Add a blanket "will login" event

Summary:
Ref T1536. Facebook currently does a check which should be on-login in registration hooks, and this is generally a reasonable hook to provide.

The "will login" event allows listeners to reject or modify a login, or just log it or whatever.

NOTE: This doesn't cover non-web logins right now -- notably Conduit. That's presumably fine.

(This can't land for a while, it depends on about 10 uncommitted revisions.)

Test Plan: Logged out and in again.

Reviewers: wez, btrahan

Reviewed By: btrahan

CC: aran

Maniphest Tasks: T1536

Differential Revision: https://secure.phabricator.com/D6202

src/applications/auth/controller/PhabricatorAuthController.php

@@ -29,17 +29,54 @@ abstract class PhabricatorAuthController extends PhabricatorController {
 
   }
 
-  protected function establishWebSession(PhabricatorUser $user) {
-    $session_key = $user->establishSession('web');
+  /**
+   * Log a user into a web session and return an @{class:AphrontResponse} which
+   * corresponds to continuing the login process.
+   *
+   * Normally, this is a redirect to the validation controller which makes sure
+   * the user's cookies are set. However, event listeners can intercept this
+   * event and do something else if they prefer.
+   *
+   * @param   PhabricatorUser   User to log the viewer in as.
+   * @return  AphrontResponse   Response which continues the login process.
+   */
+  protected function loginUser(PhabricatorUser $user) {
 
+    $response = $this->buildLoginValidateResponse($user);
+    $session_type = 'web';
+
+    $event_type = PhabricatorEventType::TYPE_AUTH_WILLLOGINUSER;
+    $event_data = array(
+      'user'        => $user,
+      'type'        => $session_type,
+      'response'    => $response,
+      'shouldLogin' => true,
+    );
+
+    $event = id(new PhabricatorEvent($event_type, $event_data))
+      ->setUser($user);
+    PhutilEventEngine::dispatchEvent($event);
+
+    $should_login = $event->getValue('shouldLogin');
+    if ($should_login) {
+      $session_key = $user->establishSession($session_type);
+
+      // NOTE: We allow disabled users to login and roadblock them later, so
+      // there's no check for users being disabled here.
+
+      $request = $this->getRequest();
+      $request->setCookie('phusr', $user->getUsername());
+      $request->setCookie('phsid', $session_key);
+
+      $this->clearRegistrationCookies();
+    }
+
+    return $event->getValue('response');
+  }
+
+  protected function clearRegistrationCookies() {
     $request = $this->getRequest();
 
-    // NOTE: We allow disabled users to login and roadblock them later, so
-    // there's no check for users being disabled here.
-
-    $request->setCookie('phusr', $user->getUsername());
-    $request->setCookie('phsid', $session_key);
-
     // Clear the registration key.
     $request->clearCookie('phreg');
 
@@ -47,11 +84,19 @@ abstract class PhabricatorAuthController extends PhabricatorController {
     $request->clearCookie('phcid');
   }
 
-  protected function buildLoginValidateResponse(PhabricatorUser $user) {
+  private function buildLoginValidateResponse(PhabricatorUser $user) {
     $validate_uri = new PhutilURI($this->getApplicationURI('validate/'));
     $validate_uri->setQueryParam('phusr', $user->getUsername());
 
     return id(new AphrontRedirectResponse())->setURI((string)$validate_uri);
   }
 
+  protected function renderError($message) {
+    return $this->renderErrorPage(
+      pht('Authentication Error'),
+      array(
+        $message,
+      ));
+  }
+
 }

src/applications/auth/controller/PhabricatorAuthLoginController.php

@@ -107,9 +107,7 @@ final class PhabricatorAuthLoginController
           'with a valid Phabricator user.'));
     }
 
-    $this->establishWebSession($user);
-
-    return $this->buildLoginValidateResponse($user);
+    return $this->loginUser($user);
   }
 
   private function processRegisterUser(PhabricatorExternalAccount $account) {
@@ -161,7 +159,7 @@ final class PhabricatorAuthLoginController
     return null;
   }
 
