python爬虫---requests库的用法

╰+攻爆jí腚メ 2023-10-08 08:46 19阅读 0赞

requests是python实现的简单易用的HTTP库，使用起来比urllib简洁很多

因为是第三方库，所以使用前需要cmd安装

pip install requests

安装完成后import一下，正常则说明可以开始使用了。

基本用法：

requests.get()用于请求目标网站，类型是一个HTTPresponse类型

![复制代码][aHR0cHM6Ly9jb21tb24uY25ibG9ncy5jb20vaW1hZ2VzL2NvcHljb2RlLmdpZg]

import requests
    
    response = requests.get('http://www.baidu.com')
    print(response.status_code)  # 打印状态码
    print(response.url)          # 打印请求url
    print(response.headers)      # 打印头信息
    print(response.cookies)      # 打印cookie信息
    print(response.text)  #以文本形式打印网页源码
    print(response.content) #以字节流形式打印

![复制代码][aHR0cHM6Ly9jb21tb24uY25ibG9ncy5jb20vaW1hZ2VzL2NvcHljb2RlLmdpZg]

运行结果：

状态码：200

url：www.baidu.com

headers信息

![format_png][]

各种请求方式：

![复制代码][aHR0cHM6Ly9jb21tb24uY25ibG9ncy5jb20vaW1hZ2VzL2NvcHljb2RlLmdpZg]

import requests
    
    requests.get('http://httpbin.org/get')
    requests.post('http://httpbin.org/post')
    requests.put('http://httpbin.org/put')
    requests.delete('http://httpbin.org/delete')
    requests.head('http://httpbin.org/get')
    requests.options('http://httpbin.org/get')

![复制代码][aHR0cHM6Ly9jb21tb24uY25ibG9ncy5jb20vaW1hZ2VzL2NvcHljb2RlLmdpZg]

基本的get请求

import requests
    
    response = requests.get('http://httpbin.org/get')
    print(response.text)

结果

![format_png 1][]

带参数的GET请求：

第一种直接将参数放在url内

import requests
    
    response = requests.get(http://httpbin.org/get?name=gemey&age=22)
    print(response.text)

结果

![format_png 2][]

另一种先将参数填写在dict中，发起请求时params参数指定为dict

![复制代码][aHR0cHM6Ly9jb21tb24uY25ibG9ncy5jb20vaW1hZ2VzL2NvcHljb2RlLmdpZg]

import requests
    
    data = {
        'name': 'tom',
        'age': 20
    }
    
    response = requests.get('http://httpbin.org/get', params=data)
    print(response.text)

![复制代码][aHR0cHM6Ly9jb21tb24uY25ibG9ncy5jb20vaW1hZ2VzL2NvcHljb2RlLmdpZg]

结果同上

解析json

![复制代码][aHR0cHM6Ly9jb21tb24uY25ibG9ncy5jb20vaW1hZ2VzL2NvcHljb2RlLmdpZg]

import requests
    
    response = requests.get('http://httpbin.org/get')
    print(response.text)
    print(response.json())  #response.json()方法同json.loads(response.text)
    print(type(response.json()))

![复制代码][aHR0cHM6Ly9jb21tb24uY25ibG9ncy5jb20vaW1hZ2VzL2NvcHljb2RlLmdpZg]

结果

![format_png 3][]

简单保存一个二进制文件

二进制内容为response.content

![复制代码][aHR0cHM6Ly9jb21tb24uY25ibG9ncy5jb20vaW1hZ2VzL2NvcHljb2RlLmdpZg]

import requests
    
    response = requests.get('http://img.ivsky.com/img/tupian/pre/201708/30/kekeersitao-002.jpg')
    b = response.content
    with open('F://fengjing.jpg','wb') as f:
        f.write(b)

![复制代码][aHR0cHM6Ly9jb21tb24uY25ibG9ncy5jb20vaW1hZ2VzL2NvcHljb2RlLmdpZg]

为你的请求添加头信息

![复制代码][aHR0cHM6Ly9jb21tb24uY25ibG9ncy5jb20vaW1hZ2VzL2NvcHljb2RlLmdpZg]

import requests

heads = {}
    heads['User-Agent'] = 'Mozilla/5.0 ' \
                              '(Macintosh; U; Intel Mac OS X 10_6_8; en-us) AppleWebKit/534.50 ' \
                              '(KHTML, like Gecko) Version/5.1 Safari/534.50'

response = requests.get('http://www.baidu.com',headers=headers)

