Implemented header protocol for Ruby client library
diff --git a/lib/rb/spec/header_protocol_spec.rb b/lib/rb/spec/header_protocol_spec.rb
new file mode 100644
index 0000000..3feb9b6
--- /dev/null
+++ b/lib/rb/spec/header_protocol_spec.rb
@@ -0,0 +1,466 @@
+#
+# Licensed to the Apache Software Foundation (ASF) under one
+# or more contributor license agreements. See the NOTICE file
+# distributed with this work for additional information
+# regarding copyright ownership. The ASF licenses this file
+# to you 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 'spec_helper'
+require_relative 'support/header_protocol_helper'
+
+describe 'HeaderProtocol' do
+  include HeaderProtocolHelper
+
+  describe Thrift::HeaderProtocol do
+    before(:each) do
+      @buffer = Thrift::MemoryBufferTransport.new
+      @protocol = Thrift::HeaderProtocol.new(@buffer)
+    end
+
+    it "should provide a to_s" do
+      expect(@protocol.to_s).to match(/header\(compact/)
+    end
+
+    it "should wrap transport in HeaderTransport" do
+      expect(@protocol.trans).to be_a(Thrift::HeaderTransport)
+    end
+
+    it "should use existing HeaderTransport if passed" do
+      header_trans = Thrift::HeaderTransport.new(@buffer)
+      protocol = Thrift::HeaderProtocol.new(header_trans)
+      expect(protocol.trans).to equal(header_trans)
+    end
+
+    describe "header management delegation" do
+      it "should delegate get_headers" do
+        # Write with headers and read back to populate read headers
+        @protocol.set_header("key", "value")
+        @protocol.write_message_begin("test", Thrift::MessageTypes::CALL, 1)
+        @protocol.write_struct_begin("args")
+        @protocol.write_field_stop
+        @protocol.write_struct_end
+        @protocol.write_message_end
+        @protocol.trans.flush
+
+        # Read back
+        data = @buffer.read(@buffer.available)
+        read_buffer = Thrift::MemoryBufferTransport.new(data)
+        read_protocol = Thrift::HeaderProtocol.new(read_buffer)
+
+        read_protocol.read_message_begin
+        headers = read_protocol.get_headers
+        expect(headers["key"]).to eq("value")
+      end
+
+      it "should delegate set_header" do
+        expect(@protocol.trans).to receive(:set_header).with("key", "value")
+        @protocol.set_header("key", "value")
+      end
+
+      it "should delegate clear_headers" do
+        expect(@protocol.trans).to receive(:clear_headers)
+        @protocol.clear_headers
+      end
+
+      it "should delegate add_transform" do
+        expect(@protocol.trans).to receive(:add_transform).with(Thrift::HeaderTransformID::ZLIB)
+        @protocol.add_transform(Thrift::HeaderTransformID::ZLIB)
+      end
+    end
+
+    describe "protocol delegation with Binary protocol" do
+      before(:each) do
+        @buffer = Thrift::MemoryBufferTransport.new
+        @protocol = Thrift::HeaderProtocol.new(@buffer, nil, Thrift::HeaderSubprotocolID::BINARY)
+      end
+
+      it "should write message begin" do
+        @protocol.write_message_begin("test_method", Thrift::MessageTypes::CALL, 123)
+        @protocol.write_message_end
+        @protocol.trans.flush
+
+        # Verify we can read it back
+        data = @buffer.read(@buffer.available)
+        read_buffer = Thrift::MemoryBufferTransport.new(data)
+        read_protocol = Thrift::HeaderProtocol.new(read_buffer)
+
+        name, type, seqid = read_protocol.read_message_begin
+        expect(name).to eq("test_method")
+        expect(type).to eq(Thrift::MessageTypes::CALL)
+        expect(seqid).to eq(123)
+      end
+
+      it "should write and read structs" do
+        @protocol.write_message_begin("test", Thrift::MessageTypes::CALL, 1)
+        @protocol.write_struct_begin("TestStruct")
+        @protocol.write_field_begin("field1", Thrift::Types::I32, 1)
+        @protocol.write_i32(42)
+        @protocol.write_field_end
+        @protocol.write_field_stop
+        @protocol.write_struct_end
+        @protocol.write_message_end
+        @protocol.trans.flush
+
+        data = @buffer.read(@buffer.available)
+        read_buffer = Thrift::MemoryBufferTransport.new(data)
+        read_protocol = Thrift::HeaderProtocol.new(read_buffer)
+
+        read_protocol.read_message_begin
+        read_protocol.read_struct_begin
