简介

`protobuf` 是什么？

Protocol buffers are Google's language-neutral, platform-neutral, extensible mechanism for serializing structured data – think XML, but smaller, faster, and simpler. You define how you want your data to be structured once, then you can use special generated source code to easily write and read your structured data to and from a variety of data streams and using a variety of languages.

Google公司开发的一种数据描述语言
一种与语言无关，平台无关的可扩展机制，用于序列化结构化数据
通过proto文件定义结构化数据，其他功能类似的比如XML、JSON等；
自带代码生成器

现在有许多框架等在使用Protocol Buffers。gRPC也是基于Protocol Buffers。 Protocol Buffers 目前有2和3两个版本号。

在gRPC中推荐使用proto3版本。

为什么叫"`Protocol Buffers`"

The name originates from the early days of the format, before we had the protocol buffer compiler to generate classes for us. At the time, there was a class called ProtocolBuffer which actually acted as a buffer for an individual method. Users would add tag/value pairs to this buffer individually by calling methods like AddValue(tag, value). The raw bytes were stored in a buffer which could then be written out once the message had been constructed.

Since that time, the "buffers" part of the name has lost its meaning, but it is still the name we use. Today, people usually use the term "protocol message" to refer to a message in an abstract sense, "protocol buffer" to refer to a serialized copy of a message, and "protocol message object" to refer to an in-memory object representing the parsed message.