Import refactored library. See MIGRATING.MD for details

lib/google/apis/core/batch.rb

@@ -0,0 +1,222 @@
+# 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.
+# 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 'hurley'
+require 'google/apis/core/multipart'
+require 'google/apis/core/http_command'
+require 'google/apis/core/upload'
+require 'google/apis/core/download'
+require 'addressable/uri'
+
+module Google
+  module Apis
+    module Core
+      # Wrapper request for batching multiple calls in a single server request
+      class BatchCommand < HttpCommand
+        BATCH_BOUNDARY = 'RubyApiBatchRequest'.freeze
+        MULTIPART_MIXED = 'multipart/mixed'
+
+        # @param [symbol] method
+        #   HTTP method
+        # @param [String,Addressable::URI, Addressable::Template] url
+        #   HTTP URL or template
+        def initialize(method, url)
+          super(method, url)
+          @calls = []
+        end
+
+        ##
+        # Add a new call to the batch request.
+        #
+        # @param [Google::Apis::Core::HttpCommand] call API Request to add
+        # @yield [result, err] Result & error when response available
+        # @return [Google::Apis::Core::BatchCommand] self
+        def add(call, &block)
+          ensure_valid_command(call)
+          @calls << [call, block]
+          self
+        end
+
+        protected
+
+        ##
+        # Deconstruct the batch response and process the individual results
+        #
+        # @param [String] content_type
+        #  Content type of body
+        # @param [String, #read] body
+        #  Response body
+        # @return [Object]
+        #   Response object
+        def decode_response_body(content_type, body)
+          m = /.*boundary=(.+)/.match(content_type)
+          if m
+            parts = split_parts(body, m[1])
+            deserializer = CallDeserializer.new
+            parts.each_index do |index|
+              call, callback = @calls[index]
+              begin
+                result = call.process_response(*deserializer.to_http_response(parts[index])) unless call.nil?
+                success(result, &callback)
+              rescue => e
+                error(e, &callback)
+              end
+            end
+          end
+          nil
+        end
+
+        def split_parts(body, boundary)
+          parts = body.split(/\r?\n?--#{Regexp.escape(boundary)}/)
+          parts[1...-1]
+        end
+
+        # Encode the batch request
+        # @return [void]
+        # @raise [Google::Apis::BatchError] if batch is empty
+        def prepare!
+          fail BatchError, 'Cannot make an empty batch request' if @calls.empty?
+
+          serializer = CallSerializer.new
+          multipart = Multipart.new(boundary: BATCH_BOUNDARY, content_type: MULTIPART_MIXED)
+          @calls.each do |(call, _)|
+            io = serializer.to_upload_io(call)
+            multipart.add_upload(io)
+          end
+          self.body = multipart.assemble
+
+          header[:content_type] = multipart.content_type
+          header[:content_length] = "#{body.length}"
+          super
+        end
+
+        def ensure_valid_command(command)
+          if command.is_a?(Google::Apis::Core::BaseUploadCommand) || command.is_a?(Google::Apis::Core::DownloadCommand)
+            fail Google::Apis::ClientError, 'Can not include media requests in batch'
+          end
+          fail Google::Apis::ClientError, 'Invalid command object' unless command.is_a?(HttpCommand)
+        end
+      end
+
+      # Wrapper request for batching multiple uploads in a single server request
+      class BatchUploadCommand < BatchCommand
+        def ensure_valid_command(command)
+          fail Google::Apis::ClientError, 'Can only include upload commands in batch' \
+            unless command.is_a?(Google::Apis::Core::BaseUploadCommand)
+        end
+
+        def prepare!
+          header['X-Goog-Upload-Protocol'] = 'batch'
+          super
+        end
+      end
+
+      # Serializes a command for embedding in a multipart batch request
+      # @private
+      class CallSerializer
+        HTTP_CONTENT_TYPE = 'application/http'
+
+        ##
+        # Serialize a single batched call for assembling the multipart message
+        #
+        # @param [Google::Apis::Core::HttpCommand] call
+        #   the call to serialize.
+        # @return [Hurley::UploadIO]
+        #   the serialized request
+        def to_upload_io(call)
+          call.prepare!
+          parts = []
+          parts << build_head(call)
+          parts << build_body(call) unless call.body.nil?
+          length = parts.inject(0) { |a, e| a + e.length }
+          Hurley::UploadIO.new(Hurley::CompositeReadIO.new(length, *parts),
+                               HTTP_CONTENT_TYPE,
+                               'ruby-api-request')
+        end
+
+        protected
+
+        def build_head(call)
+          request_head = "#{call.method.to_s.upcase} #{Addressable::URI.parse(call.url).request_uri} HTTP/1.1"
+          call.header.each do |key, value|
+            request_head << sprintf("\r\n%s: %s", key, value)
+          end
+          request_head << sprintf("\r\nHost: %s", call.url.host)
+          request_head << "\r\n\r\n"
+          StringIO.new(request_head)
+        end
+
+        def build_body(call)
+          return nil if call.body.nil?
+          return call.body if call.body.respond_to?(:read)
+          StringIO.new(call.body)
+        end
+      end
+
+      # Deconstructs a raw HTTP response part
+      # @private
+      class CallDeserializer
+        # Convert a single batched response into a BatchedCallResponse object.
+        #
+        # @param [String] call_response
+        #   the response to parse.
+        # @return [Array<(Fixnum, Hurley::Header, String)>]
+        #   Status, header, and response body.
+        def to_http_response(call_response)
+          _, outer_body = split_header_and_body(call_response)
+          status_line, payload = outer_body.split(/\n/, 2)
+          _, status = status_line.split(' ', 3)
+
+          header, body = split_header_and_body(payload)
+          [status.to_i, header, body]
+        end
+
+        protected
+
+        # Auxiliary method to split the header from the body in an HTTP response.
+        #
+        # @param [String] response
+        #   the response to parse.
+        # @return [Array<(Hurley::Header, String)>]
+        #   the header and the body, separately.
+        def split_header_and_body(response)
+          header = Hurley::Header.new
+          payload = response.lstrip
+          while payload
+            line, payload = payload.split(/\n/, 2)
+            line.sub!(/\s+\z/, '')
+            break if line.empty?
+            match = /\A([^:]+):\s*/.match(line)
+            fail BatchError, sprintf('Invalid header line in response: %s', line) if match.nil?
+            header[match[1]] = match.post_match
+          end
+          [header, payload]
+        end
+      end
+    end
+  end
+end