title: Server - Client comunication
body: <p>considering websoket connections ex. (javascript client -&gt; php / asp server) or asynchronous ajax requests, I was looking for reverse communication: server-&gt; client, to get a certain response from the server without making the request. Assuming a batch process that runs on server, which communicates the presence of a data ready to the client when the desired data has been processed. Does such architecture exist?</p>