How can I run a PHP script in the background after a form is submitted

Question

Problem I have a form that  when submitted  will run basic code to process the information submitted and insert it into a database for display on a notification website  In addition  I have a list of people who have signed up to receive these notifications via email and SMS message  This list is trivial as the moment  only pushing about 150   however it s enough to cause it takes upwards of a minute to cycle through the entire table of subscribers and send out 150  emails   The emails are being sent individually as requested by the system administrators of our email server because of mass email policies     During this time  the individual who posted the alert will sit on the last page of the form for almost a minute without any positive reinforcement that their notification is being posted  This leads to other potential problems  all that have possible solutions that I feel are less than ideal    First  the poster might think the server is lagging and click the  Submit  button again  causing the script to start over or run twice  I could solve this by using JavaScript to disable the button and replace the text to say something like  Processing      however this is less than ideal because the user will still be stuck on the page for the length of the script execution   Also  if JavaScript is disabled  this problem still exists   Second  the poster might close the tab or the browser prematurely after submitting the form  The script will keeping running on the server until it tries to write back to the browser  however if the user then browses to any page within our domain  while the script is still running   the browser hangs loading the page until the script has ended   This only happens when a tab or window of the browser is closed and not the entire browser application   Still  this is less than ideal     Possible  Solution I ve decided I want to break out the  email  part of the script into a separate file I can call after the notification has been posted  I originally thought of putting this on the confirmation page after the notification has been successfully posted  However  the user will not know this script is running and any anomalies will not be apparent to them  This script cannot fail   But  what if I can run this script as a background process  So  my question is this  How can I execute a PHP script to trigger as a background service and run completely independent of what the user has done at the form level   EDIT  This cannot be cron ed  It must run the instant the form is submitted  These are high-priority notifications  In addition  the system administrators running our servers disallow crons from running any more frequently than 5 minutes

User · Answer

If you can access the server over ssh and can run your own scripts you can make a simple fifo server using php (although you will have to recompile php with posix support for fork).

The server can be written in anything really, you probably can easily do it in python.

Or the simplest solution would be sending an HttpRequest and not reading the return data but the server might destroy the script before it finish processing.

Example server :

<?php
define('FIFO_PATH', '/home/user/input.queue');
define('FORK_COUNT', 10);

if(file_exists(FIFO_PATH)) {
    die(FIFO_PATH . ' exists, please delete it and try again.' . "\n");
}

if(!file_exists(FIFO_PATH) && !posix_mkfifo(FIFO_PATH, 0666)){
    die('Couldn\'t create the listening fifo.' . "\n");
}

$pids = array();
$fp = fopen(FIFO_PATH, 'r+');
for($i = 0; $i < FORK_COUNT; ++$i) {
    $pids[$i] = pcntl_fork();
    if(!$pids[$i]) {
        echo "process(" . posix_getpid() . ", id=$i)\n";
        while(true) {
            $line = chop(fgets($fp));
            if($line == 'quit' || $line === false) break;
            echo "processing (" . posix_getpid() . ", id=$i) :: $line\n";
        //  $data = json_decode($line);
        //  processData($data);
        }
        exit();
    }
}
fclose($fp);
foreach($pids as $pid){
    pcntl_waitpid($pid, $status);
}
unlink(FIFO_PATH);
?>

Example client :

<?php
define('FIFO_PATH', '/home/user/input.queue');
if(!file_exists(FIFO_PATH)) {
    die(FIFO_PATH . ' doesn\'t exist, please make sure the fifo server is running.' . "\n");
}

function postToQueue($data) {
    $fp = fopen(FIFO_PATH, 'w+');
    stream_set_blocking($fp, false); //don't block
    $data = json_encode($data) . "\n";
    if(fwrite($fp, $data) != strlen($data)) {
        echo "Couldn't the server might be dead or there's a bug somewhere\n";
    }
    fclose($fp);
}
$i = 1000;
while(--$i) {
    postToQueue(array('xx'=>21, 'yy' => array(1,2,3)));
}
?>

User · Answer

In my case I have 3 params  one of them is string  mensaje    exec  C  wamp bin php php5 5 12 php exe C  test N trunk api v1 Process php  idTest2  idTest3    mensaje    gt  gt  c  log log  amp       In my Process php I have this code   if   isset  argv 1       isset  argv 2       isset  argv 3             die  Error          idCurso    argv 1    idDestino    argv 2    mensaje    argv 3

User · Answer

PHP exec  php script php   can do it   From the Manual      If a program is started with this   function  in order for it to continue   running in the background  the output   of the program must be redirected to a   file or another output stream  Failing   to do so will cause PHP to hang until   the execution of the program ends    So if you redirect the output to a log file  what is a good idea anyways   your calling script will not hang and your email script will run in bg

User · Answer

And why not making a HTTP Request on the script and ignoring the response    http   php net manual en function httprequest-send php  If you make your request on the script you need to call your webserver will run it in background and you can  in your main script  show a message telling the user that the script is running

User · Answer

Assuming you are running on a  nix platform  use cron and the php executable   EDIT   There are quite a number of questions asking for  running php without cron  on SO already  Here s one   Schedule scripts without using CRON  That said  the exec   answer above sounds very promising

User · Answer

Of all the answers  none considered the ridiculously easy fastcgi finish request function  that when called  flushes all remaining output to the browser and closes the Fastcgi session and the HTTP connection  while letting the script run in the background   An example    lt  php header  Content-Type  application json    echo json encode   ok    gt  true    fastcgi finish request       The user is now disconnected from the script     do stuff with received data

