DSpace helper Google Apps Script to retrieve full text from CORE discovery

findFullText.gs

function onOpen() {
  SpreadsheetApp.getUi().createMenu("Atmire")
  .addItem('Find Full Text','findFullText')
  .addToUi();  
}

function findFullText() {
  
  var yourapikey = "REPLACEWITHYOURAPIKEY";
  var sheet = SpreadsheetApp.getActiveSpreadsheet();
  var numrows = sheet.getLastRow()+1;
  
  for( x=2 ; x<numrows ; x++){     
    var doi = sheet.getRange("C"+x).getValue();
    
    if (doi){
      var url = 'https://api.core.ac.uk/discovery/discover?doi='+doi+'&apiKey='+yourapikey;
      
      var options = {
        'method' : 'get',
        'contentType': 'application/json',
      };
      
      var response = UrlFetchApp.fetch(url, options);  
      var json = response.getContentText();
      var resultdata = JSON.parse(json);

      sheet.getRange("D"+x).setValue(resultdata.source);        
      
      var encodedURI = resultdata.fullTextLink.substring(48);
      sheet.getRange("E"+x).setValue(decodeURIComponent(encodedURI));
           
      Utilities.sleep(1000);
    }
  }
}