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MediaWiki\Session\SessionProvider Class Reference
Inheritance diagram for MediaWiki\Session\SessionProvider:
Collaboration diagram for MediaWiki\Session\SessionProvider:

Public Member Functions

 __construct ()
 
 setLogger (LoggerInterface $logger)
 
 setConfig (Config $config)
 
 setManager (SessionManager $manager)
 
 getManager ()
 
 provideSessionInfo (WebRequest $request)
 
 newSessionInfo ($id=null)
 
 mergeMetadata (array $savedMetadata, array $providedMetadata)
 
 refreshSessionInfo (SessionInfo $info, WebRequest $request, &$metadata)
 
 persistsSessionId ()
 
 canChangeUser ()
 
 getRememberUserDuration ()
 
 sessionIdWasReset (SessionBackend $session, $oldId)
 
 persistSession (SessionBackend $session, WebRequest $request)
 
 unpersistSession (WebRequest $request)
 
 preventSessionsForUser ($username)
 
 invalidateSessionsForUser (User $user)
 
 getVaryHeaders ()
 
 getVaryCookies ()
 
 suggestLoginUsername (WebRequest $request)
 
 getAllowedUserRights (SessionBackend $backend)
 
 __toString ()
 
 describe (Language $lang)
 
 whyNoSession ()
 

Protected Member Functions

 describeMessage ()
 
 hashToSessionId ($data, $key=null)
 

Protected Attributes

 $logger
 
 $config
 
 $manager
 
 $priority
 

Detailed Description

A SessionProvider provides SessionInfo and support for Session

A SessionProvider is responsible for taking a WebRequest and determining the authenticated session that it's a part of. It does this by returning an SessionInfo object with basic information about the session it thinks is associated with the request, namely the session ID and possibly the authenticated user the session belongs to.

The SessionProvider also provides for updating the WebResponse with information necessary to provide the client with data that the client will send with later requests, and for populating the Vary and Key headers with the data necessary to correctly vary the cache on these client requests.

An important part of the latter is indicating whether it even can tell the client to include such data in future requests, via the persistsSessionId() and canChangeUser() methods. The cases are (in order of decreasing commonness):

  • Cannot persist ID, no changing User: The request identifies and authenticates a particular local user, and the client cannot be instructed to include an arbitrary session ID with future requests. For example, OAuth or SSL certificate auth.
  • Can persist ID and can change User: The client can be instructed to return at least one piece of arbitrary data, that being the session ID. The user identity might also be given to the client, otherwise it's saved in the session data. For example, cookie-based sessions.
  • Can persist ID but no changing User: The request uniquely identifies and authenticates a local user, and the client can be instructed to return an arbitrary session ID with future requests. For example, HTTP Digest authentication might somehow use the 'opaque' field as a session ID (although getting MediaWiki to return 401 responses without breaking other stuff might be a challenge).
  • Cannot persist ID but can change User: I can't think of a way this would make sense.

Note that many methods that are technically "cannot persist ID" could be turned into "can persist ID but not change User" using a session cookie, as implemented by ImmutableSessionProviderWithCookie. If doing so, different session cookie names should be used for different providers to avoid collisions.

Since
1.27
See Also
https://www.mediawiki.org/wiki/Manual:SessionManager_and_AuthManager

Constructor & Destructor Documentation

MediaWiki\Session\SessionProvider::__construct ( )
Note
To fully initialize a SessionProvider, the setLogger(), setConfig(), and setManager() methods must be called (and should be called in that order). Failure to do so is liable to cause things to fail unexpectedly.

Member Function Documentation

MediaWiki\Session\SessionProvider::__toString ( )
Note
Only override this if it makes sense to instantiate multiple instances of the provider. Value returned must be unique across configured providers. If you override this, you'll likely need to override self::describeMessage() as well.
Returns
string
MediaWiki\Session\SessionProvider::canChangeUser ( )
abstract

Indicate whether the user associated with the request can be changed

If false, any session passed to self::persistSession() will have a user that was originally provided by self::provideSessionInfo(). Further, self::provideSessionInfo() may only provide sessions that have a user already set.

If true, the provider may be passed sessions with arbitrary users, and will be expected to manipulate the request in such a way that future requests will cause self::provideSessionInfo() to provide a SessionInfo with that ID. This can be as simple as not passing any 'userInfo' into SessionInfo's constructor, in which case SessionInfo will load the user from the saved session's metadata.

For example, a session provider for OAuth or SSL client certificates would function by matching the OAuth headers or certificate to a particular user, and thus would return false here since it can't arbitrarily assign those OAuth credentials or that certificate to a different user. A session provider that shoves information into cookies, on the other hand, could easily do so.

For use by only

Returns
bool
MediaWiki\Session\SessionProvider::describe ( Language  $lang)

Return an identifier for this session type

Parameters
Language$langLanguage to use.
Returns
string

Implements MediaWiki\Session\SessionProviderInterface.

