Runtime Configuration

The behaviour of these functions is affected by settings in php.ini.

Session configuration options Name


Default
Changeable
Changelog
session.save_path
""
PHP_INI_ALL
 
session.name
"PHPSESSID"
PHP_INI_ALL
 
session.save_handler
"files"
PHP_INI_ALL
 
session.auto_start
"0"
PHP_INI_PERDIR
 
session.gc_probability
"1"
PHP_INI_ALL
 
session.gc_divisor
"100"
PHP_INI_ALL
 
session.gc_maxlifetime
"1440"
PHP_INI_ALL
 
session.serialize_handler
"php"
PHP_INI_ALL
 
session.cookie_lifetime
"0"
PHP_INI_ALL
 
session.cookie_path
"/"
PHP_INI_ALL
 
session.cookie_domain
"#2"
PHP_INI_ALL
 
session.cookie_secure
"0"
PHP_INI_ALL
Prior to PHP 7.2.0, the default
was
"#2".
session.cookie_httponly
"0"
PHP_INI_ALL
Prior to PHP 7.2.0, the default
was "#2".
session.cookie_samesite
"#2"
PHP_INI_ALL
Available as of PHP 7.3.0.
session.use_strict_mode
"0"
PHP_INI_ALL
 
session.use_cookies
"1"
PHP_INI_ALL
 
session.use_only_cookies
"1"
PHP_INI_ALL
 
session.referer_check
"#2"
PHP_INI_ALL
 
session.cache_limiter
"nocache"
PHP_INI_ALL
 
session.cache_expire
"180"
PHP_INI_ALL
 
session.use_trans_sid
"0"
PHP_INI_ALL
 
session.trans_sid_tags
"a=href,area=href,frame=src,form
="
PHP_INI_ALL
Available as of PHP 7.1.0.
session.trans_sid_hosts
$_SERVER['HTTP_HOST']
PHP_INI_ALL
Available as
of
PHP 7.1.0.
session.sid_length
"32"
PHP_INI_ALL
Available as of PHP 7.1.0.
session.sid_bits_per_character
"4"
PHP_INI_ALL
Available as of PHP
7.1.0.
session.upload_progress.enabled
"1"
PHP_INI_PERDIR
 
session.upload_progress.cleanup
"1"
PHP_INI_PERDIR
 
session.upload_progress.prefix
"upload_progress_"
PHP_INI_PERDIR
 
session.upload_progress.name
"PHP_SESSION_UPLOAD_PRO
GRESS"
PHP_INI_PERDIR
 
session.upload_progress.freq
"1%"
PHP_INI_PERDIR
 
session.upload_progress.min_freq
"1"
PHP_INI_PERDIR
 
session.lazy_write
"1"
PHP_INI_ALL
 
session.hash_function
"0"
PHP_INI_ALL
Removed as of PHP 7.1.0.
session.hash_bits_per_character
"4"
PHP_INI_ALL
Removed as of PHP
7.1.0.
session.entropy_file
"#2"
PHP_INI_ALL
Removed as of PHP 7.1.0.
session.entropy_length
"0"
PHP_INI_ALL
Removed as of PHP 7.1.0


For further details and definitions of the PHP_INI_* modes, see the Where a
configuration setting may be set.

The session management system supports a number of configuration options
which you can place in your php.ini file. We will give a short overview.



session.save_handler string
session.save_handler defines the name of the handler which is used for
storing and retrieving data associated with a session. Defaults to files.
Note that individual extensions may register their own save_handlers;
registered handlers can be obtained on a per-installation basis by
referring
to phpinfo(). See also session_set_save_handler(). 



session.save_path string
session.save_path defines the argument which is passed to the save handler.
If you choose the default files handler, this is the path where the files
are created. See also session_save_path().

There is an optional N argument to this directive that determines the
number
of directory levels your session files will be spread around in. For
example, setting to '5;/tmp' may end up creating a session file and
location
like /tmp/4/b/1/e/3/sess_4b1e384ad74619bd212e236e52a5a174If . In order to
use N you must create all of these directories before use. A small shell
script exists in ext/session to do this, it's called mod_files.sh, with a
Windows version called mod_files.bat. Also note that if N is used and
greater than 0 then automatic garbage collection will not be performed, see
a copy of php.ini for further information. Also, if you use N, be sure to
surround session.save_path in "quotes" because the separator ( ;) is also
used for comments in php.ini.

