protocol-buffers简介

青旅半醒 2021-11-01 14:06 356阅读 0赞

执行安卓 自动化测试开的时候，需要安装一个库 `protocol-buffers`，这个库强大的。来看看这么使用，是做什么的？

> [https://developers.google.com/protocol-buffers/docs/pythontutorial][https_developers.google.com_protocol-buffers_docs_pythontutorial]

# 定义 #

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。类似Json或者XML的数据传输格式和规范，用于不同应用或进程之间进行通信时使用。通信时所传递的信息是通过Protobuf定义的message数据结构进行打包，然后编译成二进制的码流再进行传输或者存储。

# 优点 #

我们常用就是xml和json文件。相比这个而言，`简单、小、快、兼容性高！`。

# 用法 #

通过在.proto文件中定义协议缓冲区消息类型来指定您希望如何构建序列化信息。每个协议缓冲区消息都是一个小的逻辑信息记录，包含一系列名称 - 值对。  
.proto的用法优点类似c++ 和java。

> [https://developers.google.com/protocol-buffers/docs/pythontutorial][https_developers.google.com_protocol-buffers_docs_pythontutorial]

上面链接是python的demo。  
这个写入数据

#! /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()

读取数据

#! /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)

[https_developers.google.com_protocol-buffers_docs_pythontutorial]: https://developers.google.com/protocol-buffers/docs/pythontutorial