Deprecate SessionAuthenticator identify option

The `identify` option only verifies that the username exists in the
database, it does not verify passwords as the documentation previously
suggested. This makes it ineffective for the use case of detecting
password changes or remotely invalidating sessions.

Users should use `PrimaryKeySessionAuthenticator` instead if they need
to fetch fresh user data from the database on each request.

Also updated the Quick Start guide to clarify that SessionAuthenticator
does not need an identifier - it uses session data directly as identity.

Author: dereuromark

docs/en/authenticators.rst

@@ -18,13 +18,12 @@ Configuration options:
 
 -  **sessionKey**: The session key for the user data, default is
    ``Auth``
--  **identify**: Set this key with a value of bool ``true`` to enable checking
-   the session credentials against the identifiers. When ``true``, the configured
-   :doc:`/identifiers` are used to identify the user using data
-   stored in the session on each request. Default value is ``false``.
+-  **identify**: Deprecated in 3.4.0. This option only verifies that the
+   username exists in the database, it does not verify passwords as the
+   documentation previously suggested. Use ``PrimaryKeySessionAuthenticator``
+   instead if you need to fetch fresh user data from the database on each request.
 -  **fields**: Allows you to map the ``username`` field to the unique
-   identifier in your user storage. Defaults to ``username``. This option is
-   used when the ``identify`` option is set to true.
+   identifier in your user storage. Defaults to ``username``.
 
 PrimaryKeySession
 =================

docs/en/index.rst

@@ -32,7 +32,6 @@ imports::
     use Authentication\AuthenticationServiceInterface;
     use Authentication\AuthenticationServiceProviderInterface;
     use Authentication\Identifier\AbstractIdentifier;
-    use Authentication\Identifier\IdentifierInterface;
     use Authentication\Middleware\AuthenticationMiddleware;
     use Cake\Http\MiddlewareQueue;
     use Cake\Routing\Router;
@@ -94,23 +93,20 @@ define the ``AuthenticationService`` it wants to use. Add the following method t
             'queryParam' => 'redirect',
         ]);
 
-        // Define identifiers
         $fields = [
             AbstractIdentifier::CREDENTIAL_USERNAME => 'email',
-            AbstractIdentifier::CREDENTIAL_PASSWORD => 'password'
-        ];
-        $passwordIdentifier = [
-            'Authentication.Password' => [
-                'fields' => $fields,
-            ],
+            AbstractIdentifier::CREDENTIAL_PASSWORD => 'password',
         ];
 
         // Load the authenticators. Session should be first.
-        $service->loadAuthenticator('Authentication.Session', [
-            'identifier' => $passwordIdentifier,
-        ]);
+        // Session just uses session data directly as identity, no identifier needed.
+        $service->loadAuthenticator('Authentication.Session');
         $service->loadAuthenticator('Authentication.Form', [
-            'identifier' => $passwordIdentifier,
+            'identifier' => [
+                'Authentication.Password' => [
+                    'fields' => $fields,
+                ],
+            ],
             'fields' => $fields,
             'loginUrl' => Router::url([
                 'prefix' => false,
@@ -126,9 +122,9 @@ define the ``AuthenticationService`` it wants to use. Add the following method t
 First, we configure what to do with users when they are not authenticated.
 Next, we attach the ``Session`` and ``Form`` :doc:`/authenticators` which define the
 mechanisms that our application will use to authenticate users. ``Session`` enables us to identify
-users based on data in the session while ``Form`` enables us
-to handle a login form at the ``loginUrl``. Finally we attach an :doc:`identifier
-</identifiers>` to convert the credentials users will give us into an
+users based on data in the session - it uses the session data directly as identity without any
+database lookup. ``Form`` enables us to handle a login form at the ``loginUrl`` and uses an
+:doc:`identifier </identifiers>` to convert the credentials users will give us into an
 :doc:`identity </identity-object>` which represents our logged in user.
 
 If one of the configured authenticators was able to validate the credentials,

src/Authenticator/SessionAuthenticator.php

@@ -21,6 +21,7 @@
 use Cake\Http\Exception\UnauthorizedException;
 use Psr\Http\Message\ResponseInterface;
 use Psr\Http\Message\ServerRequestInterface;
+use function Cake\Core\deprecationWarning;
 
