本文將從以下幾點來介紹protobuf：
1.安裝
2.定義protobuf消息格式
3.編譯protobuf
4.讀寫protobuf

1.安裝

• 下載protobuf。下載地址
• 添加環境變量。將proto.exe所在的路徑名放在path下。
  如圖：
  

2.定義protobuf消息格式

我們將要使用的示例是一個非常簡單的“地址簿”應用程序，可以在文件中讀取和寫入人員的聯系人詳細信息。地址簿中的每個人都有姓名，ID，電子郵件地址和聯系電話號碼。

要創建地址簿應用程序，需要從.proto文件開始。.proto文件中的定義很簡單：為要序列化的每個數據結構添加消息，然后為消息中的每個字段指定名稱和類型。下面是.proto定義的消息文件addressbook.proto。

            
              syntax = "proto2";

package tutorial;

message Person {
required string name = 1;
required int32 id = 2;
optional string email = 3;

enum PhoneType {
MOBILE = 0;
HOME = 1;
WORK = 2;
}

message PhoneNumber {
required string number = 1;
optional PhoneType type = 2 [default = HOME];
}

repeated PhoneNumber phones = 4;
}

message AddressBook {
repeated Person people = 1;
}

            
          

關于protobuf的詳細解釋。

3.編譯protobuf
現在，有了一個.proto，需要做的下一件事就是生成需要讀寫的類AddressBook（包擴Person和PhoneNumber）消息。要做到這一點，需要運行protobuf編譯器protoc.exe對.proto進行編譯，編譯命令格式如下：

protoc -I = $ SRC_DIR --python_out = $ DST_DIR $ SRC_DIR / addressbook.proto
其中，$ SRC_DIR是源目錄（應用程序的源代碼所在的位置 - 如果不提??供值，則使用當前目錄），$ DST_DIR 是目標目錄（希望生成的代碼在哪里，通常和$SRC_DIR相同）。

我的示例程序如下圖，protoc.exe編譯器和.proto文件都在同一個目錄下，如果沒有為protoc.exe配置環境變量，則需要在命令行窗口中切換到包含protoc.exe的文件夾（也就是下圖的the_use_of_protobuf文件夾）下運行下面的命令：

protoc --python_out=./ ./addressbook.proto

然后生成

4.讀寫protobuf消息

• 寫一條消息
  現在嘗試使用protobuf類。為了將個人詳細信息寫入地址簿文件，需要創建并填充protobuf類的實例，然后將它們寫入輸出流。

這是一個程序（文件名為write.py），它從數據文件中（這里的數據文件名為data.pb）讀取AddressBook類，根據用戶輸入添加一個新Person到AddressBook中，然后再將新AddressBook寫回文件。

            
              #! /usr/bin/python

import addressbook_pb2
import sys

# This function fills in a Person message based on user input.
def PromptForAddress(person):
  person.id = int(raw_input("Enter person ID number: "))
  person.name = raw_input("Enter name: ")

  email = raw_input("Enter email address (blank for none): ")
  if email != "":
    person.email = email

  while True:
    number = raw_input("Enter a phone number (or leave blank to finish): ")
    if number == "":
      break

    phone_number = person.phones.add()
    phone_number.number = number

    type = raw_input("Is this a mobile, home, or work phone? ")
    if type == "mobile":
      phone_number.type = addressbook_pb2.Person.MOBILE
    elif type == "home":
      phone_number.type = addressbook_pb2.Person.HOME
    elif type == "work":
      phone_number.type = addressbook_pb2.Person.WORK
    else:
      print "Unknown phone type; leaving as default value."

# Main procedure:  Reads the entire address book from a file,
#   adds one person based on user input, then writes it back out to the same
#   file.
if len(sys.argv) != 2:
  print "Usage:", sys.argv[0], "ADDRESS_BOOK_FILE"
  sys.exit(-1)

address_book = addressbook_pb2.AddressBook()

# Read the existing address book.
try:
  f = open(sys.argv[1], "rb")
  address_book.ParseFromString(f.read())
  f.close()
except IOError:
  print sys.argv[1] + ": Could not open file.  Creating a new one."

# Add an address.
PromptForAddress(address_book.people.add())

# Write the new address book back to disk.
f = open(sys.argv[1], "wb")
f.write(address_book.SerializeToString())
f.close()

            
          

然后在命令窗口下執行以下命令：

python write.py data.pb

在彈出來的窗口隨便輸入兩條信息。

• 讀一條信息

            
              #! /usr/bin/python

import addressbook_pb2
import sys

# Iterates though all people in the AddressBook and prints info about them.
def ListPeople(address_book):
  for person in address_book.people:
    print "Person ID:", person.id
    print "  Name:", person.name
    if person.HasField('email'):
      print "  E-mail address:", person.email

    for phone_number in person.phones:
      if phone_number.type == addressbook_pb2.Person.MOBILE:
        print "  Mobile phone #: ",
      elif phone_number.type == addressbook_pb2.Person.HOME:
        print "  Home phone #: ",
      elif phone_number.type == addressbook_pb2.Person.WORK:
        print "  Work phone #: ",
      print phone_number.number

# Main procedure:  Reads the entire address book from a file and prints all
#   the information inside.
if len(sys.argv) != 2:
  print "Usage:", sys.argv[0], "ADDRESS_BOOK_FILE"
  sys.exit(-1)

address_book = addressbook_pb2.AddressBook()

# Read the existing address book.
f = open(sys.argv[1], "rb")
address_book.ParseFromString(f.read())
f.close()

ListPeople(address_book)

            
          

然后在命令窗口下執行以下命令：

python read.py data.pb

你可以看到輸出

到此，關于protobuf的簡單使用已經介紹完了。