requests

相比urllib，第三方庫(kù)requests更加簡(jiǎn)單人性化，是爬蟲(chóng)工作中常用的庫(kù)

requests安裝

初級(jí)爬蟲(chóng)的開(kāi)始主要是使用requests模塊安裝requests模塊：Windows系統(tǒng)：cmd中：

pip install requests

mac系統(tǒng)中：終端中：

pip3 install requestsrequests庫(kù)的基本使用

import requestsurl = ’https://www.csdn.net/’reponse = requests.get(url)#返回unicode格式的數(shù)據(jù)(str) print(reponse.text)

響應(yīng)對(duì)象response的⽅法

response.text 返回unicode格式的數(shù)據(jù)(str)response.content 返回字節(jié)流數(shù)據(jù)(⼆進(jìn)制)response.content.decode(‘utf-8’) ⼿動(dòng)進(jìn)⾏解碼response.url 返回urlresponse.encode() = ‘編碼’

狀態(tài)碼

response.status_code: 檢查響應(yīng)的狀態(tài)碼

例如：200 : 請(qǐng)求成功301 : 永久重定向302 : 臨時(shí)重定向403 : 服務(wù)器拒絕請(qǐng)求404 : 請(qǐng)求失敗(服務(wù)器⽆法根據(jù)客戶端的請(qǐng)求找到資源（⽹⻚）)500 : 服務(wù)器內(nèi)部請(qǐng)求

# 導(dǎo)入requestsimport requests# 調(diào)用requests中的get()方法來(lái)向服務(wù)器發(fā)送請(qǐng)求，括號(hào)內(nèi)的url參數(shù)就是我們# 需要訪問(wèn)的網(wǎng)址，然后將獲取到的響應(yīng)通過(guò)變量response保存起來(lái)url = ’https://www.csdn.net/’ # csdn官網(wǎng)鏈接鏈接response = requests.get(url)print(response.status_code) # response.status_code: 檢查響應(yīng)的狀態(tài)碼

200

請(qǐng)求⽅式

requests的幾種請(qǐng)求方式：

p = requests.get(url)p = requests.post(url)p = requests.put(url,data={’key’:’value’})p = requests.delete(url)p = requests.head(url)p = requests.options(url)GET請(qǐng)求

HTTP默認(rèn)的請(qǐng)求方法就是GET* 沒(méi)有請(qǐng)求體* 數(shù)據(jù)必須在1K之內(nèi)！* GET請(qǐng)求數(shù)據(jù)會(huì)暴露在瀏覽器的地址欄中

GET請(qǐng)求常用的操作：1. 在瀏覽器的地址欄中直接給出URL，那么就一定是GET請(qǐng)求2. 點(diǎn)擊頁(yè)面上的超鏈接也一定是GET請(qǐng)求3. 提交表單時(shí)，表單默認(rèn)使用GET請(qǐng)求，但可以設(shè)置為POST

POST請(qǐng)求

(1). 數(shù)據(jù)不會(huì)出現(xiàn)在地址欄中(2). 數(shù)據(jù)的大小沒(méi)有上限(3). 有請(qǐng)求體(4). 請(qǐng)求體中如果存在中文，會(huì)使用URL編碼！

requests.post()用法與requests.get()完全一致，特殊的是requests.post()有一個(gè)data參數(shù)，用來(lái)存放請(qǐng)求體數(shù)據(jù)

請(qǐng)求頭

當(dāng)我們打開(kāi)一個(gè)網(wǎng)頁(yè)時(shí)，瀏覽器要向網(wǎng)站服務(wù)器發(fā)送一個(gè)HTTP請(qǐng)求頭，然后網(wǎng)站服務(wù)器根據(jù)HTTP請(qǐng)求頭的內(nèi)容生成當(dāng)此請(qǐng)求的內(nèi)容發(fā)送給服務(wù)器。我們可以手動(dòng)設(shè)定請(qǐng)求頭的內(nèi)容：

import requestsheader = { ’User-Agent’:’Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/79.0.3945.88 Safari/537.36’}url = ’https://www.csdn.net/’reponse = requests.get(url,headers=header)#打印文本形式print(reponse.text)requests設(shè)置代理

使⽤requests添加代理只需要在請(qǐng)求⽅法中(get/post)傳遞proxies參數(shù)就可以了

cookie

cookie ：通過(guò)在客戶端記錄的信息確定⽤戶身份

HTTP是⼀種⽆連接協(xié)議,客戶端和服務(wù)器交互僅僅限于 請(qǐng)求/響應(yīng)過(guò)程,結(jié)束后 斷開(kāi),下⼀次請(qǐng)求時(shí),服務(wù)器會(huì)認(rèn)為是⼀個(gè)新的客戶端,為了維護(hù)他們之間的連接, 讓服務(wù)器知道這是前⼀個(gè)⽤戶發(fā)起的請(qǐng)求,必須在⼀個(gè)地⽅保存客戶端信息。

