Python爬虫入门的封装函数取得网站HTML页面

作为对初入爬虫的同学们，简单的封装函数调用取得HTML页面方法。这里写代码片

from urllib import request,parse
from urllib.error import HTTPError,URLError
#get方法封装
def get(url,headers=None):
    #headers必须赋予变量否则属于位置参数会在调用函数中被当成form
    return urlrequests(url,headers=headers)
#post方法封装
def post(url,form,headers=None):
    return urlrequests(url,form,headers=headers)

def urlrequests(url,form=None,headers=None):
    if headers == None:
        headers = {
            'User-Agent':'Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/67.0.3396.99 Safari/537.36'
        }
    html_bytes = b''
    try:
        if form:
            #转换成str
            form_str = parse.urlencode(form)
            #转换成bytes
            form_bytes = form_str.encode('utf-8')
            req = request.Request(url,data=form_bytes,headers=headers)
        else:
            req = request.Request(url,headers=headers)
        response = request.urlopen(req)
        html_bytes = response.read()
    except HTTPError as a:
        print(a)
    except URLError as a:
        print(a)
    return html_bytes
if __name__=='__main__':
    #根据自身需要爬去的网站改变路由和请求方法，再改变下编码
    url = 'http://www.baidu.com'
    html = get(url)
    print(html)