setValue(contLength) is returning unexpected value - http-headers

Question

Here is the complete script.
function check() {
var ss = SpreadsheetApp.getActiveSpreadsheet();
var sheet1 = ss.getSheets()[0];
var dataRange = sheet1.getDataRange().getValues();
for (var i = 1; i < dataRange.length; i++) {
var stringToDisplay=dataRange[i][0];
var result = UrlFetchApp.fetch(stringToDisplay);
var date=result.getHeaders()['Date'];
var contType=result.getHeaders()['Content-Type'];
var contLength=result.getHeaders()['Content-Length'];
for(j=0;j<10;j++)
{
if(contLength=="undefined")
{
var contLength=result.getHeaders()['Content-Length'];
}
}
var server=result.getHeaders()['Server'];
var exp=result.getHeaders()['Expires'];
var resp=result.getResponseCode();
var myDate=new Date();
sheet1.getRange(i+1,2).setValue(date);
sheet1.getRange(i+1,3).setValue(contLength);
sheet1.getRange(i+1,4).setValue(contType);
sheet1.getRange(i+1,5).setValue(server);
sheet1.getRange(i+1,6).setValue(exp);
sheet1.getRange(i+1,7).setValue(resp);
sheet1.getRange(i+1,8).setValue(myDate.toString());
}
}
I am expecting a int value here - sheet1.getRange(i+1,3).setValue(contLength). Instead it is bringing either undefined or int value, every-time the script is executed.
What could be the issue here?
Thanks,
Samir

Answer 1

While trying to debug your issue, I've added the Utilities.Sleep(1000) function to give it some time, but it gets stuck at 5 out of 17 having 'undefined'. All have "text/html; charset=utf-8" as Content-Type. It could be that only the Apache-Servers deliver the correct format (as they result in an integer). You should look at that next, to see if it's the issue.
See my shared doc.