php execute a background process

Question

I need to execute a directory copy upon a user action  but the directories are quite large  so I would like to be able to perform such an action without the user being aware of the time it takes for the copy to complete   Any suggestions would be much appreciated

User · Answer

Can you arrange to fork off a separate process  and then run your copy in the background  It s been a while since I did any PHP  but the function pcntl-fork looks promising

User · Answer

I am heavily using fast cgi finish request    In combination with a closure and register shutdown function     message   job executed    backgroundJob   function   use   message           do some work here     echo  message      Then register this closure to be executed before shutdown    register shutdown function  backgroundJob     Finally when the response was sent to the client you can close the connection to the client and continue working with the PHP process   fast cgi finish request      The closure will be executed after fast cgi finish request    The  message will not be visible at any time  And you can register as much closures as you want  but take care about script execution time   This will only work if PHP is running as a Fast CGI module  was that right

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I d just like to add a very simple example for testing this functionality on Windows   Create the following two files and save them to a web directory   foreground php    lt  php  ini set  display errors  1   error reporting E ALL    echo   lt pre gt loading page lt  pre gt     function run background process         file put contents  testprocesses php   foreground start time       time       n        echo   lt pre gt   foreground start time       time       lt  pre gt            output from the command must be redirected to a file or another output stream         http   ca php net manual en function exec php      exec  php background php  gt  testoutput php 2 gt  amp 1  amp  echo       output        echo   lt pre gt   foreground end time       time       lt  pre gt        file put contents  testprocesses php   foreground end time       time       n   FILE APPEND       return  output     echo   lt pre gt calling run background process lt  pre gt      output   run background process     echo   lt pre gt output      print r  output   echo   lt  pre gt    echo   lt pre gt end of page lt  pre gt      gt    background php    lt   file put contents  testprocesses php   background start time       time       n   FILE APPEND   sleep 10   file put contents  testprocesses php   background end time       time       n   FILE APPEND     gt    Give IUSR permission to write to the directory in which you created the above files  Give IUSR permission to READ and EXECUTE C  Windows System32 cmd exe  Hit foreground php from a web browser  The following should be rendered to the browser w the current timestamps and local resource   in the output array   loading page calling run background process   foreground start time   1266003600   foreground end time   1266003600 output   Array        0    gt  15010   end of page   You should see testoutput php in the same directory as the above files were saved  and it should be empty  You should see testprocesses php in the same directory as the above files were saved  and it should contain the following text w the current timestamps   foreground start time   1266003600 foreground end time   1266003600 background start time   1266003600 background end time   1266003610

User · Answer

Here is a function to launch a background process in PHP  Finally created one that actually works on Windows too  after a lot of reading and testing different approaches and parameters   function LaunchBackgroundProcess  command        Run command Asynchroniously  in a separate thread    if PHP OS   WINNT     PHP OS   WIN32     PHP OS   Windows           Windows      command    start        command      else          Linux UNIX      command    command     dev null  amp           handle   popen  command   r      if  handle   false       pclose  handle       return true      else       return false          Note 1  On windows  do not use  B parameter as suggested elsewhere  It forces process to run the same console window as start command itself  resulting in the process being processed synchronously  To run the process in a separate thread  asynchronously   do not use  B   Note 2  The empty double quotes after start    are required if the command is a quoted path  start command interprets the first quoted parameter as window title

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You might want to try to append this to your command   gt  dev null 2 gt  dev null  amp    eg   shell exec  service named reload  gt  dev null 2 gt  dev null  amp

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You might try a queuing system like Resque  You then can generate a job  that processes the information and quite fast return with the  processing  image  With this approach you won t know when it is finished though   This solution is intended for larger scale applications  where you don t want your front machines to do the heavy lifting  so they can process user requests  Therefore it might or might not work with physical data like files and folders  but for processing more complicated logic or other asynchronous tasks  ie new registrations mails  it is nice to have and very scalable

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Thanks to this answer  A perfect tool to run a background process would be Symfony Process Component  which is based on proc   functions  but it s much easier to use  See its documentation for more information

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If you are looking to execute a background process via PHP  pipe the command s output to  dev null and add  amp  to the end of the command  exec  quot bg process  gt   dev null  amp  quot     Note that you can not utilize the  output parameter of exec   or else PHP will hang  probably until the process completes

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Assuming this is running on a Linux machine  I ve always handled it like this   exec sprintf   s  gt   s 2 gt  amp 1  amp  echo     gt  gt   s    cmd   outputfile   pidfile      This launches the command  cmd  redirects the command output to  outputfile  and writes the process id to  pidfile   That lets you easily monitor what the process is doing and if it s still running   function isRunning  pid       try           result   shell exec sprintf  ps  d    pid            if  count preg split    n     result    gt  2               return true                 catch Exception  e         return false

User · Answer

Instead of initiating a background process  what about creating a trigger file and having a scheduler like cron or autosys periodically execute a script that looks for and acts on the trigger files  The triggers could contain instructions or even raw commands  better yet  just make it a shell script