![复制代码][aHR0cHM6Ly9jb21tb24uY25ibG9ncy5jb20vaW1hZ2VzL2NvcHljb2RlLmdpZg]

使用代理

同添加headers方法，代理参数也要是一个dict

这里使用requests库爬取了IP代理网站的IP与端口和类型

因为是免费的，使用的代理地址很快就失效了。

![复制代码][aHR0cHM6Ly9jb21tb24uY25ibG9ncy5jb20vaW1hZ2VzL2NvcHljb2RlLmdpZg]

import requests
    import re
    
    def get_html(url):
        proxy = {
            'http': '120.25.253.234:812',
            'https' '163.125.222.244:8123'
        }
        heads = {}
        heads['User-Agent'] = 'Mozilla/5.0 (Windows NT 10.0; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/49.0.2623.221 Safari/537.36 SE 2.X MetaSr 1.0'
        req = requests.get(url, headers=heads,proxies=proxy)
        html = req.text
        return html
    
    def get_ipport(html):
        regex = r'<td data-title="IP">(.+)</td>'
        iplist = re.findall(regex, html)
        regex2 = '<td data-title="PORT">(.+)</td>'
        portlist = re.findall(regex2, html)
        regex3 = r'<td data-title="类型">(.+)</td>'
        typelist = re.findall(regex3, html)
        sumray = []
        for i in iplist:
            for p in portlist:
                for t in typelist:
                    pass
                pass
            a = t+','+i + ':' + p
            sumray.append(a)
        print('高匿代理')
        print(sumray)
    
    
    if __name__ == '__main__':
        url = 'http://www.kuaidaili.com/free/'
        get_ipport(get_html(url))

![复制代码][aHR0cHM6Ly9jb21tb24uY25ibG9ncy5jb20vaW1hZ2VzL2NvcHljb2RlLmdpZg]

结果：

![format_png 4][]

基本POST请求：

import requests
    
    data = {'name':'tom','age':'22'}
    
    response = requests.post('http://httpbin.org/post', data=data)

![format_png 5][]

获取cookie

![复制代码][aHR0cHM6Ly9jb21tb24uY25ibG9ncy5jb20vaW1hZ2VzL2NvcHljb2RlLmdpZg]

#获取cookie
    import requests
    
    response = requests.get('http://www.baidu.com')
    print(response.cookies)
    print(type(response.cookies))
    for k,v in response.cookies.items():
        print(k+':'+v)

![复制代码][aHR0cHM6Ly9jb21tb24uY25ibG9ncy5jb20vaW1hZ2VzL2NvcHljb2RlLmdpZg]

结果：

![format_png 6][]

会话维持

![复制代码][aHR0cHM6Ly9jb21tb24uY25ibG9ncy5jb20vaW1hZ2VzL2NvcHljb2RlLmdpZg]

import requests
    
    session = requests.Session()
    session.get('http://httpbin.org/cookies/set/number/12345')
    response = session.get('http://httpbin.org/cookies')
    print(response.text)

![复制代码][aHR0cHM6Ly9jb21tb24uY25ibG9ncy5jb20vaW1hZ2VzL2NvcHljb2RlLmdpZg]

结果：

![format_png 7][]

证书验证设置

![复制代码][aHR0cHM6Ly9jb21tb24uY25ibG9ncy5jb20vaW1hZ2VzL2NvcHljb2RlLmdpZg]

import requests
    from requests.packages import urllib3
    
    urllib3.disable_warnings()  #从urllib3中消除警告
    response = requests.get('https://www.12306.cn',verify=False)  #证书验证设为FALSE
    print(response.status_code)
    
    打印结果：200

![复制代码][aHR0cHM6Ly9jb21tb24uY25ibG9ncy5jb20vaW1hZ2VzL2NvcHljb2RlLmdpZg]

超时异常捕获

![复制代码][aHR0cHM6Ly9jb21tb24uY25ibG9ncy5jb20vaW1hZ2VzL2NvcHljb2RlLmdpZg]

import requests
    from requests.exceptions import ReadTimeout
    
    try:
        res = requests.get('http://httpbin.org', timeout=0.1)
        print(res.status_code)
    except ReadTimeout:
        print(timeout)

![复制代码][aHR0cHM6Ly9jb21tb24uY25ibG9ncy5jb20vaW1hZ2VzL2NvcHljb2RlLmdpZg]

