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  • (六)python语法之网络编程

    目录

    1.TCP

    #1 服务端 server.py
import socket    

host = '127.0.0.1'       # 设置ip
port = 9000              # 设置端口

# 创建socket对象
s = socket.socket(socket.AF_INET, socket.SOCK_STREAM) 
s.bind((host, port))     # 绑定ip和端口
s.listen(5)              # 等待客户端连接
print("开始监听...")

while True:
    c, addr = s.accept() # 建立客户端连接
    print('客户端地址：', addr)

    data = c.recv(2048)
    print("消息：", data.decode('utf-8'))

    c.send(b'Welcome to connect!')
    c.close()            # 关闭连接

    
#2 客户端 client.py
import socket  

host = '127.0.0.1' 
port = 9000        

s = socket.socket(socket.AF_INET, socket.SOCK_STREAM) 
s.connect((host, port))

s.send(b'Hello')

data, addr = s.recvfrom(1024)
print(data.decode('utf-8'))

s.close()

    2.UDP

    #1 server.py
import socket

host = '127.0.0.1' # 设置ip
port = 9000        # 设置端口

# 创建socket对象
s = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)  
s.bind((host, port))

while True:
    data, addr = s.recvfrom(1024)
    print('server收到来自 {} 的消息：'.format(addr), data)
    s.sendto(data.upper(), addr)
    
s.close()


#2 client.py
import socket

host = '127.0.0.1' # 设置ip
port = 9000        # 设置端口

c = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)

c.sendto(b'hello', (host, port))
data, addr = c.recvfrom(1024)
print('客户端收到来自 {} 的消息：'.format(addr), data)
    
c.close()

    3.requests

    import requests

#1 返回值
r = requests.get('https://www.baidu.com')
r.status_code        # 状态码
r.text               # HTML源码
r.content            # 网页二进制内容
r.json               # json文件

r.headers            # 返回的headers
r.request.headers    # 请求的headers
r.cookies            # 获取cookies

r.encoding           # 从header中猜测的编码
r.apparent_encoding  # 从内容分析的编码
r.raise_for_status() # 状态码不是200触发异常

#2 get请求
headers = {'User-Agent': 'Mozilla/5.0'}
payload = {'key': 'value'}
cookies = dict(mycookies='mycookies')
requests.get(url, headers=headers, params=payload, cookies=cookies, timeout=5)
     
#3 post请求
payload = {'key': 'value'}
requests.post(url, data=payload)
requests.post(url, data=json.dumps(payload)) 

files = {'file': open('test.txt', 'rb')}
requests.post(url, files=files) # 上传文件

#4 proxies代理
proxies = {'https': 'http://x.x.x.x:8000'}
requests.post(url, proxies=proxies)

    4.selenium

    # pip install selenium  
# 下载ChromeDriver，放置在代码同目录下即可 

#1 基本使用
from selenium import webdriver
from selenium.webdriver.common.keys import Keys
from selenium.webdriver.common.by import By

browser = webdriver.Chrome()         
browser.get("https://www.baidu.com") 
 
print(browser.current_url)
print(browser.get_cookies())
print(browser.page_source)  # 获取HTML源码

# 通过id获取元素
element = browser.find_element_by_id("kw") 
print(element.id)       # 获取ID
print(element.text)     # 获取文本
print(element.location) # 获取位置
print(element.tag_name) # 获取标签名
print(element.size)     # 获取大小
print(element.get_attribute('class')) # 获取属性

# 向元素输入内容
element.send_keys("Python")   
element.send_keys(Keys.ENTER) # 模拟回车键
element.clear()               # 清除内容

# 通过Xpath获取元素
element = browser.find_element(By.XPATH, '//*[@id="su"]')
element.click()  # 模拟点击

#2 wait等待
from selenium import webdriver
from selenium.webdriver.common.by import By
from selenium.webdriver.support.ui import WebDriverWait
from selenium.webdriver.support import expected_conditions as EC
from selenium.common.exceptions import TimeoutException