The file storage module creates files using mode 600 by default. This
default can be changed with the optional MODE argument: N;MODE;/path where
MODE is the octal representation of the mode. Setting MODE does not affect
the process umask.
Warning
If this is set to a world-readable directory, such as /tmp ( the default),
other users on the server may be able to hijack sessions by getting the
list
of files in that directory.


Caution
When using the optional directory level argument N, as described above,
note
that using a value higher than 1 or 2 is inappropriate for most sites due
to
the large number of directories required: for example, a value of 3 implies
that ( 2 ** session.sid_bits_per_character) ** 3 directories exist on the
filesystem, which can result in a lot of wasted space and inodes.


Only use N greater than 2 if you are absolutely certain that your site is
large enough to require it.



session.name string
session.name specifies the name of the session which is used as cookie
name.
It should only contain alphanumeric characters. Defaults to PHPSESSID. See
also session_name(). 



session.auto_start bool
session.auto_start specifies whether the session module starts a session
automatically on request startup. Defaults to 0 ( disabled). 



session.serialize_handler string
session.serialize_handler defines the name of the handler which is used to
serialize/deserialize data. PHP serialize format ( name php_serialize), PHP
internal formats ( name php and php_binary) and WDDX are supported ( name
wddx). WDDX is only available, if PHP is compiled with WDDX support.
php_serialize uses plain serialize/unserialize function internally and does
not have limitations that php and php_binary have. Older serialize handlers
cannot store numeric index nor string index contains special characters ( |
and !) in $_SESSION. Use php_serialize to avoid numeric index or special
character errors at script shutdown. Defaults to php. 



session.gc_probability int
session.gc_probability in conjunction with session.gc_divisor is used to
manage probability that the gc ( garbage collection) routine is started.
Defaults to 1. See session.gc_divisor for details. 



session.gc_divisor int
session.gc_divisor coupled with session.gc_probability defines the
probability that the gc ( garbage collection) process is started on every
session initialization. The probability is calculated by using
gc_probability/gc_divisor, e.g. 1/100 means there is a 1% chance that the
GC
process starts on each request. session.gc_divisor defaults to 100. 



session.gc_maxlifetime int
session.gc_maxlifetime specifies the number of seconds after which data
will
be seen as 'garbage' and potentially cleaned up. Garbage collection may
occur during session start ( depending on session.gc_probability and
session.gc_divisor). Defaults to 1440 ( 24 minutes).

Note: 
If different scripts have different values of session.gc_maxlifetime but
share the same place for storing the session data then the script with the
minimum value will be cleaning the data. In this case, use this directive
together with session.save_path.



session.referer_check string
    session.referer_check contains the substring you want to check each
HTTP
Referer for. If the Referer was sent by the client and the substring was
not
found, the embedded session id will be marked as invalid. Defaults to the
empty string. 



session.entropy_file string
session.entropy_file gives a path to an external resource ( file) which
will
be used as an additional entropy source in the session id creation process.
Examples are /dev/random or /dev/urandom which are available on many Unix
systems. This feature is supported on Windows. Setting
session.entropy_length to a non zero value will make PHP use the Windows
Random API as entropy source.

Note: 
Removed in PHP 7.1.0. session.entropy_file defaults to /dev/urandom or
/dev/arandom if it is available.



session.entropy_length int
    session.entropy_length specifies the number of bytes which will be read
from the file specified above. Defaults to 32. Removed in PHP 7.1.0. 



session.use_strict_mode bool
session.use_strict_mode specifies whether the module will use strict
session
id mode. If this mode is enabled, the module does not accept uninitialized
session IDs. If an uninitialized session ID is sent from the browser, a new
session ID is sent to the browser. Applications are protected from session
fixation via session adoption with strict mode. Defaults to 0 ( disabled).

Note: 
Enabling session.use_strict_mode is mandatory for general session security.
All sites are advised to enable this. See session_create_id() example code
for more details.

