include path parameters in params hash for ruby environment (#249)

* include path parameters in params hash for ruby environment

* Improve code organization and documentation for ruby environment.

* Document Ruby examples

environments/ruby/fission/context.rb

@@ -0,0 +1,17 @@
+# frozen_string_literal: true
+
+require_relative 'request'
+
+module Fission
+  class Context
+    attr_reader :env
+
+    def initialize(env)
+      @env = env
+    end
+
+    def request
+      @request ||= Request.new(env)
+    end
+  end
+end

environments/ruby/fission/handler.rb

@@ -0,0 +1,19 @@
+# frozen_string_literal: true
+
+require_relative 'context'
+
+module Fission
+  module Handler
+    def self.call(env)
+      response = if method(:handler).arity > 0
+        handler(Context.new(env))
+      else
+        handler
+      end
+
+      response.is_a?(Array) ? response : Rack::Response.new([response]).finish
+    rescue
+      Rack::Response.new(['500 Internal Server Error'], 500, {}).finish
+    end
+  end
+end

environments/ruby/fission/request.rb

@@ -0,0 +1,31 @@
+# frozen_string_literal: true
+
+module Fission
+  HEADER_PREFIX = 'HTTP_'
+  PARAM_HEADER_PREFIX = 'HTTP_X_FISSION_PARAMS_'
+  PARAMETERS_KEY = 'fission.request.parameters'
+
+  class Request < Rack::Request
+    def headers
+      Hash[
+        *env.select { |k,v| k.start_with?(HEADER_PREFIX) }
+             .map { |k,v| [k.sub(/\A#{HEADER_PREFIX}/, '').split('_').map(&:capitalize).join('-'), v] }
+             .sort
+             .flatten
+      ]
+    end
+
+    def params
+      env[PARAMETERS_KEY] ||= super.merge(path_parameters)
+    end
+
+    def path_parameters
+      Hash[
+        *env.select { |k,v| k.start_with?(PARAM_HEADER_PREFIX) }
+             .map { |k,v| [k.sub(/\A#{PARAM_HEADER_PREFIX}/, '').downcase, v] }
+             .sort
+             .flatten
+      ]
+    end
+  end
+end

environments/ruby/fission/specializer.rb

@@ -0,0 +1,14 @@
+# frozen_string_literal: true
+
+module Fission
+  CODE_PATH = '/userfunc/user'
+
+  module Specializer
+    def self.call(env)
+      load CODE_PATH
+      Rack::Response.new([], 201).finish
+    rescue
+      Rack::Response.new(['500 Internal Server Error'], 500, {}).finish
+    end
+  end
+end