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javascriptajaxjquerylong-polling

Stop Long Polling Function in JS


I have a page where I have implemented a long polling function to check the timestamp of a record, so it will update if the data has been edited.

<script type="text/javascript">
var poll_url = 'http://mysite.com/poll/;
var my_ts = <?php $_SESSION['template_timestamp']; ?>;
(function poll(){
    $.ajax({ 
        url: poll_url,
        type: 'post',
        success: function(data){
            if ((data.ts > 0) {
                // check if expired
                if (data.ts > my_ts) {
                    // it has expired, so reload the page
                    $("#dialog-message").html('Record has been edited.');
                    // show popup
                    $("#dialog-message").dialog({
                        modal: true,
                        buttons: {
                            Reload: function() {
                                $(this).dialog("close");
                                $('#pleaseWait').show();
                                window.location.href = '/records/overview';
                            }
                        }
                    });
                }
            } else {
                // is still null
                console.log('error');
            }
        }, 
        dataType: "json", 
        complete: poll, timeout: 30000 
    });
})();
</script>

The problem I have is that there is also another action which invokes a JS ajax call, which when called I would like to force the long polling function to stop.
Is there a way to do this?


Solution

  • The following SO question may provide the answer... Abort Ajax requests using jQuery

    Applying that to your code snippet, you might get something along the lines of...

    <script type="text/javascript">
    var poll_url = 'http://mysite.com/poll/';
    var my_ts = <?php $_SESSION['template_timestamp']; ?>;
    var poll_xhr;
    
    (function poll(){
        poll_xhr = $.ajax({ 
            url: poll_url,
            type: 'post',
            success: function(data){
                // Code removed
            }, 
            dataType: "json", 
            complete: poll, 
            timeout: 30000 
        });
    })();
    
    // To kill the AJAX request, put this where it makes sense
    poll_xhr.abort();
    </script>