 /**
  * Session Authenticator
@@ -31,9 +32,10 @@ class SessionAuthenticator extends AbstractAuthenticator implements PersistenceI
      * Default config for this object.
      * - `fields` The fields to use to verify a user by.
      * - `sessionKey` Session key.
-     * - `identify` Whether to identify user data stored in a session. This is
-     *   useful if you want to remotely end sessions that have a different password stored,
-     *   or if your identification logic needs additional conditions before a user can login.
+     * - `identify` Whether to identify user data stored in a session.
+     *   Deprecated: This option only verifies that the username exists in the database,
+     *   it does not verify passwords. Use `PrimaryKeySessionAuthenticator` instead if you
+     *   need to fetch fresh user data from the database on each request.
      *
      * @var array
      */
@@ -65,6 +67,12 @@ public function authenticate(ServerRequestInterface $request): ResultInterface
         }
 
         if ($this->getConfig('identify') === true) {
+            deprecationWarning(
+                '3.4.0',
+                'The `identify` option is deprecated. ' .
+                'This option only verifies that the username exists, not the password. ' .
+                'Use `PrimaryKeySessionAuthenticator` instead to fetch fresh user data on each request.',
+            );
             $credentials = [];
             foreach ($this->getConfig('fields') as $key => $field) {
                 $credentials[$key] = $user[$field];

tests/TestCase/AuthenticationServiceTest.php

@@ -172,6 +172,7 @@ public function testAuthenticateWithChallengeDisabled()
      * Integration test for session auth + identify always getting a fresh user record.
      *
      * @return void
+     * @deprecated The `identify` option is deprecated.
      */
     public function testAuthenticationWithSessionIdentify()
     {
@@ -197,25 +198,28 @@ public function testAuthenticationWithSessionIdentify()
                 ],
             ]);
         };
-        $service = $factory();
-        $result = $service->authenticate($request);
-        $this->assertTrue($result->isValid());
-
-        $dateValue = new DateTime('2022-01-01 10:11:12');
-        $identity = $result->getData();
-        $this->assertEquals($identity->username, $user->username);
-        $this->assertNotEquals($identity->created, $dateValue);
-
-        // Update the user so that we can ensure session is reading from the db.
-        $user->created = $dateValue;
-        $users->saveOrFail($user);
 
-        $service = $factory();
-        $result = $service->authenticate($request);
-        $this->assertTrue($result->isValid());
-        $identity = $result->getData();
-        $this->assertEquals($identity->username, $user->username);
-        $this->assertEquals($identity->created, $dateValue);
+        $this->deprecated(function () use ($factory, $request, $users, $user) {
+            $service = $factory();
+            $result = $service->authenticate($request);
+            $this->assertTrue($result->isValid());
+
+            $dateValue = new DateTime('2022-01-01 10:11:12');
+            $identity = $result->getData();
+            $this->assertEquals($identity->username, $user->username);
+            $this->assertNotEquals($identity->created, $dateValue);
+
+            // Update the user so that we can ensure session is reading from the db.
+            $user->created = $dateValue;
+            $users->saveOrFail($user);
+
+            $service = $factory();
+            $result = $service->authenticate($request);
+            $this->assertTrue($result->isValid());
+            $identity = $result->getData();
+            $this->assertEquals($identity->username, $user->username);
+            $this->assertEquals($identity->created, $dateValue);
+        });
     }
 
     /**

tests/TestCase/Authenticator/SessionAuthenticatorTest.php

@@ -203,6 +203,7 @@ public function testAuthenticateFailure()
      * Test successful session data verification by database lookup
      *
      * @return void
+     * @deprecated The `identify` option is deprecated.
      */
     public function testVerifyByDatabaseSuccess()
     {
@@ -221,16 +222,19 @@ public function testVerifyByDatabaseSuccess()
         $authenticator = new SessionAuthenticator($this->identifiers, [
             'identify' => true,
         ]);
-        $result = $authenticator->authenticate($request);
+        $this->deprecated(function () use ($authenticator, $request) {
+            $result = $authenticator->authenticate($request);
 
-        $this->assertInstanceOf(Result::class, $result);
-        $this->assertSame(Result::SUCCESS, $result->getStatus());
+            $this->assertInstanceOf(Result::class, $result);
+            $this->assertSame(Result::SUCCESS, $result->getStatus());
+        });
     }
 
     /**
      * Test session data verification by database lookup failure
      *
      * @return void
+     * @deprecated The `identify` option is deprecated.
      */
     public function testVerifyByDatabaseFailure()
     {
@@ -249,10 +253,12 @@ public function testVerifyByDatabaseFailure()
         $authenticator = new SessionAuthenticator($this->identifiers, [
             'identify' => true,
         ]);
-        $result = $authenticator->authenticate($request);
+        $this->deprecated(function () use ($authenticator, $request) {
+            $result = $authenticator->authenticate($request);
 
-        $this->assertInstanceOf(Result::class, $result);
-        $this->assertSame(Result::FAILURE_CREDENTIALS_INVALID, $result->getStatus());
+            $this->assertInstanceOf(Result::class, $result);
+            $this->assertSame(Result::FAILURE_CREDENTIALS_INVALID, $result->getStatus());
+        });
     }
 
     /**