day01

1、爬虫介绍：

 2、第一个爬虫程序：

from urllib.request import urlopen
url= "http://www.baidu.com"  # 记得是http，不是https

response = urlopen(url)
info = response.read()  # 获取内容
# print(info.decode())    # 设置编码，decode()默认是utf-8

print(response.getcode()) # 获得状态码  200
print(response.geturl())  # 获得真实url  http://www.baidu.com
print(response.info())    # 获得响应头

3、Request请求信息：

from urllib.request import urlopen,Request
from random import choice
url= "http://www.baidu.com"  # 记得是http，不是https
User_Agent = [
    "User-Agent: Mozilla/4.0 (compatible; MSIE 7.0; Windows NT 5.1; 360SE)",
    "Opera 11.11 – WindowsUser-Agent:Opera/9.80 (Windows NT 6.1; U; en) Presto/2.8.131 Version/11.11",
    "User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_7_0) AppleWebKit/535.11 (KHTML, like Gecko) 
　　　Chrome/17.0.963.56 Safari/535.11"
]
headers= {
    "User-Agent":choice(User_Agent)   # 随机获得User-agent
}
request = Request(url,headers=headers)
print(request.get_header("User-agent"))   # 获得请求头的User-agent信息

response = urlopen(request)
info = response.read()  # 获取内容
print(info.decode())    # 设置编码，decode()默认是utf-8

4、random中choice：

from random import choice
from fake_useragent import UserAgent
User_Agent = [
    "Opera 11.12 – MACUser-Agent:Opera/9.80 (Macintosh; Intel Mac OS X 10.6.8; U; en) Presto/2.8.131 Version/11.11",
    "Opera 11.11 – WindowsUser-Agent:Opera/9.80 (Windows NT 6.1; U; en) Presto/2.8.131 Version/11.11",
    "Chrome 17.0 – MACUser-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_7_0) AppleWebKit/535.11 (KHTML, like Gecko) Chrome/17.0.963.56 Safari/535.11"
]

c = choice(User_Agent) #  随机获得一个求头
print(c)

c= UserAgent()  # 随机获得user-agent
print(c.chrome)
print(c.firefox)
print(c.ie)

 5、get请求之中文处理：

from urllib.request import urlopen,Request
from random import choice
from urllib.parse import quote,urlencode

# url =  "https://www.baidu.com/s?wd=尚学堂"    # 这样会出错

# 处理中文：方式一
wd = quote("尚学堂")
# url= "https://www.baidu.com/s?wd={}".format(wd)  

# 处理中文：方式二
args = {
    "wd":"尚学堂",
    "id":"11"
}
url= "https://www.baidu.com/s?wd={}".format(urlencode(args)) 
# print(url)  # https://www.baidu.com/s?wd=wd=%E5%B0%9A%E5%AD%A6%E5%A0%82&id=11

headers= {
    "User-Agent": "User-Agent: Mozilla/4.0 (compatible; MSIE 7.0; Windows NT 5.1; 360SE)",
}
request = Request(url,headers=headers)
response = urlopen(request)
print(response.read().decode())

 6、爬取贴吧：

from urllib.request import urlopen,Request
from random import choice
from urllib.parse import quote,urlencode
from fake_useragent import UserAgent

def get_html(num,title):
    base_url = "http://tieba.baidu.com/f?{}"
    headers = {
        "User-Agent": UserAgent().random
    }
    for pn in range(int(num)):
        args = {
            "kw": "尚学堂",
            "ie": "utf - 8",
            "pn": pn * 50
        }
        request = Request(url,headers=headers)
        print("正在爬取")
        response = urlopen(request)
        filename = "第"+str(pn)+"页.html"
        save(filename,response.read())

def save(filename,content):
    html = content.decode()
    with open(filename,"wb") as f:
        f.write(content)

def main():
    num = input("请输入爬取的页数:")
    title = input("请输入爬取的题目:")
    get_html(num,title)  # 调用函数

if __name__ == "__main__":
    main()

7、post请求之登录：

from urllib.request import Request,urlopen
from urllib.parse import urlencode
url = "https://www.sxt.cn/index/login/login.html"
headers = {
    "User-Agent":"Mozilla/5.0 (Windows NT 6.1; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/70.0.3538.67 Safari/537.36"
}
data = {
    "user": "17703181473",
    "password": "12346"
}
# post请求，Request中有data，字典先变成字符串(urlencode)，再变成字节(encode)
# 必须加encode,变成字节
request = Request(url,data=urlencode(data).encode(),headers=headers)
resposne = urlopen(request)
print(resposne.read().decode())