How to fix cart codeigniter?

CONTROLLER

In my controller I add product like this, cart is redirecting but not adding a product, how can this be fixed?

function tambah()
{
    $data_produk= array('id'          => $this->input->post('id'),
                        'nama_produk' => $this->input->post('nama_produk'),
                        'harga'       => $this->input->post('harga'),
                        'gambar'      => $this->input->post('gambar'),
                        //'seller'    => $this->input->post('seller'),
                        'qty'     => $this->input->post('qty')
                    );
    //die(print_r($data_produk));
    $this->cart->insert($data_produk);

    $cart = $this->cart->contents();

    if(!empty($cart)){
        // print_r($cart);
    }
    redirect('product');
}

VIEW ;

<div class="col-md-8">
    <div class="product_list">
        <div class="row">
        <?php foreach($shopall as $row){ ?>
            <div class="col-lg-6 col-sm-6">
                <div class="single_product_item">
                     <img src="assets/img/categori/product1.png" alt="" class="img-fluid">
                     <div class="card_area">

                     <form action="<?php echo base_url();?>cart/tambah" method="post" accept-charset="utf-8">
                         <div class="product_count_area" style="margin:-40PX -35PX 0PX 0PX;">
                             <p style="text-align:center;">Rp. <?php echo number_format($row['harga'],0,",",".");?></p>
                             <div class="product_count d-inline-block">
                                 <span class="product_count_item inumber-decrement"> <i class="ti-minus"></i></span>
                                 <input class="product_count_item input-number" name="qty" type="number" value="1" min="1" max="99">
                                  <span class="product_count_item number-increment"> <i class="ti-plus"></i></span>
                              </div>
                           </div>
                           <p><a href="<?php echo base_url('cart/detail/'.$row['id']) ?>"><?php echo $row['nama_produk'] ?></a></p>

                           <input type="hidden" name="id" value="<?php echo $row['id']; ?>" />
                           <input type="hidden" name="nama_produk" value="<?php echo $row['nama_produk']; ?>" />
                           <input type="hidden" name="harga" value="<?php echo $row['harga']; ?>" />
                           <input type="hidden" name="gambar" value="<?php echo $row['gambar']; ?>" />
                           <div style="text-align:center; margin:-20px;" class="add_to_cart">
                           <!--<button type="submit" class="btn_3">add to cart</button>-->
                           <button type="submit" class="btn btn-sm btn-success"><i class="glyphicon glyphicon-shopping-cart"></i> Beli</button>
                       </div>
                   </form>
                   </div>
            </div>
        </div>
    <?php } ?>  
    </div>
    <div class="load_more_btn text-center">
        <a href="#" class="btn_3">Load More</a>
    </div>
  </div>
</div>

In my last project I could use cart functionality with it, but in this project cart remains empty, can you point me where my code is wrong?

Solution

Codeigniter Cart Using English in it array keys, (unless you modified it somehow)

This should work - Notes: Add any extra data you may need to save under options, don't define your own array key. check here for more Codeingiter Cart

  $data_produk = array(
        'id'      => 'sku_123ABC',
        'qty'     => 1,
        'price'   => 39.95,
        'name'    => 'T-Shirt',
        'options' => array('Size' => 'L', 'Color' => 'Red')
);

instead of this

$data_produk= array('id' => $this->input->post('id'),
                        'nama_produk' => $this->input->post('nama_produk'),
                        'harga'       => $this->input->post('harga'),
                        'gambar'      => $this->input->post('gambar'),
                        //'seller'    => $this->input->post('seller'),
                        'qty'     => $this->input->post('qty')
                    );

Try to map that according to your language