CakePHP Questions

flush(); and ob_flush() work well to send out status messages to a long running process. There's a way to do this inline in a page and another way using iframes.

Basically if you load up page information into an iframe you can update that iframe as the page loads with status messages by flushing out messages to the output buffer. This will necessarily circumvent the natural cake rendering path but something like this would work for the code in our controller.

ob_start();
while(!$this->isDone()){

    echo '<div class="status-message">Still running...</div>';
    ob_flush();
    flush();
}
ob_end_flush();

Here's a link to php output buffer goodness

http://www.php.net/manual/en/ref.outcontrol.php

You can simply link this to the contents of the iframe and as it runs it will update the display with the divs.

Alternatively you can use AJAX and poll the AJAX call to see if there is any more data and if there is - render that output to the DOM. The downside is that this only works in FF, Safari and Opera so IE users only get all the output at the very end.

The following is in jquery but would be similar in any other framework-

<script type="text/javascript">
$(document).ready( function(){
    // Get the X-HTTP Request object	
    var xhr = $.ajax({
    	type: 'POST',
    	url: '/mycontrollers/ajaxfunction',
    	dataType: 'html',
    	success: function(msg){
    			
             alert('Success');
        }
    	
    }	
    );
    
    // set the onreadystatechange function to be our custom one
    xhr.onreadystatechange = xhrTest;
 
    function xhrTest(e){
    	
    	// Ready state keeps track of what ready state the ajax call is returning
    	var evt = e || window.event;
    	var rs = xhr.readyState || "None";

        // Everytime the page updates with more data FF and Safari will
        // fire onreadystatechange with the result status (rs) == 3
	// Stream for FF and Safari
    	if (rs == 3){
   		// take those messages and update our messages div
	    		$("#myMessages").html(this.responseText);
	    	}

    }
});
</script>

Here's a little on the xhttp object

http://www.tizag.com/ajaxTutorial/ajaxxmlhttprequest.php

Answered by davidwuon 12/1/10

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