urllib3库的学习
参考链接:https://urllib3.readthedocs.io/en/latest/user-guide.html#using-timeouts
0x01:
Making Requests
首先我们肯定要安装urllib3这个库了(python3支持)
pip install urllib3
然后我们在编写任何脚本之前需要导入这个模块
import urllib3
现在我们需要一个PoolManager去建立一个request，这个的connection pooling的作用是为了thread safety
语句为:http=urllib3.PoolManager()
现在我们尝试一下get请求
import urllib3
http=urllib3.PoolManager()
r=http.request('GET','http://httpbin.org/robots.txt')
print(r.data)
>>b'User-agent: *\nDisallow: /deny\n'
request()返回一个HTTPResponse对象，我们可以使用request()对任何HTTP verb做请求
如下所示:post请求
import urllib3
http=urllib3.PoolManager()
r=http.request('POST','http://httpbin.org/post',fields={'hello':'world'})
0X02:
Response content
这个HTTPResponse对象提供了status，data，headers等属性
import urllib3
http=urllib3.PoolManager()
r=http.request('GET','http://httpbin.org/ip')
print(r.status)
print(r.data)
print(r.headers)
200
b'{\n "origin": "120.203.18.108"\n}\n'
HTTPHeaderDict({'Connection': 'keep-alive', 'Server': 'gunicorn/19.7.1', 'Date': 'Thu, 03 May 2018 06:50:51 GMT', 'Content-Type': 'application/json', 'Access-Control-Allow-Origin': '*', 'Access-Control-Allow-Credentials': 'true', 'X-Powered-By': 'Flask', 'X-Processed-Time': '0', 'Content-Length': '33', 'Via': '1.1 vegur'})
0x03：Json content
json文本在加载之前需要进行一次utf-8解密，将这个data进行一次反序列化，当然记得导入json模块
import json
r=http.request('GET','http://httpbin.org/ip')
print(json.loads(r.data.decode('utf-8')))
{'origin': '120.203.18.108'}
0x04:Binary content
data响应的属性始终设置为表示响应内容的字节字符串
r=http.request('GET','http://httpbin.org/bytes/8')
print(r.data)
b';P\x8aq\x97uO.'
注意：对于很大的response，我们有的时候需要去stream这个response
Streaming and IO
我们设置preload_content to False是为了urllib3能够stream这个请求文本，streamI()能够让我们迭代响应内容文本
注意:我们在使用preload_content=False的时候，我们应该调用release_conn()将http连接释放
import urllib3
http=urllib3.PoolManager()
r=http.request('GET','http://httpbin.org/bytes/1024',preload_content=False)
for chunk in r.stream(32):
print(chunk)
r.release_conn()
我们也可以将HTTPResponse实例视为文件类对象，这样的话可以让我们做下缓冲
import urllib3
http=urllib3.PoolManager()r=http.request('GET','http://httpbin.org/bytes/1024',preload_content=False)
r.read()
Calls toread将阻塞，直到有更多的相应的数据可用
r=http.request('GET','http://httpbin.org/bytes/1024',preload_content=False)
reader=io.BufferedReader(r,8)
print(reader.read(4))
r.release_conn()
b'\x959\xc3\x10'
我们也可以使用类文件对象来执行诸如codecs以下内容解码内容的操作
import codecs
reader=codecs.getreader('utf-8')
r=http.request('GET','http://httpbin.org/ip',preload_content=False)
print(json.load(reader(r)))
>>{'origin': '120.203.18.108'}
0x05:Request data
Headers
我们可以在headers参数中指定标题作为字典request()
import urllib3
http=urllib3.PoolManager()
r=http.request('GET','http://httpbin.org/headers',headers={'X-Something':'value'})
print(json.loads(r.data.decode('utf-8'))['headers'])
>>{'Accept-Encoding': 'identity', 'Connection': 'close', 'Host': 'httpbin.org', 'X-Something': 'value'}
Query parameters
对于get，head和delete请求，我们可以简单的传递参数作为一个字典fields参数request()
r=http.request('GET','http://httpbin.org/get',fields={'arg':'value'})
print(json.loads(r.data.decode('utf-8'))['args'])
>>{'arg': 'value'}
对于post和put请求，我们需要在url中手动编码查询参数
import urllib3
from urllib.parse import urlencode
encoded_args=urlencode({'arg':'value'})
url='http://httpbin.org/post?'+encoded_args
r=http.request('POST','url')
print(json.loads(r.data.decode('utf-8'))['args'])
Form data
对于put和post请求，urllib3将会自动的对表单提供给参数的字典进行编码
r=http.request('POST','http://httpbin.org/post',fields={'field':'value'})
print(json.loads(r.data.decode('utf-8'))['form'])
>>{'field': 'value'}
Json
我们可以通过将编码指定为body参数并在Content-Type调用的时候设置标题，来向json来发送请求
data={'attribute':'value'}
encoded_data=json.dumps(data).encode('utf-8')
r=http.request('POST','http://httpbin.org/post',body=encoded_data,headers={'Content-Type':'application/json'})
print(json.loads(r.data.decode('utf-8'))['json'])
