How to catch UrlFetchApp.fetch exception

Question

Is there any way to catch the exception from UrlFetchApp.fetch?

I thought I can use response.getResponseCode() to check the response code, but I'm not able to, for e.g when there is 404 error, the script not continue and just stop at UrlFetchApp.fetch

Eric Koleda · Accepted Answer · 2014-06-26T14:37:37.323

32

Edit: This parameter is now documented here.

You can use the undocumented advanced option "muteHttpExceptions" to disable exceptions when a non-200 status code is returned, and then inspect the status code of the response. More information and an example is available on this issue.

edited Jun 26 '14 at 14:37

answered Jul 30 '12 at 20:32

Eric Koleda

12,420
1
33
51

score 32 · Answer 2 · answered Mar 02 '16 at 14:52

The trick is passing the muteHttpExceptions param of UrlFetchApp.fetch().

Here an example (untested):

var payload = {"value": "key"}
var response = UrlFetchApp.fetch(
            url,
            {
              method: "PUT",
              contentType: "application/json",
              payload: JSON.stringify(payload),
              muteHttpExceptions: true,
            }
          );
var responseCode = response.getResponseCode()
var responseBody = response.getContentText()

if (responseCode === 200) {
  var responseJson = JSON.parse(responseBody)
  // ...
} else {
  Logger.log(Utilities.formatString("Request failed. Expected 200, got %d: %s", responseCode, responseBody))
  // ...
}

For some reason if the URL is not available (e.g. the service you're trying to use is down) it still looks like is throwing an error so you may still need to use a try/catch block.

Waqar Ahmad · Answer 3 · 2012-07-30T09:49:01.037

3

why don't you use try catch and handle the error in catch block

try{
    //Your original code, UrlFetch etc
  }
  catch(e){
    // Logger.log(e);
    //Handle error e here 
    // Parse e to get the response code
  }

edited Jul 30 '12 at 09:49

answered Jul 30 '12 at 09:37

Waqar Ahmad

3,716
1
16
27

Thanks for quick response. Is it possible to find out what is the response code when there is exception? – louis Jul 30 '12 at 09:43
1

You will get an error string in e which you can parse to get the error code. – Waqar Ahmad Jul 30 '12 at 09:48
2

But parsing `e` is not that straight forward, since UrlFetchApp wraps the response inside a text message.. I won't suggest this method. – Shay Yzhakov Feb 12 '20 at 09:44

Shay Yzhakov · Answer 4 · 2020-02-12T09:55:15.413

You can manually parse the caught error, but it's not recommended. When catching the exception (that is being thrown in case muteHttpExceptions is turned off), the error object would be in the following format:

{
   "message": "Request failed for ___ returned code___. Truncated server response: {___SERVER_RESPONSE_OBJECT___} (use muteHttpExceptions option to examine full response)",
   "name": "Exception",
   "fileName": "___FILE_NAME___",
   "lineNumber": ___LINE_NUMBER___,
   "stack": "___STACK_DETAILS___"
}

If you for some reason prefer not using muteHttpExceptions, you could catch the exception e, look at e.message, substring the text between "Truncated server response: " and " (use muteHttpExceptions option to examine full response)", JSON.parse() it, and the returned object would be the error returned from the api call.

I wouldn't suggest it over muteHttpExceptions, just wanted to show the best way to get the error object this way.

Anyways, try-catch your UrlFetchApp.fetch() call to make sure you catch the unhandled exceptions, like 404.

How to catch UrlFetchApp.fetch exception

4 Answers4

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