+        name, type, id = read_protocol.read_field_begin
+        expect(type).to eq(Thrift::Types::I32)
+        expect(id).to eq(1)
+        value = read_protocol.read_i32
+        expect(value).to eq(42)
+      end
+
+      it "should write and read all primitive types" do
+        @protocol.write_message_begin("test", Thrift::MessageTypes::CALL, 1)
+        @protocol.write_struct_begin("TestStruct")
+
+        @protocol.write_field_begin("bool", Thrift::Types::BOOL, 1)
+        @protocol.write_bool(true)
+        @protocol.write_field_end
+
+        @protocol.write_field_begin("byte", Thrift::Types::BYTE, 2)
+        @protocol.write_byte(127)
+        @protocol.write_field_end
+
+        @protocol.write_field_begin("i16", Thrift::Types::I16, 3)
+        @protocol.write_i16(32767)
+        @protocol.write_field_end
+
+        @protocol.write_field_begin("i32", Thrift::Types::I32, 4)
+        @protocol.write_i32(2147483647)
+        @protocol.write_field_end
+
+        @protocol.write_field_begin("i64", Thrift::Types::I64, 5)
+        @protocol.write_i64(9223372036854775807)
+        @protocol.write_field_end
+
+        @protocol.write_field_begin("double", Thrift::Types::DOUBLE, 6)
+        @protocol.write_double(3.14159)
+        @protocol.write_field_end
+
+        @protocol.write_field_begin("string", Thrift::Types::STRING, 7)
+        @protocol.write_string("hello")
+        @protocol.write_field_end
+
+        @protocol.write_field_stop
+        @protocol.write_struct_end
+        @protocol.write_message_end
+        @protocol.trans.flush
+
+        data = @buffer.read(@buffer.available)
+        read_buffer = Thrift::MemoryBufferTransport.new(data)
+        read_protocol = Thrift::HeaderProtocol.new(read_buffer)
+
+        read_protocol.read_message_begin
+        read_protocol.read_struct_begin
+
+        # bool
+        _, type, _ = read_protocol.read_field_begin
+        expect(type).to eq(Thrift::Types::BOOL)
+        expect(read_protocol.read_bool).to eq(true)
+        read_protocol.read_field_end
+
+        # byte
+        _, type, _ = read_protocol.read_field_begin
+        expect(type).to eq(Thrift::Types::BYTE)
+        expect(read_protocol.read_byte).to eq(127)
+        read_protocol.read_field_end
+
+        # i16
+        _, type, _ = read_protocol.read_field_begin
+        expect(type).to eq(Thrift::Types::I16)
+        expect(read_protocol.read_i16).to eq(32767)
+        read_protocol.read_field_end
+
+        # i32
+        _, type, _ = read_protocol.read_field_begin
+        expect(type).to eq(Thrift::Types::I32)
+        expect(read_protocol.read_i32).to eq(2147483647)
+        read_protocol.read_field_end
+
+        # i64
+        _, type, _ = read_protocol.read_field_begin
+        expect(type).to eq(Thrift::Types::I64)
+        expect(read_protocol.read_i64).to eq(9223372036854775807)
+        read_protocol.read_field_end
+
+        # double
+        _, type, _ = read_protocol.read_field_begin
+        expect(type).to eq(Thrift::Types::DOUBLE)
+        expect(read_protocol.read_double).to be_within(0.00001).of(3.14159)
+        read_protocol.read_field_end
+
+        # string
+        _, type, _ = read_protocol.read_field_begin
+        expect(type).to eq(Thrift::Types::STRING)
+        expect(read_protocol.read_string).to eq("hello")
+        read_protocol.read_field_end
+      end
+    end
+
+    describe "protocol delegation with Compact protocol" do
+      before(:each) do
+        @buffer = Thrift::MemoryBufferTransport.new
+        @protocol = Thrift::HeaderProtocol.new(
+          @buffer,
+          nil,
+          Thrift::HeaderSubprotocolID::COMPACT
+        )
+      end
+
+      it "should use Compact protocol" do
+        expect(@protocol.to_s).to match(/header\(compact/)
+      end
+
+      it "should write and read with Compact protocol" do
+        @protocol.write_message_begin("test", Thrift::MessageTypes::CALL, 1)
+        @protocol.write_struct_begin("Test")
+        @protocol.write_field_begin("field", Thrift::Types::I32, 1)
+        @protocol.write_i32(999)
+        @protocol.write_field_end
+        @protocol.write_field_stop
+        @protocol.write_struct_end
+        @protocol.write_message_end
+        @protocol.trans.flush
+
+        data = @buffer.read(@buffer.available)
+        read_buffer = Thrift::MemoryBufferTransport.new(data)
