Google Drive API v3 use JSON instead of P12 (Service Account) - Unexpected character

Question

Error: Unexpected character encountered while parsing value: e. Path '', line 0, position 0.

I am using the Google .Net Client library to access the Google drive API v3 specifically the Google.Apis.Drive.v3 package. I am authorizing using "Service Account" with C#.

Authorization with the p12 key is no problem. However, JSON is recommended and p12 format is maintained for backward compatibility.

I downloaded the JSON file from the Google Developers Console and tried to make the authorization with the following code:

    public static Google.Apis.Drive.v3.DriveService AuthenticateServiceAccountJSON(string keyFilePath) {

        // check the file exists
        if (!File.Exists(keyFilePath)) {
            Console.WriteLine("An Error occurred - Key file does not exist");
            return null;
        }

        string[] scopes = new string[] { DriveService.Scope.Drive,                  // view and manage your files and documents
                                         DriveService.Scope.DriveAppdata,           // view and manage its own configuration data
                                         DriveService.Scope.DriveFile,              // view and manage files created by this app
                                         DriveService.Scope.DriveMetadataReadonly,  // view metadata for files
                                         DriveService.Scope.DriveReadonly,          // view files and documents on your drive
                                         DriveService.Scope.DriveScripts };         // modify your app scripts     

        try {
            using (var stream = new FileStream(keyFilePath, FileMode.Open, FileAccess.Read)) {
                var credential = GoogleCredential.FromStream(stream);
                if (credential.IsCreateScopedRequired) {
                    credential.CreateScoped(scopes);
                }
                // Create the service.
                Google.Apis.Drive.v3.DriveService service = new Google.Apis.Drive.v3.DriveService(new BaseClientService.Initializer() {
                    HttpClientInitializer = credential,
                    ApplicationName = "MyDrive",
                });
                return service;
            }
        } catch (Exception ex) {
            Console.WriteLine(ex.InnerException);
            return null;

        }
    }

I have looked at the JSON file in notepad and it seems encrypted.

"ewogICJ0eXBlIjogInNlcnZpY2VfYWNjb3VudCIsCiAgInByb2plY3RfaWQiOiAicmFkaWFudC1tZXJjdXJ5LTEyMjkwNyIsCiAgIn.........."

Is it ok to continue using the P12 ?

they both should work personally I use the p12 file. This should help https://github.com/google/google-api-dotnet-client/issues/659 — Linda Lawton - DaImTo, Mar 02 '16 at 10:26
Thank you, I 'm going to use the p12. If there is anyone who can say something about the JSON file, or how it should work then let me know. — Marcel, Mar 02 '16 at 12:50

score 4 · Answer 1 · answered Apr 14 '16 at 18:33

This works for me using the JSON credentials file from the Google Developers Console. I am using the Analytics Service, but just swap out the appropriate names for the Drive service:

private AnalyticsReportingService service;

public async Task GetAuthorizationByServiceAccount()
    {
        string[] scopes = new string[] { AnalyticsReportingService.Scope.AnalyticsReadonly }; // Put your scopes here
        var keyFilePath = AppContext.BaseDirectory + @"KeyFile.json";

        //Console.WriteLine("Key File: " + keyFilePath);

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

        var credential = GoogleCredential.FromStream(stream);
        credential = credential.CreateScoped(scopes);

        service = new AnalyticsReportingService(new BaseClientService.Initializer()
        {
            HttpClientInitializer = credential,
            ApplicationName = "<Your App Name here>",
        });
    }

This was helpful, thanks. I ended up putting the json file in a resource, but the above got me going.. — sobelito, Jul 17 '16 at 04:07
Do you know how can I extract the Token so I can build a Server-Side authorization and build the google charts? https://ga-dev-tools.appspot.com/embed-api/server-side-authorization/ — Patrick, Jan 27 '17 at 18:01

score 1 · Answer 2 · answered Apr 04 '16 at 13:39

Make sure that you are downloading proper file...

GoogleCredential.FromStream(stream)

works with JSON file. Its should look something like this:

{
  "type": "service_account",
  "project_id": "",
  "private_key_id": "",
  "private_key": "-----BEGIN PRIVATE KEY-----
---END PRIVATE KEY-----\n",
  "client_email": "",
  "client_id": "",
  "auth_uri": "https://accounts.google.com/o/oauth2/auth",
  "token_uri": "https://accounts.google.com/o/oauth2/token",
  "auth_provider_x509_cert_url": "https://www.googleapis.com/oauth2/v1/certs",
  "client_x509_cert_url": ""
}

You can get this file at https://console.developers.google.com/apis/credentials by clicking Download JSON button on the right side of the grid showing client IDs. Just make sure that Type for selected ID is "Service account client".

Google Drive API v3 use JSON instead of P12 (Service Account) - Unexpected character

2 Answers2