How to provide Credentials programmatically to use google drive api in c# or vb.net?

Question

I made a program that uses google drive api to read data from a file on google drive.

the first time you run the app it opens a web browser asking to sign in with google drive account.

I want to provide the app the username and password so that it get the credentials automatically, so that users won't need to know the username and password of my google drive account.

here is the code in vb.net:

    Dim credential As UserCredential

    Using stream = New FileStream("client_secret.json", FileMode.Open, FileAccess.Read)
        Dim credPath As String = System.Environment.GetFolderPath(
            System.Environment.SpecialFolder.Personal)
        credPath = Path.Combine(credPath, ".credentials/drive-dotnet-quickstart.json")

        credential = GoogleWebAuthorizationBroker.AuthorizeAsync(
        GoogleClientSecrets.Load(stream).Secrets,
        Scopes,
        "user",
        CancellationToken.None,
        New FileDataStore(credPath, True)).Result
        'Console.WriteLine("Credential file saved to: " + credPath)
    End Using

    //I want to provide the username and password in the app so that it doesn't open a web browser asking for them

    ' Create Drive API service.
    Dim initializer = New BaseClientService.Initializer
    initializer.HttpClientInitializer = credential
    initializer.ApplicationName = ApplicationName
    Dim service = New DriveService(initializer)

    ' Define parameters of request.
    Dim listRequest As FilesResource.ListRequest = service.Files.List()
    listRequest.PageSize = 10
    listRequest.Fields = "nextPageToken, files(id, name)"

    ' List files.
    Dim files As IList(Of Google.Apis.Drive.v3.Data.File) = listRequest.Execute().Files

here is the code in c#:

        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/drive-dotnet-quickstart.json");

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

        //I want to provide the username and password in the app so that it doesn't open a web browser asking for them

        // Create Drive API service.
        var service = new DriveService(new BaseClientService.Initializer()
        {
            HttpClientInitializer = credential,
            ApplicationName = ApplicationName,
        });

        // Define parameters of request.
        FilesResource.ListRequest listRequest = service.Files.List();
        listRequest.PageSize = 10;
        listRequest.Fields = "nextPageToken, files(id, name)";

        // List files.
        IList<Google.Apis.Drive.v3.Data.File> files = listRequest.Execute()
            .Files;

Answer 1

Unfortunately you cant embed a login and password like that. I do have another option for you.

It sounds like you are trying to allow users access to your personal Google drive account. In that case you should be using a service account and Not Oauth2. Oauth2 requires user interaction in the form of a webpage to grant an application access to the Users own google drive account. While service accounts are pre authorized by the developer in the background.

Think of a service account as a dummy user. You can grant it access to your google drive account by sharing a folder in your google drive with the service accounts email address.

Here is some sample code for authenticating with a service account.

/// <summary>
    /// Authenticating to Google using a Service account
    /// Documentation: https://developers.google.com/accounts/docs/OAuth2#serviceaccount
    /// </summary>
    /// <param name="serviceAccountEmail">From Google Developer console https://console.developers.google.com</param>
    /// <param name="serviceAccountCredentialFilePath">Location of the .p12 or Json Service account key file downloaded from Google Developer console https://console.developers.google.com</param>
    /// <returns>AnalyticsService used to make requests against the Analytics API</returns>
    public static DriveService AuthenticateServiceAccount(string serviceAccountEmail, string serviceAccountCredentialFilePath)
    {
        try
        {
            if (string.IsNullOrEmpty(serviceAccountCredentialFilePath))
                throw new Exception("Path to the service account credentials file is required.");
            if (!File.Exists(serviceAccountCredentialFilePath))
                throw new Exception("The service account credentials file does not exist at: " + serviceAccountCredentialFilePath);
            if (string.IsNullOrEmpty(serviceAccountEmail))
                throw new Exception("ServiceAccountEmail is required.");

            // These are the scopes of permissions you need. It is best to request only what you need and not all of them
            string[] scopes = new string[] { AnalyticsReportingService.Scope.Analytics };             // View your Google Analytics data

            // For Json file
            if (Path.GetExtension(serviceAccountCredentialFilePath).ToLower() == ".json")
            {
                GoogleCredential credential;
                using (var stream = new FileStream(serviceAccountCredentialFilePath, FileMode.Open, FileAccess.Read))
                {
                    credential = GoogleCredential.FromStream(stream)
                         .CreateScoped(scopes);
                }

                // Create the  Analytics service.
                return new DriveService(new BaseClientService.Initializer()
                {
                    HttpClientInitializer = credential,
                    ApplicationName = "Drive Service account Authentication Sample",
                });
            }
            else if (Path.GetExtension(serviceAccountCredentialFilePath).ToLower() == ".p12")
            {   // If its a P12 file

                var certificate = new X509Certificate2(serviceAccountCredentialFilePath, "notasecret", X509KeyStorageFlags.MachineKeySet | X509KeyStorageFlags.Exportable);
                var credential = new ServiceAccountCredential(new ServiceAccountCredential.Initializer(serviceAccountEmail)
                {
                    Scopes = scopes
                }.FromCertificate(certificate));

                // Create the  Drive service.
                return new DriveService(new BaseClientService.Initializer()
                {
                    HttpClientInitializer = credential,
                    ApplicationName = "Drive Authentication Sample",
                });
            }
            else
            {
                throw new Exception("Unsupported Service accounts credentials.");
            }

        }
        catch (Exception ex)
        {
            Console.WriteLine("Create service account DriveService failed" + ex.Message);
            throw new Exception("CreateServiceAccountDriveFailed", ex);
        }
    }
}

Usage:

  var service = AuthenticateServiceAccount("1046123799103-6v9cj8jbub068jgmss54m9gkuk4q2qu8@developer.gserviceaccount.com", @"C:\Users\linda_l\Documents\Diamto Test Everything Project\ServiceAccountTest\Diamto Test Everything Project-145ed16d5d47.json");

Code ripped from my unofficial google drive sample project serviceaccount.cs I also have an article that goes deeper into service accounts Google Developer console service account