Check if PHP session has already started

Question

I have a PHP file that is sometimes called from a page that has started a session and sometimes from a page that doesn t have session started  Therefore when I have session start   on this script I sometimes get the error message for  session already started   For that I ve put these lines   if  isset   COOKIE  PHPSESSID         session start        but this time I got this warning message      Notice  Undefined variable   SESSION    Is there a better way to check if session has already started   If I use  session start will it make things work properly and just shut up the warnings

User · Answer

PHP 5 4 introduced session status    which is more reliable than relying on session id     Consider the following snippet     session id  test    var export session id              true  but session is still not started  var export session status      PHP SESSION ACTIVE      false   So  to check whether a session is started  the recommended way in PHP 5 4 is now   session status      PHP SESSION ACTIVE

User · Answer

For versions of PHP prior to PHP 5 4 0   if session id                   session isn t started     Though  IMHO  you should really think about refactoring your session management code if you don t know whether or not a session is started     That said  my opinion is subjective  and there are situations  examples of which are described in the comments below  where it may not be possible to know if the session is started

User · Answer

Prior to PHP 5 4 there is no reliable way of knowing other than setting a global flag   Consider   var dump   SESSION      null session start    var dump   SESSION      array session destroy    var dump   SESSION      array  but session isn t active    Or   session id       returns empty string session start    session id       returns session hash session destroy    session id       returns empty string  ok  but then session id  foo       tell php the session id to use session id       returns  foo   but no session is active    So  prior to PHP 5 4 you should set a global boolean

User · Answer

Replace session start    with   if   isset  a         a   False      if   a    TRUE            session start             a   TRUE

User · Answer

Based on my practice  before accessing the   SESSION   you need to call session start every time to use the script  See the link below for manual   http   php net manual en function session-start php  For me at least session start is confusing as a name  A session load can be more clear

User · Answer

if  version compare phpversion     5 4 0     lt            if session id                    session start               else        if  session status      PHP SESSION NONE            session start

User · Answer

On PHP 5 3 this works for me   if  strlen session id          session name  someSpecialName        session start         then you have  If you do not put the not at if statement beginning the session will start any way I do not why

User · Answer

You should reorganize your code so that you call session start   exactly once per page execution

User · Answer

Recommended way for versions of PHP  gt   5 4 0   PHP 7 if  session status       PHP SESSION NONE        session start       Reference  http   www php net manual en function session-status php For versions of PHP  lt  5 4 0 if session id                session start

User · Answer

The only thing you need to do is    lt  php if  isset   SESSION     session start        gt

User · Answer

session start    if  empty   SESSION  user                code    else       header  location index php

User · Answer

Response BASED on  Meliza Ramos Response see first response  and http   php net manual en function phpversion php     ACTIONS    define PHP VERSION ID if not exist define function to check version based on PHP VERSION ID define function to openSession   secure   only use openSession           PHP VERSION ID is available as of PHP 5 2 7  if our        version is lower than that  then emulate it     if   defined  PHP VERSION ID               version   explode      PHP VERSION            define  PHP VERSION ID     version 0    10000    version 1    100    version 2                  PHP VERSION ID is defined as a number  where the higher the number            is  the newer a PHP version is used  It s defined as used in the above            expression                         version id    major version   10000    minor version   100    release version                        Now with PHP VERSION ID we can check for features this PHP version            may have  this doesn t require to use version compare   everytime            you check if the current PHP version may not support a feature                        For example  we may here define the PHP VERSION   constants thats            not available in versions prior to 5 2 7          if  PHP VERSION ID  lt  50207                define  PHP MAJOR VERSION      version 0                define  PHP MINOR VERSION      version 1                define  PHP RELEASE VERSION    version 2                    and so on                           function phpVersionAtLeast  strVersion    0 0 0                  version   explode       strVersion             questionVer    version 0    10000    version 1    100    version 2            if PHP VERSION ID  gt    questionVer              return true          else             return false              function openSession                 if phpVersionAtLeast  5 4 0                          if session status    PHP SESSION NONE                  session start                      else    under 5 4 0                       if session id                          session start

User · Answer

Check this     lt  php        return bool    function is session started         if   php sapi name        cli              if   version compare phpversion     5 4 0     gt                     return session status       PHP SESSION ACTIVE   TRUE   FALSE            else               return session id            FALSE   TRUE                      return FALSE        Example if   is session started       FALSE   session start      gt    Source http   php net

User · Answer

This should work for all PHP versions  It determines the PHP version  then checks to see if the session is started based on the PHP version  Then if the session is not started it starts it   function start session       if version compare phpversion     5 4 0      -1       if  session status      PHP SESSION NONE          session start              else       if session id                  session start

User · Answer

if  version compare PHP VERSION   5 4 0    gt   0         sess   session status        if   sess    PHP SESSION NONE            session start            else       if     SESSION            session start              Actually  it is now too late to explain it here anyway as its been solved  This was a  inc file of one of my projects where you configure a menu for a restaurant by selecting a dish and remove add or change the order  The server I was working at did not had the actual version so I made it more flexible  It s up to the authors wish to use and try it out

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For all php version  if   function exists  session status       amp  amp  session status       PHP SESSION ACTIVE      session id        session start

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Not sure about efficiency of such solution  but this is from working project This is also used if you need to define the default language               Start session       Fall back to ukrainian language           function valid session         if session id                  session start              SESSION  lang    uk             SESSION  lang id   3            return true

User · Answer

You can use the following solution to check if a PHP session has already started   if session id              echo Session isn t Start     else       echo Session Started

User · Answer

you can do this  and it s really easy   if   isset   SESSION   session start      Hope it helps

User · Answer

Is this code snippet work for you   if   count   SESSION  gt 0        session start

User · Answer

before a function call suppresses any errors that may be reported during the function call   Adding a   before session start tells PHP to avoid printing error messages   For example   Using session start   after you ve already printed something to the browser results in an error so PHP will display something like  headers cannot be sent  started at  line 12     session start   will still fail in this case  but the error message is not printed on screen   Before including the files or redirecting to new page use the exit   function  otherwise it will give an error    This code can be used in all cases         lt  php          if  session status       PHP SESSION ACTIVE    session id                        session start                     gt

User · Answer

i ended up with double check of status  php 5 4   if session status       PHP SESSION ACTIVE  session start      if session status       PHP SESSION ACTIVE  die  session start failed

User · Answer

if  session id             session start        hope it helps

User · Answer

This is what I use to determine if a session has started  By using empty and isset as follows   if  empty   SESSION    amp  amp   isset   SESSION          session start

User · Answer

PHP VERSION ID is available as of PHP 5 2 7  so check this first and if necessary   create it   session status is available as of PHP 5 4   so we have to check this too   if   defined  PHP VERSION ID           version   explode      PHP VERSION       define  PHP VERSION ID     version 0    10000    version 1    100    version 2      else       version   PHP VERSION ID    if  version  lt  50400       if session id                    session start           else      if  session status       PHP SESSION ACTIVE            session start

User · Answer

Use session id    it returns an empty string if not set  It s more reliable than checking the   COOKIE   if  strlen session id     lt  1        session start

[php] Check if PHP session has already started

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