This is a really simple webhook implementation that gets Api.ai classification JSON (i.e. a JSON output of Api.ai /query endpoint) and returns a fulfillment response.
It's a google search fulfillment service that uses Custom Search API. The service takes parameters from the action and requests a more abstract search based on the user's initial naive question from Google's Custom Search API.
The service returns the result in the Api.ai webhook-compatible response JSON to Api.ai chatbot.