Flask cannot parse JSON in Tabulator AJAX request (using advanced configuration) - flask

Question

I regularly use Tabulator's setData() method. I usually set parameters in the URL args, and have no problems with it. But I now have a complex use case that will be easier to solve if I can put a JSON payload into the request.
I've followed the Tabulator documentation for an advanced configuration.
I've made a series of attempts (putting the JSON in various places, using quotes/double quotes in the JSON, etc) at trying to work out the problem. The Flask server always returns this error:
Failed to decode JSON object: Expecting value: line 1 column 1 (char 0)
What makes me suspect the problem is with Tabulator, not Flask, is because I printed request.__dict__ and couldn't find the JSON in the request. (I.e. that seems to the reason for the error.)
The below example, which triggers the same error, is taken from the Fetch documentation (Tabulator uses the Fetch API).
Is there anything wrong with the below or should I be looking harder at Flask?
const data = { username: 'example' };
var ajaxURL = "/data/results";
var ajaxConfig = {
method:"POST",
headers: {
'Content-Type': 'application/json',
'X-CSRFToken': csrf_token,
},
body: JSON.stringify(data)
};
ResultsTable.setData( ajaxURL, {}, ajaxConfig);
Notes:
I'm using the latest version of Tabulator (4.9).
ResultsTable is set elsewhere in the code and is successfully loading default data when the page loads. The use case kicks in when the user sets their own parameters for the data.
The CSRF token, which is set elsewhere in the code, is there because Flask requires it.

Answer 1

The reason that is failing is that Tabulator will build out its own request body when it builds a request and that will override your config.
In your usage case, you will need to override the build in ajax request promise and add your own function that makes the ajax request and then resolves the data.
You can do this using the ajaxRequestFunc.
Checkout the Ajax Request Documentation for full details