HttpComponents HttpCore
  1. HttpComponents HttpCore
  2. HTTPCORE-288

Change TCP_NODELAY and SO_KEEPALIVE on the fly

    Details

    • Type: Improvement Improvement
    • Status: Closed
    • Priority: Minor Minor
    • Resolution: Fixed
    • Affects Version/s: 4.2-alpha2
    • Fix Version/s: 4.2
    • Component/s: HttpCore, HttpCore NIO
    • Labels:
      None

      Description

      Request:
      HttpConnection#setTcpNoDelay() and setSocketKeepalive() methods to modify those socket settings on the fly like can be done with setSocketTimeout()

      Motivation:
      Set different socket options depending on the request to support different services on the same port. E.g. turn on TCP_NODELAY for requests to an AJAX-based unix shell, but turn it off for transferring large files. Turn on SO_KEEPALIVE and turn off socket timeout for long poll (comet) requests, but not for other requests.

      Potential problem:
      When using persistent connections it is easy to forget that these options survive to the next request. This situation exists with socket timeout already, though. You have to remember to set it back when sending a response if you don't want it for the next request. Perhaps a way to set timeout/nodelay/keepalive temporarily only for the current request is useful. Either way, I'd be happy to just be able to set nodelay and keepalive on the fly.

        Activity

        Hide
        Oleg Kalnichevski added a comment -

        HTTPCORE-295 provided a means of getting access to the underlying socket of non-blocking connections thus allowing modification of socket settings at execution time. It is quite a hack but it is all we can do without breaking the API.

        Oleg

        Show
        Oleg Kalnichevski added a comment - HTTPCORE-295 provided a means of getting access to the underlying socket of non-blocking connections thus allowing modification of socket settings at execution time. It is quite a hack but it is all we can do without breaking the API. Oleg
        Hide
        Oleg Kalnichevski added a comment -

        HttpConnection interface cannot be changed until 5.0 but what we can do in the meantime is adding those methods to the default HTTP connection implementation classes.

        Oleg

        Show
        Oleg Kalnichevski added a comment - HttpConnection interface cannot be changed until 5.0 but what we can do in the meantime is adding those methods to the default HTTP connection implementation classes. Oleg
        Hide
        Geir Harald Hansen added a comment -

        I always just assumed it would work but have never tried it.

        I googled around a bit. I could not find any info on Linux, but I found two webpages on Windows. According to http://msdn.microsoft.com/en-us/library/windows/desktop/ee470551%28v=vs.85%29.aspx running on Windows Vista or later you can set SO_KEEPALIVE before or after a call to connect() but not during an asynchronous connect() that has not yet completed. An example at http://msdn.microsoft.com/en-us/library/windows/desktop/ms740476%28v=vs.85%29.aspx shows binding a listening socket to a port and then modifying SO_KEEPALIVE afterwards.

        The javadoc at http://docs.oracle.com/javase/6/docs/api/java/net/Socket.html doesn't say anything about it. It may be useful to also expose Socket#setTrafficClass - but the previous URL does warn that changing traffic class for an existing connection may not work, depending on the underlying TCP stack. I have no idea if the major platforms support such modification for active connections. Anyway, there is no such information for SO_KEEPALIVE and TCP_NODELAY.

        Show
        Geir Harald Hansen added a comment - I always just assumed it would work but have never tried it. I googled around a bit. I could not find any info on Linux, but I found two webpages on Windows. According to http://msdn.microsoft.com/en-us/library/windows/desktop/ee470551%28v=vs.85%29.aspx running on Windows Vista or later you can set SO_KEEPALIVE before or after a call to connect() but not during an asynchronous connect() that has not yet completed. An example at http://msdn.microsoft.com/en-us/library/windows/desktop/ms740476%28v=vs.85%29.aspx shows binding a listening socket to a port and then modifying SO_KEEPALIVE afterwards. The javadoc at http://docs.oracle.com/javase/6/docs/api/java/net/Socket.html doesn't say anything about it. It may be useful to also expose Socket#setTrafficClass - but the previous URL does warn that changing traffic class for an existing connection may not work, depending on the underlying TCP stack. I have no idea if the major platforms support such modification for active connections. Anyway, there is no such information for SO_KEEPALIVE and TCP_NODELAY.
        Hide
        Oleg Kalnichevski added a comment -

        For some reason I always thought TCP_NODELAY and SO_KEEPALIVE only could be applied to newly created sockets only. Are you sure they can be changed on an already initialized socket?

        Oleg

        Show
        Oleg Kalnichevski added a comment - For some reason I always thought TCP_NODELAY and SO_KEEPALIVE only could be applied to newly created sockets only. Are you sure they can be changed on an already initialized socket? Oleg

          People

          • Assignee:
            Unassigned
            Reporter:
            Geir Harald Hansen
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            Dates

            • Created:
              Updated:
              Resolved:

              Development