How to gracefully tell client the transmission is finished so the browser will display the page immediately?

Question

Greeting guys,

I'm working on my php framework. It has a response manager to wrapper php's header, cookie, and buffer functions. I use this to send result page to user.

However, even the page header and contents already be sent by using ob_start -> ob_end_flush -> flush, the browser still hanging and wait for script to complete.

It cause problems when i want to do some slow job like update current user's session or just send a mail or upload something. User will have to wait until everything done, even they already have the whole page including header.

What I want to know is, how to make browser know the page is completely loaded, so it can display the page right now?

Thank you!

//////////////////////////// Abandoned Solutions ////////////////////////////

Abandoned Solution 1

In the past, i usually use the combination of ob_start -> ob_end_flush -> ob_flush -> flush to fix this problem, it seems will like this:

function send($content) {
    ob_start();

    echo $content;

    ob_end_flush();
    ob_flush();
    flush();

    return true;
}

But the ob_flush will throw a E_NOTICE says it have "No buffer to flush". I don't want to fix this by just mute this E_NOTICE (and in fact, in my framework, there is no way to mute any error). So this is not the way to solve this problem.

Abandoned Solution 2

I also try to close connection after content sent, code will like this:

function send($content) {
    ob_start();

    header('Connection: close');

    echo $content;

    ob_end_flush();

    flush();

    return true;
}

It can solve the problem with out any error, but it bring another problem: Seems client's connection will be close after page received, and when they want to open another page, they have to reconnect. This will generate extra load on network.

Abandoned Solution 3

Yeah, some people suggested me to use fastcgi, and use fastcgi_finish_request(); But i want to make my code more compatible between environments, so it actually not a option.

Why would the browser hang? Once the PHP is done output is sent and connection is closed. Try a `die;` after the flush and see if anything changes. Does your PHP script terminate properly? — CodeAngry, Jul 16 '13 at 01:54
@CodeAngry: Sorry, but i don't want to use die, it will make my question pointless. I want to make script continue run after page sent. — , Jul 16 '13 at 02:05

score 0 · Answer 1 · edited May 23 '17 at 12:29

On IIS you cannot break the connection before the fastcgi finishes. You need to use fascgi_finish_request()^ to manually force the finish of the current CGI.

On Apache you can use the Content-Length: 0 redirect trick^ which works great but does not work on IIS (at least not in my experience).

PS: And make sure you do the ignore_user_abort(true) and extend the runtime limit set_time_limit(0)(infinte) before any of these to prevent PHP from closing when connection is closed by client.

PPS: Tasks run after page is sent should go into cronjobs. It's the cleaner way to do things.

How to gracefully tell client the transmission is finished so the browser will display the page immediately?

1 Answers1