request_adapter.rb

module Api
  class RequestAdapter
    delegate :subject, :subject_id, :collection, :collection_id, :subcollection, :subcollection_id, :subcollection?, :path, :version?, :to => :href

    def initialize(req, params)
      @request = req
      @params = params
    end

    def to_hash
      [:method, :action, :fullpath, :url, :base,
       :path, :prefix, :version, :api_prefix,
       :collection, :c_suffix, :collection_id, :subcollection, :subcollection_id]
        .each_with_object({}) { |attr, hash| hash[attr] = send(attr) }
    end

    def action
      # for basic HTTP POST, default action is "create" with data being the POST body
      @action ||= case method
                  when :get         then 'read'
                  when :put, :patch then 'edit'
                  when :delete      then 'delete'
                  when :options     then 'options'
                  else json_body['action'] || 'create'
                  end
    end

    def api_prefix
      @api_prefix ||= "#{base}#{prefix}"
    end

    def api_suffix
      @api_suffix ||= "?provider_class=#{@params['provider_class']}" if @params['provider_class']
    end

    def attributes
      @attributes ||= @params['attributes'].to_s.split(',')
    end

    def base
      url.partition(fullpath)[0] # http://target
    end

    def c_suffix
      @params[:c_suffix]
    end

    def expand?(what)
      expand_requested.include?(what.to_s)
    end

    def hide?(thing)
      @hide ||= @params["hide"].to_s.split(",")
      @hide.include?(thing)
    end

    def json_body
      @json_body ||= begin
                       body = @request.body.read if @request.body
                       body.blank? || body == "null" ? {} : JSON.parse(body)
                     end
    end

    def method
      @method ||= @request.request_method.downcase.to_sym # :get, :patch, ...
    end

    def version
      @version ||= if version?
                     href.version[1..-1] # Switching API Version
                   else
                     ManageIQ::Api::VERSION # Default API Version
                   end
    end

    def url
      @request.url # http://target/api/...
    end

    def prefix(version = true)
      prefix = "/#{path.split('/')[1]}" # /api
      return prefix unless version
      version? ? "#{prefix}/#{href.version}" : prefix
    end

    def href
      @href ||= Href.new(url)
    end

    def resources
      if json_body.key?("resources")
        json_body["resources"]
      else
        [resource]
      end
    end

    def resource
      json_body.fetch("resource", json_body.except("action"))
    end

    private

    def expand_requested
      @expand ||= @params['expand'].to_s.split(',')
    end

    def fullpath
      @request.fullpath # /api/...&param=value...
    end
  end
end