google-apps-script - UrlFetchApp.fetch(url) 间歇性 "Unexpected error"

Question

为了检查 HTTP 服务状态，我编写了脚本，通过电子表格检查 URL 列表，检查它们是向上还是向下，脚本每五分钟驱动一次。

我有罕见的间歇性“意外错误”错误来自 UrlFetchApp.fetch(url) 和来自
如果我在几秒钟后重复请求，有时会出现 DNS 和超时错误。

如果有人可以提供帮助，没有几个实际问题:
我用 Utilities.sleep(5000) 暂停了 5 秒，
可以吗，或者有更好的等待方式
几秒钟后再次尝试获取？

为什么即使我在 5 秒后重复请求也会收到“意外错误”
五分钟后再次运行没有“意外错误”!？

我怎样才能改进下面的代码？

实际脚本:

/* 
Periodically check status of web sites :-)
Google Apps for Busines UrlFetch daily limit is 100.000 requests,

Algorithm
  read site and old status from sheet
  check site and set new status  
  if status changed send email (+sms in future by using twilio)
  update status in spreadsheet

"Site, Status code, Time of last change, Last error description"
*/
function main() {
  var sheet = SpreadsheetApp.getActiveSheet() ;
  var currentRow, oldStatusCode, newStatusCode ;
  var url, response, err, subject, message ; 
  var today = new Date() ;

  currentRow = 2
  while ((url = sheet.getRange(currentRow, 1).getValue()) != "") {
    oldStatusCode = sheet.getRange(currentRow, 2).getValue() ;
    newStatusCode = "Ok"
    subject = "mCheck: " + url + " Up Status Change!" ;  
    message = url + " Up Status Change!" + "\n Time: " + today.toUTCString() ;

    var tries = 3 ; // Check at least three times that status changed and it is not a one time glitch
    do {
      try {
        response = UrlFetchApp.fetch(url) ;
      } catch (err) {
      newStatusCode = "Down"
      sheet.getRange(currentRow, 4).setValue(err.message) ;
      subject = "mCheck: " + url + " Down Status Change!" ;  
      message = url + " Down Status Change!" + "\n Error message: " + err.message + "\n Time: " + today.toUTCString() ;
      if (err.message.indexOf("Unexpected") > -1) { // If UrlFetch failed on Google side just ignore this iteration...
        newStatusCode = oldStatusCode ;
      }
    }
    if (oldStatusCode != newStatusCode) { // In case of status change wait 5 seconds before trying again
      Utilities.sleep(5000) ;
    }
    --tries ;
  } while ((oldStatusCode != newStatusCode) && tries >= 0)

  if (oldStatusCode != newStatusCode) {
    sheet.getRange(currentRow, 2).setValue(newStatusCode) ;
    sheet.getRange(currentRow, 3).setValue(today.toUTCString()) ;
    if (oldStatusCode != "") {
      MailApp.sendEmail(email_to, subject, message) ;
    }
  }
  ++currentRow;
 } 

}

Answer 1

您可以使用 muteHttpExceptions parameter用于捕获故障。如果响应代码指示失败，则 fetch 不会抛出异常，而是返回 HTTPResponse。

sample

var params = {muteHttpExceptions:true};
response = UrlFetchApp.fetch(url, params);

你可以 use a cURL或类比 Sheldue。

sample

curl 。将此设置在您的操作系统中。

curl -L URL_OF_YOUR_SCRIPT

添加到脚本

function doGet(e) {
    var result = {'status': 'ok'};
    try{
        main();
    }catch(err){
        result.['status'] = err;
    }
  return ContentService.createTextOutput(JSON.stringify(result)).setMimeType(ContentService.MimeType.JSON);
 }

您应该 deploy your script as a Web App为了这。

如果您将使用第二个示例，则不再需要 Utilities.sleep(5000)。

最好的事物。