Python学习第二阶段Day2（json/pickle）、 shelve、xml、PyYAML、configparser、hashlib模块

1.json/pickle   略。

2.shelve模块

import shelve

# shelve 以key value的形式序列化，value为对象
class Foo(object):
    def __init__(self, n):
        self.n = n
s = shelve.open("shelve_test")
name = ["alex", "rain", "test"]
s["test"] = name
s["a"] = Foo(1)
s["b"] = Foo(2)


# 反序列化，提取对象

print(s.items())        # 提取所有
print(s.get("test"))    # 提取单个

s.close()

 3.xml的处理

xml文件：country.xml

<?xml version="1.0"?>
<data>
    <country name="Liechtenstein">
        <rank updated="yes">2</rank>
        <year>2008</year>
        <gdppc>141100</gdppc>
        <neighbor name="Austria" direction="E"/>
        <neighbor name="Switzerland" direction="W"/>
    </country>
    <country name="Singapore">
        <rank updated="yes">5</rank>
        <year>2011</year>
        <gdppc>59900</gdppc>
        <neighbor name="Malaysia" direction="N"/>
    </country>
    <country name="Panama">
        <rank updated="yes">69</rank>
        <year>2011</year>
        <gdppc>13600</gdppc>
        <neighbor name="Costa Rica" direction="W"/>
        <neighbor name="Colombia" direction="E"/>
    </country>
</data>

遍历等处理：

import xml.etree.ElementTree as ET

tree = ET.parse("country.xml")
root = tree.getroot()　　 # data 根节点

'''
一般的节点<tag attrib="value"> text <tag/>
自结束标签<tag attrib="value"/>
'''

# 遍历xml文档
for child in root:
    print(child.tag, child.attrib)
    for i in child:
        print(i.tag, i.text)

# 只遍历year 节点
for node in root.iter('year'):
    print(node.tag, node.text)

 修改和删除：

import xml.etree.ElementTree as ET

tree = ET.parse("country.xml")
root = tree.getroot()

# 修改
for node in root.iter('year'):
    new_year = int(node.text) + 1
    node.text = str(new_year)
    node.set("updated", "yes")

tree.write("country.xml")

# 删除node
for country in root.findall('country'):  # 或者root.iter('country')
    rank = int(country.find('rank').text)
    if rank > 50:
        root.remove(country)

tree.write('country.xml')

生成xml文件：

import xml.etree.ElementTree as ET

new_xml = ET.Element("infolist")
info = ET.SubElement(new_xml, "info", attrib={"enrolled": "yes"})
name = ET.SubElement(info, "name")
name.text = 'akira'
age = ET.SubElement(info, "age", attrib={"checked": "no"})
age.text = '33'
sex = ET.SubElement(info, "sex")
sex.text = 'F'

info1 = ET.SubElement(new_xml, "info", attrib={"enrolled": "yes"})
name1 = ET.SubElement(info1, "name")
name1.text = 'alen'
age1 = ET.SubElement(info1, "age", attrib={"checked": "no"})
age1.text = '22'
sex1 = ET.SubElement(info1, "sex")
sex1.text = 'M'

et = ET.ElementTree(new_xml)  # 生成文档对象
et.write("test.xml", encoding="utf-8", xml_declaration=True)  
                                    # <?xml version='1.0' encoding='utf-8'?>
ET.dump(new_xml)  # 打印生成的格

生成的xml内容：

<?xml version='1.0' encoding='utf-8'?>
<infolist>
    <info enrolled="yes">
        <name>akira</name>
        <age checked="no">33</age>
        <sex>F</sex>
    </info>
    <info enrolled="yes">
        <name>alen</name>
        <age checked="no">22</age>
        <sex>M</sex>
    </info>
</infolist>

 4.YAML

Python也可以很容易的处理ymal文档格式，只不过需要安装一个模块，参考文档：http://pyyaml.org/wiki/PyYAMLDocumentation 

例如下面的格式

/etc/http/conf/http.conf:
  file.managed:
    - source: salt://apache/http.conf
    - user: root
    - group: root
    - mode: 644
    - template: jinja
    - defaults:
        custom_var: "default value"
        other_var: 123

5.configparser

修改配置文件的，格式：

[DEFAULT]
ServerAliveInterval = 45
Compression = yes
CompressionLevel = 9
ForwardX11 = yes
 