SERVICE_ARGS = ['--load-images=false', '--disk-cache=true']
browser = webdriver.PhantomJS(service_args=SERVICE_ARGS)
browser.set_window_size(1400, 900)

# 实现页面等待的对象
wait = WebDriverWait(browser, 10) 

def search(url):
    try:
        browser.get(url)
        # 等待指定的元素加载
        element = wait.until(EC.presence_of_element_located((By.CSS_SELECTOR, "#kw")))        
    except TimeoutException:
        search(url)

search('https://www.baidu.com')

    5.BeautifulSoup

    from bs4 import BeautifulSoup
import re

html_doc = '''
<!DOCTYPE html>
<html><head><title>百度一下，你就知道 </title></head>
<body>
  <div id="u1">
    <a class="mnav" href="http://news.baidu.com" id="news">新闻</a>
    <a class="mnav" href="https://www.hao123.com">hao123</a>
    <a class="mnav" href="http://map.baidu.com" id="map">地图</a>
    <a class="mnav" href="http://v.baidu.com" id="video">视频</a>
    <a class="mnav" href="http://tieba.baidu.com" id="tieba">贴吧</a>
  </div>
</body>
</html>
'''

#1 创建BeautifulSoup对象
soup = BeautifulSoup(html_doc, 'html.parser') 
# 获取格式化html内容
print(soup.prettify())

#2 获取第一个匹配标签a的内容
print(soup.a)          
# <a class="mnav" href="http://news.baidu.com" id="news">新闻</a>

# 返回标签a属性class的值
print(soup.a['class']) 
# ['mnav']

# 返回标签a属性的字典
print(soup.a.attrs)    
# {'class': ['mnav'], 'href': 'http://news.baidu.com', 'id': 'news'}

# 返回标签a的内容
print(soup.a.string)   
# 新闻

#3 CSS选择器，返回列表
print(soup.select('#map'))
# [<a class="mnav" href="http://map.baidu.com" id="map">地图</a>]
print(soup.select('div a[id="map"]')) 
# [<a class="mnav" href="http://map.baidu.com" id="map">地图</a>]

#4 find_all()搜索
print(soup.find_all('a', id='video'))
# [<a class="mnav" href="http://v.baidu.com" id="video">视频</a>]
print(soup.find_all(re.compile("^a")))
# [<a class="mnav" href="http://news.baidu.com" id="news">新闻</a>, <a class="mnav" href="https://www.hao123.com">hao123</a>, <a class="mnav" href="http://map.baidu.com" id="map">地图</a>, <a class="mnav" href="http://v.baidu.com" id="video">视频</a>, <a class="mnav" href="http://tieba.baidu.com" id="tieba">贴吧</a>]

# find_all()搜索文档中的字符串
print(soup.find_all(text=re.compile("^贴"))) 
# ['贴吧']

# find_all()传自定义方法搜索
def func(tag):
    return tag.has_attr('class') and not tag.has_attr('id')
print(soup.find_all(func))  
# [<a class="mnav" href="https://www.hao123.com">hao123</a>]

    6.PyQuery

    from pyquery import PyQuery as pq  
from lxml import etree

html_doc = '''
<!DOCTYPE html>
<html><head><title>百度一下，你就知道 </title></head>
<body>
  <div id="u1">
    <a class="mnav" href="http://news.baidu.com" id="news">新闻</a>
    <a class="mnav" href="https://www.hao123.com">hao123</a>
    <a class="mnav" href="http://map.baidu.com" id="map">地图</a>
    <a class="mnav" href="http://v.baidu.com" id="video">视频</a>
    <a class="mnav" href="http://tieba.baidu.com" id="tieba">贴吧</a>
  </div>
</body>
</html>
'''

#1 初始化
doc = pq(etree.fromstring(html_doc)) 

#2 CSS选择器
item = doc('#news')

print(item.attr('href')) 
# http://news.baidu.com

print(item.text())       
# 新闻

#3 链式使用 
items = doc('#u1').find('a').items()
for item in items:
    print(item.text()) 
    # 新闻 hao123 地图 视频 贴吧
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  • 原文地址：https://www.cnblogs.com/qxcheng/p/13536108.html
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