Websockets with tomcat clustering and session replication

[Nir A <ni...@netomedia.com>]

Hi,

Ive asked here before about how do i get a session replication over
websockets sessions.
Mark Thomas  answered me that i should try and link the httpsession with
the websocket and then i will gain the replication abilities.

So, I listended and implemented it just like in this url:
http://stackoverflow.com/questions/17936440/accessing-httpsession-from-httpservletrequest-in-a-web-socket-socketendpoint

So now, I'm able to get the session for each client. and I Do get
replication! pretty nice!

Only problem is,  While i'm adding new attributes to the primary session
(in tomcat#1 for example) , the replicated sessions (in tomcat#2 for
example) does NOT contain any attribues.
The session backup is there but no attributes at all.


My POC web application has one html page with javascript web socket
send\recieve messages.

What i did notice that might shade light on whats the problem is the
following scenario:

If i press f5 on the browser, the web page is loaded and a new http
handshake is taking place. when that happens all the attributes do
replicate!!!

Is there a way to make the attribute replicate without the need of
refreshing the page?

Thanks!

Re: Websockets with tomcat clustering and session replication

[Nir A <ni...@netomedia.com>]

Yeah but, I would like to link the websocket session with the http session
of the handshake. and that way i will be able to imitiate the session
replication abilities for websocket.

This mechanism works as intended only problem is the replication not
replicate http session attribute while the websocket connection is
happening (since this is not a regular httpsession \ request cycle) my
question is - can i activate manually some kind of action on the http
session to make it "Refresh" so the tomcat will replicate it every time i
set new attribute? (I remind you again that pressing f5 will reconnect the
websocket and the attributes are being copied).


Thanks.


On Dec 2, 2013 8:51 PM, "Rossen Stoyanchev" <rs...@gopivotal.com>
wrote:

> On Sun, Dec 1, 2013 at 4:33 PM, Nir A <ni...@netomedia.com> wrote:
>
> My POC web application has one html page with javascript web socket
> > send\recieve messages.
> >
> > What i did notice that might shade light on whats the problem is the
> > following scenario:
> >
> > If i press f5 on the browser, the web page is loaded and a new http
> > handshake is taking place. when that happens all the attributes do
> > replicate!!!
> >
> > Is there a way to make the attribute replicate without the need of
> > refreshing the page?
> >
>
> In HTTP you have many requests associated with a session id. With session
> replication, each new request could go to a different server and still
> access the same HTTP session attributes.
>
> In WebSocket on the other hand there is a single connection the server and
> if you lose it, you have to reconnect, which is probably what pressing F5
> does for you. Unless I'm missing something, you have to detect when the
> WebSocket connection is closed on client side and reconnect.
>
> Rossen
>

Re: Websockets with tomcat clustering and session replication

[Rossen Stoyanchev <rs...@gopivotal.com>]

On Sun, Dec 1, 2013 at 4:33 PM, Nir A <ni...@netomedia.com> wrote:

My POC web application has one html page with javascript web socket
> send\recieve messages.
>
> What i did notice that might shade light on whats the problem is the
> following scenario:
>
> If i press f5 on the browser, the web page is loaded and a new http
> handshake is taking place. when that happens all the attributes do
> replicate!!!
>
> Is there a way to make the attribute replicate without the need of
> refreshing the page?
>

In HTTP you have many requests associated with a session id. With session
replication, each new request could go to a different server and still
access the same HTTP session attributes.

In WebSocket on the other hand there is a single connection the server and
if you lose it, you have to reconnect, which is probably what pressing F5
does for you. Unless I'm missing something, you have to detect when the
WebSocket connection is closed on client side and reconnect.

Rossen

Re: Websockets with tomcat clustering and session replication

[Nir A <ni...@netomedia.com>]

Can you come up with an alternative ? Or can you think of a way to fool
tomcat in thinking its in a regular cycle?
On Dec 2, 2013 3:16 PM, "Johan Compagner" <jc...@servoy.com> wrote:

> The problem is i guess, that you access the http session outside of a
> normal http request cycle
> So tomcat doesn't notice anything
>
> And also is it not a "spec" or behavior requirement that you don't hold on
> to your http session objects outside of requests?
>
>
>
>
> On 1 December 2013 15:33, Nir A <ni...@netomedia.com> wrote:
>
> > Hi,
> >
> > Ive asked here before about how do i get a session replication over
> > websockets sessions.
> > Mark Thomas  answered me that i should try and link the httpsession with
> > the websocket and then i will gain the replication abilities.
> >
> > So, I listended and implemented it just like in this url:
> >
> >
> http://stackoverflow.com/questions/17936440/accessing-httpsession-from-httpservletrequest-in-a-web-socket-socketendpoint
> >
> > So now, I'm able to get the session for each client. and I Do get
> > replication! pretty nice!
> >
> > Only problem is,  While i'm adding new attributes to the primary session
> > (in tomcat#1 for example) , the replicated sessions (in tomcat#2 for
> > example) does NOT contain any attribues.
> > The session backup is there but no attributes at all.
> >
> >
> > My POC web application has one html page with javascript web socket
> > send\recieve messages.
> >
> > What i did notice that might shade light on whats the problem is the
> > following scenario:
> >
> > If i press f5 on the browser, the web page is loaded and a new http
> > handshake is taking place. when that happens all the attributes do
> > replicate!!!
> >
> > Is there a way to make the attribute replicate without the need of
> > refreshing the page?
> >
> > Thanks!
> >
>
>
>
> --
> Johan Compagner
> Servoy
>

Re: Websockets with tomcat clustering and session replication

[Johan Compagner <jc...@servoy.com>]

The problem is i guess, that you access the http session outside of a
normal http request cycle
So tomcat doesn't notice anything

And also is it not a "spec" or behavior requirement that you don't hold on
to your http session objects outside of requests?




On 1 December 2013 15:33, Nir A <ni...@netomedia.com> wrote:

> Hi,
>
> Ive asked here before about how do i get a session replication over
> websockets sessions.
> Mark Thomas  answered me that i should try and link the httpsession with
> the websocket and then i will gain the replication abilities.
>
> So, I listended and implemented it just like in this url:
>
> http://stackoverflow.com/questions/17936440/accessing-httpsession-from-httpservletrequest-in-a-web-socket-socketendpoint
>
> So now, I'm able to get the session for each client. and I Do get
> replication! pretty nice!
>
> Only problem is,  While i'm adding new attributes to the primary session
> (in tomcat#1 for example) , the replicated sessions (in tomcat#2 for
> example) does NOT contain any attribues.
> The session backup is there but no attributes at all.
>
>
> My POC web application has one html page with javascript web socket
> send\recieve messages.
>
> What i did notice that might shade light on whats the problem is the
> following scenario:
>
> If i press f5 on the browser, the web page is loaded and a new http
> handshake is taking place. when that happens all the attributes do
> replicate!!!
>
> Is there a way to make the attribute replicate without the need of
> refreshing the page?
>
> Thanks!
>



-- 
Johan Compagner
Servoy