Warning
If a custom session handler registered via session_set_save_handler() does
not implement SessionUpdateTimestampHandlerInterface::validateId(), nor
supplies the validate_sid callback, respectively, strict session ID mode is
effectively disabled, regardless of the value of this directive.
Particularly note that SessionHandler does not implement
SessionHandler::validateId().



session.use_cookies bool
session.use_cookies specifies whether the module will use cookies to store
the session id on the client side. Defaults to 1 ( enabled). 



session.use_only_cookies bool
session.use_only_cookies specifies whether the module will only use cookies
to store the session id on the client side. Enabling this setting prevents
attacks involved passing session ids in URLs. Defaults to 1 ( enabled). 



session.cookie_lifetime int
session.cookie_lifetime specifies the lifetime of the cookie in seconds
which is sent to the browser. The value 0 means "until the browser is
closed." Defaults to 0. See also session_get_cookie_params() and
session_set_cookie_params().

Note: 
The expiration timestamp is set relative to the server time, which is not
necessarily the same as the time in the client's browser.



session.cookie_path string
session.cookie_path specifies path to set in the session cookie. Defaults
to
/. See also session_get_cookie_params() and session_set_cookie_params(). 



session.cookie_domain string
session.cookie_domain specifies the domain to set in the session cookie.
Default is none at all meaning the host name of the server which generated
the cookie according to cookies specification. See also
session_get_cookie_params() and session_set_cookie_params(). 



session.cookie_secure bool
session.cookie_secure specifies whether cookies should only be sent over
secure connections. Defaults to off. See also session_get_cookie_params()
and session_set_cookie_params(). 



session.cookie_httponly bool
Marks the cookie as accessible only through the HTTP protocol. This means
that the cookie won't be accessible by scripting languages, such as
JavaScript. This setting can effectively help to reduce identity theft
through XSS attacks ( although it is not supported by all browsers). 



session.cookie_samesite string
Allows servers to assert that a cookie ought not to be sent along with
cross
-site requests. This assertion allows user agents to mitigate the risk of
cross-origin information leakage, and provides some protection against
cross
-site request forgery attacks. Note that this is not supported by all
browsers. An empty value means that no SameSite cookie attribute will be
set. Lax and Strict mean that the cookie will not be sent cross-domain for
POST requests; Lax will sent the cookie for cross-domain GET requests,
while
Strict will not. 



session.cache_limiter string
session.cache_limiter specifies the cache control method used for session
pages. It may be one of the following values: nocache, private,
private_no_expire, or public. Defaults to nocache. See also the
session_cache_limiter() documentation for information about what these
values mean. 



session.cache_expire int
session.cache_expire specifies time-to-live for cached session pages in
minutes, this has no effect for nocache limiter. Defaults to 180. See also
session_cache_expire(). 



session.use_trans_sid bool
session.use_trans_sid whether transparent sid support is enabled or not.
Defaults to 0 ( disabled).

Note: 
URL based session management has additional security risks compared to
cookie based session management. Users may send a URL that contains an
active session ID to their friends by email or users may save a URL that
contains a session ID to their bookmarks and access your site with the same
session ID always, for example. Since PHP 7.1.0, full URL path, e.g.
https://php.net/, is handled by trans sid feature. Previous PHP handled
relative URL path only. Rewrite target hosts are defined by
session.trans_sid_hosts.  



session.trans_sid_tags string
session.trans_sid_tags specifies which HTML tags are rewritten to include
session id when transparent sid support is enabled. Defaults to
a=href,area=href,frame=src,input=src,form= form is special tag.  is added
as form variable.

Note: 
Before PHP 7.1.0, url_rewriter.tags was used for this purpose. Since PHP
7.1.0, fieldset is no longer considered as special tag.



session.trans_sid_hosts string
session.trans_sid_hosts specifies which hosts are rewritten to include
session id when transparent sid support is enabled. Defaults to
$_SERVER['HTTP_HOST'] Multiple hosts can be specified by ",", no space is
allowed between hosts. e.g. php.net,wiki.php.net,bugs.php.net 



session.sid_length int
    session.sid_length allows you to specify the length of session ID
string. Session ID length can be between 22 to 256. The default is 32. If
you need compatibility you may specify 32, 40, etc. Longer session ID is
harder to guess. At least 32 chars are recommended.

