How to post user generated photos to Facebook using Koala?

I'm using the Koala gem in a Rails 3.2 app.

I'm trying to post an action that includes a user generated photo to a Facebook application. According to FB's docs, the url I need to post to is:

https://graph.facebook.com/uid/namespace:action?object=http://path/to/page&image[0][url]=http://path/to/image.jpg&image[0][user_generated]=true

If I test this manually using Facebook's debugger, it works perfectly. But I'm having trouble achieving this with Koala.

I'm using the following method:

Koala::Facebook::API.new(app_token).put_connections( uid, namepsace:action, url )

If I use:

url = "http://path/to/page"

then the action is posted to Facebook correctly, but without the user generated photo.

If I use:

url = "http://path/to/page&image[0][url]=http://path/to/image.jpgimage[0][user_generated]=true"

I receive an error in the logs

#<Koala::Facebook::APIError: OAuthException: (#3502) Object at URL http://path/to/page&image[0][url]=http://path/to/image.jpg&image[0][user_generated]=true has og:type of 'website'. The property 'object' requires an object of og:type 'namespace:object'.  (http response code: 404)>

What is the correct way to construct the required post url using Koala? Or what is a good approach to begin debugging my current code? Or am I totally on the wrong track with this?

Solution

I struggled a ton with this too, both because of Facebook's documentation and Koala's which are not super clear in my opinion:

Koala::Facebook::API.new(access_token).put_connections(
  uid,
  "namespace:action",
  "product" => "[URL_TO_PRODUCT]",
  "image[0][user_generated]" => true,
  "image[0][url]" => "[URL_TO_USER_GENERATED_IMAGE]",
  "fb:explicitly_shared" => true,
  "message" => "[DESCRIPTION]"
)

The other thing was that the target URL had to have og:type="namespace:product"

Hope this helps