Not able to read nested properties from doPost(e) - google-apps-script

Question

I am trying to create a webservice using the Contentservice in Apps Script and doPost(e) function to interact with Google Apps AdminDirectory service
Here is the overview of my code. I saved this as my server and published it as a websapp
function doPost(e) {
var data = e.parameter;
var resourceType = data.resourceType;
var method = data.method;
var resource = data.resource;
var resourceParams = resource.parameters;
//other code to work with AdminDIrectory
// return ContentService.createTextOutput(myoutputdata).setMimeType(ContentService.MimeType.JSON);
}
In my client code which I wrote using Apps Script to test the webservice
function test() {
var jsonData = {
authKey : 'HwZMVe3ZCGuPOhTSmdcfOqsl12345678',
resourceType : 'user',
method : 'get',
resource : {
parameters : {
userKey : 'waqar.ahmad#mydomain.com'
}
}
}
var url = 'https://script.google.com/macros/s/xyzabc12345678_wE3CQV06APje6497dyI7Hh-mQMUFM0pYDrk/exec';
var params = {
method : 'POST',
payload : jsonData
}
var resp = UrlFetchApp.fetch(url, params).getContentText();
Logger.log(resp);
}
Now when I try to read e.parameter.resource.parameters on server side, it gives error and shows that e.parameter.resource is string type.
How I can read nested objects on server side? It seems, it is recognizing only first level parameters.

Answer 1

Using
function doPost(e) {
return ContentService.createTextOutput(JSON.stringify(e.parameter)).setMimeType(ContentService.MimeType.JSON);
You get the response
"{"authKey":"HwZMVe3ZCGuPOhTSmdcfOqsl12345678","resource":"{parameters={userKey=waqar.ahmad#mydomain.com}}","method":"get","resourceType":"user"}"
so it looks like it is flattening any nests into a string. In the comments of a similar problem it is noted that the documentation for UrlFetchApp permits the payload to be "It can be a String, a byte array, or a JavaScript key/value map", but I assume this doesn't extend to nested key/value maps.
As noted in the other answer the solution would be to stringify the payload e.g.
var params = {
method : 'POST',
payload : {'data':JSON.stringify(jsonData)}
};
I had problems handling the payload just as a string which is why I used a key value
On the server side script you can handle with
function doPost(e) {
var data = JSON.parse(e.parameter.data);
var userKey = data.resource.parameters.userKey;
...
}

Answer 2

Maybe it arrives as JSON string? If that's the case you'd have to parse it back-end, something like:
resourceObj = JSON_PARSE_METHOD(e.parameter.resource);
for example in PHP this would be
$resourceObj = json_decode(e->parameter->resource);
You could find out if it's a JSON string by printing its value (or debugging it) on the backend.
Hope this helps. Cheers