Create a draft order from the cart, with Mechanic.

Mechanic is an automation development platform for Shopify. :)

Create a draft order from the cart

by Isaac Bowen (team@usemechanic.com)

Use this task as a starting point, for allowing visitors to submit their carts to be transformed into draft orders, associated with their customer account. Installing and customizing this task requires some level of comfort with Liquid, HTML, and JavaScript.

Runs . Configuration includes shared secret, mechanic webhook event topic, and mechanic webhook url.

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Documentation

Installation

  1. Create a Mechanic webhook (learn how), and update this task's options to reflect the webhook's configuration.
  2. In an appropriate place in your cart template, add a button to send the cart data to Mechanic. Use the following code to get started:

    <input
      type="button"
      id="mechanic_cart_submit"
      value="Send to Mechanic"
      data-cart="{{ cart | json | escape }}"
      data-customer-id="{{ customer.id | json | escape }}"
      data-customer-id-signature="{{ customer.id | hmac_sha256: "secret!" | json | escape }}"
    >
    

    Note the "secret!" - this must match the "Shared secret" option you choose in the task's configuration.

  3. Adjust to taste. :) The code in the task script and in the online storefront JavaScript are meant to be a beginning point, as you build out the experience you're looking for. If you have any questions about the Mechanic side of this, get in touch!

Developer details

Mechanic is designed to benefit everybody: merchants, customers, developers, agencies, Gurus, everybody.

That’s why we make it easy to configure automation without code, why we make it easy to tweak the underlying code once tasks are installed, and why we publish it all here for everyone to learn from.

Events
Options
shared secret (required), mechanic webhook event topic (required), mechanic webhook url (required)
Script
{% assign line_items = array %}

{% for item in event.data.cart.items %}
  {% assign line_item = hash %}
  {% assign line_item["variant_id"] = item.variant_id %}
  {% assign line_item["quantity"] = item.quantity %}
  {% assign line_items[line_items.size] = line_item %}
{% endfor %}

{% if event.data.customerId %}
  {% assign expected_signature = event.data.customerId | hmac_sha256: options.shared_secret__required %}
  {% if expected_signature == event.data.customerIdSignature %}
    {% assign customer_id = event.data.customerId %}
  {% endif %}
{% endif %}

{% action "shopify" %}
  [
    "create",
    "draft_order",
    {
      "customer": {
        "id": {{ customer_id | json }}
      },
      "line_items": {{ line_items | json }}
    }
  ]
{% endaction %}
Mechanic tasks are written in Liquid, which makes them easy to write and easy to modify. Learn more about our platform.
Online store JavaScript
$('#mechanic_cart_submit').click(function(event) {
  event.preventDefault();

  $.ajax({
    url: {{ options.mechanic_webhook_url__required | json }},
    data: JSON.stringify({
      cart: JSON.parse(this.dataset.cart),
      customerId: JSON.parse(this.dataset.customerId),
      customerIdSignature: JSON.parse(this.dataset.customerIdSignature)
    }),
    contentType: 'application/json',
    method: 'POST',
  });
});
When this task is installed, this code is loaded into the online storefront using a ScriptTag.