Manual:Hooks/SessionMetadata

SessionMetadata
Available from version 1.27.0 (Gerrit change 243223)
Add metadata to a session being saved
Define function:
public static function onSessionMetadata( $backend, &$metadata, $requests ) { ... }
Attach hook: In extension.json:
{
	"Hooks": {
		"SessionMetadata": "MediaWiki\\Extension\\MyExtension\\Hooks::onSessionMetadata"
	}
}
Called from: File(s): session/SessionBackend.php
Function(s): save
Interface: SessionMetadataHook.php

For more information about attaching hooks, see Manual:Hooks .
For examples of extensions using this hook, see Category:SessionMetadata extensions.


Details

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Parameters
  • $backend: SessionBackend being saved.
  • &$metadata: Array of metadata to be stored. Add new keys here. Must be serializable.
  • $requests: Array of WebRequests potentially being saved to. Generally 0-1 real request and 0+ FauxRequests.
What is allowed
  • adding extra metadata to the session is allowed
What is not allowed
  • changing existing keys is not allowed

The metadata can be used to invalidate the session via the SessionCheckInfo hook (e.g. to tie sessions to IPs, one could add the IP address in SessionMetadata and check it against the actual IP address of the request in SessionCheckInfo).

A SessionProvider adding metadata for its own session does not need this hook; it should instead pass the metadata to the SessionInfo constructor, or call SessionBackend::setProviderMetadata(), or use its mergeMetadata() or refreshSessionInfo() methods (which will be called on every request) to update existing metadata.

The default keys in $metadata are:

  • provider (string) - the classname of the SessionProvider
  • providerMetadata (array|null) - metadata from the provider
  • userId (int)
  • userName (string)
  • userToken (string)
  • remember (bool) - "remember me" flag for this session
  • forceHTTPS (bool) - whether the user should be forced to use HTTPS.
  • expires (int) - time of expiry as a Unix timestamp
  • loggedOut (int|null) - Unix timestamp of when the user logged out (for a session that's anonymous but was logged-in earlier)
  • persisted (bool) - whether the session is persisted (ie. the next request from the client will be recognized as belonging to the same session). Typically this means whether the session cookie has been set (or at least added to the current response).

Troubleshooting

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If you get one of these exceptions thrown from the class SessionBackend:

UnexpectedValueException: SessionMetadata hook changed metadata key "provider"
UnexpectedValueException: SessionMetadata hook changed metadata key "providerMetadata"
UnexpectedValueException: SessionMetadata hook changed metadata key "userId"
UnexpectedValueException: SessionMetadata hook changed metadata key "userName"
UnexpectedValueException: SessionMetadata hook changed metadata key "userToken"
UnexpectedValueException: SessionMetadata hook changed metadata key "remember"
UnexpectedValueException: SessionMetadata hook changed metadata key "forceHTTPS"
UnexpectedValueException: SessionMetadata hook changed metadata key "expires"
UnexpectedValueException: SessionMetadata hook changed metadata key "loggedOut"
UnexpectedValueException: SessionMetadata hook changed metadata key "persisted"

It means these metadata were changed in the hook and they shouldn't.

To change already-existing keys, use dedicated methods instead. Look at the class SessionBackend.

See also

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