DATA SERIALIZATION WITH GOOGLE PROTOCOL BUFFERS

By: William Kibira

What is Data Serialization

● The process of translating a data structure and its object state into a format that can be stored in a memory buffer, file or transported on a network.

● End goal being that it can be reconstructed in another computer environment.

Reasons as To why We do this

● Persist Objects [Store and later Retrieve them]● Perform Remote Procedural Calls● Create Distributed Objects [Corba , JavaRMI,

ICE]

Key Words

● Computer Environment

- Programming Languages

- Operating Systems

- Architectures and processors

● Platform Independent Solutions

Popular Platform Independent Solutions

● JSON and XML● BSON and Binary XML● Google Protocol Buffer , Thrift , Avro

Ref

http://en.wikipedia.org/wiki/Comparison_of_data_serialization_formats

JSON AND XML

● Most popular● Easily Human Readable to some extent● Most Web based APIs use it by default● Lots of generators for this stuff

How to works

● You write an IDL [Interface Description Language] . Kinda like CORBA IDLs but , much cleaner and more flexible.

● Pass it through a C++ based code generator● Get your Boiler plate code in a given language

you specified

GOOGLE PROTOCOL BUFFERS

● This is a platform independent language independent data serialization solution similar to XML in structure but much smaller in size and easier to structure .

● Been there since 2001 , made open in 2008

JSON BINARY FORMATS

● JSON is darn easy to read , If you can read binary , you definitely need to see a doctor.

● JSON [Gets fat even on little Data], Binary really compact{"deposit_money": "12345678"}

JSON BINARY

'0x6d', '0x6f', '0x6e', '0x01', '0xBC614E'

'0x65', '0x79', '0x31',

'0x32', '0x33', '0x34',

'0x35', '0x36', '0x37',

'0x38'

SPEED AT PARSING

● JSON is Fairly fast but , Binary is close to machine speed since it is readily parse-able.

FLOW

Schema / IDL

C++ Code Generator

C++ JAVA Python JavaScript

Server /Client application bases

What does a Schema Look Like ?

Howto Generate the Code

● Use the protobuffer compiler by specifying the language you want out put and the file.proto

● Protoc -I=/DIR_to_Schema/ --out_language=FOLDER_TO_Buffer/ DIR_TO_Schema/file.proto

A Look in my Terminal

What is Inside My XX.java

SIZE COMPARISON

RMI

GPB

JSON

XML

0 100 200 300 400 500 600 700 800 900 1000

905

250

559

836

Runtime Performance

Server CPU AVG Client CPU AVG Time

Protobuf 30.0% 37.75% 01:19:48

JSON 20.0% 75.00% 04:44:83

XML 12.00 80.75% 05:27:45

Versioning

● This is to do with backward compatibility between Protocol buffers that are old or new

● Old server new Client and Vice Versa

Even if a field has changed , the data will be parsed

Other Protocol Buffers

● MessagePack [.Net]● Thrift [Facebook]● Avro

Reasons To use Protocol Buffers

● They are smaller to push around over networks

● Easier [If Not easiest] to structure● Give a sense object oriented structuring

Reasons Not To use it

● Well, you will have to maintain both the server and clients .

● They may in most cases not be easy to learn● They are not an industry standard.● I am just trying to be fair here :)

SIMPLE DEMO CHAT APPS

● Simple chat application working on both desktops, laptops and Also on different Operating systems

● Partial Inspiration from the Fifth Estate

THE END

● Links to Check out

Google Protocol Buffers Main Page

https://developers.google.com/protocol-buffers/

● Apache Thrift

https://thrift.apache.org/