Import refactored library. See MIGRATING.MD for details

lib/google/apis/core/http_command.rb

@@ -0,0 +1,275 @@
+# Copyright 2015 Google Inc.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+require 'addressable/uri'
+require 'addressable/template'
+require 'google/apis/options'
+require 'google/apis/errors'
+require 'retriable'
+require 'hurley'
+require 'hurley/addressable'
+require 'google/apis/core/logging'
+require 'pp'
+
+module Google
+  module Apis
+    module Core
+      # Command for HTTP request/response.
+      class HttpCommand
+        include Logging
+
+        RETRIABLE_ERRORS = [Google::Apis::ServerError, Google::Apis::RateLimitError, Google::Apis::TransmissionError]
+
+        # Request options
+        # @return [Google::Apis::RequestOptions]
+        attr_accessor :options
+
+        # HTTP request URL
+        # @return [String, Addressable::URI]
+        attr_accessor :url
+
+        # HTTP headers
+        # @return [Hurley::Header]
+        attr_accessor :header
+
+        # Request body
+        # @return [#read]
+        attr_accessor :body
+
+        # HTTP method
+        # @return [symbol]
+        attr_accessor :method
+
+        # HTTP Client
+        # @return [Hurley::Client]
+        attr_accessor :connection
+
+        # Query params
+        # @return [Hash]
+        attr_accessor :query
+
+        # Path params for URL Template
+        # @return [Hash]
+        attr_accessor :params
+
+        # @param [symbol] method
+        #   HTTP method
+        # @param [String,Addressable::URI, Addressable::Template] url
+        #   HTTP URL or template
+        # @param [String, #read] body
+        #   Request body
+        def initialize(method, url, body: nil)
+          self.options = Google::Apis::RequestOptions.default.dup
+          self.url = url
+          self.url = Addressable::Template.new(url) if url.is_a?(String)
+          self.method = method
+          self.header = Hurley::Header.new
+          self.body = body
+          self.query = {}
+          self.params = {}
+        end
+
+        # Execute the command, retrying as necessary
+        #
+        # @param [Hurley::Client] client
+        #   HTTP client
+        # @yield [result, err] Result or error if block supplied
+        # @return [Object]
+        # @raise [Google::Apis::ServerError] An error occurred on the server and the request can be retried
+        # @raise [Google::Apis::ClientError] The request is invalid and should not be retried without modification
+        # @raise [Google::Apis::AuthorizationError] Authorization is required
+        def execute(client)
+          prepare!
+          proc = block_given? ? Proc.new : nil
+          begin
+            Retriable.retriable tries: options.retries + 1,
+                                base_interval: 1,
+                                multiplier: 2,
+                                on: RETRIABLE_ERRORS do |try|
+              # This 2nd level retriable only catches auth errors, and supports 1 retry, which allows
+              # auth to be re-attempted without having to retry all sorts of other failures like
+              # NotFound, etc
+              auth_tries = (try == 1 && authorization_refreshable? ? 2 : 1)
+              Retriable.retriable tries: auth_tries,
+                                  on: [Google::Apis::AuthorizationError],
+                                  on_retry: proc { |*| refresh_authorization } do
+                return execute_once(client, &proc)
+              end
+            end
+          rescue => e
+            raise e if proc.nil?
+          end
+        ensure
+          release!
+        end
+
+        # Refresh the authorization authorization after a 401 error
+        #
+        # @private
+        # @return [void]
+        def refresh_authorization
+          # Handled implicitly by auth lib, here in case need to override
+          logger.debug('Retrying after authentication failure')
+        end
+
+        # Check if attached credentials can be automatically refreshed
+        # @return [Boolean]
+        def authorization_refreshable?
+          options.authorization.respond_to?(:apply!)
+        end
+
+        # Prepare the request (e.g. calculate headers, serialize data, etc) before sending
+        #
+        # @private
+        # @return [void]
+        def prepare!
+          header.update(options.header) if options && options.header
+          self.url = url.expand(params) if url.is_a?(Addressable::Template)
+          url.query_values = query
+        end
+
+        # Release any resources used by this command
+        # @private
+        # @return [void]
+        def release!
