(feat) - WIP - embed the proxy client in the main SDK.

To allow code re-use.
Need to add unit tests, caching based on context, bootstrapping and be sure that the proxy client SDK mirrors the general client.

lib/unleash/context.rb

@@ -32,6 +32,24 @@ def get_by_name(name)
       end
     end
 
+    # provide the context as expected by the url params
+    # TODO(rarruda): add unit test
+    def as_uri_params
+      [*ATTRS, :properties]
+        .flatten
+        .reject{ |k| self.send(k).nil? }
+        .map do |k|
+        if k == :properties
+          self.properties
+            .map{ |property, pval| "properties[#{property}]=#{pval}" }
+            .join("&")
+        else
+          "#{k}=#{self.send(k)}"
+        end
+      end
+        .join("&")
+    end
+
     private
 
     # Method to fetch values from hash for two types of keys: string in camelCase and symbol in snake_case

lib/unleash/proxy/client.rb

@@ -0,0 +1,72 @@
+require 'unleash/util/http'
+require 'unleash/context'
+
+module Unleash
+  module Proxy
+    class Client
+      attr_accessor :proxy_url, :proxy_http_headers, :toggles
+
+      def initialize(opts)
+        self.proxy_url = opts[:proxy_url]
+        self.proxy_http_headers = opts[:proxy_http_headers]
+      end
+
+      def is_enabled?(feature, context = nil, default_value_param = false, &fallback_blk)
+        Unleash.logger.debug "Unleash::Client.is_enabled? feature: #{feature} with context #{context}"
+
+        retrieve_toggles
+
+        default_value = if block_given?
+                          default_value_param || !!fallback_blk.call(feature, context)
+                        else
+                          default_value_param
+                        end
+
+        toggle_as_hash = toggles.select{ |toggle| toggle['name'] == feature }&.first
+
+        if toggle_as_hash.nil?
+          Unleash.logger.debug "Unleash::Client.is_enabled? feature: #{feature} not found"
+          return default_value
+        end
+
+        !!toggle['enabled']
+      end
+
+      # enabled? is a more ruby idiomatic method name than is_enabled?
+      alias enabled? is_enabled?
+
+      # execute a code block (passed as a parameter), if is_enabled? is true.
+      def if_enabled(feature, context = nil, default_value = false, &blk)
+        yield(blk) if is_enabled?(feature, context, default_value)
+      end
+
+      def get_variant(feature, _context = Unleash::Context.new, fallback_variant = Unleash::FeatureToggle.disabled_variant)
+        retrieve_toggles
+
+        toggle_as_hash = toggles.select{ |toggle| toggle['name'] == feature }&.first
+
+        return Unleash::Variant.new(toggle_as_hash['variant']) if toggle_as_hash.is_a?(Hash) && toggle_as_hash.has_key?('variant')
+
+        fallback_variant
+      end
+
+      private
+
+      def retrieve_toggles
+        request_url = self.proxy_url.dup
+        request_url += "?#{context.as_uri_params}" unless context.nil?
+
+        # Send the request, if possible
+        begin
+          toggles_response = Unleash::Util::Http.get(request_url, nil, self.proxy_http_headers)
+        rescue StandardError => e
+          Unleash.logger.error "unable to retrieve toggles from the unleash server due to exception #{e.class}:'#{e}'."
+          Unleash.logger.error "stacktrace: #{e.backtrace}"
+        end
+
+        self.toggles = JSON.parse(toggles_response)['toggles']
+        # TODO(rarruda): handle malformed responses
+      end
+    end
+  end
+end