Apache HttpClient TCP Keep-Alive (socket keep-alive)

Question

I have http request that takes too much time to be processed by the server (about 5 minutes). Because connection becomes idle for 5 minutes, proxy server shutdowns the connection. I'm trying to use TCP Keep-Alive in Apache DefaultHttpClient to make connection be alive for a long time (Not confuse TCP Keep-Alive with HTTP Keep-Alive that simply doesn't closes connection after response is sent).

Apache http core has following parameter SO_KEEPALIVE: http://hc.apache.org/httpcomponents-core-ga/httpcore/apidocs/org/apache/http/params/CoreConnectionPNames.html#SO_KEEPALIVE. However, due to DefaultHttpClient javadocs I can't customize client's behavior with that parameter: https://hc.apache.org/httpcomponents-client-ga/httpclient/apidocs/org/apache/http/impl/client/DefaultHttpClient.html.

I did this, however, seems it doesn't work:

HttpClient client = getHttpClient();
client.getParams().setParameter(CoreConnectionPNames.SO_KEEPALIVE, true);

Do you know how to make DefaultHttpClient use TCP Keep-Alive strategy?

To make it work I needed to set keepalive timeouts. But they can be set only on OS level, not in java code. Here is how I set them on Linux: sudo sysctl -w net.ipv4.tcp_keepalive_time=60 , sudo sysctl -w net.ipv4.tcp_keepalive_intvl=60 , sudo sysctl -w net.ipv4.tcp_keepalive_probes=10 . Value is amount of seconds. — baratali
This is not an app level solution! An OS level solution introduces misunderstandings and documentation errors. Would be better if we could find an OS level solution! — Ajay Gautam

baratali baratali · Accepted Answer · 2017-02-14T13:59:27

To make it work I needed to set keepalive timeouts. But they can be set only on OS level, not in Java code. As I know, it's not possible to set keepalive timeouts in Java code.

Here is how I set them on Linux:

sudo sysctl -w net.ipv4.tcp_keepalive_time=60
sudo sysctl -w net.ipv4.tcp_keepalive_intvl=60
sudo sysctl -w net.ipv4.tcp_keepalive_probes=10

Value is amount of seconds.

Apache HttpClient TCP Keep-Alive (socket keep-alive)

1 Answers