GDrive JS

var chokidar = require('chokidar');
var fs = require('fs');
var readline = require('readline');
var google = require('googleapis');
var googleAuth = require('google-auth-library');
var mime = require('mime');
var path = require('path');


//var SCOPES = ['https://www.googleapis.com/auth/drive.metadata.readonly'];
var SCOPES = ['https://www.googleapis.com/auth/drive'];
var TOKEN_DIR = (process.env.HOME || process.env.HOMEPATH ||
    process.env.USERPROFILE) + '/.credentials/';
var TOKEN_PATH = TOKEN_DIR + 'drive-nodejs-quickstart.json';

//Make sure this folder exist on your Google Drive Account
var GOOGLE_DRIVE_FOLDER = "SyncPro"
//The folder that we Sync with the Google Drive Storage
var LOCAL_SYNC_FOLDER = "watch_me"
// Constructor
function GDrive() {
    // always initialize all instance properties
    this.drive;
    this.auth;
    // Load client secrets from a local file.
    fs.readFile('client_secret.json', function processClientSecrets(err, content) {
      if (err) {
        console.log('Error loading client secret file: ' + err);
        return;
      }
      // Authorize a client with the loaded credentials, then call the
      // Drive API.
      authorize(JSON.parse(content), find_folder);
    });

    function authorize(credentials, callback) {
      var clientSecret = credentials.installed.client_secret;
      var clientId = credentials.installed.client_id;
      var redirectUrl = credentials.installed.redirect_uris[0];
      var auth = new googleAuth();
      var oauth2Client = new auth.OAuth2(clientId, clientSecret, redirectUrl);

      // Check if we have previously stored a token.
      fs.readFile(TOKEN_PATH, function(err, token) {
        if (err) {
          getNewToken(oauth2Client, callback);
        } else {
          oauth2Client.credentials = JSON.parse(token);
          callback(oauth2Client);
        }
      });
    }

    function find_folder(auth){

          var fetchPage = function(pageToken, pageFn, callback) {
              var service = google.drive('v3');
              service.files.list({
                auth:auth,
                q: "name contains '"+ GOOGLE_DRIVE_FOLDER +"' and mimeType = 'application/vnd.google-apps.folder'",
                fields: 'nextPageToken, files(id, name)',
                spaces: 'drive',
                pageToken: pageToken
              }, function(err, res) {
                if(err) {
                  callback(err);
                } else {
                  res.files.forEach(function(file) {
                    console.log('Found file: ', file.name, file.id);
                    load_watcher(auth,file.id);
                  });
                  if (res.nextPageToken) {
                    console.log("Page token", res.nextPageToken);
                    pageFn(res.nextPageToken, pageFn, callback);
                  } else {
                    callback();
                  }
                }
              });
            };
            fetchPage(null, fetchPage, function(err) {
              if (err) {
                // Handle error
                console.log(err);
              } else {
                // All pages fetched
              }
            });
    }

    function load_watcher(auth,PARENT_FOLDER_ID){
        var watcher = chokidar.watch(LOCAL_SYNC_FOLDER, {
          ignored: /[\/\\]\./,
          persistent: true ,
          alwaysState: true
        });

        var log = console.log.bind(console);
        watcher
        .on('add', function(path) {
            log('File', path, 'has been added');
            googleDrive_upFile(path,auth,PARENT_FOLDER_ID)
        })
        .on('addDir', function(path) {
            if(path != LOCAL_SYNC_FOLDER){
                log('Directory', path, 'has been added');
                googleDrive_upFolder(path,auth,PARENT_FOLDER_ID)
            }
        })
        .on('change', function(path) {
            log('File', path, 'has been changed');
            googleDrive_upFile(path,auth,PARENT_FOLDER_ID)
        })
        .on('unlink', function(path) {
            log('File', path, 'has been removed');
            watcher.unwatch(path);
        })
        .on('unlinkDir', function(pathX) {
            log('Directory', path, 'has been removed');
            //TODO: the shit below does not work.
            //implement method to find the ID of the FOLDER we want to delete from GDrive
            //googleDrive_delFolder(get_id_of_file(path.basename(pathX)),auth,PARENT_FOLDER_ID)
            watcher.unwatch(pathX);
        })
        .on('error', function(error) { log('Error happened', error); })
        .on('ready', function() { log('Initial scan complete. Ready for changes.'); })
    }

