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)‘))
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): Read timed out. (read timeout=0.01)
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): Max retries exceeded with url: / (Caused by NewConnectionError(‘<urllib3.connection.HTTPConnection object at 0x7f75826665f8>: Failed to establish a new connection: [Errno -2] Name or service not known‘,))
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): Max retries exceeded with url: http://github.com/ (Caused by ProxyError(‘Cannot connect to proxy.‘, NewConnectionError(‘<urllib3.connection.HTTPConnection object at 0x7fce3438c6d8>: Failed to establish a new connection: [Errno 111] Connection refused‘,)))
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): Max retries exceeded with url: http://github.com/ (Caused by ConnectTimeoutError(<urllib3.connection.HTTPConnection object at 0x7fa8896cc6d8>, ‘Connection to 10.200.123.123 timed out. (connect timeout=6.05)‘))
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): Read timed out. (read timeout=0.5)
可能是断网导致，抛出 requests.exceptions.ConnectionError
requests.get(‘http://github.com‘, timeout=(6.05, 27.05)) # 抛出错误 requests.exceptions.ConnectionError: HTTPConnectionPool(host=‘github.com‘, port=80): Max retries exceeded with url: / (Caused by NewConnectionError(‘<urllib3.connection.HTTPConnection object at 0x7fc8c17675f8>: Failed to establish a new connection: [Errno -3] Temporary failure in name resolution‘,))
你可以告诉 requests 在经过以 timeout 参数设定的秒数时间之后停止等待响应。基本上所有的生产代码都应该使用这一参数。如果不使用，你的程序可能会永远失去响应： >>> requests.get(‘http://github.com‘, timeout=0.001) Traceback (most recent call last): File "<stdin>", line 1, in <module> requests.exceptions.Timeout: HTTPConnectionPool(host=‘github.com‘, port=80): Request timed out. (timeout=0.001) 并不是整个下载响应的时间限制，而是如果服务器在 timeout 秒内没有应答，将会引发一个异常（更精确地说，是在 timeout 秒内没有从基础套接字上接收到任何字节的数据时） - 遇到网络问题（如：DNS 查询失败、拒绝连接等）时，Requests 会抛出一个 requests.exceptions.ConnectionError 异常。 - 如果 HTTP 请求返回了不成功的状态码， Response.raise_for_status() 会抛出一个 HTTPError 异常。 - 若请求超时，则抛出一个 Timeout 异常。 - 若请求超过了设定的最大重定向次数，则会抛出一个 TooManyRedirects 异常。 - 所有Requests显式抛出的异常都继承自 requests.exceptions.RequestException 。
原文：https://www.cnblogs.com/hls-code/p/14861976.html