C# Google Drive APIv3 Upload File

Question

I'm making a simple Application that Links to a Google Drive Account and then can Upload Files to any Directory and respond with a (direct) download Link. I already got my User Credentials and DriveService objects, but I can't seem to find any good examples or Docs. on the APIv3.

As I'm not very familiar with OAuth, I'm asking for a nice and clear explanation on how to Upload a File with byte[] content now.

My Code for Linking the Application to a Google Drive Account: (Not sure if this works perfectly)

    UserCredential credential;


        string dir = Directory.GetCurrentDirectory();
        string path = Path.Combine(dir, "credentials.json");

        File.WriteAllBytes(path, Properties.Resources.GDJSON);

        using(var stream = new FileStream(path, FileMode.Open, FileAccess.Read)) {
            string credPath = Path.Combine(dir, "privatecredentials.json");

            credential = GoogleWebAuthorizationBroker.AuthorizeAsync(
                GoogleClientSecrets.Load(stream).Secrets,
                Scopes,
                "user",
                CancellationToken.None,
                new FileDataStore(credPath, true)).Result;
        }

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

        File.Delete(path);

My Code for Uploading so far: (Does not work obviously)

        public void Upload(string name, byte[] content) {

        Google.Apis.Drive.v3.Data.File body = new Google.Apis.Drive.v3.Data.File();
        body.Name = name;
        body.Description = "My description";
        body.MimeType = GetMimeType(name);
        body.Parents = new List() { new ParentReference() { Id = _parent } };


        System.IO.MemoryStream stream = new System.IO.MemoryStream(content);
        try {
            FilesResource.InsertMediaUpload request = _service.Files.Insert(body, stream, GetMimeType(_uploadFile));
            request.Upload();
            return request.ResponseBody;
        } catch(Exception) { }
    }

Thanks!

Answer 1

Once you have enabled your Drive API, registered your project and obtained your credentials from the Developer Consol, you can use the following code for recieving the user's consent and obtaining an authenticated Drive Service

string[] scopes = new string[] { DriveService.Scope.Drive,
                             DriveService.Scope.DriveFile};
var clientId = "xxxxxx";      // From https://console.developers.google.com
var clientSecret = "xxxxxxx";          // From https://console.developers.google.com
// here is where we Request the user to give us access, or use the Refresh Token that was previously stored in %AppData%
var credential = GoogleWebAuthorizationBroker.AuthorizeAsync(new ClientSecrets { ClientId = clientId,
                                                                              ClientSecret = clientSecret},
                                                        scopes,
                                                        Environment.UserName,
                                                        CancellationToken.None,
                                                        new FileDataStore("MyAppsToken")).Result; 
//Once consent is recieved, your token will be stored locally on the AppData directory, so that next time you wont be prompted for consent. 

DriveService service = new DriveService(new BaseClientService.Initializer()
{
   HttpClientInitializer = credential,
   ApplicationName = "MyAppName",
});
service.HttpClient.Timeout = TimeSpan.FromMinutes(100); 
//Long Operations like file uploads might timeout. 100 is just precautionary value, can be set to any reasonable value depending on what you use your service for.

Following is a working piece of code for uploading to Drive.

    // _service: Valid, authenticated Drive service
    // _uploadFile: Full path to the file to upload
    // _parent: ID of the parent directory to which the file should be uploaded

public static Google.Apis.Drive.v2.Data.File uploadFile(DriveService _service, string _uploadFile, string _parent, string _descrp = "Uploaded with .NET!")
{
   if (System.IO.File.Exists(_uploadFile))
   {
       File body = new File();
       body.Title = System.IO.Path.GetFileName(_uploadFile);
       body.Description = _descrp;
       body.MimeType = GetMimeType(_uploadFile);
       body.Parents = new List<ParentReference>() { new ParentReference() { Id = _parent } };

       byte[] byteArray = System.IO.File.ReadAllBytes(_uploadFile);
       System.IO.MemoryStream stream = new System.IO.MemoryStream(byteArray);
       try
       {
           FilesResource.InsertMediaUpload request = _service.Files.Insert(body, stream, GetMimeType(_uploadFile));
           request.Upload();
           return request.ResponseBody;
       }
       catch(Exception e)
       {
           MessageBox.Show(e.Message,"Error Occured");
       }
   }
   else
   {
       MessageBox.Show("The file does not exist.","404");
   }
}

Here's the little function for determining the MimeType:

private static string GetMimeType(string fileName)
{
    string mimeType = "application/unknown";
    string ext = System.IO.Path.GetExtension(fileName).ToLower();
    Microsoft.Win32.RegistryKey regKey = Microsoft.Win32.Registry.ClassesRoot.OpenSubKey(ext);
    if (regKey != null && regKey.GetValue("Content Type") != null)
        mimeType = regKey.GetValue("Content Type").ToString();
    return mimeType;
}

Additionally, you can register for the ProgressChanged event and get the upload status.

 request.ProgressChanged += UploadProgessEvent;
 request.ChunkSize = FilesResource.InsertMediaUpload.MinimumChunkSize; // Minimum ChunkSize allowed by Google is 256*1024 bytes. ie 256KB. 

And

 private void UploadProgessEvent(Google.Apis.Upload.IUploadProgress obj)
 {
     label1.Text = ((obj.ByteSent*100)/TotalSize).ToString() + "%";

    // do updation stuff
 }

That's pretty much it on Uploading..

Source.

Answer 2

If you've followed Google Drive API's .NET Quickstart guide, then you probably remember during first launch, a web page from google drive was prompting for authorization grant to access google drive with "Read only" permission?

The default scope "DriveService.Scope.DriveReadonly" from the quickstart guide can't be used if you intend on uploading files.

This worked for me

1. Remove "Drive ProtoType" from Apps connected to your account

2. Create another set of credentials with a new application name eg "Drive API .NET Quickstart2" in API Manager

3. Request access with this scope "DriveService.Scope.DriveFile" private static readonly string[] Scopes = { DriveService.Scope.DriveReadonly }; private static readonly string ApplicationName = "Drive API .NET Quickstart2";}

4. You should land on a new page from google drive requesting new grant

   Drive Prototype would like to: View and manage Google Drive files and folders that you have opened or created with this app

After allowing access, your application should be able to upload.