Ruby Gem Rest-Client vs cURL, HTTP 415

Question

I have a cURL call that works but when I translate it using the Ruby Gem rest-client I get:

RestClient::UnsupportedMediaType: 415 Unsupported Media Type

Here is the cURL I used that worked:

curl \
-X POST \
-H "Content-Type:application/json" \
-H "Authorization: Bearer MY_TOKEN" \
-H "Amazon-Advertising-API-Scope: MY_SCOPE" \
-d '{"campaignType":"sponsoredProducts","reportDate":"20161013","metrics":"impressions,clicks,cost"}' \
https://advertising-api.amazon.com/v1/productAds/report

Here is the Ruby that returns the HTTP 415 status:

yesterday = Date.today - 1
RestClient::Request.execute(
  method:  :post,
  url:     'https://advertising-api.amazon.com/v1/productAds/report',
  headers:
  {
    'Content-Type'                 => 'application/json',
    'Authorization'                => "Bearer #{ENV['AD_ACCESS_TOKEN']}",
    'Amazon-Advertising-API-Scope' => ENV['AD_PROFILE_ID']
  },
  payload:
  {
    'campaignType' => 'sponsoredProducts',
    'reportDate' => "#{yesterday.year}#{yesterday.month}#{yesterday.day}",
    'metrics' => 'impressions,clicks,cost'
  }
)

Answer 1

The payload hash needed to be converted to JSON.

...
payload:
{
  ...
}.to_json
...