Tip
Compatibility Note: Use 32 instead of session.hash_function=0 ( MD5) and
session.hash_bits_per_character=4, session.hash_function=1 ( SHA1) and
session.hash_bits_per_character=6. Use 26 instead of
session.hash_function=0
( MD5) and session.hash_bits_per_character=5. Use 22 instead of
session.hash_function=0 ( MD5) and session.hash_bits_per_character=6. You
must configure INI values to have at least 128 bits in session ID. Do not
forget to set an appropriate value for session.sid_bits_per_character,
otherwise you will have weaker session ID.

Note: 
This setting is introduced in PHP 7.1.0. 




session.sid_bits_per_character int
session.sid_bits_per_character allows you to specify the number of bits in
encoded session ID character. The possible values are '4' ( 0-9, a-f), '5' (
0
-9, a-v), and '6' ( 0-9, a-z, A-Z, "-", ","). The default is 4. The more
bits
results in stronger session ID. 5 is recommended value for most
environments.

Note: 
This setting is introduced in PHP 7.1.0.



session.hash_function mixed
session.hash_function allows you to specify the hash algorithm used to
generate the session IDs. '0' means MD5 ( 128 bits) and '1' means SHA-1 (
160
bits).

    It is also possible to specify any of the algorithms provided by the
hash extension ( if it is available), like sha512 or whirlpool. A complete
list of supported algorithms can be obtained with the hash_algos()
function.

Note: 
Removed in PHP 7.1.0.



session.hash_bits_per_character int
    session.hash_bits_per_character allows you to define how many bits are
stored in each character when converting the binary hash data to something
readable. The possible values are '4' ( 0-9, a-f), '5' ( 0-9, a-v), and '6'
( 0
-9, a-z, A-Z, "-", ",").

Note: 
Removed in PHP 7.1.0.



session.upload_progress.enabled bool
Enables upload progress tracking, populating the $_SESSION variable.
Defaults to 1, enabled. 



session.upload_progress.cleanup bool
Cleanup the progress information as soon as all POST data has been read
( i.e. upload completed). Defaults to 1, enabled.

Note: 
It is highly recommended to keep this feature enabled.



session.upload_progress.prefix string
A prefix used for the upload progress key in the $_SESSION. This key will
be
concatenated with the value of $_POST[ini_get( "sessi
on.upload_progress.name")] to provide a unique index. Defaults to
"upload_progress_". 



session.upload_progress.name string
The name of the key to be used in $_SESSION storing the progress
information. See also session.upload_progress.prefix. If
$_POST[ini_get( "session.upload_progress.name")] is not passed or
available,
upload progressing will not be recorded. Defaults to
"PHP_SESSION_UPLOAD_PROGRESS". 



session.upload_progress.freq mixed
Defines how often the upload progress information should be updated. This
can be defined in bytes ( i.e. "update progress information after every 100
bytes"), or in percentages ( i.e. "update progress information after
receiving every 1% of the whole filesize"). Defaults to "1%".



session.upload_progress.min_freq int
    The minimum delay between updates, in seconds. Defaults to "1" ( one
second). 


session.lazy_write bool
session.lazy_write, when set to 1, means that session data is only
rewritten
if it changes. Defaults to 1, enabled. 

Upload progress will not be registered unless sessio
n.upload_progress.enabled is enabled, and the $_POST
[ini_get( "session.upload_progress.name")] variable is set. See Session
Upload Progress for more details on this functionality.
＋add a note



User Contributed Notes 20 notes



Christopher Kramer 8 years ago
On debian ( based) systems, changing session.gc_maxlifetime at runtime has
no
real effect. Debian disables PHP's own garbage collector by setting
session.gc_probability=0. Instead it has a cronjob running every 30 minutes
( see /etc/cron.d/php5) that cleans up old sessions. This cronjob basically
looks into your php.ini and uses the value of session.gc_maxlifetime there
to decide which sessions to clean ( see /usr/lib/php5/maxlifetime).

You can adjust the global value in your php.ini ( usually
/etc/php5/apache2/php.ini). Or you can change the session.save_path so
debian's cronjob will not clean up your sessions anymore. Then you need to
either do your own garbage collection with your own cronjob or enable PHP's
garbage collection ( php then needs sufficient privileges on the
save_path).

