Can't Retrieve Post data from JQuery Ajax request in Code Igniter

Question

I am using AJAX to create a filtering mechanism, in my code i get the data from the filter fields and send them to the Controller through the AJAX request, when i receive the data i update the table accordingly.

This is my Ajax Script:

var suppliername = "Apple";
jQuery.ajax({            
    type: "POST",           
    url: "<?php echo base_url(); ?>index.php/Welcome/get",            
    dataType: "json",
    data: {
        supplier_name: suppliername,
    },
    success: function(html){
        console.log("yay");
        hot.loadData(html);         
    }        
}); 

And this is my Controller:

public function get(){
        $where="";

        $field="supplier_name";
        $value=$this->input->post($field);
        if($value!= null){
            $supplier_name = $value;
            $where = $where.$field.'="'.$value.'"';
            $where = $where." AND ";
        }
        else{
            $where = $where.$field.'='.$field;
            $where = $where." AND ";
        }

        $field="category";
        $value=$this->input->post($field);
        if($value!= null){
            $supplier_name = $value;
            $where = $where.$field.'="'.$value.'"';
            //$where = $where." AND ";
        }
        else{
            $where = $where.$field.'='.$field;
            //$where = $where." AND ";
        }

        echo json_encode($this->inventory_m->get(null,$where));
        die();
    }

when i manually edit the values in the controller the filter works perfectly, but when i use $this->input->post($field) it does nothing, i tried to print the get and post arrays and both are empty.

Answer 1

I am not allowed to comment so I am posting it as an answer.

Here is my solution and explanation for the problem. It has to do with CodeIgniter not being able to fetch JSON. jQuery does some under the hood tricks and transforms your data into form-data-x, that's why it works.

The solution is to use $this->input->raw_input_stream to fetch your JSON and decode it using php's json_decode. Check the full answer and code below:

Retrieve JSON POST data in CodeIgniter