Force connection close lighttpd

Question

I need to run code in background for some time, after output is send to client.
But connection blocks and won't close until job is finished.

Looked at :
How do I close a connection early?
https://www.php.net/manual/en/features.connection-handling.php#71172
(and other linked answers)

I ended up with code :

    // credit : https://stackoverflow.com/questions/138374/how-do-i-close-a-connection-early#141026
    //          and related sources
    // broken on : lighttpd/1.4.53 - php/7.1.3

    $size=ob_get_length();
    header("Content-Length: $size",1);
    header("Connection: close",1);
    header("Content-Encoding: none\r\n");

    // flush all output
    ob_end_flush();
    ob_flush();
    flush();
    ob_end_clean();

    // if you're using sessions, this prevents subsequent requests
    // from hanging while the background process executes
    if (session_id()) session_write_close();

    ... some code for 10 seconds here

I tried both :
    server.max-keep-alive-idle=0
    server.max-keep-alive-requests = 0
Taken from :
    lighttpd force close connection
    https://serverfault.com/questions/283377/force-connection-close-lighttpd
(put inside /etc/lighttpd/lighttpd.conf)

My setup :
    lighttpd/1.4.53
    php/7.1.3
    Firefox 68.6.0esr (32-bit)
    Raspberry Pi 4
    Raspbian
    uname -a : Linux raspberrypi 4.19.97-v7l+ #1294 SMP Thu Jan 30 13:21:14 GMT 2020 armv7l GNU/Linux

Enabled lighttpd modules :
    10-accesslog.conf
    10-fastcgi.conf
    10-rewrite.conf
    15-fastcgi-php.conf
    90-javascript-alias.conf

Purpose :
It's simple MUD game code.
It is there to refresh AIs once per second.
It is periodicaly started by player's presence in game like this :

1] Script will process player's command,
    then connection should be closed to not bother player's browser
2] check lock-file and if it's free - lock it
3] then stay in background for 10 updates
    After that, file is unlocked,
    so another player's command can start another bg job

could you be more detailed about what you're trying to accomplish by displaying more of your code? What is executing this code? — Nibb, Apr 02 '20 at 14:34
@Nibb sure .. I isolated functional example here : https://pastebin.com/WBTDKVVC — Jirka Justra, Apr 03 '20 at 02:26
@Nibb .. sorry, I now realized, that my question was really not well stated ... added 'purpose' at and of question — Jirka Justra, Apr 03 '20 at 22:33

score 0 · Answer 1 · answered Apr 03 '20 at 15:23

If your code needs to do processing after it has sent a CGI response, then your code needs to do so in a separate execution context, since the CGI has done its job when it sends the CGI response, and lighttpd will then send a SIGTERM signal to your script.

One way to run code after sending a CGI response is to run the code in the background after sending a CGI response. See https://www.php.net/manual/en/function.posix-setsid.php

Another way is for your CGI to put a job into a job queue and have a standalone daemon, separate from the CGI, process the queue, e.g. using a redis server.

It is meant to be run on server without such level of control (payed hosting), so I came up with this self-started background thingy .. I forgot to mention it, sorry — Jirka Justra, Apr 03 '20 at 22:54

Force connection close lighttpd

1 Answers1

Linked