IssueTracker

A short description of the issue:
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I have several scripts that have been in place for years that enabled us to automate queries of systems like Salesforce and use that data in Workspace (i.e .Google Sheets). In this case, the key components are:
1) Apps Script script created web app (including doGet(e) function, deployed  as a web app, run as me, available to anyone in the Workspace domain)
2) Apps Script script calling the web app via URLFetchApp.fetch (this call passes in the query that the web app uses to pass to the other system)

Note, I have already performed troubleshooting to ensure there is no issue with OAuth and my ability to query Salesforce. A test query using the service returns expected data. In addition, I've created  a test script that calls a test web app with a simple doGet() function, and even that is failing.

What I've narrowed it down to is it appears that URLFetchApp is not passing along the credentials of the user executing the script. When I paste the web app URL (including added parameters), the web app functions and displays the expected output.

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A small code sample that reliably reproduces the issue. The sample should run as-is or with minimal setup, without external dependencies.
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Function deployed as web app (deployment type = web app; execute as=me; who has access=anyone within my domain)
function doGet(e) {
  var params = JSON.stringify(e);
 
  return HtmlService.createHtmlOutput(params);
}

Function calling web app
function testWebApp() {

    var options =
      {
        "method" : "GET",  
        "followRedirects" : true,
        "muteHttpExceptions": true
      };

        var url = "https://script.google.com/a/macros/mydomain.com/s/<ID of web app>/exec?name=test-script";
        var response = UrlFetchApp.fetch(url, options);
        Logger.log(response.getContentText());

}

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What steps will reproduce the problem?
1.*****Create script for web app
2.*****Deploy web app (deployment type = web app; execute as=me; who has access=anyone within my domain)
3.*****Create script to call web app
4.*****Run web app via broswer (should get success)
5.*****Run web app via URLFetchApp (should get failure)

What is the expected output? What do you see instead?  If you see error messages, please provide them.
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Expected:
In the test script I include, the web app should simple parse and log/display the parameters sent to the web app

What is returned on failure:
In my testing, the return of URLFetchApp.fetch is the Google Sign In page. This is after the executing user 'allows' the access external services prompt and with no additional authentication required for the web app

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Please provide any additional information below.
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The scripts that have been running using this configuration have been in place for years without issue. The last successful run looks like it was on March 30, 2022.