Google Docs script to automate Twitter posting

Twitter.gs

// source: https://ctrlq.org/code/19702-twitter-image-upload

function autoTweet() {
  var ss = SpreadsheetApp.getActiveSpreadsheet();
  var sheet = ss.getSheetByName("schedule"); // This must match the sheet name!
  var rows = sheet.getRange("A:D").getValues();
  var titleList = [], newValues = [],
      response, doc, title;

  var twitterCallback = function(rowIndex, err, result) {
    if (err) {
      sheet.getRange("A:A").offset(rowIndex, 0, 1, 2).setValues([ [ "", new Date() + "\r\n" + err.toString() ] ]) 
      throw err;
      return
    }      
    
    sheet.getRange("A:A").offset(rowIndex, 0, 1, 2).setValues([ [ 
      "" + result.text +"\r\n"+ result.id_str, 
      new Date() 
    ] ]) 
  }
  
  for (var rowIndex = 0, len = rows.length; rowIndex < len; rowIndex++) {
    if (rows[rowIndex][1] == '') {
      Logger.log('next post image: '+ rows[rowIndex][2])        
      Logger.log('next post text: '+ rows[rowIndex][3])

      sendTweetwithImage({ 
        image: rows[rowIndex][2],
        text: rows[rowIndex][3]
      }, twitterCallback.bind(this, rowIndex));

      break;
    }
  }

  Logger.log("No tweets found")
  
  return null; 
}

function sendTweetwithImage(post, callback) {
  
  // get access tokens from https://dev.twitter.com/oauth/tools/signature-generator/12277450?nid=619
  // https://dev.twitter.com/oauth/pin-based
  // authorize, callback is "oob" for pin based
  // call https://api.twitter.com/oauth/authenticate?oauth_token=<oayth token> 
  // https://api.twitter.com/oauth/access_token ? oauth_verifier=<pin>
  
  var twitterKeys= {
    TWITTER_CONSUMER_KEY: "xxx",
    TWITTER_CONSUMER_SECRET: "xxx",
    TWITTER_ACCESS_TOKEN: "yyy",
    TWITTER_ACCESS_SECRET: "yyy"    
  };
  
  var props = PropertiesService.getUserProperties();
  
  props.setProperties(twitterKeys);
  
  var twit = new Twitter.OAuth(props);
  
  if ( twit.hasAccess() ) {
    
    try {
      var imageUrl = post.image;
      var imageBlob = twit.grabImage(imageUrl, "image/jpeg");
      var uploadImg = twit.uploadMedia(imageBlob);
      
      if (uploadImg) {
       
        var response = twit.sendTweet(post.text, {
          media_ids: uploadImg.media_id_string
        });
        
        if (response) {
          
          Logger.log("Tweet Sent " + response.id_str);
          callback(null, response)
          
        } else {
          
          // Tweet could not be sent
          // Error will be handled below, or
          // Go to View -> Logs to see the error message
        }
        
      }
    } catch (f) {
      Logger.log(f.toString());
      callback(f)
    }
    
  }  
}

// util functions for the sheet
function encode(value) {
  return encodeURIComponent(value);
}