+        read_protocol = Thrift::HeaderProtocol.new(read_buffer, nil, Thrift::HeaderSubprotocolID::COMPACT)
+
+        read_protocol.read_message_begin
+        read_protocol.read_struct_begin
+        _, type, _ = read_protocol.read_field_begin
+        expect(type).to eq(Thrift::Types::I32)
+        expect(read_protocol.read_i32).to eq(999)
+      end
+    end
+
+    describe "unknown protocol handling" do
+      it "should write an exception response on unknown protocol id" do
+        header_data = +""
+        header_data << varint32(0x10)
+        header_data << varint32(0)
+        frame = build_header_frame(header_data)
+
+        buffer = Thrift::MemoryBufferTransport.new(frame)
+        protocol = Thrift::HeaderProtocol.new(buffer)
+
+        expect { protocol.read_message_begin }.to raise_error(Thrift::ProtocolException)
+
+        response = buffer.read(buffer.available)
+        expect(response.bytesize).to be > 0
+        magic = response[4, 2].unpack('n').first
+        expect(magic).to eq(Thrift::HeaderTransport::HEADER_MAGIC)
+      end
+    end
+
+    describe "protocol auto-detection with legacy frames" do
+      it "should detect framed compact messages" do
+        write_buffer = Thrift::MemoryBufferTransport.new
+        write_protocol = Thrift::CompactProtocol.new(write_buffer)
+
+        write_protocol.write_message_begin("legacy_framed", Thrift::MessageTypes::CALL, 7)
+        write_protocol.write_struct_begin("Args")
+        write_protocol.write_field_stop
+        write_protocol.write_struct_end
+        write_protocol.write_message_end
+
+        payload = write_buffer.read(write_buffer.available)
+        framed = [payload.bytesize].pack('N') + payload
+
+        read_buffer = Thrift::MemoryBufferTransport.new(framed)
+        protocol = Thrift::HeaderProtocol.new(read_buffer)
+
+        name, type, seqid = protocol.read_message_begin
+        expect(name).to eq("legacy_framed")
+        expect(type).to eq(Thrift::MessageTypes::CALL)
+        expect(seqid).to eq(7)
+
+        protocol.read_struct_begin
+        _, field_type, _ = protocol.read_field_begin
+        expect(field_type).to eq(Thrift::Types::STOP)
+        protocol.read_struct_end
+        protocol.read_message_end
+      end
+
+      it "should detect unframed compact messages" do
+        write_buffer = Thrift::MemoryBufferTransport.new
+        write_protocol = Thrift::CompactProtocol.new(write_buffer)
+
+        write_protocol.write_message_begin("legacy_unframed", Thrift::MessageTypes::CALL, 9)
+        write_protocol.write_struct_begin("Args")
+        write_protocol.write_field_stop
+        write_protocol.write_struct_end
+        write_protocol.write_message_end
+
+        payload = write_buffer.read(write_buffer.available)
+
+        read_buffer = Thrift::MemoryBufferTransport.new(payload)
+        protocol = Thrift::HeaderProtocol.new(read_buffer)
+
+        name, type, seqid = protocol.read_message_begin
+        expect(name).to eq("legacy_unframed")
+        expect(type).to eq(Thrift::MessageTypes::CALL)
+        expect(seqid).to eq(9)
+
+        protocol.read_struct_begin
+        _, field_type, _ = protocol.read_field_begin
+        expect(field_type).to eq(Thrift::Types::STOP)
+        protocol.read_struct_end
+        protocol.read_message_end
+      end
+    end
+
+    describe "with compression" do
+      it "should work with ZLIB transform" do
+        @protocol.add_transform(Thrift::HeaderTransformID::ZLIB)
+
+        @protocol.write_message_begin("compressed_test", Thrift::MessageTypes::CALL, 42)
+        @protocol.write_struct_begin("Args")
+        @protocol.write_field_begin("data", Thrift::Types::STRING, 1)
+        @protocol.write_string("a" * 100) # Compressible data
+        @protocol.write_field_end
+        @protocol.write_field_stop
+        @protocol.write_struct_end
+        @protocol.write_message_end
+        @protocol.trans.flush
+
+        data = @buffer.read(@buffer.available)
+        read_buffer = Thrift::MemoryBufferTransport.new(data)
+        read_protocol = Thrift::HeaderProtocol.new(read_buffer)
+
+        name, type, seqid = read_protocol.read_message_begin
+        expect(name).to eq("compressed_test")
+        expect(seqid).to eq(42)
+
+        read_protocol.read_struct_begin
+        _, _, _ = read_protocol.read_field_begin
