How can I pass an object with an embedded object from JavaScript (jQuery/ajax) to Python (Flask)?

Question

I am attempting to pass structured data from a web page to a flask handler, but I am getting key errors.

In the web page's JavaScript, I have an object that has two elements, one a value, the other an object.

The problem is on the Flask/Python side. I can get the first element ( "cid" ) with this:

print request.form ["cid"]

That works. But, I can't access or get to any of the att(ribute) values ( "att" ).

So, this, request.form ["att"] returns KeyError: 'att'

I am able to access request.form["att[sw1]"] but this is flattening my data type.

I'd like to get the att elements as a list or dictionary so that I can loop through them in my application. I essentially want request.form["att"]["sw1"] or request.form.att["sw1"] .

   var controllerData = {
              sw1  : $('#sw1').val(),
              sw2  : $('#sw2').val(),
              sw3  : $('#sw3').val(),
              sw4  : $('#sw4').val()}

   var updateData = {cid : 1, att: controllerData };

   $.ajax({
     type: "POST",
     url:  "/SetSettings",
     data: updateData,
     success: function(d) { },
     error: function(d) {alert('Error saving settings!');},
     dataType: "json"
   });

Answer 1

You must serialize your data object to string with JSON.stringify() .

$.ajax({
   type: "POST",
   url:  "/SetSettings",
   data: JSON.stringify(updateData),
   success: function(d) { },
   error: function(d) {alert('Error saving settings!');},
   dataType: "json"
});

PS: Some object, eg window or object containing cyclic dependencies cannot be serialized this way