Python，流请求期间捕获超时

Question

我正在阅读下面代码中所述请求库的XML事件。一旦请求启动，我该如何提出连接丢失错误？服务器正在模拟HTTP推送/长轮询 - >http://en.wikipedia.org/wiki/Push_technology#Long_polling，并且默认情况下不会结束。 如果10分钟后没有新消息，则应退出while循环。

import requests 
from time import time 


if __name__ == '__main__': 
    #: Set a default content-length 
    content_length = 512 
    try: 
     requests_stream = requests.get('http://agent.mtconnect.org:80/sample?interval=0', stream=True, timeout=2) 
     while True: 
      start_time = time() 
      #: Read three lines to determine the content-length   
      for line in requests_stream.iter_lines(3, decode_unicode=None): 
       if line.startswith('Content-length'): 
        content_length = int(''.join(x for x in line if x.isdigit())) 
        #: pause the generator 
        break 

      #: Continue the generator and read the exact amount of the body.   
      for xml in requests_stream.iter_content(content_length): 
       print "Received XML document with content length of %s in %s seconds" % (len(xml), time() - start_time) 
       break 

    except requests.exceptions.RequestException as e: 
     print('error: ', e) 

服务器推送可以与卷曲通过命令行进行测试：

curl http://agent.mtconnect.org:80/sample\?interval\=0 

Answer 1

这可能不是最好的方法，但可以使用多运行在一个单独的进程请求。 像这样的东西应该工作：

import multiprocessing 
import requests 
import time 

class RequestClient(multiprocessing.Process): 
    def run(self): 
     # Write all your code to process the requests here 
     content_length = 512 
     try: 
      requests_stream = requests.get('http://agent.mtconnect.org:80/sample?interval=0', stream=True, timeout=2) 

      start_time = time.time() 
      for line in requests_stream.iter_lines(3, decode_unicode=None): 
       if line.startswith('Content-length'): 
        content_length = int(''.join(x for x in line if x.isdigit())) 
        break 

      for xml in requests_stream.iter_content(content_length): 
       print "Received XML document with content length of %s in %s seconds" % (len(xml), time.time() - start_time) 
       break 
     except requests.exceptions.RequestException as e: 
      print('error: ', e) 


While True: 
    childProcess = RequestClient() 
    childProcess.start() 

    # Wait for 10mins 
    start_time = time.time() 
    while time.time() - start_time <= 600: 
     # Check if the process is still active 
     if not childProcess.is_alive(): 
      # Request completed 
      break 
     time.sleep(5) # Give the system some breathing time 

    # Check if the process is still active after 10mins. 
    if childProcess.is_alive(): 
     # Shutdown the process 
     childProcess.terminate() 
     raise RuntimeError("Connection Timed-out") 

不完美的代码，你的问题，但你的想法。