**注意一下 是import urllib.request 还是 form urllib import request**
0. urlopen()
语法:urllib.request.urlopen(url, data=None, [timeout, ]*, cafile=None, capath=None, cadefault=False, context=None)
实例0:(这个函数 一般就使用三个参数 url data timeout)
- 添加的data参数需要使用bytes()方法将参数转换为字节流(区别于str的一种类型 是一种比特流 010010010)编码的格式的内容,即bytes类型。
- response.read()是bytes类型的数据,需要decode(解码)一下。
import urllib.parse
import urllib.request
import urllib.error
url = 'http://httpbin.org/post'
data = bytes(urllib.parse.urlencode({'word': 'hello'}), encoding='utf8')
try:
response = urllib.request.urlopen(url, data=data,timeout=1)
except urllib.error.URLError as e:
if isinstance(e.reason, socket.timeout):
print('TIME OUT')
else:
print(response.read().decode("utf-8"))
输出结果:
{
"args": {},
"data": "",
"files": {},
"form": {
"word": "hello"
},
"headers": {
"Accept-Encoding": "identity",
"Content-Length": "10",
"Content-Type": "application/x-www-form-urlencoded",
"Host": "httpbin.org",
"User-Agent": "Python-urllib/3.6"
},
"json": null,
"origin": "101.206.170.234, 101.206.170.234",
"url": "https://httpbin.org/post"
}
实例1:查看i状态码、响应头、响应头里server字段的信息
import urllib.request
response = urllib.request.urlopen('https://www.python.org')
print(response.status)
print(response.getheaders())
print(response.getheader('Server'))
输出结果:
200
[('Server', 'nginx'), ('Content-Type', 'text/html; charset=utf-8'), ('X-Frame-Options', 'DENY'), ('Via', '1.1 vegur'), ('Via', '1.1 varnish'), ('Content-Length', '48410'), ('Accept-Ranges', 'bytes'), ('Date', 'Tue, 09 Apr 2019 02:32:34 GMT'), ('Via', '1.1 varnish'), ('Age', '722'), ('Connection', 'close'), ('X-Served-By', 'cache-iad2126-IAD, cache-hnd18751-HND'), ('X-Cache', 'MISS, HIT'), ('X-Cache-Hits', '0, 1223'), ('X-Timer', 'S1554777154.210361,VS0,VE0'), ('Vary', 'Cookie'), ('Strict-Transport-Security', 'max-age=63072000; includeSubDomains')]
nginx
使用urllib库的urlopen()方法有很大的局限性,比如不能设置响应头的信息等。所以需要引入request()方法。
1. Request()
实例0:(这两种方法的实现效果是一样的)
import urllib.request
response = urllib.request.urlopen('https://www.python.org')
print(response.read().decode('utf-8'))
######################################
import urllib.request
req = urllib.request.Request('https://python.org')
response = urllib.request.urlopen(req)
print(response.read().decode('utf-8'))
下面主要讲解下使用Request()方法来实现get请求
和post请求
,并设置参数。
实例1:(post请求)
from urllib import request, parse
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'))
亦可使用add_header()方法来添加报头,实现浏览器的模拟,添加data属性亦可如下书写:
补充:还可以使用bulid_opener()修改报头,不过多阐述,够用了就好。
from urllib import request, parse
url = 'http://httpbin.org/post'
dict = {
'name': 'Germey'
}
data = parse.urlencode(dict).encode('utf-8')
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'))
实例2:(get请求) 百度关键字的查询
from urllib import request,parse
url = 'http://www.baidu.com/s?wd='
key = '路飞'
key_code = parse.quote(key)
url_all = url + key_code
"""
#第二种写法
url = 'http://www.baidu.com/s'
key = '路飞'
wd = parse.urlencode({'wd':key})
url_all = url + '?' + wd
"""
req = request.Request(url_all)
response = request.urlopen(req)
print(response.read().decode('utf-8'))
在这里,对编码decode、reqest模块里的quote()方法、urlencode()方法 等就有疑问了,,对此,做一些说明:
- parse.quote:将str数据转换为对应的编码
- parse.urlencode:将字典中的k:v转换为K:编码后的v
- parse.unquote:将编码后的数据转化为编码前的数据
- decode 字符串解码 decode("utf-8")跟read()搭配很配!
- encode 字符串编码
- encoding指定编码格式
>>> str0 = '我爱你'
>>> str1 = str0.encode('gb2312')
>>> str1
b'\xce\xd2\xb0\xae\xc4\xe3'
>>> str2 = str0.encode('gbk')
>>> str2
b'\xce\xd2\xb0\xae\xc4\xe3'
>>> str3 = str0.encode('utf-8')
>>> str3
b'\xe6\x88\x91\xe7\x88\xb1\xe4\xbd\xa0'
>>> str00 = str1.decode('gb2312')
>>> str00
'我爱你'
>>> str11 = str1.decode('utf-8') #报错,因为str1是gb2312编码的
Traceback (most recent call last):
File "<pyshell#9>", line 1, in <module>
str11 = str1.decode('utf-8')
UnicodeDecodeError: 'utf-8' codec can't decode byte 0xce in position 0: invalid continuation byte
在这里,可能又有疑问了?read()、readline()、readlines()的区别:
- read():全部,字符串str
- reasline():一行
- readlines():全部,列表list
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