>>{'attribute': 'value'}
Files&binary data
要使用multipart/form-data编码上传文件，可以使用与表单数据相同的方法，并将文件字段指定为一下元组(file_name,file_data)
with open('test.txt')as fp:
file_data=fp.read()
r=http.request('POST','http://httpbin.org/post',fields={'filefields':('test.txt',file_data)})
print(json.loads(r.data.decode('utf-8'))['files'])
尽管指定文件名不是严格要求的，但是为了匹配浏览器的行为，建议使用它。当然我们还可以传递元组的第三项来显式的指定文件的MIME类型
with open('test.txt')as fp:
file_data=fp.read()
r=http.request('POST','http://httpbin.org/post',fields={'filefields':('test.txt',file_data,'text/plain')})
print(json.loads(r.data.decode('utf-8'))['files'])
要发送原始的二进制数据，只需要指定body参数，还建议设置Content-Type标题
with open('test.jpg','rb')as fp:
binary_data=fp.read()
r=http.request('POST','http://httpbin.org/post',body=binary_data,headers={'Content-Type':'image/jpeg'})
print(json.loads(r.data.decode('utf-8'))['data'])
>>data:application/octet-stream;base64,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
0x06:Certificate verfication
强烈建议始终使用ssl验证。默认情况下，urllib3不验证https请求
为了启用验证，我们需要一组根证书。最简单而且最可靠的方法就是使用火狐提供的根证书包的certifi包
pip install certifi
获得证书后，我们可以创建一个PoolManager在发出请求的时候验证证书的方法
http=urllib3.PoolManager(cer_reqs='CERT_REQUIRED',ca_certs=certifi.where())
这个PoolManager将会自动的处理证书的验证，并在SSLError再验证失败的时候提出
r=http.request('GET','https://google.com')
r=http.request('GET', 'https://expired.badssl.com')
注意:如果需要，你可以使用操作系统提供的证书。只需要指定证书包的完整路径作为ca_carts参数而不是certifi.where()。例如，大多数linux操作系统存储证书/etc/ssl/certs/ca-certificates.crt。其他的操作系统可能很难。
0x07:Using timeouts
超时允许你控制请求在被中止前运行多长时间。再简单情况下，你可以将超时指定为float to request()
http=urllib3.PoolManager()
r=http.request('GET','http://httpbin.org/delay/3',timeout=4.0)
print(r.status)
>>200
http=urllib3.PoolManager()
r=http.request('GET','http://httpbin.org/delay/3',timeout=2.5)
print(r.status)
>>ReadTimeoutError
对于更加精细的控制，你可以使用一个Timeout实例，让你指定单独的连接和读取超时
http=urllib3.PoolManager()
r=http.request('GET','http://httpbin.org/delay/3',timeout=urllib3.Timeout(connect=1.0))
http=urllib3.PoolManager()
r=http.request('GET','http://httpbin.org/delay/3',timeout=urllib3.Timeout(connect=1.0,read=2.0))
print(r.status)
如果你希望所有的请求都受到相同的超时时间限制的话，我们可以在PoolManager级别上指定超时值
http=urllib3.PoolManage(timeout=3.0)
http=urllib3.PoolManage(timeout=3.0,read=2.0)
当然我们任然可以指定timeout来覆盖这个PoolManager超时的request()
0x08：Retrying requests
urllib3可以自动的重试idempotent等请求。同样的机制可以处理重定向。你可以使用retries参数to来控制重试requests()，默认情况下，urllib3将重试请求3次冰球跟随最多3次重定向。要更改重试次数，只需要指定一个整数即可
http=urllib3.PoolManager()
r=http.request('GET','http://httpbin.org/ip',retries=10)
print(r.status)
为了能够取消所有的重试和重定向，可以使用retries=False
http=urllib3.PoolManager()
r=http.request('GET','http://httpbin.org/redirect/1',retries=False)
print(r.status)
>>302
要禁用重定向但是需要保留重试，请指定redirect=False
http=urllib3.PoolManager()
r=http.request('GET','http://httpbin.org/redirect/1',redirect=False）
print(r.status)
>>302
为了更细化的控制，你可以使用一个retry实例。这个类允许你更好的控制请求重试的方式
例如:总共执行3次重试，但仅限于2次重定向。
http=urllib3.PoolManager()
r=http.request('GET','http://httpbin.org/redirect/1',retries=urllib3.Retry(3,redirect=2))
print(r.status)
当然你也可以禁用太多的重定向的异常，并且返回302响应
http=urllib3.PoolManager()
r=http.request('GET','http://httpbin.org/redirect/1',retries=urllib3.Retry(redirect=2,raise_on_redirect=False))
print(r.status)
如果你希望所有的请求都遵循相同的重试策略，那门可以在PoolManager级别上指定重试。
http=urllib3.PoolManager(retries=False)
http=urllib3.PoolManager(retries=urllib3.retry(5,redirect=2))
当然我们同样是可以使用retries来覆盖这个PoolManager的重试策略request()
0x09:Errors&Exceptions
urllib3包装较低级别的异常，例如:
http=urllib3.PoolManager()
try:
r=http.request('GET', 'nx.example.com', retries=False)
print(r.status)
except urllib3.exceptions.NewConnectionError:
print("urllib3 connection error!")
0x010：Logging
如果你使用的是标准库logging模块，urllib3将会发出多个日志。在某些情况下，这不可能是不可取的。你可以使用标准记录器界面来更改urllib3记录器的日志级别
logging.getLogger('urllib3').setLevel(logging.WARNING)