Data is not posting showing Internal server error - php

Question

On click of buy now button product should add to cart button but it's not showing cart button even control is not going inside success function it is showing Internal server error when i refresh my page in cart button product is showing but it should work on click. How to resolve this?
Error in console showing like below:
Failed to load resource: the server responded with a status of 500
(Internal Server Error)
HTML code:
<button type="button" id="button-cart" data-loading-text="Loading..." class="btn btn-primary btn-lg btn-block buynow"><span class="bagImg mybtm"><i></i>Buy Now</span></button>
Jquery code:
$('#button-cart').on('click', function() {
$.ajax({
url: 'index.php?route=checkout/cart/add',
type: 'post',
data: $('#product input[type=\'text\'], #product input[type=\'hidden\'], #product input[type=\'radio\']:checked, #product input[type=\'checkbox\']:checked, #product select, #product textarea'),
dataType: 'json',
beforeSend: function() {
$('#button-cart').button('loading');
},
complete: function() {
$('#button-cart').button('reset');
},
success: function(json) {
console.log(json);
$('.alert, .text-danger').remove();
$('.form-group').removeClass('has-error');
if (json['error']) {
if (json['error']['option']) {
for (i in json['error']['option']) {
var element = $('#input-option' + i.replace('_', '-'));
if (element.parent().hasClass('input-group')) {
$('.breadcrumb').after('<div class="alert alert-danger">' + json['error']['option'][i] + '</div>');
} else {
$('.breadcrumb').after('<div class="alert alert-danger">' + json['error']['option'][i] + '</div>');
}
}
}
if (json['error']['recurring']) {
$('select[name=\'recurring_id\']').after('<div class="text-danger">' + json['error']['recurring'] + '</div>');
}
// Highlight any found errors
$('.text-danger').parent().addClass('has-error');
}
if (json['success']) {
$('.breadcrumb').after('<div class="alert alert-success">' + json['success'] + '<button type="button" class="close" data-dismiss="alert">×</button></div>');
$('#cart-total').html(json['total']);
$('#cart > ul').load('index.php?route=common/cart/info ul li');
}
$('html, body').animate({ scrollTop: 0 }, 'slow');
window.location.href='checkout/checkout';
},
error: function(json){
console.log(json);
}
});
});
Controller function:
public function add() {
$this->load->language('checkout/cart');
$json = array();
if (isset($this->request->post['product_id'])) {
$product_id = (int)$this->request->post['product_id'];
} else {
$product_id = 0;
}
$this->load->model('catalog/product');
$product_info = $this->model_catalog_product->getProduct($product_id);
if ($product_info) {
if (isset($this->request->post['quantity'])) {
$quantity = (int)$this->request->post['quantity'];
} else {
$quantity = 1;
}
if (isset($this->request->post['option'])) {
$option = array_filter($this->request->post['option']);
} else {
$option = array();
}
$product_options = $this->model_catalog_product->getProductOptions($this->request->post['product_id']);
foreach ($product_options as $product_option) {
if ($product_option['required'] && empty($option[$product_option['product_option_id']])) {
$json['error']['option'][$product_option['product_option_id']] = sprintf($this->language->get('error_required'), $product_option['name']);
}
}
if (isset($this->request->post['recurring_id'])) {
$recurring_id = $this->request->post['recurring_id'];
} else {
$recurring_id = 0;
}
$recurrings = $this->model_catalog_product->getProfiles($product_info['product_id']);
if ($recurrings) {
$recurring_ids = array();
foreach ($recurrings as $recurring) {
$recurring_ids[] = $recurring['recurring_id'];
}
if (!in_array($recurring_id, $recurring_ids)) {
$json['error']['recurring'] = $this->language->get('error_recurring_required');
}
}
if (!$json) {
$this->cart->add($this->request->post['product_id'], $this->request->post['quantity'], $option, $recurring_id);
$json['success'] = sprintf($this->language->get('text_success'), $this->url->link('product/product', 'product_id=' . $this->request->post['product_id']), $product_info['name'], $this->url->link('checkout/cart'));
unset($this->session->data['shipping_method']);
unset($this->session->data['shipping_methods']);
unset($this->session->data['payment_method']);
unset($this->session->data['payment_methods']);
// Totals
$this->load->model('extension/extension');
$total_data = array();
$total = 0;
$taxes = $this->cart->getTaxes();
// Display prices
if (($this->config->get('config_customer_price') && $this->customer->isLogged()) || !$this->config->get('config_customer_price')) {
$sort_order = array();
$results = $this->model_extension_extension->getExtensions('total');
foreach ($results as $key => $value) {
$sort_order[$key] = $this->config->get($value['code'] . '_sort_order');
}
array_multisort($sort_order, SORT_ASC, $results);
foreach ($results as $result) {
if ($this->config->get($result['code'] . '_status')) {
$this->load->model('total/' . $result['code']);
$this->{'model_total_' . $result['code']}->getTotal($total_data, $total, $taxes);
}
}
$sort_order = array();
foreach ($total_data as $key => $value) {
$sort_order[$key] = $value['sort_order'];
}
array_multisort($sort_order, SORT_ASC, $total_data);
}
$json['total'] = sprintf($this->language->get('text_items'), $this->cart->countProducts() + (isset($this->session->data['vouchers']) ? count($this->session->data['vouchers']) : 0), $this->currency->format($total));
} else {
$json['redirect'] = str_replace('&', '&', $this->url->link('product/product', 'product_id=' . $this->request->post['product_id']));
}
}
$this->response->addHeader('Content-Type: application/json');
$this->response->setOutput(json_encode($json));
}

Answer 1

Resolved It... There was nothing wrong with the script / code.. On server enabled 755 permission through out the site and made 777 for Cache / Upload folders... That did the trick....
Thx all for the help and response... :)