How to Enable NHTTP in WSO2 ESB

PTT (Pass Through Transport) transport is the default transport that is shipped with ESB (At the time of this post ESB 4.9.0) It is the recommended transport which brings blistering fast performance to WSO2 ESB, you can read more about this from here. But the old HTTP-NIO transport also ships with the ESB by default and it's disable in the default pack, in some scenarios you might need to enable this transport.

HTTP-NIO transport is a module of the Apache Synapse project. The two classes that implement the receiver and sender APIs are org.apache.synapse.transport.nhttp.HttpCoreNIOListener and org.apache.synapse.transport.nhttp.HttpCoreNIOSender respectively. These classes are available in the JAR file named synapse-nhttp-transport.jar. The transport implementation is based on Apache HTTP Core - NIO and uses a configurable pool of non-blocking worker threads to grab incoming HTTP messages off the wire. You can read more about NHTTP from here.

Enabling nhttp is very simple, and I'm writing this down if some one couldn't find out how to do this.

In-order to enable NHTTP follow the instructions below,

1. Shutdown the server if already running
2. Navigate to <WSO2_HOME>/repository/conf/axis2 directory.
3. Now take a backup of axis2.xml file and delete that file.
4. Now rename the axis2_nhttp.xml to axis2.xml.
5. Now start the Server again.

For NTTP different set of configuration are used and these reside in the axis2_nhttp.xml file, by default this is disabled and when the axis2.xml is replaced with the axis2_nhttp.xml these configuration takes effect.