Google Drive V3 and service account for get files list from Google Drive Account (C#)

[Daniele Volpe]

Hi, i'm programming in c# and i want to get the list of files from a Google Drive Account.

The authentication work fine, but when i do: 

FilesResource.ListRequest listRequest = service.Files.List();

var files = listRequest.Execute();

I have the error [401]: Invalid Credentials

Please help me and sorry for my english,

Daniele.

[George (Cloud Platform Support)]

Hello Daniele, 

It looks as if credentials have not been set properly for your project. How did you set app authentication, exactly, and how did you ascertain it works fine, as you mention? You can gather more detail by reading points a. to h. at Step 1 on the ".NET Quickstart" documentation page. In fact, following the whole example provided on that page may prove generally helpful in your case. 

The actual code example on this page is somewhat more elaborate than your example: 

// 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; 

You are encouraged to adapt this code snippet for your particular situation, and post the results back here. 

[Daniele Volpe]

Hi George, this is my code.

string[] scopes = new string[] { DriveService.Scope.Drive }; // Full access

 

            var keyFilePath = Environment.CurrentDirectory + "JSON_FILE_LOCATION";   

            if (!System.IO.File.Exists(keyFilePath))

            {

                Console.WriteLine("An Error occurred - Key file does not exist");

            }

 

            try

            {

                using (var stream = new FileStream(keyFilePath, FileMode.Open, FileAccess.Read))

                {

 

                    var googleCredential = GoogleCredential.FromStream(stream);

                    if (googleCredential.IsCreateScopedRequired)

                    {

                        googleCredential.CreateScoped(scopes);

                    }

 

                    // Create the service.

                    DriveService service = new DriveService(new BaseClientService.Initializer()

                    {

                        HttpClientInitializer = googleCredential,

                        ApplicationName = "APP_NAME",

                    });

 

                    try

                    {

                        FilesResource.ListRequest listRequest = service.Files.List();

                        FileList files = listRequest.Execute();

                    }

                    catch (Exception e)

                    {

                        Console.WriteLine("An error occurred: " + e.Message);

                    }

       

                }

            }

            catch (Exception ex)

            {

                Console.WriteLine(ex.InnerException);

            }

 

        }

And this is the exception :

 

Eccezione generata: 'Google.GoogleApiException' in mscorlib.dll

An error occurred: Google.Apis.Requests.RequestError

Invalid Credentials [401]

Errors [

       Message[Invalid Credentials] Location[Authorization - header] Reason[authError] Domain[global]

]

[George (Cloud Platform Support)]

What happens if you use the line: 

// List files.

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

in place of line: 

FileList files = listRequest.Execute();

[Daniele Volpe]

Ok, now this code is working but there is a problem.

When the program looks for files inside Google Drive i cant' see my files but only a file called "Getting started".

If i open Google Drive from the website i haven't this file in my cloud, but i can see only my files.... ?

Why ? With the code i look in the wrong directory ?

Thank you.

 ---------------------------------------------------------------------      

            string[] scopes = new string[] { DriveService.Scope.Drive };

 

            GoogleCredential credential;

            using (var stream = new FileStream(JSON_PATH, FileMode.Open, FileAccess.Read))

            {

                credential = GoogleCredential.FromStream(stream);

            }

 

            DriveService service = new DriveService(new BaseClientService.Initializer()

            {

                HttpClientInitializer = credential.CreateScoped(scopes),

                ApplicationName = APPLICATION_NAME

            });

 

            FilesResource.ListRequest listRequest = service.Files.List();

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

            if (files != null && files.Count > 0)

                    {

                        foreach (var file in files)

                        {

                            Console.WriteLine("{0} ({1}) {2}", file.Name, file.Id);

                        }

                    }

------------------------------------------------------------------ 

[Daniele Volpe]

Now all is working.

I have add the service account email authorization in every files i want to search.

Thank you for the help :)

[George (Cloud Platform Support)]

Hi Daniele!

A more detailed report on your solution might prove of great help for people encountering the same issue in future.