Why does Debian not use PHP's garbarage collection?
For security reasons, they store session data in a place ( /var/lib/php5)
with very stringent permissions. With the sticky bit set, only root is
allowed to rename or delete files there, so PHP itself cannot clean up old
session data. See https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=267720



GreenReaper 8 years ago
We found a session.save_path depth of 3 led to excessive wastage of inodes
and in fact disk space in storing the directory tree. dir_indexes option on
ext2/3/4 makes larger directories more feasible anyway, so we decided to
move to a depth of 2 instead.

It took a little puzzling to figure out how to move the existing PHP
sessions up one directory tree, but we ended up running this in the root
sessions directory:

#!/bin/sh
for a in ./* ; do
    cd ./$a
    pwd
    for b in ./* ; do
        cd ./$b
        pwd
        # Move existing sessions out
        find ./* -xdev -type f -print0 | xargs -0 mv -t .
        # Remove subdirectories
        find ./* -xdev -type d -print0 | xargs -0 rmdir
        cd ..
  done
  cd ..
done

This script may not be the best way to do it, but it got the job done fast.
You can modify it for different depths by adding or removing "for" loops.

The documentation gives a depth of 5 as an example, but five is right out.
If you're going beyond 2, you're at the scale where you may want to to look
at a large memcached or redis instance instead.




info at thimbleopensource dot com 7 years ago
I found out that if you need to set custom session settings, you only need
to do it once when session starts. Then session maintains its settings,
even
if you use ini_set and change them, original session still will use it's
original setting until it expires.

Just thought it might be useful to someone.



boan dot web at outlook dot com 4 years ago
session.cache_limiter may be empty string to disable cache headers
entirely.

Quote:
> Setting the cache limiter to '' will turn off automatic sending of cache
headers entirely.

http://php.net/manual/en/function.session-cache-limiter.php




jlevene at etisoftware dot com 10 years ago
Being unable to find an actual copy of mod_files.sh, and seeing lots of
complaints/bug fix requests for it, here's one that works.  It gets all its
parameters from PHP.INI, so you don't have the opportunity to mess up:

 #!/bin/bash
#
# Creates directories for PHP session storage.
# Replaces the one that "comes with" PHP, which ( a) doesn't always come
with
it
# and ( b) doesn't work so great.
#
# This version takes no parameters, and uses the values in PHP.INI ( if it
# can find it).
#
# Works in OS-X and CentOS ( and probably all other) Linux.
#
# Feb '13 by Jeff Levene.

[[ $amp;# -gt 0 ]] && echo "$0 requires NO command-line parameters.
It gets does whatever is called for in the PHP.INI file ( if it can find
it).
" && exit 1

# Find the PHP.INI file, if possible:
phpIni=/usr/local/lib/php.ini                        # Default PHP.INI
location
[[ ! -f "$phpIni" ]] && phpIni=/etc/php.ini            # Secondary location
[[ ! -f "$phpIni" ]] && phpIni=                        # Found it?

# Outputs the given ( as $1) parameter from the PHP.INI file:
# The "empty" brackets have a SPACE and a TAB in them.
#
PhpConfigParam() {
    [[ ! "$phpIni" ]] && return
    # Get the line from the INI file:
    varLine=`grep "^[     ]*$1[     ]*=" "$phpIni"`

    # Extract the value:
    value=`expr "$varLine" : ".*$1[     ]*=[     ]*['\"]*\( [^'\"]*\)"`
    echo "$value"
    }

if [[ "$phpIni" ]]
then
    savePath=`PhpConfigParam session.save_path`
    # If there's a number and semicolon at the front, remove them:
    dirDepth=`expr "$savePath" : '\( [0-9]*\)'`
    [[ "$dirDepth" ]] && savePath=`expr "$savePath" : '[0-9]*;\( .*\)'` ||
dirDepth=0
    bits=`PhpConfigParam session.hash_bits_per_character`
    case "x$bits" in
        x)    echo "hash_bits_per_character not defined.  Not running." ;
exit 2 ;;
        x4) alphabet='0 1 2 3 4 5 6 7 8 9 a b c d e f' ;;
        x5) alphabet='0 1 2 3 4 5 6 7 8 9 a b c d e f g h i j k l m n o p q
r s t u v' ;;
        x6) alphabet='0 1 2 3 4 5 6 7 8 9 a b c d e f g h i j k l m n o p q
r s t u v'
            alphabet="$alphabet w x y z A B C D E F G H I J K L M N O P Q R
S T U V W"
            alphabet="$alphabet X Y Z - ,"
            ;;
        *)    echo "unrecognized hash_bits_per_character.  Not running." ;
exit 2 ;;
    esac
else
    echo "Cannot find the PHP.INI file.  Not running.  Sorry."
    exit 2
fi

