CODEWITHSUNDEEP
javascriptphpjqueryajax
AdrianUsagi
AdrianUsagi

Reputation: 39

Server Side Broadcast Update PHP

I want to build an application which will automatically broadcast notification(s) to a user when data on server is changed. So far, I just know one method of doing this i.e. using JQuery setInterval. Using this function, every client requests data through ajax to server, asking if something changed.

The weakness of this method is every client must send a packet every specific time interval, so my server receives huge data packet. It's so frustrating to manage the server. Are there any alternatives for this besides Jquery setInterval?

Upvotes: 1

Views: 268

Answers (1)

Andreas Furster
Andreas Furster

Reputation: 1638

If Websockets is not an option for you, you could use one ajax request to the server. Than server side go into a infinite loop. Use the sleep function to not overload the memory. Than check each time if there is something changed. If so, break out the loop and return the data. On the client side send immediately the next request.

After a bit of research it's called "Ajax long-polling requests".
Here is a explanation.

The PHP code would look something like this:

$prevHash = $_GET['hash'];

while(true){
   $currHash = GetHashFromTable('myTable');
   if ($prevHash != $currRowCount) break;
   sleep(3);
}

$response[0] = GetDataFromTable('myTable');
$response[1] = GetHashFromTable('myTable');

echo json_encode($response);

Update

Long polling is not the best option. Better to use web-sockets. If you want to compare the differences, see this answer: https://stackoverflow.com/a/10029326/3269816

Upvotes: 2

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