Magento 2: Add color option to cart REST API

Question

I am calling this API to get product details:

GET https://domain.com/index.php/rest/V1/products/:SKU

and get this response:

<id>678</id>
  <sku>Mysku</sku>
  <name>myName</name>
  <attribute_set_id>4</attribute_set_id>
  <price>0</price>
  <status>1</status>
  <visibility>4</visibility>
  <type_id>configurable</type_id>
  <created_at>2017-04-23 15:01:05</created_at>
  <updated_at>2017-04-30 17:57:28</updated_at>
  <weight>0.1</weight>
  <extension_attributes>
    <configurable_product_options>
      <item>
        <id>38</id>
        <attribute_id>93</attribute_id>
        <label>Color</label>
        <position>0</position>
        <values>
          <item>
            <value_index>56</value_index>
          </item>
          <item>
            <value_index>61</value_index>
          </item>
          <item>
            <value_index>62</value_index>
          </item>
        </values>
        <product_id>678</product_id>
      </item>
    </configurable_product_options>
    <configurable_product_links>
      <item>675</item>
      <item>676</item>
      <item>677</item>
    </configurable_product_links>
  </extension_attributes>
....

I have a color in response. How can I add color option to cart. I tried with:

POST https://domain/rest/V1/guest-carts/3f9a39f1524fb936d932b7e80a3e8cc1/items

Params: {

"cartItem" :
{
"sku" : "Mysku",
"qty" : 1,
"quoteId" : "3f9a39f1524fb936d932b7e80a3e8cc1",

   "productOption":{
            "extensionAttributes":{
                "customOptions":[
                    {
                        "optionId":"38",
                        "optionValue":"56"
                    }
                    ]
            }
        }

}
}

And get this error:

message "You need to choose options for your item."

I think I have something wrong in parameters. can any one help ?

Answer 1

Perhaps it's because you're using the custom options object - you need to use the "configurable_item_options" object to pass through the configurable attributes.

{
  "cartItem": {
    "item_id": 0,
    "sku": "string",
    "qty": 0,
    "name": "string",
    "price": 0,
    "product_type": "string",
    "quote_id": "string",
    "product_option": {
    "extension_attributes": {
       "configurable_item_options": [
         {
          "option_id": "string",
          "option_value": 0,
          "extension_attributes": {}
        }
      ]
    }
  },
  "extension_attributes": {}
  }
}