-  private function renderError($message) {
+  protected function renderError($message) {
     $title = pht('Login Failed');
 
     $view = new AphrontErrorView();

src/applications/auth/controller/PhabricatorAuthRegisterController.php

@@ -205,13 +205,11 @@ final class PhabricatorAuthRegisterController
 
           $user->saveTransaction();
 
-          $this->establishWebSession($user);
-
           if (!$email_obj->getIsVerified()) {
             $email_obj->sendVerificationEmail($user);
           }
 
-          return $this->buildLoginValidateResponse($user);
+          return $this->loginUser($user);
         } catch (AphrontQueryDuplicateKeyException $exception) {
           $same_username = id(new PhabricatorUser())->loadOneWhere(
             'userName = %s',
@@ -480,7 +478,7 @@ final class PhabricatorAuthRegisterController
     }
   }
 
-  private function renderError($message) {
+  protected function renderError($message) {
     return $this->renderErrorPage(
       pht('Registration Failed'),
       array($message));

src/applications/auth/controller/PhabricatorAuthStartController.php

@@ -180,7 +180,7 @@ final class PhabricatorAuthStartController
     return id(new AphrontPlainTextResponse())->setContent($message);
   }
 
-  private function renderError($message) {
+  protected function renderError($message) {
     return $this->renderErrorPage(
       pht('Authentication Failure'),
       array($message));

src/applications/auth/controller/PhabricatorEmailTokenController.php

@@ -73,8 +73,6 @@ final class PhabricatorEmailTokenController
       $target_email->save();
     unset($unguarded);
 
-    $this->establishWebSession($target_user);
-
     $next = '/';
     if (!PhabricatorEnv::getEnvConfig('auth.password-auth-enabled')) {
       $panels = id(new PhabricatorSettingsPanelOAuth())->buildPanels();
@@ -95,6 +93,6 @@ final class PhabricatorEmailTokenController
 
     $request->setCookie('next_uri', $next);
 
-    return $this->buildLoginValidateResponse($target_user);
+    return $this->loginUser($target_user);
   }
 }

src/applications/auth/controller/PhabricatorLDAPLoginController.php

@@ -90,9 +90,7 @@ final class PhabricatorLDAPLoginController extends PhabricatorAuthController {
 
           $this->saveLDAPInfo($ldap_info);
 
-          $this->establishWebSession($known_user);
-
-          return $this->buildLoginValidateResponse($known_user);
+          return $this->loginUser($known_user);
         }
 
         $controller = newv('PhabricatorLDAPRegistrationController',

src/applications/auth/controller/PhabricatorLoginController.php

@@ -138,8 +138,7 @@ final class PhabricatorLoginController
         }
 
         if (!$errors) {
-          $this->establishWebSession($user);
-          return $this->buildLoginValidateResponse($user);
+          return $this->loginUser($user);
         } else {
           $log = PhabricatorUserLog::newLog(
             null,

src/applications/auth/controller/PhabricatorOAuthLoginController.php

@@ -148,9 +148,7 @@ final class PhabricatorOAuthLoginController
 
       $this->saveOAuthInfo($oauth_info);
 
-      $this->establishWebSession($known_user);
-
-      return $this->buildLoginValidateResponse($known_user);
+      return $this->loginUser($known_user);
     }
 
     $oauth_email = $provider->retrieveUserEmail();

src/infrastructure/events/constant/PhabricatorEventType.php

@@ -37,5 +37,6 @@ final class PhabricatorEventType extends PhutilEventType {
 
   const TYPE_PEOPLE_DIDRENDERMENU           = 'people.didRenderMenu';
   const TYPE_AUTH_WILLREGISTERUSER          = 'auth.willRegisterUser';
+  const TYPE_AUTH_WILLLOGINUSER             = 'auth.willLoginUser';
 
 }