302 Redirect Blues

[Shaun H]

I keep getting a "Moved Temporarily" (302 redirect) response when sending a basic curl command to a very simple doPost.

The project test is very simple - this is the entire Code.gs code:

function doPost(e) {

  return ContentService.createTextOutput(JSON.stringify({ message: "Received" }))

    .setMimeType(ContentService.MimeType.JSON);

}

I have tried creating both a personal and a workgroup Google account, both getting the same results.

I have tried it from a different network (home/personal).

The executions logs are not showing details - just that they have been "completed" without failing - but from the curl command side, a 302 is deadly.

I have set project settings with:
Execute as: Me
Who has access: Anyone
GCP Project: default

Here's the curl command I have used (with my id removed):
curl -X POST "https://script.google.com/macros/s/[removedforsecurity]/exec?action=processData" -H "Content-Type: application/json" -d "{\"upcCode\":\"089036422802\"}"

I have also tried:
curl -X POST "https://script.google.com/macros/s/ [removedforsecurity]  /exec" -H "Content-Type: application/json" -d "{\"upcCode\":\"089036422802\"}"

curl response is:
<!-- GSE Default Error -->
<H1>Moved Temporarily</H1>

The Execution logs are no help either; they report as completed without failing, but they also do not allow me to click on them either.  Even when I add a line: Logger.log("received") as the first line in the doPost.

Any thoughts as to how this can be resolved?

Thanks!

[DimuDesigns]

HTTP POST requests always redirect (302) for GAS Web Apps. 

The client making the request has to be able to follow the redirect to retrieve your JSON response payload - if it can't you're pretty much out of luck.

If you need to handle POST requests without a redirect then you have to leverage something other than GAS.

One option is to use a Google Cloud Run Function instead.

[Google Pony]

Solution to Google Apps Script 302 Redirect Issue

Q) Why It Happens?
A) Google Apps Script Web Apps always return a 302 redirect for POST requests. Some clients (like curl) do not follow redirects by default.

Recommended Solutions:

1. Use -L in Curl to Follow Redirects
curl -X POST -L "https://script.google.com/macros/s/[removed]/exec" \

     -H "Content-Type: application/json" \
     -d "{\"upcCode\":\"089036422802\"}"

2. Use fetch() in JavaScript (Auto-Follows Redirects)

fetch("https://script.google.com/macros/s/[removed]/exec", {

  method: "POST",

  headers: { "Content-Type": "application/json" },

  body: JSON.stringify({ upcCode: "089036422802" })

}).then(res => res.json())

  .then(data => console.log(data));

3. Switch to GET (If Possible)
 Modify Code.gs:

const doGet = (e) => ContentService.createTextOutput(JSON.stringify({ upcCode: e.parameter.upcCode })).setMimeType(ContentService.MimeType.JSON);

Use GET request:
curl -X GET "https://script.google.com/macros/s/[removed]/exec?upcCode=089036422802"

4. Use Google Cloud Run (For Full Control)
 If you need strict control over POST responses, migrate to Google Cloud Run.
Best Option: Use -L in curl or fetch() in JavaScript.
 For API control, consider Google Cloud Run.

Sincerely yours,

Sandeep Kumar Vollala

Developer - India