session_name

(PHP 4, PHP 5, PHP 7, PHP 8)

session_name — Lee y/o modifica el nombre de la sesión

Descripción

session_name(?string $name = null): string|false

session_name() devuelve el nombre de la sesión actual. Si se proporciona el argumento name, session_name() modificará el nombre de la sesión y devolverá el anterior nombre de la sesión.

Si se proporciona un nuevo nombre de sesión name, session_name() modifica la cookie HTTP (y el contenido de salida cuando session.transid está activado). Una vez enviada la cookie HTTP, llamar a session_name() desencadena un E_WARNING. session_name() debe ser llamado antes de session_start() para que la sesión funcione correctamente.

El nombre de la sesión se reinicia al valor por defecto, almacenado en session.name al inicio. Por lo tanto, debe llamarse a session_name() para cada petición (y antes de que session_start() sea llamado).

Parámetros

name

El nombre de sesión se utiliza como nombre para las cookies y las URLs (es decir, PHPSESSID). Solo debe contener caracteres alfanuméricos; debe ser corto y descriptivo (especialmente para los usuarios que tienen activada la alerta de cookies). Si name se proporciona y no es null, el nombre de la sesión actual será reemplazado por este valor.

Advertencia

Los nombres de sesión no pueden contener solo números, al menos una letra debe estar presente. De lo contrario, se generará un identificador de sesión cada vez.

Valores devueltos

Devuelve el nombre de la sesión actual. Si se proporciona el argumento name y la función actualiza el nombre de la sesión, entonces el anterior nombre de sesión será devuelto, o false si ocurre un error.

Historial de cambios

Versión	Descripción
8.0.0	`name` ahora es nullable.
7.2.0	session_name() verifica el estado de la sesión, anteriormente solo verificaba el estado de la cookie. Por lo tanto, las versiones anteriores de session_name() permiten la llamada a session_name() después de session_start() lo que puede causar el fallo de PHP y puede dar lugar a comportamientos extraños.

Ejemplos

Ejemplo #1 Ejemplo con session_name()

<?php

/* elige el nombre de sesión: WebsiteID */

$previous_name = session_name("WebsiteID");

echo "El nombre anterior de la sesión era $previous_name<br />";
?>

Ver también

La directiva de configuración session.name

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User Contributed Notes 9 notes

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146

Hongliang Qiang ¶

21 years ago

This may sound no-brainer: the session_name() function will have no essential effect if you set session.auto_start to "true" in php.ini . And the obvious explanation is the session already started thus cannot be altered before the session_name() function--wherever it is in the script--is executed, same reason session_name needs to be called before session_start() as documented.

I know it is really not a big deal. But I had a quite hard time before figuring this out, and hope it might be helpful to someone like me.

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php at wiz dot cx ¶

16 years ago

if you try to name a php session "example.com" it gets converted to "example_com" and everything breaks.

don't use a period in your session name.

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relsqui at chiliahedron dot com ¶

16 years ago

Remember, kids--you MUST use session_name() first if you want to use session_set_cookie_params() to, say, change the session timeout. Otherwise it won't work, won't give any error, and nothing in the documentation (that I've seen, anyway) will explain why.

Thanks to brandan of bildungsroman.com who left a note under session_set_cookie_params() explaining this or I'd probably still be throwing my hands up about it.

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Joseph Dalrymple ¶

14 years ago

For those wondering, this function is expensive!

On a script that was executing in a consistent 0.0025 seconds, just the use of session_name("foo") shot my execution time up to ~0.09s. By simply sacrificing session_name("foo"), I sped my script up by roughly 0.09 seconds.

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Victor H ¶

9 years ago

As  Joseph Dalrymple said, adding session_name do slow down a little bit the execution time.
But, what i've observed is that it decreased the fluctuation between requests.
Requests on my script fluctuated between 0,045 and 0,022 seconds. With session_name("myapp"), it goes to 0,050 and 0,045. Not a big deal, but that's a point to note.

For those with problems setting the name, when session.auto_start is set to 1, you need to set the session.name on php.ini!

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mmulej at gmail dot com ¶

4 years ago

Hope this is not out of php.net noting scope.

session_name('name') must be set before session_start() because the former changes ini settings and the latter reads them. For the same reason session_set_cookie_params($options) must be set before session_start() as well.

I find it best to do the following.

function is_session_started()
{
    if (php_sapi_name() === 'cli')
        return false;

    if (version_compare(phpversion(), '5.4.0', '>='))
        return session_status() === PHP_SESSION_ACTIVE;

    return session_id() !== '';
}
if (!is_session_started()) {
    session_name($session_name);
    session_set_cookie_params($cookie_options);
    session_start();
}

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tony at marston-home dot demon dot co dot uk ¶

7 years ago

The description that session_name() gets and/or sets the name of the current session is technically wrong. It does nothing but deal with the value originally supplied by the session.name value within the php.ini file.

Thus:-
$name = session_name();
is functionally equivalent to
$name = ini_get('session.name');
and 
session_name('newname);
is functionally equivalent to
ini_set('session.name','newname');

This also means that:
$old_name = session_name('newname');
is functionally equivalent to
$old_name = ini_set('session.name','newname');

The current value of session.name is not attached to a session until session_start() is called. Once session_start() has used session.name to lookup the session_id() in the cookie data the name becomes irrelevant as all further operations on the session data are keyed by the session_id().

Note that changing session.name while a session is currently active will not update the name in any session cookie. The new name does not take effect until the next call to session_start(), and this requires that the current session, which was created with the previous value for session.name, be closed.

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-3

tony at marston-home dot demon dot co dot uk ¶

7 years ago

The description has recently been modified to contain the statement "When new session name is supplied, session_name() modifies HTTP cookie". This is not correct as session_name() has never modified any cookie data. A change in session.name does not become effective until session_start() is called, and it is session_start() that creates the cookie if it does not already exist.

See the following bug report for details: https://bugs.php.net/bug.php?id=76413

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-3

descartavel1+php at gmail dot com ¶

2 years ago

Always try to set the prefix for your session name attribute to either `__Host-` or `__Secure-` to benefit from Browsers improved security. See https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Set-Cookie#attributes

Also, if you have auto_session enabled, you must set this name in session.name in your config (php.ini, htaccess, etc)

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