异常处理

在你不确定会发生什么错误时，尽量使用try...except来捕获异常

所有的requests exception：

### [Exceptions][] ###

![复制代码][aHR0cHM6Ly9jb21tb24uY25ibG9ncy5jb20vaW1hZ2VzL2NvcHljb2RlLmdpZg]

import requests
    from requests.exceptions import ReadTimeout,HTTPError,RequestException
    
    try:
        response = requests.get('http://www.baidu.com',timeout=0.5)
        print(response.status_code)
    except ReadTimeout:
        print('timeout')
    except HTTPError:
        print('httperror')
    except RequestException:
        print('reqerror')

![复制代码][aHR0cHM6Ly9jb21tb24uY25ibG9ncy5jb20vaW1hZ2VzL2NvcHljb2RlLmdpZg]

来源：[https://www.cnblogs.com/mzc1997/p/7813801.html][https_www.cnblogs.com_mzc1997_p_7813801.html]

[aHR0cHM6Ly9jb21tb24uY25ibG9ncy5jb20vaW1hZ2VzL2NvcHljb2RlLmdpZg]: https://imgconvert.csdnimg.cn/aHR0cHM6Ly9jb21tb24uY25ibG9ncy5jb20vaW1hZ2VzL2NvcHljb2RlLmdpZg
[format_png]: https://imgconvert.csdnimg.cn/aHR0cHM6Ly9pbWFnZXMyMDE3LmNuYmxvZ3MuY29tL2Jsb2cvMTI0NTMyNC8yMDE3MTEvMTI0NTMyNC0yMDE3MTEyMjEzNDExMDQ2MS0zNTk1MDA0MjUucG5n?x-oss-process=image/format,png
[format_png 1]: https://imgconvert.csdnimg.cn/aHR0cHM6Ly9pbWFnZXMyMDE3LmNuYmxvZ3MuY29tL2Jsb2cvMTI0NTMyNC8yMDE3MTEvMTI0NTMyNC0yMDE3MTEyMjEzNDAwOTYxOC00NjU1NTI3NzIucG5n?x-oss-process=image/format,png
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[format_png 3]: https://imgconvert.csdnimg.cn/aHR0cHM6Ly9pbWFnZXMyMDE3LmNuYmxvZ3MuY29tL2Jsb2cvMTI0NTMyNC8yMDE3MTEvMTI0NTMyNC0yMDE3MTEyMjEzNDQ1MTU1NS01MzY2MDU1NTIucG5n?x-oss-process=image/format,png
[format_png 4]: https://imgconvert.csdnimg.cn/aHR0cHM6Ly9pbWFnZXMyMDE3LmNuYmxvZ3MuY29tL2Jsb2cvMTI0NTMyNC8yMDE3MTEvMTI0NTMyNC0yMDE3MTEyMjE5NDU0MTc3NC0xODg3OTY3MTYwLnBuZw?x-oss-process=image/format,png
[format_png 5]: https://imgconvert.csdnimg.cn/aHR0cHM6Ly9pbWFnZXMyMDE3LmNuYmxvZ3MuY29tL2Jsb2cvMTI0NTMyNC8yMDE3MTEvMTI0NTMyNC0yMDE3MTEyMjIxMDQyOTEwMi0xMTYzMDQwOTQucG5n?x-oss-process=image/format,png
[format_png 6]: https://imgconvert.csdnimg.cn/aHR0cHM6Ly9pbWFnZXMyMDE3LmNuYmxvZ3MuY29tL2Jsb2cvMTI0NTMyNC8yMDE3MTEvMTI0NTMyNC0yMDE3MTEyMjIxMDYyOTg2OC00MTU4ODIyLnBuZw?x-oss-process=image/format,png
[format_png 7]: https://imgconvert.csdnimg.cn/aHR0cHM6Ly9pbWFnZXMyMDE3LmNuYmxvZ3MuY29tL2Jsb2cvMTI0NTMyNC8yMDE3MTEvMTI0NTMyNC0yMDE3MTEyMjIxMTAxMDY5Ni04OTU3OTQ5NDIucG5n?x-oss-process=image/format,png
[Exceptions]: http://www.python-requests.org/en/master/api/#exceptions
[https_www.cnblogs.com_mzc1997_p_7813801.html]: https://www.cnblogs.com/mzc1997/p/7813801.html