Python3爬蟲之模擬post登陸及get登陸

一、模擬登陸需要賬號，密碼的網(wǎng)址

一些不需要登陸的網(wǎng)址操作已經(jīng)試過了，這次來用Python嘗試需要登陸的網(wǎng)址，來利用cookie模擬登陸

由于我們教務系統(tǒng)有驗證碼偏困難一點，故挑了個軟柿子捏，賽氪，https://www.saikr.com

我用的是火狐瀏覽器自帶的F12開發(fā)者工具，打開網(wǎng)址輸入賬號，密碼，登陸，如圖

可以看到捕捉到很多post和get請求，第一個post請求就是我們提交賬號和密碼的，

點擊post請求的參數(shù)選項可以看到我們提交的參數(shù)在bian表單數(shù)據(jù)里，name為賬戶名，pass為加密后的密碼，remember為是否記住密碼，0為不記住密碼。

我們再來看看headers，即消息頭

我們把這些請求頭加到post請求的headers后對網(wǎng)頁進行模擬登陸，

Cookie為必填項，否則會報錯：

{"code":403,"message":"訪問超時，請重試，多次出現(xiàn)此提示請聯(lián)系QQ：1409765583","data":[]}

便可以創(chuàng)建一個帶有cookie的opener，在第一次訪問登錄的URL時，將登錄后的cookie保存下來，然后利用帶有這個cookie的opener來訪問該網(wǎng)址的其他版塊，查看登錄之后才能看到的信息。

比如我是登陸https://www.saikr.com/login后模擬登陸了“我的競賽”版塊https://www.saikr.com/u/5598522

代碼如下：

import urllib
from urllib import request
from http import cookiejar
login_url = "https://www.saikr.com/login"
postdata ={
"name": "your account","pass": "your password(加密后）"
}
header = {
"Accept":"application/json, text/javascript, */*; q=0.01",
"Accept-Language":"zh-CN,zh;q=0.8,zh-TW;q=0.7,zh-HK;q=0.5,en-US;q=0.3,en;q=0.2",
"Connection":"keep-alive",
"Host":"www.saikr.com",
"Referer":"https://www.saikr.com/login",
"Cookie":"your cookie",
"Content-Type":"application/x-www-form-urlencoded; charset=UTF-8",
"TE":"Trailers","X-Requested-With":"XMLHttpRequest"
}
postdata = urllib.parse.urlencode(postdata).encode('utf8')
#req = requests.post(url,postdata,header)
#聲明一個CookieJar對象實例來保存cookie
cookie = cookiejar.CookieJar()
#利用urllib.request庫的HTTPCookieProcessor對象來創(chuàng)建cookie處理器,也就CookieHandler
cookie_support = request.HTTPCookieProcessor(cookie)
 #通過CookieHandler創(chuàng)建opener
opener = request.build_opener(cookie_support)
#創(chuàng)建Request對象
my_url="https://www.saikr.com/u/5598522"
req1 = request.Request(url=login_url, data=postdata, headers=header)#post請求
req2 = request.Request(url=my_url)#利用構造的opener不需要cookie即可登陸，get請求
response1 = opener.open(req1)
response2 = opener.open(req2)
print(response1.read().decode('utf8'))
print(response2.read().decode('utf8'))

到此就告一段落了：

ps：有點小插曲，當在headers里加入

Accept-Encoding

gzip, deflate, br

時，最后在 print(response1.read().decode('utf8'))時便會報錯

UnicodeDecodeError: 'utf-8' codec can't decode byte 0x8b in position 1: invalid start byte

原因：在請求header中設置了'Accept-Encoding': 'gzip, deflate'

參考鏈接：https://www.cnblogs.com/chyu/p/4558782.html

解決方法：去掉Accept-Encoding后就正常了

二、模擬登陸網(wǎng)址常用方法總結

1.通過urllib庫的request庫的函數(shù)進行請求

from urllib import request
#get請求
------------------------------------------------------
#不加headers
response=request.urlopen(url)
page_source = response.read().decode('utf-8')

#加headers,由于urllib.request.urlopen() 函數(shù)不接受headers參數(shù)，所以需要構建一個urllib.request.Request對象來實現(xiàn)請求頭的設置
req= request.Request(url=url,headers=headers)
response=request.urlopen(req)
page_source = response.read().decode('utf-8')

#post請求
-------------------------------------------------------
postdata = urllib.parse.urlencode(data).encode('utf-8')#必須進行重編碼
req= request.Request(url=url,data=postdata,headers=headers)
response=request.urlopen(req)
page_source = response.read().decode('utf-8')
#使用cookie訪問其他版塊
#聲明一個CookieJar對象實例來保存cookie
cookie = cookiejar.CookieJar()
#利用urllib.request庫的HTTPCookieProcessor對象來創(chuàng)建cookie處理器,也就CookieHandler
cookie_support = request.HTTPCookieProcessor(cookie)
 #通過CookieHandler創(chuàng)建opener
opener = request.build_opener(cookie_support)
# 將Opener安裝位全局，覆蓋urlopen函數(shù)，也可以臨時使用opener.open()函數(shù)
#urllib.request.install_opener(opener)
#創(chuàng)建Request對象
my_url="https://www.saikr.com/u/5598522"
req2 = request.Request(url=my_url)
response1 = opener.open(req1)
response2 = opener.open(req2)
#或者直接response2=opener.open(my_url)
print(response1.read().decode('utf8'))
print(response2.read().decode('utf8'))

2.通過requests庫的get和post函數(shù)

import requests
import urllib
import json
#get請求
-----------------------------------------------------------
#method1
url="https://www.saikr.com/"
params={ 'key1': 'value1','key2': 'value2' }
real_url = base_url + urllib.parse.urlencode(params)
#real_url="https://www.saikr.com/key1=value1&key2=value2"
response=requests.get(real_url)
#method2
response=requests.get(url,params)
print(response.text)#<class 'str'>
print(response.content)# <class 'bytes'>

#post請求
login_url = "https://www.saikr.com/login"
postdata ={
"name": "1324802616@qq.com","pass": "my password",
}
header = {
"Accept":"application/json, text/javascript, */*; q=0.01",
"Accept-Language":"zh-CN,zh;q=0.8,zh-TW;q=0.7,zh-HK;q=0.5,en-US;q=0.3,en;q=0.2",
"Connection":"keep-alive",
"Host":"www.saikr.com",
"Referer":"https://www.saikr.com/login",
"Cookie":"mycookie",
"Content-Type":"application/x-www-form-urlencoded; charset=UTF-8",
"TE":"Trailers","X-Requested-With":"XMLHttpRequest"
}
#requests中的post中傳入的data可以不進行重編碼
#login_postdata = urllib.parse.urlencode(postdata).encode('utf8')
response=requests.post(url=login_url,data=postdata,headers=header)#<class 'requests.models.Response'>
#以下三種都可以解析結果
json1 = response1.json()#<class 'dict'>
json2= json.loads(response1.text)#<class 'dict'>
json_str = response2.content.decode('utf-8')#<class 'str'>

#利用session維持會話訪問其他版塊
--------------------------------------------------------------------
login_url = "https://www.saikr.com/login"
postdata ={
"name": "1324802616@qq.com","pass": "my password",
}
header = {
"Accept":"application/json, text/javascript, */*; q=0.01",
"Connection":"keep-alive",
"Referer":"https://www.saikr.com/login",
"Cookie":"mycookie",
}
session = requests.session()
response = session.post(url=url, data=data, headers=headers)
my_url="https://www.saikr.com/u/5598522"
response1 = session.get(url=my_url, headers=headers)
print(response1.json())

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