+        result = read_protocol.read_string
+        expect(result).to eq("a" * 100)
+      end
+    end
+
+    describe "containers" do
+      it "should write and read lists" do
+        @protocol.write_message_begin("test", Thrift::MessageTypes::CALL, 1)
+        @protocol.write_struct_begin("Test")
+        @protocol.write_field_begin("list", Thrift::Types::LIST, 1)
+        @protocol.write_list_begin(Thrift::Types::I32, 3)
+        @protocol.write_i32(1)
+        @protocol.write_i32(2)
+        @protocol.write_i32(3)
+        @protocol.write_list_end
+        @protocol.write_field_end
+        @protocol.write_field_stop
+        @protocol.write_struct_end
+        @protocol.write_message_end
+        @protocol.trans.flush
+
+        data = @buffer.read(@buffer.available)
+        read_buffer = Thrift::MemoryBufferTransport.new(data)
+        read_protocol = Thrift::HeaderProtocol.new(read_buffer)
+
+        read_protocol.read_message_begin
+        read_protocol.read_struct_begin
+        _, _, _ = read_protocol.read_field_begin
+        etype, size = read_protocol.read_list_begin
+        expect(etype).to eq(Thrift::Types::I32)
+        expect(size).to eq(3)
+        expect(read_protocol.read_i32).to eq(1)
+        expect(read_protocol.read_i32).to eq(2)
+        expect(read_protocol.read_i32).to eq(3)
+      end
+
+      it "should write and read maps" do
+        @protocol.write_message_begin("test", Thrift::MessageTypes::CALL, 1)
+        @protocol.write_struct_begin("Test")
+        @protocol.write_field_begin("map", Thrift::Types::MAP, 1)
+        @protocol.write_map_begin(Thrift::Types::STRING, Thrift::Types::I32, 2)
+        @protocol.write_string("a")
+        @protocol.write_i32(1)
+        @protocol.write_string("b")
+        @protocol.write_i32(2)
+        @protocol.write_map_end
+        @protocol.write_field_end
+        @protocol.write_field_stop
+        @protocol.write_struct_end
+        @protocol.write_message_end
+        @protocol.trans.flush
+
+        data = @buffer.read(@buffer.available)
+        read_buffer = Thrift::MemoryBufferTransport.new(data)
+        read_protocol = Thrift::HeaderProtocol.new(read_buffer)
+
+        read_protocol.read_message_begin
+        read_protocol.read_struct_begin
+        _, _, _ = read_protocol.read_field_begin
+        ktype, vtype, size = read_protocol.read_map_begin
+        expect(ktype).to eq(Thrift::Types::STRING)
+        expect(vtype).to eq(Thrift::Types::I32)
+        expect(size).to eq(2)
+      end
+
+      it "should write and read sets" do
+        @protocol.write_message_begin("test", Thrift::MessageTypes::CALL, 1)
+        @protocol.write_struct_begin("Test")
+        @protocol.write_field_begin("set", Thrift::Types::SET, 1)
+        @protocol.write_set_begin(Thrift::Types::STRING, 2)
+        @protocol.write_string("x")
+        @protocol.write_string("y")
+        @protocol.write_set_end
+        @protocol.write_field_end
+        @protocol.write_field_stop
+        @protocol.write_struct_end
+        @protocol.write_message_end
+        @protocol.trans.flush
+
+        data = @buffer.read(@buffer.available)
+        read_buffer = Thrift::MemoryBufferTransport.new(data)
+        read_protocol = Thrift::HeaderProtocol.new(read_buffer)
+
+        read_protocol.read_message_begin
+        read_protocol.read_struct_begin
+        _, _, _ = read_protocol.read_field_begin
+        etype, size = read_protocol.read_set_begin
+        expect(etype).to eq(Thrift::Types::STRING)
+        expect(size).to eq(2)
+      end
+    end
+  end
+
+  describe Thrift::HeaderProtocolFactory do
+    it "should create HeaderProtocol" do
+      factory = Thrift::HeaderProtocolFactory.new
+      buffer = Thrift::MemoryBufferTransport.new
+      protocol = factory.get_protocol(buffer)
+      expect(protocol).to be_a(Thrift::HeaderProtocol)
+    end
+
+    it "should provide a reasonable to_s" do
+      expect(Thrift::HeaderProtocolFactory.new.to_s).to eq("header")
+    end
+
+    it "should pass configuration to protocol" do
+      factory = Thrift::HeaderProtocolFactory.new(nil, Thrift::HeaderSubprotocolID::COMPACT)
+      buffer = Thrift::MemoryBufferTransport.new
+      protocol = factory.get_protocol(buffer)
+      expect(protocol.to_s).to match(/compact/)
+    end
+  end
+end