POST data not appearing in CakePHP controller

Don't encode post data as json

The code in the question won't appear in any php script, the reason is this:

contentType: "json"

It's not a form-url-encoded request, so e.g. the following code:

print_r($_POST);print_r(file_get_contents('php://input'));

will output:

Array()'{"customer":123}'

If you want to submit data as json, you'll need to read the raw request body:

$data = json_decode(file_get_contents('php://input'));

There might be times when that's desirable (api usage), but that isn't the normal way to use $.post.

The normal way

The normal way to submit data, is to let jQuery take care of encoding things for you:

$.ajax({      url: "/orders/finalize_payment",      type: "POST",      dataType: "json",  // this is optional - indicates the expected response format    data: {"customer": customer_id},      success: function(){                     alert("success");      }});

This will submit the post data as application/x-www-form-urlencoded and be available as $this->request->data in the controller.

Why $.post works

I changed the request from AJAX to $.post and it worked. I still have no clue why

Implicitly with the updated code in the question you have:

• removed the JSON.stringify call
• changed from submitting json to submitting application/x-www-form-urlencoded

As such, it's not that $.post works and $.ajax didn't ($.post infact just calls $.ajax) - it's that the parameters for the resultant $.ajax call are correct with the syntax in the question.

As you're using CakePHP you may find adding RequestHandler to your components fixes the problem.

public $components = array([snip], 'RequestHandler');

Doing this allowed me to transparently access JSON posted data using $this->request->data. The other answer's advice to not encode POST data as JSON becomes a bit awkward, given that certain JS frameworks, such as Angular, post JSON as default.

Using raw data and json you can use:

$data = $this->request->input('json_decode');

**Data is an object now, not an array.

Then you can use:

  $this->MyModel->save($data).