# The depth of directories to create is $1.  0 means just create the named
# directory.  Directory to start with is $2.
#
# Used recursively, so variables must be "local".

doDir() 
{
    local dir="$2"
    if [[ -d "$dir" ]]
    then
        echo "Directory '$dir' already exists.  No problem."
    elif [[ -f "$dir" ]]
    then
        echo "FILE '$dir' exists.  Aborting." ; exit 2
    else
        if mkdir "$dir"
        then
            echo "Directory '$dir' created."
        else
            echo "Cannot create directory '$dir'.  Aborting." ; exit 2
        fi
    fi
    chmod a+rwx "$dir"
    if [[ $1 -gt 0 ]]
    then
        local depth=$( (  $1 - 1 ))
        for letter in $alphabet
        do    doDir $depth "$dir/$letter"
        done
    fi
}
   
echo "Running with savePath='$savePath', dirDepth=$dirDepth, and
bitsPerCharacter=$bits."
sleep 3

doDir $dirDepth "$savePath"

exit 0



hassankhodadadeh at NOSPAM dot gmail dot com 11 years ago
max value for "session.gc_maxlifetime" is 65535. values bigger than this
may
cause  php session stops working.



Wouter 12 years ago
When setting the session.cookie_lifetime directive in a .htaccess use
string
format like;

php_value session.cookie_lifetime "123456"

and not

php_value session.cookie_lifetime 123456

Using a integer as stated above dit not work in my case ( Apache/2.2.11
( Ubuntu) PHP/5.2.6-3ubuntu4.5 with Suhosin-Patch mod_ssl/2.2.11
OpenSSL/0.9.8g)




li-lingjie 5 years ago
Use SessionHandlerInterface interface Custom redis session, found the
following:

Use ini_set ( 'session.save_path', "tcp: //127.0.0.1: 6379? Auth =
password"); will be reported:

PHP Fatal error: session_start (): Failed to initialize storage module:
user
( path: tcp: //127.0.0.1: 6379? Auth = password);

Using session_save_path ( "tcp: //127.0.0.1: 6379? Auth = password") will
not



ohcc at 163 dot com 5 years ago
You should take more care configuring session.gc_maxlifetime when virtual
hosts share the same session-saving directory. One host's session data may
be gc'ed when another host runs php.



descartavel1+php at gmail dot com 2 days ago
You should set `session.name` to use either prefix `__Host-` or `__Secure
-`.
See https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Set
-Cookie#attributes




Nicholas 12 years ago
Transient sessions do not appear to be working in 5.3.3

E.g.

 
<?php
    ini_set( "session.use_cookies", 0);
    ini_set( "session.use_trans_sid", 1);
    session_start();
    
    if( isset( $_SESSION["foo"])) 
    {
        echo "Foo: " . $_SESSION["foo"];
    } else 
    {
        $_SESSION["foo"] = "Bar";
        echo "<a href=?" . session_name() . "=" . session_id() 
            . ">Begin test</a>";
    }
?>
This works in 5.2.5, but not 5.3.3



AskApache 12 years ago
This is how I set my session.save_path
session.save_path = "1;/home/askapache/tmp/s"
So to create the folder structure you can use this compatible shell script,
if you want to create with 777 permissions change the umask to 0000;
sh -o braceexpand -c "umask 0077;mkdir -p s/{0..9}/{a..z} s/{a..z}/{0..9}"

Then you can create a cronjob to clean the session folder by adding this to
your crontab which deletes any session files older than an hour:
@daily find /home/askapache/tmp/s -type f -mmin +60 -exec rm -f {} \;
&>/dev/null

That will create sessions in folder like:
/home/askapache/tmp/s/b/sess_b1aba5q6io4lv01bpc6t52h0ift227j6

I don't think any non-mega site will need to go more than 1 levels deep.  
Otherwise you create so many directories that it slows the performance 
gained by this.