MediaWiki\Session\SessionProvider::describeMessage ( )
protected

Return a Message identifying this session type

This default implementation takes the class name, lowercases it, replaces backslashes with dashes, and prefixes 'sessionprovider-' to determine the message key. For example, MediaWiki produces 'sessionprovider-mediawiki-session-cookiesessionprovider'.

Note
If self::__toString() is overridden, this will likely need to be overridden as well.
Warning
This will be called early during MediaWiki startup. Do not use $wgUser, $wgLang, $wgOut, $wgParser, or their equivalents via RequestContext from this method!
Returns
MediaWiki\Session\SessionProvider::getAllowedUserRights ( SessionBackend  $backend)

Fetch the rights allowed the user when the specified session is active.

This is mainly meant for allowing the user to restrict access to the account by certain methods; you probably want to use this with MWGrants. The returned rights will be intersected with the user's actual rights.

Parameters
SessionBackend$backend
Returns
null|string[] Allowed user rights, or null to allow all.
MediaWiki\Session\SessionProvider::getManager ( )

Get the session manager

Returns
SessionManager
MediaWiki\Session\SessionProvider::getRememberUserDuration ( )

Returns the duration (in seconds) for which users will be remembered when Session::setRememberUser() is set. Null means setting the remember flag will have no effect (and endpoints should not offer that option).

Returns
int|null
MediaWiki\Session\SessionProvider::getVaryCookies ( )

Return the list of cookies that need varying on. For use by only

Returns
string[]
MediaWiki\Session\SessionProvider::getVaryHeaders ( )

Return the HTTP headers that need varying on.

The return value is such that someone could theoretically do this:

foreach ( $provider->getVaryHeaders() as $header => $options ) {
$outputPage->addVaryHeader( $header, $options );
}

For use by only

Returns
array
MediaWiki\Session\SessionProvider::hashToSessionId (   $data,
  $key = null 
)
finalprotected

Hash data as a session ID

Generally this will only be used when self::persistsSessionId() is false and the provider has to base the session ID on the verified user's identity or other static data. The SessionInfo should then typically have the 'forceUse' flag set to avoid persistent session failure if validation of the stored data fails.

Parameters
string$data
string | null$keyDefaults to $this->config->get( 'SecretKey' )
Returns
string
MediaWiki\Session\SessionProvider::invalidateSessionsForUser ( User  $user)

Invalidate existing sessions for a user

If the provider has its own equivalent of CookieSessionProvider's Token cookie (and doesn't use User::getToken() to implement it), it should reset whatever token it does use here.

For use by only

Parameters
User$user
MediaWiki\Session\SessionProvider::mergeMetadata ( array  $savedMetadata,
array  $providedMetadata 
)

Merge saved session provider metadata

This method will be used to compare the metadata returned by provideSessionInfo() with the saved metadata (which has been returned by provideSessionInfo() the last time the session was saved), and merge the two into the new saved metadata, or abort if the current request is not a valid continuation of the session.

The default implementation checks that anything in both arrays is identical, then returns $providedMetadata.

For use by only

Parameters
array$savedMetadataSaved provider metadata
array$providedMetadataProvided provider metadata (from the SessionInfo)
Returns
array Resulting metadata
Exceptions
MetadataMergeExceptionIf the metadata cannot be merged. Such exceptions will be handled by SessionManager and are a safe way of rejecting a suspicious or incompatible session. The provider is expected to write an appropriate message to its logger.
int Session priority Used for the default MediaWiki\Session\SessionProvider::newSessionInfo (   $id = null)

Provide session info for a new, empty session

Return null if such a session cannot be created. This base implementation assumes that it only makes sense if a session ID can be persisted and changing users is allowed.

For use by only

Parameters
string | null$idID to force for the new session
Returns
SessionInfo|null If non-null, must return true for $info->isIdSafe(); pass true for $data['idIsSafe'] to ensure this.

could be used by subclasses too.

MediaWiki\Session\SessionProvider::persistSession ( SessionBackend  $session,
WebRequest  $request 
)
abstract

Persist a session into a request/response

For example, you might set cookies for the session's ID, user ID, user name, and user token on the passed request.

To correctly persist a user independently of the session ID, the provider should persist both the user ID (or name, but preferably the ID) and the user token. When reading the data from the request, it should construct a User object from the ID/name and then verify that the User object's token matches the token included in the request. Should the tokens not match, an anonymous user must be passed to SessionInfo::__construct().

When persisting a user independently of the session ID, $session->shouldRememberUser() should be checked first. If this returns false, the user token must not be saved to cookies. The user name and/or ID may be persisted, and should be used to construct an unverified UserInfo to pass to SessionInfo::__construct().

A backend that cannot persist sesison ID or user info should implement this as a no-op.