+        end
+
+        # Check the response and either decode body or raise error
+        #
+        # @param [Fixnum] status
+        #   HTTP status code of response
+        # @param [Hurley::Header] header
+        #   Response headers
+        # @param [String, #read] body
+        #  Response body
+        # @return [Object]
+        #   Response object
+        # @raise [Google::Apis::ServerError] An error occurred on the server and the request can be retried
+        # @raise [Google::Apis::ClientError] The request is invalid and should not be retried without modification
+        # @raise [Google::Apis::AuthorizationError] Authorization is required
+        def process_response(status, header, body)
+          check_status(status, body)
+          decode_response_body(header[:content_type], body)
+        end
+
+        # Check the response and raise error if needed
+        #
+        # @param [Fixnum] status
+        #   HTTP status code of response
+        # @param [String] body
+        #   HTTP response body
+        # @return [void]
+        # @raise [Google::Apis::ServerError] An error occurred on the server and the request can be retried
+        # @raise [Google::Apis::ClientError] The request is invalid and should not be retried without modification
+        # @raise [Google::Apis::AuthorizationError] Authorization is required
+        def check_status(status, body = nil)
+          # TODO: 304 Not Modified depends on context...
+          case status
+          when 200...300
+            nil
+          when 301, 302, 303, 307
+            fail Google::Apis::RedirectError, header[:location]
+          when 401
+            fail Google::Apis::AuthorizationError, body
+          when 304, 400, 402...500
+            fail Google::Apis::ClientError, body
+          when 500...600
+            fail Google::Apis::ServerError, body
+          else
+            logger.warn(sprintf('Encountered unexpected status code %s', status))
+            fail Google::Apis::TransmissionError, body
+          end
+        end
+
+        # Process the actual response body. Intended to be overridden by subclasses
+        #
+        # @param [String] _content_type
+        #  Content type of body
+        # @param [String, #read] body
+        #  Response body
+        # @return [Object]
+        def decode_response_body(_content_type, body)
+          body
+        end
+
+        # Process a success response
+        # @param [Object] result
+        #  Result object
+        # @return [Object] result if no block given
+        # @yield [result, nil] if block given
+        def success(result, &block)
+          logger.debug { sprintf('Success - %s', PP.pp(result, '')) }
+          block.call(result, nil) if block_given?
+          result
+        end
+
+        # Process an error response
+        # @param [StandardError] err
+        #  Error object
+        # @param [Boolean] rethrow
+        #  True if error should be raised again after handling
+        # @return [void]
+        # @yield [nil, err] if block given
+        # @raise [StandardError] if no block
+        def error(err, rethrow: false, &block)
+          logger.debug { sprintf('Error - %s', PP.pp(err, '')) }
+          err = Google::Apis::TransmissionError.new(err) if err.is_a?(Hurley::ClientError)
+          block.call(nil, err) if block_given?
+          fail err if rethrow || block.nil?
+        end
+
+        # Execute the command once.
+        #
+        # @private
+        # @param [Hurley::Client] client
+        #   HTTP client
+        # @yield [result, err] Result or error if block supplied
+        # @return [Object]
+        # @raise [Google::Apis::ServerError] An error occurred on the server and the request can be retried
+        # @raise [Google::Apis::ClientError] The request is invalid and should not be retried without modification
+        # @raise [Google::Apis::AuthorizationError] Authorization is required
+        def execute_once(client, &block)
+          body.rewind if body.respond_to?(:rewind)
+          begin
+            logger.debug { sprintf('Sending HTTP %s %s', method, url) }
+            response = client.send(method, url, body) do |req|
+              apply_request_options(req)
+            end
+            logger.debug { response.status_code }
+            logger.debug { response.inspect }
+            response = process_response(response.status_code, response.header, response.body)
+            success(response, &block)
+          rescue => e
+            logger.debug { sprintf('Caught error %s', e) }
+            error(e, rethrow: true, &block)
+          end
+        end
+
+        # Update the request with any specified options.
+        # @param [Hurley::Request] req
+        #  HTTP request
+        # @return [void]
+        def apply_request_options(req)
+          if options.authorization.respond_to?(:apply!)
+            options.authorization.apply!(req.header)
+          elsif options.authorization.is_a?(String)
+            req.header[:authorization] = sprintf('Bearer %s', options.authorization)
+          end
+          req.header.update(header)
+          req.options.timeout = options.timeout_sec
+        end
+      end
+    end
+  end
+end