title: Magento 1.9.X add product with custom options to cart from external site
body: <p>I have an external website which allows a customer to design a product, then uses an HTML form to post this data.  I need to take this information and add this product (with custom options) to the customer's cart in our Magento website, but I'm not sure how to go about this.</p>
  
  <p>I tried something simple at first using URL redirect, but Magento 1.9.X no longer supports adding to cart like this:</p>
  
  <pre><code>$cart_url = "website.com/checkout/cart/add/product=" . $product_id . "&amp;qty=1" //Include custom options somehow
  
  &lt;form action=&lt;?php echo $cart_url?&gt;&gt;
       &lt;input type="hidden" value="pid"&gt; product id &lt;/input&gt;
       &lt;input type="hidden" value="option1"&gt; custom option 1&lt;/input&gt;
  &lt;/form&gt;
  </code></pre>
  
  <p>Doing research shows that I can also add an item with custom options through either writing a custom Controller or Events/Observers to add the item, but as I'm new to Magento I'm not sure how to trigger events and observer functions from outside of Magento.</p>
  
  <p>Any help to point me in the right direction would be appreciated.</p>