1.什么是Urllib Python内置的HTTP请求库
urllib.request 请求模块
urllib.error 异常处理模块
urllib.parse url解析模块
urllib.robotparser robots.txt解析模块
2.urlopen:访问网页
#直接打开网页
response = urllib.request.urlopen('http://www.baidu.com')
#post请求网页
data = bytes(urllib.parse.urlencode({'word': 'hello'}), encoding='utf8')
response = urllib.request.urlopen('http://httpbin.org/post', data=data)
#设定请求时间
response = urllib.request.urlopen('http://httpbin.org/get', timeout=1)
#超出响应时间报错
try:
response = urllib.request.urlopen('http://httpbin.org/get', timeout=0.1)
except urllib.error.URLError as e:
if isinstance(e.reason, socket.timeout):
print('TIME OUT')
3.响应
response = urllib.request.urlopen('https://www.python.org')
#响应类型
print(type(response))
#状态码
print(response.status)
#响应头
print(response.getheaders())
#服务器
print(response.getheader('Server'))
#响应内容
print(response.read().decode('utf-8'))
4.Request：通过构造一个request访问
#构造一个带有url的request通过urlopen访问
request = urllib.request.Request('https://python.org')
response = urllib.request.urlopen(request)
print(response.read().decode('utf-8'))
#这是一个内容全面的request
url = 'http://httpbin.org/post'
headers = {
'User-Agent': 'Mozilla/4.0 (compatible; MSIE 5.5; Windows NT)',
'Host': 'httpbin.org'
}
dict = {
'name': 'Germey'
}
data = bytes(parse.urlencode(dict), encoding='utf8')
req = request.Request(url=url, data=data, headers=headers, method='POST')
response = request.urlopen(req)
print(response.read().decode('utf-8'))
#补充request的响应头，add_header可多次调用
url = 'http://httpbin.org/post'
dict = {
'name': 'Germey'
}
data = bytes(parse.urlencode(dict), encoding='utf8')
req = request.Request(url=url, data=data, method='POST')
req.add_header('User-Agent', 'Mozilla/4.0 (compatible; MSIE 5.5; Windows NT)')
response = request.urlopen(req)
print(response.read().decode('utf-8'))
5.Handler
#代理访问
proxy_handler = urllib.request.ProxyHandler({
'http': 'http://',
'https': 'https://'
})
opener = urllib.request.build_opener(proxy_handler)
response = opener.open('http://httpbin.org/get')
print(response.read())
#cookie:维持登录状态
#获取cookie
cookie = http.cookiejar.CookieJar()
handler = urllib.request.HTTPCookieProcessor(cookie)
opener = urllib.request.build_opener(handler)
response = opener.open('http://www.baidu.com')
for item in cookie:
print(item.name+"="+item.value)
#保存cookie到文件里
filename = "cookie.txt"
cookie = http.cookiejar.MozillaCookieJar(filename)
handler = urllib.request.HTTPCookieProcessor(cookie)
opener = urllib.request.build_opener(handler)
response = opener.open('http://www.baidu.com')
cookie.save(ignore_discard=True, ignore_expires=True)
#另一种保存方式
filename = 'cookie.txt'
cookie = http.cookiejar.LWPCookieJar(filename)
handler = urllib.request.HTTPCookieProcessor(cookie)
opener = urllib.request.build_opener(handler)
response = opener.open('http://www.baidu.com')
cookie.save(ignore_discard=True, ignore_expires=True)
#读取cookie
cookie = http.cookiejar.LWPCookieJar()
cookie.load('cookie.txt', ignore_discard=True, ignore_expires=True)
handler = urllib.request.HTTPCookieProcessor(cookie)
opener = urllib.request.build_opener(handler)
response = opener.open('http://www.baidu.com')
print(response.read().decode('utf-8'))
6.异常处理
#抛出异常
try:
response = request.urlopen('http://cuiqingcai.com/index.htm')
except error.HTTPError as e:
print(e.reason, e.code, e.headers, sep='
')
except error.URLError as e:
print(e.reason)
else:
print('Request Successfully')
#判断异常
try:
response = urllib.request.urlopen('https://www.baidu.com', timeout=0.01)
except urllib.error.URLError as e:
print(type(e.reason))
if isinstance(e.reason, socket.timeout):
print('TIME OUT')
7.url解析
#urlparse
urllib.parse.urlparse(urlstring, scheme='', allow_fragments=True)
#urlunparse构造一个url
data = ['http', 'www.baidu.com', 'index.html', 'user', 'a=6', 'comment']
print(urlunparse(data))
#urljoin拼接新的url，以后一个为基准，用前一个url补足后一个url
print(urljoin('http://www.baidu.com', 'FAQ.html'))
print(urljoin('http://www.baidu.com', 'https://cuiqingcai.com/FAQ.html'))
print(urljoin('http://www.baidu.com/about.html', 'https://cuiqingcai.com/FAQ.html'))
print(urljoin('http://www.baidu.com/about.html', 'https://cuiqingcai.com/FAQ.html?question=2'))
print(urljoin('http://www.baidu.com?wd=abc', 'https://cuiqingcai.com/index.php'))
print(urljoin('http://www.baidu.com', '?category=2#comment'))
print(urljoin('www.baidu.com', '?category=2#comment'))
print(urljoin('www.baidu.com#comment', '?category=2'))
#urlcode组合url
params = {
'name': 'germey',
'age': 22
}
base_url = 'http://www.baidu.com?'
url = base_url + urlencode(params)
print(url)