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For those of us using Windows  look at this   Reference  http   php net manual en function exec php 43917     I too wrestled with getting a program to run in the background in   Windows while the script continues to execute   This method unlike the   other solutions allows you to start any program minimized  maximized    or with no window at all   llbra phpbrasil s solution does work but it   sometimes produces an unwanted window on the desktop when you really   want the task to run hidden    start Notepad exe minimized in the background     lt  php   WshShell   new COM  WScript Shell      oExec    WshShell- gt Run  notepad exe   7  false      gt     start a shell command invisible in the background     lt  php   WshShell   new COM  WScript Shell      oExec    WshShell- gt Run  cmd  C dir  S  windir    0  false      gt     start MSPaint maximized and wait for you to close it before continuing the script     lt  php   WshShell   new COM  WScript Shell      oExec    WshShell- gt Run  mspaint exe   3  true      gt     For more info on the Run   method go to   http   msdn microsoft com library en-us script56 html wsMthRun asp  Edited URL   Go to https   technet microsoft com en-us library ee156605 aspx instead as the link above no longer exists

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I know it is a 100 year old post  but anyway  thought it might be useful to someone  You can put an invisible image somewhere on the page pointing to the url that needs to run in the background  like this    lt img src  run-in-background php  border  0  alt    width  1  height  1    gt

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If using PHP there is a much easier way to do this using pcntl fork   http   www php net manual en function pcntl-fork php

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A working solution for both Windows and Linux  Find more on My github page   function run process  cmd  outputFile     dev null    append   false                        pid 0                  if  strtoupper substr PHP OS  0  3        WIN       This is a server using Windows                             cmd    wmic process call create     cmd      find  ProcessId                             handle   popen  start  B     cmd   r                             read   fread  handle  200     Read the output                           pid substr  read strpos  read      1                            pid substr  pid 0 strpos  pid                                  pid    int  pid                          pclose  handle     Close                  else                       pid    int shell exec sprintf   s  s  s 2 gt  amp 1  amp  echo       cmd    append      gt  gt       gt     outputFile                                          return  pid                            function is process running  pid                   if  strtoupper substr PHP OS  0  3        WIN       This is a server using Windows                              tasklist  FI  PID eq 6480                       result   shell exec  tasklist  FI  PID eq    pid                            if  count preg split    n     result    gt  0  amp  amp   preg match   No tasks     result                             return true                                         else                       result   shell exec sprintf  ps  d 2 gt  amp 1    pid                        if  count preg split    n     result    gt  2  amp  amp   preg match   ERROR  Process ID out of range     result                             return true                                                          return false                            function stop process  pid                       if  strtoupper substr PHP OS  0  3        WIN       This is a server using Windows                                 result   shell exec  taskkill  PID    pid                            if  count preg split    n     result    gt  0  amp  amp   preg match   No tasks     result                                 return true                                                 else                               result   shell exec sprintf  kill  d 2 gt  amp 1    pid                            if   preg match   No such process     result                                 return true

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Use this function to run your program in background  It cross-platform and fully customizable    lt  php function startBackgroundProcess       command       stdin   null       redirectStdout   null       redirectStderr   null       cwd   null       env   null       other options   null          descriptorspec   array          1   gt  is string  redirectStdout    array  file    redirectStdout   w     array  pipe    w            2   gt  is string  redirectStderr    array  file    redirectStderr   w     array  pipe    w               if  is string  stdin              descriptorspec 0    array  pipe    r               proc   proc open  command   descriptorspec   pipes   cwd   env   other options       if   is resource  proc             throw new  Exception  Failed to start background process by command   command              if  is string  stdin             fwrite  pipes 0    stdin           fclose  pipes 0              if   is string  redirectStdout             fclose  pipes 1              if   is string  redirectStderr             fclose  pipes 2              return  proc      Note that after command started  by default this function closes the stdin and stdout of running process  You can redirect process output into some file via  redirectStdout and  redirectStderr arguments   Note for windows users  You cannot redirect stdout stderr to nul in the following manner   startBackgroundProcess  ping yandex com   null   nul    nul      However  you can do this   startBackgroundProcess  ping yandex com  gt nul 2 gt  amp 1      Notes for  nix users   1  Use exec shell command if you want get actual PID    proc   startBackgroundProcess  exec ping yandex com -c 15   null    dev null     dev null    print r proc get status  proc      2  Use  stdin argument if you want to pass some data to the input of your program   startBackgroundProcess  cat  gt  input txt    Hello world  n

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Well i found a bit faster and easier version to use  shell exec  screen -dmS  name of screen  command       and it works

User · Answer

PHP scripting is not like other desktop application developing language  In desktop application languages we can set daemon threads to run a background process but in PHP a process is occuring when user request for a page  However It is possible to set a background job using server s cron job functionality  which php script runs

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Write the process as a server-side script in whatever language  php bash perl etc  is handy and then call it from the process control functions in your php script   The function probably detects if standard io is used as the output stream and if it is then that will set the return value  if not then it ends   proc close  proc open     command --foo 1  amp    array     foo        I tested this quickly from the command line using  sleep 25s  as the command and it worked like a charm    Answer found here

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If you need to just do something in background without the PHP page waiting for it to complete  you could use another  background  PHP script that is  invoked  with wget command  This background PHP script will be executed with privileges  of course  as any other PHP script on your system   Here is an example on Windows using wget from gnuwin32 packages   The background code  file test-proc-bg php  as an exmple      sleep 5        some delay file put contents  test txt   date  Y-m-d H i s u        writes time in a file   The foreground script  the one invoking       proc command    wget exe http   localhost test-proc-bg php -q -O - -b    proc   popen  proc command   r    pclose  proc     You must use the popen pclose for this to work properly   The wget options   -q    keeps wget quiet  -O -  outputs to stdout  -b    works on background

[php] php execute a background process

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