outlookcaldavsynchronizer/CalDavSynchronizer.OAuth.Google/GoogleHttpClientFactory.cs

// This file is Part of CalDavSynchronizer (http://outlookcaldavsynchronizer.sourceforge.net/)
// Copyright (c) 2015 Gerhard Zehetbauer
// Copyright (c) 2015 Alexander Nimmervoll
// 
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU Affero General Public License as
// published by the Free Software Foundation, either version 3 of the
// License, or (at your option) any later version.
// 
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU Affero General Public License for more details.
// 
// You should have received a copy of the GNU Affero General Public License
// along with this program.  If not, see <http://www.gnu.org/licenses/>.

using System.Linq;
using System.Net;
using System.Net.Http;
using System.Reflection;
using System.Threading;
using System.Threading.Tasks;
using Google;
using Google.Apis.Auth.OAuth2;
using Google.Apis.Auth.OAuth2.Flows;
using Google.Apis.Http;
using Google.Apis.Services;
using Google.Apis.Tasks.v1;
using Google.Apis.Tasks.v1.Data;
using Google.Apis.Util.Store;
using Google.Contacts;
using Google.GData.Client;
using Google.GData.Contacts;
using log4net;

namespace CalDavSynchronizer.OAuth.Google
{
    public static class GoogleHttpClientFactory
    {
        private static readonly ILog s_logger = LogManager.GetLogger(MethodInfo.GetCurrentMethod().DeclaringType);

        private static ClientSecrets CreateClientSecrets() => new ClientSecrets
        {
            ClientId = "13856942399-rp437ddbn6406hfokpe5rqnosgnejodc.apps.googleusercontent.com",
            ClientSecret = "WG276vw5WCcc2H4SSaYJ03VO"
        };

        public static async Task<HttpClient> CreateHttpClient(string user, string userAgentHeader, IWebProxy proxy)
        {
            var userCredential = await LoginToGoogle(user, proxy);

            var client = new ProxySupportedHttpClientFactory(proxy).CreateHttpClient(new CreateHttpClientArgs() {ApplicationName = userAgentHeader});
            userCredential.Initialize(client);

            return client;
        }

        private static async Task<UserCredential> LoginToGoogle(string user, IWebProxy proxyOrNull)
        {
            GoogleAuthorizationCodeFlow.Initializer initializer = new GoogleAuthorizationCodeFlow.Initializer
            {
                ClientSecrets = CreateClientSecrets(),
                HttpClientFactory = new ProxySupportedHttpClientFactory(proxyOrNull),
                Scopes = new[]
                {
                    "https://www.googleapis.com/auth/calendar",
                    "https://www.googleapis.com/auth/carddav",
                    "https://www.googleapis.com/auth/tasks",
                    "https://www.google.com/m8/feeds/" // => contacts
                },
                DataStore = new FileDataStore(GoogleWebAuthorizationBroker.Folder)
            };

            var authorizer = new AuthorizationCodeInstalledApp(
                new AuthorizationCodeFlowWithLoginHint(initializer, user),
                new LocalServerCodeReceiver());

            return await authorizer.AuthorizeAsync(user, CancellationToken.None);
        }

        /// <remarks>
        /// This has to be done here, since UserCredential cannot be used in CalDavSynchronizer,
        /// since it leads to a 'The "FindRibbons" task failed unexpectedly' Error
        /// ( see https://connect.microsoft.com/VisualStudio/feedback/details/651634/the-findribbons-task-failed-unexpectedly)
        /// </remarks>
        public static async Task<TasksService> LoginToGoogleTasksService(string user, IWebProxy proxyOrNull)
        {
            var credential = await LoginToGoogle(user, proxyOrNull);
            var service = CreateTaskService(credential, proxyOrNull);

            try
            {
                await service.Tasklists.List().ExecuteAsync();
                return service;
            }
            catch (GoogleApiException x)
            {
                s_logger.Error("Trying to access google task service failed. Revoking  token and reauthorizing.", x);

                await credential.RevokeTokenAsync(CancellationToken.None);
                await GoogleWebAuthorizationBroker.ReauthorizeAsync(credential, CancellationToken.None);
                return CreateTaskService(credential, proxyOrNull);
            }
        }

        private static TasksService CreateTaskService(UserCredential credential, IWebProxy proxyOrNull)
        {
            return new TasksService(new BaseClientService.Initializer
            {
                HttpClientFactory = new ProxySupportedHttpClientFactory(proxyOrNull),
                HttpClientInitializer = credential,
                ApplicationName = "Outlook CalDav Synchronizer",
            });
        }

        private static OAuth2Parameters CreateOAuth2Parameters(ClientSecrets clientSecrets, UserCredential credential)
        {
            return new OAuth2Parameters
            {
                ClientId = clientSecrets.ClientId,
                ClientSecret = clientSecrets.ClientSecret,
                AccessToken = credential.Token.AccessToken,
                RefreshToken = credential.Token.RefreshToken
            };
        }

        public static async Task<ContactsRequest> LoginToContactsService(string user, IWebProxy proxyOrNull)
        {
            var clientSecrets = CreateClientSecrets();
            var credential = await LoginToGoogle(user, proxyOrNull);

            var parameters = CreateOAuth2Parameters(clientSecrets, credential);
            var contactsRequest = new ContactsRequest(CreateRequestSettings(parameters));

            ContactsQuery query = new ContactsQuery(ContactsQuery.CreateContactsUri("default"));
            query.NumberToRetrieve = 1;
            try
            {
                var feed = contactsRequest.Service.Query(query);
            }
            catch (GDataRequestException x)
            {
                s_logger.Error("Trying to access google contacts API failed. Revoking  token and reauthorizing.", x);

                await credential.RevokeTokenAsync(CancellationToken.None);
                await GoogleWebAuthorizationBroker.ReauthorizeAsync(credential, CancellationToken.None);
                parameters = CreateOAuth2Parameters(clientSecrets, credential);
                contactsRequest = new ContactsRequest(CreateRequestSettings(parameters));
            }

            if (proxyOrNull != null)
                contactsRequest.Proxy = proxyOrNull;

            return contactsRequest;
        }

        private static RequestSettings CreateRequestSettings(OAuth2Parameters parameters)
        {
            return new RequestSettings("Outlook CalDav Synchronizer", parameters);
        }
    }
}