    function googleDrive_upFolder(folder_data,auth,folder_id){
        var fileMetadata = {
          'name' : path.basename(folder_data),
          parents: [ folder_id ],
          'mimeType' : 'application/vnd.google-apps.folder'
        };
        var service = google.drive('v3');
        service.files.create({
           auth:auth,
           resource: fileMetadata,
           fields: 'id'
        }, function(err, file) {
          if(err) {
            // Handle error
            console.log(err);
          } else {
            console.log('Folder Id: ', file.id);
          }
        });
    }
    function googleDrive_delFolder(folder_data,auth,folder_id){

        var service = google.drive('v3');
        service.files.delete({
           fileId:folder_id,
           auth:auth,
           fields: 'id'
        }, function(err, file) {
          if(err) {
            // Handle error
            console.log(err);
          } else {
            console.log('Folder Id: ', file.id);
          }
        });
    }

    function googleDrive_upFile(file_data,auth,folder_id){
        var folderId = folder_id;
        var fileMetadata = {
          name: path.basename(file_data),
          parents: [ folderId ]
        };
        var media = {
          mimeType: mime.lookup(file_data),
          body: fs.createReadStream(file_data)
        };
        var service = google.drive('v3');
        service.files.create({
           auth:auth,
           resource: fileMetadata,
           media: media,
           fields: 'id'
        }, function(err, file) {
          if(err) {
            // Handle error
            console.log(err);
          } else {
            console.log('File Id: ', file.id);
          }
        });
    }

    function get_id_of_file(auth,fileName){
        var fetchPage = function(pageToken, pageFn, callback) {
              var service = google.drive('v3');
              service.files.list({
                auth:auth,
                q: "name contains '"+fileName+"'",
                fields: 'nextPageToken, files(id, name)',
                spaces: 'drive',
                pageToken: pageToken
              }, function(err, res) {
                if(err) {
                  callback(err);
                } else {
                  res.files.forEach(function(file) {
                    console.log('Found file: ', file.name, file.id);
                  });
                  if (res.nextPageToken) {
                    console.log("Page token", res.nextPageToken);
                    pageFn(res.nextPageToken, pageFn, callback);
                  } else {
                    callback();
                  }
                }
              });
            };
            fetchPage(null, fetchPage, function(err) {
              if (err) {
                // Handle error
                console.log(err);
              } else {
                // All pages fetched
              }
            });

    }

    function listFiles(auth) {
      var service = google.drive('v3');
      service.files.list({
        auth: auth,
        pageSize: 20,
        fields: "nextPageToken, files(id, name)"
      }, function(err, response) {
        if (err) {
          console.log('The API returned an error: ' + err);
          return;
        }
        var files = response.files;
        if (files.length == 0) {
          console.log('No files found.');
        } else {
          console.log('File List:'+"<br>");
          for (var i = 0; i < files.length; i++) {
            var file = files[i];
            console.log(file.name+"<br>");
          }
        }
      });
    }

    function getNewToken(oauth2Client, callback) {
      var authUrl = oauth2Client.generateAuthUrl({
        access_type: 'offline',
        scope: SCOPES
      });
      console.log('Authorize this app by visiting this url: ', authUrl);
      var rl = readline.createInterface({
        input: process.stdin,
        output: process.stdout
      });
      rl.question('Enter the code from that page here: ', function(code) {
        rl.close();
        oauth2Client.getToken(code, function(err, token) {
          if (err) {
            console.log('Error while trying to retrieve access token', err);
            return;
          }
          oauth2Client.credentials = token;
          storeToken(token);
          callback(oauth2Client);
        });
      });
    }

    function storeToken(token) {
      try {
        fs.mkdirSync(TOKEN_DIR);
      } catch (err) {
        if (err.code != 'EEXIST') {
          throw err;
        }
      }
      fs.writeFile(TOKEN_PATH, JSON.stringify(token));
      console.log('Token stored to ' + TOKEN_PATH);
    }
}
var f = new GDrive();