps.GoogleMailSettings;

GoogleMailSettingsService service = new GoogleMailSettingsService("yourdomain", "your-apps");
service.setUserCredentials("adminUsername", "adminPassword");    
service.CreateSendAs("liz", "Sales", "[email protected]", "", "true");

So searching for these references I find this page: https://code.google.com/p/google-gdata/ or the nuget package: www.nuget.org/packages/Google.GData.Apps/ the latest version is 2.2.0

Since we are switching to the new api's using console projects Oauth2 and service-account my question is, can I use the dll also using the same authentication as for the newest api's

the new api's use this authentication method:

X509Certificate2 certificate = new X509Certificate2(@"\location\P12File.p12", "notasecret", X509KeyStorageFlags.Exportable);
IEnumerable<string> scopes = new[] { DirectoryService.Scope.AdminDirectoryUser, DirectoryService.Scope.AdminDirectoryUserSecurity };
ServiceAccountCredential credential = new ServiceAccountCredential(
    new ServiceAccountCredential.Initializer("[email protected]")
    {
        Scopes = scopes,
        User = "[email protected]"
    }.FromCertificate(certificate));

// Create the service.
var service = new DirectoryService(
    new BaseClientService.Initializer()
    {
        HttpClientInitializer = credential,
        ApplicationName = "Admin directory Provisioning Sample",
    });

service.Users.Delete(userKey).Execute();

Answer 1

I've took the example to create the OAuth flow from the directory API https://developers.google.com/admin-sdk/directory/v1/quickstart/dotnet and used it to connect to the emailsettings api service.

    static string[] Scopes = { "https://apps-apis.google.com/a/feeds/emailsettings/2.0/" };
        static string ApplicationName = "your-apps";

    static void Main(string[] args)
    {
        UserCredential credential;


        using (var stream =
            new FileStream("../../client_secret.json", FileMode.Open, FileAccess.Read))
        {
            string credPath = System.Environment.GetFolderPath(
                System.Environment.SpecialFolder.Personal);
            credPath = Path.Combine(credPath, ".credentials");

            credential = GoogleWebAuthorizationBroker.AuthorizeAsync(
                GoogleClientSecrets.Load(stream).Secrets,
                Scopes,
                "user",
                CancellationToken.None,
                new FileDataStore(credPath, true)).Result;
            Console.WriteLine("Credential file saved to: " + credPath);
        }

        OAuth2Parameters parameter = new OAuth2Parameters()
        {
            AccessToken = credential.Token.AccessToken
        };


        GOAuth2RequestFactory requestFactory = new GOAuth2RequestFactory("apps", ApplicationName, parameter);
        GoogleMailSettingsService service = new GoogleMailSettingsService("example.com", ApplicationName);
        service.RequestFactory = requestFactory;



        service.CreateSendAs("liz", "Sales", "[email protected]", "", "true");
        Console.Read();

    }

Answer 2

For the Email Settings API and any other GData classes that are Services you can use something like the following:

using Google.GData.Apps;
using Google.GData.Apps.GoogleMailSettings;
using Google.GData.Client;

// Name of my cli application
string applicationName = "Test-OAuth2";

// Installed (non-web) application
string redirectUri = "urn:ietf:wg:oauth:2.0:oob";

// Requesting access to Contacts API and Groups Provisioning API
string scopes = "https://apps-apis.google.com/a/feeds/emailsettings/2.0/";

// Stuff usually found on client_secrets.json
string clientId = CLIENT_ID;
string clientSecret = CLIENT_SECRET;
string domain = CLIENT_DOMAIN;

// Prepare OAuth parameters
OAuth2Parameters parameters = new OAuth2Parameters() {
    ClientId = clientId,
    ClientSecret = clientSecret,
    RedirectUri = redirectUri,
    Scope = scopes
};

// Request authorization from the user
string url = OAuthUtil.CreateOAuth2AuthorizationUrl(parameters);
Console.WriteLine("Authorize URI: " + url);

// Fetch the access code from console
parameters.AccessCode = Console.ReadLine();

// Get an access token
OAuthUtil.GetAccessToken(parameters);

try {
    // Create a new request factory so it uses our OAuth credentials
    GOAuth2RequestFactory requestFactory = new GOAuth2RequestFactory("apps", applicationName, parameters);

    GoogleMailSettingsService service = new GoogleMailSettingsService(domain, applicationName);
    service.RequestFactory = requestFactory;

    // Update the signature for the user testUserName
    service.UpdateSignature("[email protected]", "My tiny signature");
} catch (AppsException a) {
    Console.WriteLine("A Google Apps error occurred.");
    Console.WriteLine();
    Console.WriteLine("Error code: {0}", a.ErrorCode);
    Console.WriteLine("Invalid input: {0}", a.InvalidInput);
    Console.WriteLine("Reason: {0}", a.Reason);
}

You can see a full example in the OAuth samples provided with GData here: https://code.google.com/p/google-gdata/source/browse/trunk/clients/cs/samples/oauth2_sample/oauth2demo.cs

For other GData classes which use Requests, the flow is similar but instead you create a RequestSettings object and pass it into your GData request object constructor as shown here: https://code.google.com/p/google-gdata/source/browse/trunk/clients/cs/samples/oauth2_sample/oauth2demo.cs#63