requests操作Cookies很簡(jiǎn)單，只需要指定cookies參數(shù)即可

import requests#這段cookies是從CSDN官網(wǎng)控制臺(tái)中復(fù)制的header = { ’User-Agent’:’Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/79.0.3945.88 Safari/537.36’, ’cookie’: ’uuid_tt_dd=10_30835064740-1583844255125-466273; dc_session_id=10_1583844255125.696601; __gads=ID=23811027bd34da29:T=1583844256:S=ALNI_MY6f7VlmNJKxrkHd2WKUIBQ34Bbnw; UserName=xdc1812547560; UserInfo=708aa833b2064ba9bb8ab0be63866b58; UserToken=708aa833b2064ba9bb8ab0be63866b58; UserNick=xdc1812547560; AU=F85; UN=xdc1812547560; BT=1590317415705; p_uid=U000000; Hm_ct_6bcd52f51e9b3dce32bec4a3997715ac=6525*1*10_30835064740-1583844255125-466273!5744*1*xdc1812547560; Hm_up_6bcd52f51e9b3dce32bec4a3997715ac=%7B%22islogin%22%3A%7B%22value%22%3A%221%22%2C%22scope%22%3A1%7D%2C%22isonline%22%3A%7B%22value%22%3A%221%22%2C%22scope%22%3A1%7D%2C%22isvip%22%3A%7B%22value%22%3A%220%22%2C%22scope%22%3A1%7D%2C%22uid_%22%3A%7B%22value%22%3A%22xdc1812547560%22%2C%22scope%22%3A1%7D%7D; log_Id_click=1; Hm_lvt_feacd7cde2017fd3b499802fc6a6dbb4=1595575203; Hm_up_feacd7cde2017fd3b499802fc6a6dbb4=%7B%22islogin%22%3A%7B%22value%22%3A%221%22%2C%22scope%22%3A1%7D%2C%22isonline%22%3A%7B%22value%22%3A%221%22%2C%22scope%22%3A1%7D%2C%22isvip%22%3A%7B%22value%22%3A%220%22%2C%22scope%22%3A1%7D%2C%22uid_%22%3A%7B%22value%22%3A%22xdc1812547560%22%2C%22scope%22%3A1%7D%7D; Hm_ct_feacd7cde2017fd3b499802fc6a6dbb4=5744*1*xdc1812547560!6525*1*10_30835064740-1583844255125-466273; Hm_up_facf15707d34a73694bf5c0d571a4a72=%7B%22islogin%22%3A%7B%22value%22%3A%221%22%2C%22scope%22%3A1%7D%2C%22isonline%22%3A%7B%22value%22%3A%221%22%2C%22scope%22%3A1%7D%2C%22isvip%22%3A%7B%22value%22%3A%220%22%2C%22scope%22%3A1%7D%2C%22uid_%22%3A%7B%22value%22%3A%22xdc1812547560%22%2C%22scope%22%3A1%7D%7D; Hm_ct_facf15707d34a73694bf5c0d571a4a72=5744*1*xdc1812547560!6525*1*10_30835064740-1583844255125-466273; announcement=%257B%2522isLogin%2522%253Atrue%252C%2522announcementUrl%2522%253A%2522https%253A%252F%252Flive.csdn.net%252Froom%252Fyzkskaka%252Fats4dBdZ%253Futm_source%253D908346557%2522%252C%2522announcementCount%2522%253A0%257D; Hm_lvt_facf15707d34a73694bf5c0d571a4a72=1596946584,1597134917,1597155835,1597206739; searchHistoryArray=%255B%2522%25E8%258F%259C%25E9%25B8%259FIT%25E5%25A5%25B3%2522%252C%2522%25E5%25AE%25A2%25E6%259C%258D%2522%255D; log_Id_pv=7; log_Id_view=8; dc_sid=c0efd34d6da090a1fccd033091e0dc53; TY_SESSION_ID=7d77f76f-a4b1-43ef-9bb5-0aebee8ee475; c_ref=https%3A//www.baidu.com/link; c_first_ref=www.baidu.com; c_first_page=https%3A//www.csdn.net/; Hm_lvt_6bcd52f51e9b3dce32bec4a3997715ac=1597245305,1597254589,1597290418,1597378513; c_segment=1; dc_tos=qf1jz2; Hm_lpvt_6bcd52f51e9b3dce32bec4a3997715ac=1597387359’}url = ’https://www.csdn.net/’reponse = requests.get(url,headers=header)#打印文本形式print(reponse.text)session

session ：通過(guò)在服務(wù)端記錄的信息確定⽤戶身份這⾥這個(gè)session就是⼀個(gè)指 的是會(huì)話會(huì)話對(duì)象是一種高級(jí)的用法，可以跨請(qǐng)求保持某些參數(shù)，比如在同一個(gè)Session實(shí)例之間保存Cookie，像瀏覽器一樣，我們并不需要每次請(qǐng)求Cookie，Session會(huì)自動(dòng)在后續(xù)的請(qǐng)求中添加獲取的Cookie，這種處理方式在同一站點(diǎn)連續(xù)請(qǐng)求中特別方便

處理不信任的SSL證書(shū)

什么是SSL證書(shū)？SSL證書(shū)是數(shù)字證書(shū)的⼀種，類(lèi)似于駕駛證、護(hù)照和營(yíng)業(yè)執(zhí)照的電⼦副本。

因?yàn)榕渲迷诜?wù)器上，也稱(chēng)為SSL服務(wù)器證書(shū)。SSL 證書(shū)就是遵守 SSL協(xié) 議，由受信任的數(shù)字證書(shū)頒發(fā)機(jī)構(gòu)CA，在驗(yàn)證服務(wù)器身份后頒發(fā)，具有服務(wù) 器身份驗(yàn)證和數(shù)據(jù)傳輸加密功能我們來(lái)爬一個(gè)證書(shū)不太合格的網(wǎng)站

import requestsurl = ’https://inv-veri.chinatax.gov.cn/’resp = requests.get(url)print(resp.text)

它報(bào)了一個(gè)錯(cuò)

我們來(lái)修改一下代碼

import requestsurl = ’https://inv-veri.chinatax.gov.cn/’resp = requests.get(url,verify = False)print(resp.text)

我們的代碼又能成功爬取了

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