[bitbucket.org]
User = hg
 
[topsecret.server.com]
Port = 50022
ForwardX11 = no

解析：（读取配置文件，并查询条目）

import configparser

conf = configparser.ConfigParser()
conf.read("example.conf")
print(conf.defaults())  # DEFAULT下的条目：
                        # ["ServerAliveInterval":45,"Compression","yes"...]
print(conf.sections())  # 所有选项除DEFAULT:["bitbucket.org","topsecret.server.com"]

print(conf["DEFAULT"]["ForwardX11"])  # DEFAULT选项中的"ForwardX11"的值
print(conf["bitbucket.org"]["User"])
print(conf["topsecret.server.com"]["Port"])

for key in conf["DEFAULT"]:   # 遍历DEFAULT条目
    print(key, conf["DEFAULT"][key])

写入：

import configparser

conf = configparser.ConfigParser()  # 创建配置文件对象
conf.read("example.conf")           # 读取配置文件



conf.write(open("filename.conf", "w"))  # 配置文件对象写入文件

用Python生成这个文档：

import configparser
 
config = configparser.ConfigParser()
config["DEFAULT"] = {'ServerAliveInterval': '45',
                      'Compression': 'yes',
                     'CompressionLevel': '9'}
 
config['bitbucket.org'] = {}
config['bitbucket.org']['User'] = 'hg'
config['topsecret.server.com'] = {}
topsecret = config['topsecret.server.com']
topsecret['Host Port'] = '50022'     # mutates the parser
topsecret['ForwardX11'] = 'no'  # same here
config['DEFAULT']['ForwardX11'] = 'yes'
with open('example.ini', 'w') as configfile:
   config.write(configfile)

“增，删，改”：

import ConfigParser
  
config = ConfigParser.ConfigParser()
config.read('i.cfg')
  
# ########## 读 ##########
#secs = config.sections()
#print secs
#options = config.options('group2')
#print options
  
#item_list = config.items('group2')
#print item_list
  
#val = config.get('group1','key')
#val = config.getint('group1','key')
  
# ########## 改写 ##########
#sec = config.remove_section('group1')
#config.write(open('i.cfg', "w"))
  
#sec = config.has_section('wupeiqi')
#sec = config.add_section('wupeiqi')
#config.write(open('i.cfg', "w"))
  
  
#config.set('group2','k1',11111)
#config.write(open('i.cfg', "w"))
  
#config.remove_option('group2','age')
#config.write(open('i.cfg', "w"))

6、hashlib

加密相关操作，3.x里代替了md5和sha模块，提供 SHA1 , 224，256，384，512，MD5算法，MD5算法是hash散列表的一种实现，也是应用最广泛的一种

 hashlib，hash字符串转数字，字典就是用hash做的，字符串排序，存取速度快，

网站防篡改报警功能，定时wget网站首页，如果文件没有变更，MD5值不变

SHA1----MD5   越来越复杂，越来越安全，都是基于hash的

hmac消息加密速度比较快

中文需要 ("中文".encode(encoding="utf8"))    MD5的加密，其他SHA..一样的用法

import hashlib

#  先加hello， 再加world
m = hashlib.md5()
m.update("hello".encode("utf8"))
print(type("hello".encode("utf8")))  # <class 'bytes'>
m.update("world".encode("utf8"))
print(m.digest())       # MD5 二进制表示b'xfc^x03x8d8xa5p2x08TAxe7xfepx10xb0'
print(m.hexdigest())    # 十六进制表示fc5e038d38a57032085441e7fe7010b0

# 直接helloworld
m1 = hashlib.md5()
m1.update("helloworld".encode("utf8"))
print(m.digest())       # b'xfc^x03x8d8xa5p2x08TAxe7xfepx10xb0'
print(m.hexdigest())    # fc5e038d38a57032085441e7fe7010b0

还不够吊？python 还有一个 hmac 模块，它内部对我们创建 key 和 内容 再进行处理然后再加密

散列消息鉴别码，简称HMAC，是一种基于消息鉴别码MAC（Message Authentication Code）的鉴别机制。使用HMAC时,消息通讯的双方，通过验证消息中加入的鉴别密钥K来鉴别消息的真伪；

一般用于网络通信中消息加密，前提是双方先要约定好key,就像接头暗号一样，然后消息发送把用key把消息加密，接收方用key ＋ 消息明文再加密，拿加密后的值 跟 发送者的相对比是否相等，这样就能验证消息的真实性，及发送者的合法性了。

import hmac
h = hmac.new('天王盖地虎'.encode("utf8"), '宝塔镇河妖'.encode("utf8"))
print (h.hexdigest())