I tried to use websockets in OFBiz. I simply added tomcat-embed-websocket.jar in catalina lib and created one webapp for websocket and also added server endpoint class.
It didn't work. After that, I tried the same thing with plain j2ee application with embedded tomcat. It worked there.
I researched on above issue in OFBiz and got the reason. Websockets implementation need jar scanning enabled and it is currently disabled in OFBiz. Below is the code snippet of disabling jar scan from CatalinaContainer.java:
Jar scanning enabling increase OFBiz server startup time upto couples of minutes (in my case, it took approx 8 minutes), so we don't want this much of startup time for OFBiz.
I got the following document where I found the reason why websocket is not working if scanning disabled.
Here tips are given to decrease the startup time. This tips also include disabling of jar scanning.
We can say disabling jar scanning is right approach because if we enable it then scanner will scan all the jars loaded in OFBiz startup that we don't want.
But, If we want websockets working then we have to enable jar scanning.
For enabling jar scanning, we need below code:
Solution: We can add filter on jar scanning. It will allow only some kind of jars only. For example: jars having websockets endpoints. I am attaching patch for the same here.
I added filter like if jar name string contains "discoverable" word then only it will be considered for jar scan. We can change jar name of our jars using build.xml to make it discoverable for jar scanning.
For example: I have added my websocket endpoint class in "specialpurpose/ecommerce/src" and changed the "name" property in build.xml of ecommerce component from "ofbiz-ecommerce"
to "ofbiz-ecommerce-discoverable". Here is the code snippet from build.xml:
This change will create the jar with name "ofbiz-ecommerce-discoverable.jar" in "ecommerce/build/lib/".
Now created jar will be scanned in jar scanner as its name contains "discoverable" word in it.
This change will not increase server start up time more than couple of seconds (in my case, it just two seconds). So scanning time totally depends on the list of jars scanned.
Conclusion: We can use websocket support with the help of jar filters.
I am also attaching the version 8.0.33 tomcat-embed-websocket.jar.