User · Answer

On Linux Unix servers  you can execute a job in the background by using proc open    descriptorspec   array     array  pipe    r                     stdin    array  file    myfile txt    a       stdout    array  pipe    w                     stderr      proc   proc open  php email script php  amp     descriptorspec   pipes     The  amp  being the important bit here  The script will continue even if the original script has ended

User · Answer

As I know you cannot do this in easy way  see fork exec etc  don t work under windows    may be you can reverse the approach  use the background of the browser posting the form in ajax  so if the post still work you ve no wait time  This can help even if you have to do some long elaboration   About sending mail it s always suggest to use a spooler  may be a local  amp  quick smtp server that accept your requests and the spool them to the real MTA or put all in a DB  than use a cron that spool the queue  The cron may be on another machine calling the spooler as external url             wget -O  dev null http   www example com spooler php

User · Answer

Use Amphp to execute jobs in parallel  amp  asynchronously   Install the library  composer require amphp parallel-functions   Code sample   lt  php  require  vendor autoload php    use Amp Promise  use Amp ParallelFunctions    echo  started lt  br gt      promises 1    ParallelFunctions parallel function            Send Email         promises 2    ParallelFunctions parallel function            Send SMS         Promise wait Promise all  promises     echo  finished     Fo your use case  You can do something like below   lt  php  use function Amp ParallelFunctions parallelMap  use function Amp Promise wait    responses   wait parallelMap        a example com        b example com        c example com      function   to        return send mail  to

User · Answer

How about this    Your PHP script that holds the form saves a flag or some value into a database or file  A second PHP script polls for this value periodically and if it s been set  it triggers the Email script in a synchronous manner    This second PHP script should be set to run as a cron

User · Answer

This is works for me  tyr this  exec    php asyn php         gt   dev null 2 gt  dev null  amp

User · Answer

Background cron job sounds like a good idea for this   You ll need ssh access to the machine to run the script as a cron     php scriptname php to run it

User · Answer

The simpler way to run a PHP script in background is  php script php  gt  dev null  amp    The script will run in background and the page will also reach the action page faster

User · Answer

Doing some experimentation with exec and shell exec I have uncovered a solution that worked perfectly  I choose to use shell exec so I can log every notification process that happens  or doesn t    shell exec returns as a string and this was easier than using exec  assigning the output to a variable and then opening a file to write to    I m using the following line to invoke the email script   shell exec   path to php  path to send notifications php     post id     alert   gt  gt   path to alert log paging log  amp       It is important to notice the  amp  at the end of the command  as pointed out by  netcoder   This UNIX command runs a process in the background   The extra variables surrounded in single quotes after the path to the script are set as   SERVER  argv   variables that I can call within my script    The email script then outputs to my log file using the  gt  gt  and will output something like this    2011-01-07 11 01 26  Alert Notifications Sent for http   alerts illinoisstate edu 2049  SCRIPT  38 71 seconds   2011-01-07 11 01 34  CRITICAL ERROR  Alert Notifications NOT sent for http   alerts illinoisstate edu 2049  SCRIPT  23 12 seconds

User · Answer

If you re on Windows  research proc open or popen     But if we re on the same server  Linux  running cpanel then this is the right approach      usr bin php   lt  php  pid   shell exec  nohup nice php -f              path to your script php   dev null 2 gt  amp 1  amp  echo       While exec  ps  pid        you can also have a streamer here like fprintf              or fgets     gt    Don t use fork   or curl if you doubt you can handle them  it s just like abusing your server  Lastly  on the script php file which is called above  take note of this make sure you wrote    lt  php ignore user abort TRUE   set time limit 0   ob start        lt -- really optional but this is pure php    Code to be tested on background  ob flush    flush       this two do the output process if you need some            then to make all the logic possible   str repeat     1500       for progress bars or loading images  sleep 2     standard limit    gt

User · Answer

for background worker i think you should try this technique it will help to call as many as pages you like all pages will run at once independently without waiting for each page response as asynchronous   form action page php        lt  php      post async  http   localhost projectname testpage php    Keywordname testValue          post async  http   localhost projectname testpage php    Keywordname testValue2          post async  http   localhost projectname otherpage php    Keywordname anyValue          call as many as pages you like all pages will run at once   independently without waiting for each page response as asynchronous       your form db insertion or other code goes here do what ever you want   above code will work as background job this line will direct hit before   above lines response                        gt                   lt  php                                        Executes a PHP page asynchronously so the current page does not have to wait for it to     finish running                                                           function post async  url  params                                          post string    params                        parts parse url  url                         fp   fsockopen  parts  host                            isset  parts  port     parts  port   80                           errno   errstr  30                         out    GET    parts  path      post string    HTTP 1 1 r n    you can use POST instead of GET if you like                      out    Host     parts  host     r n                        out    Content-Type  application x-www-form-urlencoded r n                        out    Content-Length    strlen  post string    r n                        out    Connection  Close r n r n                       fwrite  fp   out                       fclose  fp                                       gt    testpage php       lt       echo   REQUEST  Keywordname     case1 Output  gt  testValue   here do your background operations it will not halt main page       gt    PS if you want to send url parameters as loop then follow this answer  https   stackoverflow com a 41225209 6295712

[php] How can I run a PHP script in the background after a form is submitted?

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