python使用requests语句报错的原因有哪些

python中使用requests语句报错的原因主要有以下几种情况：

1 连接超时

服务器在指定时间内没有应答，抛出 requests.exceptions.ConnectTimeout

requests.get('http://github.com', timeout=0.001)

# 抛出错误

requests.exceptions.ConnectTimeout: HTTPConnectionPool(host='github.com', port=80): Max retries exceeded with url: / (Caused by ConnectTimeoutError(<urllib3.connection.HTTPConnection object at 0x7f1b16da75f8>, 'Connection to github.com timed out. (connect timeout=0.001)'))

2. 连接、读取超时

若分别指定连接和读取的超时时间，服务器在指定时间没有应答，抛出 requests.exceptions.ConnectTimeout

– timeout=([连接超时时间], [读取超时时间])

– 连接：客户端连接服务器并并发送http请求服务器

– 读取：客户端等待服务器发送第一个字节之前的时间

requests.get('http://github.com',timeout=(6.05,0.01))
#抛出错误
requests.exceptions.ReadTimeout:HTTPConnectionPool(host='github.com',port=80):Readtimedout.
(readtimeout=0.01)

3. 未知的服务器

抛出requests.exceptions.ConnectionError
requests.get('http://github.comasf',timeout=(6.05,27.05))
#抛出错误
requests.exceptions.ConnectionError:HTTPConnectionPool(host='github.comasf',port=80):Maxretriesexceeded
withurl:/(CausedbyNewConnectionError('<urllib3.connection.HTTPConnectionobjectat0x7f75826665f8>:
Failedtoestablishanewconnection:[Errno-2]Nameorservicenotknown',))

4. 代理连接不上

代理服务器拒绝建立连接，端口拒绝连接或未开放，抛出 requests.exceptions.ProxyError

requests.get('http://github.com',timeout=(6.05,27.05),proxies={"http":"192.168.10.1:800"})
#抛出错误
requests.exceptions.ProxyError:HTTPConnectionPool(host='192.168.10.1',port=800):Maxretriesexceededwith
url:http://github.com/(CausedbyProxyError('Cannotconnecttoproxy.',NewConnectionError('<urllib3.
connection.HTTPConnectionobjectat0x7fce3438c6d8>:Failedtoestablishanewconnection:[Errno111]
Connectionrefused',)))

5. 连接代理超时

代理服务器没有响应 requests.exceptions.ConnectTimeout

requests.get('http://github.com',timeout=(6.05,27.05),proxies={"http":"10.200.123.123:800"})
#抛出错误
requests.exceptions.ConnectTimeout:HTTPConnectionPool(host='10.200.123.123',port=800):Maxretriesexceeded
withurl:http://github.com/(CausedbyConnectTimeoutError(<urllib3.connection.HTTPConnectionobjectat
0x7fa8896cc6d8>,'Connectionto10.200.123.123timedout.(connecttimeout=6.05)'))

6. 代理读取超时

说明与代理建立连接成功，代理也发送请求到目标站点，但是代理读取目标站点资源超时

即使代理访问很快，如果代理服务器访问的目标站点超时，这个锅还是代理服务器背

假定代理可用，timeout就是向代理服务器的连接和读取过程的超时时间，不用关心代理服务器是否连接和读取成功

requests.get('http://github.com',timeout=(2,0.01),proxies={"http":"192.168.10.1:800"})
#抛出错误
requests.exceptions.ReadTimeout:HTTPConnectionPool(host='192.168.10.1:800',port=1080):Readtimedout.(read
timeout=0.5)

7. 网络环境异常

requests.get('http://github.com',timeout=(6.05,27.05))
#抛出错误
requests.exceptions.ConnectionError:HTTPConnectionPool(host='github.com',port=80):Maxretriesexceededwith
url:/
(CausedbyNewConnectionError('<urllib3.connection.HTTPConnectionobjectat0x7fc8c17675f8>:Failedto
establishanew
connection:[Errno-3]Temporaryfailureinnameresolution',))