00 at f00n dot com 14 years ago
After having many problems with garbage collection not clearing my
sessions
I have resolved it through the following.

First I found this in the php.ini ( not something i noticed as i use
phpinfo(); to see my hosting ini).

; NOTE: If you are using the subdirectory option for storing session files
;       ( see session.save_path above), then garbage collection does *not*
;       happen automatically.  You will need to do your own garbage

; collection through a shell script, cron entry, or some other method. ;   

  For example, the following script would is the equivalent of
;       setting session.gc_maxlifetime to 1440 ( 1440 seconds = 24
minutes):
;          cd /path/to/sessions; find -cmin +24 | xargs rm

With this is mind there are options.

1. dont use a custom save_path.
** This means if your isp hasnt defaulted your session temp to something
safer than install default or you are using a shared directory for session
data then you would be wise to use named sessions to keep your session from
being viewable in other people's scripts.  Creating a unique_id name for
this is the common method. **
use your custom folder but write a garbage
collection script.
use a custom handler and a database




mikaelkael at php dot net 14 years ago
Recently, I needed to change the session save_path in my program under
Windows. With an ini_set( 'session.save_path', '../data/sessions'); ( and
session.gc_divisor = 1 for test), I always obtain 'Error #8
session_start():
ps_files_cleanup_dir: opendir( ../data/sessions) failed: Result too large'.

I corrected this by changing with ini_set( 'session.save_path',
realpath( '../data/sessions'));



orbill 12 years ago
apparently the default value for session.use_only_cookies has changed in
5.3.3 from 0 to 1. If you haven't set this in your php.ini or your code to
0
transparent sessions won't work.



white-gandalf at web dot de 5 years ago
session.use_strict_mode does very little to strengthen your security: only
one very specific variant of attack is migitated by this ( where the
attacker
hands an "empty" sid to the victim to adapt his own browser to that session
later) - versus for example the case where he pre-opens a session, handing
the sid of that one to the victim, so the victim gets adapted to the pre
-opened session. In the latter case this flag does nothing to help. In
every
other scenario with other vulnerabilities where the session id gets leaked,
the flag helps nigher.

But this flag renders the php function session_id() useless in its
parameterized variant, thus preventing any php functionality that builds
upon this function.



sony-santos at bol dot com dot br 14 years ago
In response to 00 at f00n, this very page explains:

"( ...) if N is used and greater than 0 then automatic garbage collection
will not be performed ( ...)"

So you can actually use custom save_path with automatic garbage collection,
since you don't use the subdirectory option ( that N subdirectory levels).



polygon dot co dot in at gmail dot com 1 year ago
In php.ini, session.save_handler defines the name of the handler which is
used for storing and retrieving data associated with a session. [Defaults
to
files.]

By default session.save_handler has support for below

session.save_handler = files
session.save_handler = sqlite
session.save_handler = redis
session.save_handler = memcached

These locks the session by default for any HTTP request using session.
Locking means, a user can't access session related pages until current
request is completed.

So, if you are thinking that switching to these will increase performance;
the answer is NO! because of locking behaviour.

To overcome/customise the session locking behaviour use as below.

session.save_handler = user
This is for all ( including list above) modes of session storage.

For "user" type save_handler, we can ignore locks for better performance (
as
explained in function session_set_save_handler). But for this we need to
take care to use sessions only for authenticity and not for passing data
from one script to other.

For passing data accross scripts use GET method to achieve the goal.



phpforcharity dot 5 dot pistos at geoshell dot com 14 years ago
To get session IDs to show up in URIs, and not get stored via cookies, you
must not only set session.use_cookies to 0, but also set
session.use_trans_sid to 1.  Otherwise, the session ID goes neither in a
cookie nor in URIs!



Anonymous 6 years ago
In response to this comment: http://php.net/manual/e
n/session.configuration.php#107990 where it is claimed that gc_maxlifetime
values larger than 65535 break the session system. I cannot reproduce this.

I've set gc_maxlifetime to 31536000 ( 1 year) and the session system works
just fine. I haven't tried how long a session lasts now ( I'm in the
process
of testing this), but it certainly doesn't break PHP sessions.