Woocommerce submit to payment gateway - wordpress

Question

I am developing wordpress plugin for Woocommerce payment.
As I can see I have to extend WC_Payment_Gateway and implement method "process_payment". I have looked into some examples and found that this method should return something like:
array(
'result' => 'success',
'redirect' => $redirectUrl
);
and then control is returned to WC_Checkout which will redirect to provided url.
Problem is that our payment provider requires to submit form to his page instead of redirect. Having that API restriction in mind I am asking what is the best way to connect with my payment provider?
Is there a way to submit form instead of redirection?

Answer 1

You can achieve it as illustrated and commented below by extending the WooCommerce WC_Payment_Gateway class with the following methods:
public function __construct() {
$this->id = 'my-payment-gateway';
$this->icon = plugins_url( '/path/to/image.extension', __FILE__ );
$this->has_fields = true;
$this->method_title = __( 'My Payment Gateway', 'txdomain' );
$this->method_description = __( 'Add some descriptions here.', 'txdomain' );
$this->init_form_fields();
$this->init_settings();
$this->title = $this->get_option( 'title' );
$this->description = $this->get_option( 'description' );
add_action( 'woocommerce_update_options_payment_gateways_' . $this->id, array(
$this,
'process_admin_options'
) );
// below is the hook you need for that purpose
add_action( 'woocommerce_receipt_' . $this->id, array(
$this,
'pay_for_order'
) );
}
// here, your process payment method, returning the pay for order page
// where you will can submit the form to your payment gateway providers' page
public function process_payment( $order_id ) {
$order = new WC_Order( $order_id );
return array(
'result' => 'success',
'redirect' => $order->get_checkout_payment_url( true )
);
}
// here, prepare your form and submit it to the required URL
public function pay_for_order( $order_id ) {
$order = new WC_Order( $order_id );
echo '<p>' . __( 'Redirecting to payment provider.', 'txtdomain' ) . '</p>';
// add a note to show order has been placed and the user redirected
$order->add_order_note( __( 'Order placed and user redirected.', 'txtdomain' ) );
// update the status of the order should need be
$order->update_status( 'on-hold', __( 'Awaiting payment.', 'txtdomain' ) );
// remember to empty the cart of the user
WC()->cart->empty_cart();
// perform a click action on the submit button of the form you are going to return
wc_enqueue_js( 'jQuery( "#submit-form" ).click();' );
// return your form with the needed parameters
return '<form action="' . 'https://example.com' . '" method="post" target="_top">
<input type="hidden" name="merchant_key" value="">
<input type="hidden" name="success_url" value="">
<input type="hidden" name="cancelled_url" value="">
<input type="hidden" name="deferred_url" value="">
<input type="hidden" name="invoice_id" value="">
<input type="hidden" name="total" value="">
<div class="btn-submit-payment" style="display: none;">
<button type="submit" id="submit-form"></button>
</div>
</form>';
}