Add access to authentication state via context

src/main/php/web/auth/Context.class.php

@@ -0,0 +1,7 @@
+<?php namespace web\auth;
+
+abstract class Context {
+
+  /** Logs out the user. Always returns true */
+  public abstract function logout(): bool;
+}

src/main/php/web/auth/SessionBased.class.php

@@ -59,8 +59,8 @@ private function authorize($session, $result) {
    * Executes authentication flow. On success, the user is looked up and
    * registered in the session under a key "user".
    *
-   * @param  web.Request $request
-   * @param  web.Response $response
+   * @param  web.Request $req
+   * @param  web.Response $res
    * @param  web.filters.Invocation
    * @return var
    */
@@ -96,6 +96,10 @@ public function filter($req, $res, $invocation) {
       $session->transmit($res);
     }
 
-    return $invocation->proceed($req->pass('user', $user)->pass('token', $token), $res);
+    $context= new SessionContext($session, $req, $res);
+    return $invocation->proceed(
+      $req->pass('context', $context)->pass('user', $user)->pass('token', $token),
+      $res
+    );
   }
 }

src/main/php/web/auth/SessionContext.class.php

@@ -0,0 +1,45 @@
+<?php namespace web\auth;
+
+use web\session\ISession;
+use web\{Request, Response};
+
+class SessionContext extends Context {
+  private $session, $request, $response;
+
+  /** Creates a new session context */
+  public function __construct(ISession $session, Request $request, Response $response) {
+    $this->session= $session;
+    $this->request= $request;
+    $this->response= $response;
+  }
+
+  public function user() {
+    return ($this->session->value('auth') ?? [null, $this->session->value('user')])[1];
+  }
+
+  public function claims() {
+    return ($this->session->value('auth') ?? [null, $this->session->value('user')])[0];
+  }
+
+  /** Modifies context with given changes */
+  public function modify(iterable $changes): self {
+    [$claims, $user]= $this->session->value('auth') ?? [null, $this->session->value('user')];
+    foreach ($changes as $key => $value) {
+      $user[$key]= $value;
+    }
+
+    $this->session->register('auth', [$claims, $user]);
+    $this->session->transmit($this->response);
+    $this->request->pass('user', $user);
+    return $this;
+  }
+
+  /** Destroys underlying session, effectively logging out the user */
+  public function logout(): bool {
+    if ($this->session->valid()) {
+      $this->session->destroy();
+      $this->session->transmit($this->response);
+    }
+    return true;
+  }
+}

src/test/php/web/auth/unittest/SessionBasedTest.class.php

@@ -2,7 +2,7 @@
 
 use lang\IllegalStateException;
 use test\{Assert, Test};
-use web\auth\{Flow, SessionBased};
+use web\auth\{Flow, SessionBased, Context};
 use web\io\{TestInput, TestOutput};
 use web\session\{ForTesting, ISession};
 use web\{Request, Response};
@@ -120,6 +120,18 @@ public function passes_token() {
     Assert::equals(SessionBased::TOKEN_LENGTH, strlen(base64_decode($token)));
   }
 
+  #[Test]
+  public function passes_context() {
+    $user= ['username' => 'test'];
+
+    $auth= new SessionBased($this->authenticate($user), new ForTesting());
+    $this->handle([], $auth->required(function($req, $res) use(&$passed) {
+      $passed= $req->value('context');
+    }));
+
+    Assert::instance(Context::class, $passed);
+  }
+
   #[Test]
   public function session_is_attached_when_redirecting() {
     $auth= new SessionBased($this->authenticate(null), newinstance(ForTesting::class, [], [
@@ -155,4 +167,45 @@ public function session_is_attached_after_authentication() {
     Assert::equals(1, $attached->value('times'));
     Assert::equals($user, $attached->value('auth')[1]);
   }
+
+  #[Test]
+  public function user_accessible_from_context() {
+    $user= ['username' => 'test'];
+    $passed= null;
+
+    $auth= new SessionBased($this->authenticate($user), new ForTesting());
+    $this->handle([], $auth->required(function($req, $res) use(&$passed) {
+      $passed= $req->value('context')->user();
+    }));
+
+    Assert::equals($user, $passed);
+  }
+
+  #[Test]
+  public function session_and_request_values_modified() {
+    $user= ['username' => 'test'];
+    $modified= null;
+
+    $sessions= new ForTesting();
+    $auth= new SessionBased($this->authenticate($user), $sessions);
+    $this->handle([], $auth->required(function($req, $res) use(&$modified) {
+      $req->value('context')->modify(['theme' => 'dark']);
+      $modified= $req->value('user')['theme'];
+    }));
+
+    $session= current($sessions->all());
+    Assert::equals('dark', $modified);
+    Assert::equals($user + ['theme' => 'dark'], $session->value('auth')[1]);
+  }
+
+  #[Test]
+  public function session_is_destroyed_on_logout() {
+    $sessions= new ForTesting();
+    $auth= new SessionBased($this->authenticate(['username' => 'test']), $sessions);
+    $this->handle([], $auth->required(function($req, $res) {
+      $req->value('context')->logout();
+    }));
+
+    Assert::equals([], $sessions->all());
+  }
 }