mORMot Open Source

Daniel

Member

Registered: 2016-12-08

Posts: 23

Using Keepalive ?

Both Synopse sockets and websockets seem to implement KeepAlive mechanism.
I'm using WebSockets and I'd like to make use of KeepAlive to detect disconnects.

I tried playing with the available properties but could not get it to do anything.

I assume that once connection is established any subsequent disconnect should be detected after keepAlive period expires.

So, what do I have to do/set for KeepAlive to be in use ?

ab

Administrator

From: France

Registered: 2010-06-21

Posts: 14,655

Website

Re: Using Keepalive ?

KeepAlive is for HTTP. It is just a wish from the client to not have the connection closed for a given time.
But most Web servers do close the connection after a while or a number of messages.
Then the connection is quickly re-opened at TCP level.

WebSockets have a more coherent mechanism, with proper disconnection and regular ping/pong messages to check the connection.
It will really keep alive the connection.

By default, if you use TSQLHttpClientWebsockets, this mechanism will be built-in.
If you want easy disconnection detection, e.g. to reconfigure some services when using asynchronous callbacks, check TDDDRestClientWebSockets from dddInfraApps.pas. Inherit from it, then override the DefineApplication and RegisterServices virtual methods.