For use by only

Parameters
SessionBackend$sessionSession to persist
WebRequest$requestRequest into which to persist the session
MediaWiki\Session\SessionProvider::persistsSessionId ( )
abstract

Indicate whether self::persistSession() can save arbitrary session IDs

If false, any session passed to self::persistSession() will have an ID that was originally provided by self::provideSessionInfo().

If true, the provider may be passed sessions with arbitrary session IDs, and will be expected to manipulate the request in such a way that future requests will cause self::provideSessionInfo() to provide a SessionInfo with that ID.

For example, a session provider for OAuth would function by matching the OAuth headers to a particular user, and then would use self::hashToSessionId() to turn the user and OAuth client ID (and maybe also the user token and client secret) into a session ID, and therefore can't easily assign that user+client a different ID. Similarly, a session provider for SSL client certificates would function by matching the certificate to a particular user, and then would use self::hashToSessionId() to turn the user and certificate fingerprint into a session ID, and therefore can't easily assign a different ID either. On the other hand, a provider that saves the session ID into a cookie can easily just set the cookie to a different value.

For use by only

Returns
bool
MediaWiki\Session\SessionProvider::preventSessionsForUser (   $username)

Prevent future sessions for the user

If the provider is capable of returning a SessionInfo with a verified UserInfo for the named user in some manner other than by validating against $user->getToken(), steps must be taken to prevent that from occurring in the future. This might add the username to a blacklist, or it might just delete whatever authentication credentials would allow such a session in the first place (e.g. remove all OAuth grants or delete record of the SSL client certificate).

The intention is that the named account will never again be usable for normal login (i.e. there is no way to undo the prevention of access).

Note that the passed user name might not exist locally (i.e. User::idFromName( $username ) === 0); the name should still be prevented, if applicable.

For use by only

Parameters
string$username
MediaWiki\Session\SessionProvider::provideSessionInfo ( WebRequest  $request)
abstract

Provide session info for a request

If no session exists for the request, return null. Otherwise return an SessionInfo object identifying the session.

If multiple SessionProviders provide sessions, the one with highest priority wins. In case of a tie, an exception is thrown. SessionProviders are encouraged to make priorities user-configurable unless only max-priority makes sense.

Warning
This will be called early in the MediaWiki setup process, before $wgUser, $wgLang, $wgOut, $wgParser, $wgTitle, and corresponding pieces of the main RequestContext are set up! If you try to use these, things will break.
Note
The SessionProvider must not attempt to auto-create users. MediaWiki will do this later (when it's safe) if the chosen session has a user with a valid name but no ID. For use by only
Parameters
WebRequest$request
Returns
SessionInfo|null
MediaWiki\Session\SessionProvider::refreshSessionInfo ( SessionInfo  $info,
WebRequest  $request,
$metadata 
)

Validate a loaded SessionInfo and refresh provider metadata

This is similar in purpose to the 'SessionCheckInfo' hook, and also allows for updating the provider metadata. On failure, the provider is expected to write an appropriate message to its logger.

For use by only

Parameters
SessionInfo$infoAny changes by mergeMetadata() will already be reflected here.
WebRequest$request
array | null&$metadataProvider metadata, may be altered.
Returns
bool Return false to reject the SessionInfo after all.
MediaWiki\Session\SessionProvider::sessionIdWasReset ( SessionBackend  $session,
  $oldId 
)

Notification that the session ID was reset

No need to persist here, persistSession() will be called if appropriate.

For use by only

Parameters
SessionBackend$sessionSession to persist
string$oldIdOld session ID
MediaWiki\Session\SessionProvider::setConfig ( Config  $config)

Set configuration

Parameters
Config$config
MediaWiki\Session\SessionProvider::setLogger ( LoggerInterface  $logger)

Sets a logger instance on the object.

Parameters
LoggerInterface$logger
Returns
void

Implements Psr\Log\LoggerAwareInterface.

MediaWiki\Session\SessionProvider::setManager ( SessionManager  $manager)

Set the session manager

Parameters
SessionManager$manager
MediaWiki\Session\SessionProvider::suggestLoginUsername ( WebRequest  $request)

Get a suggested username for the login form For use by only

Parameters
WebRequest$request
Returns
string|null
MediaWiki\Session\SessionProvider::unpersistSession ( WebRequest  $request)
abstract

Remove any persisted session from a request/response

For example, blank and expire any cookies set by self::persistSession().

A backend that cannot persist sesison ID or user info should implement this as a no-op.

For use by only

Parameters
WebRequest$requestRequest from which to remove any session data
MediaWiki\Session\SessionProvider::whyNoSession ( )

Return a Message for why sessions might not be being persisted.

For example, "check whether you're blocking our cookies".

Returns
Message|null

Implements MediaWiki\Session\SessionProviderInterface.


The documentation for this class was generated from the following file: