In this cookbook I will attempt to explain how to use the lightweight version of Role-Based Access Control using a php file. This version does not use database but a php file and is controlled by CPhpAuthManager class.
By default when setting up this particular type of rbac Yii will look for any defined roles in a file named auth.php and located in protected/data/auth.php - for sake of easiness we'll use the example of user RBAC to the blog demo.
Info: Yii expects to read auth.php and get an array() out of it. So we need to create auth.php and return array(); Yii also needs to write to that file when changing roles so make sure to provide enough permission access to that file needed by the system.
HOWEVER: since Yii rewrites the auth.php file into a form that's far more difficult to edit, it's a good idea to edit a auth.txt file, where you can format and comment properly, then copy it to auth.php when you're ready to try it. The first time Yii rewrites auth.php it will be apparent why you want to do this.
Declare some roles in our auth.txt file:
// protected/data/auth.php return array( 'reader' => array ( 'type'=>CAuthItem::TYPE_ROLE, 'description'=>'Can only read a post', 'bizRule'=>'', 'data'=>'' ), 'commentor' => array ( 'type'=>CAuthItem::TYPE_ROLE, 'description'=>'Can post a comment', 'bizRule'=>'', 'data'=>'' ), 'admin' => array ( 'type'=>CAuthItem::TYPE_ROLE, 'description'=>'Can read a post and post a comment', 'children'=>array( 'reader','commentor' ), 'bizRule'=>'', 'data'=>'' ) );
The above code declares 3 different types of roles:
1 - reader - this type of role can only read a post but not post any comments
2 - commentor - this role gives access only to the comments form section to post a comment.
3 - admin - which can read a post and post a comment (consists of both roles above).
The bizRules and data elements aren't needed by this role scheme, but CPhpAuthManager seems to require them (and it will fail without them).
Once you've edited the file, put it in place:
$ cp auth.txt auth.php $ chmod a+w auth.php _# make sure Apache can write to it_
If you have to make a change to the roles, do it in the .txt file and re-copy to auth.php
Now that we've setup our roles we should move to apply them in action. In this example I will only apply them to our PostController as below:
// in protected/controllers/PostController.php class PostController extends CController { public function filters() { return array( 'accessControl' // required to enable accessRules ); } public function accessRules() { return array( array('allow', // allow readers only access to the view file 'actions'=>array('view'), 'roles'=>array('reader') ), array('deny', // deny everybody else 'users' => array('*') ) ); } ...
The above code should be pretty clear - allow user with 'reader' role access to the view action.
NOTE: Yii accessRules default to allow, so the explicit deny is required if you want this behavior.
Next we add an additional field to our tbl_user. We call that field role (varchar 30). We also need two user entries in this table. We already have the 'demo' one from the blog tutorial and add a 'test' one. In the 'demo' role field entry 'reader' as data and for 'test' enter 'admin' as a role.
Now we need to tell Yii when a user logs in what role s/he gets. I do this part in my UserIdentity class which takes care of my authentication for my blog. Here is how my UserIdentity class looks like:
public function authenticate() { $user=User::model()->find('LOWER(username)=?',array(strtolower($this->username))); if($user===null) $this->errorCode=self::ERROR_USERNAME_INVALID; else if(!$user->validatePassword($this->password)) $this->errorCode=self::ERROR_PASSWORD_INVALID; else { $this->_id=$user->id; $this->username=$user->username; $auth=Yii::app()->authManager; if(!$auth->isAssigned($user->role,$this->_id)) { if($auth->assign($user->role,$this->_id)) { Yii::app()->authManager->save(); } } $this->errorCode=self::ERROR_NONE; } return $this->errorCode==self::ERROR_NONE; }
The code we have added to the original UserIdentity class is:
$auth=Yii::app()->authManager; //initializes the authManager if(!$auth->isAssigned($user->role,$this->_id)) //checks if the role for this user has already been assigned and if it is NOT than it returns true and continues with assigning it below { if($auth->assign($user->role,$this->_id)) //assigns the role to the user { Yii::app()->authManager->save(); //saves the above declaration } }
Info: Please see comments at the end of the lines for explanation on what every line of code does. It is important to remember that it is good practice to check if a roles has already been assigned becuase Yii assignes roles and does not delete them until you call the revoke() function. In case you forget and try to re-assign a role Yii will return an error. Another important point is when you assign a role you must save it by calling Yii::app()->authManager->save();
$auth=Yii::app()->authManager;
The code snippet above initializes the authManager, which we need to setup in our protected/config/main.php config file as follows:
// protected/config/main.php return array( ... 'components'=>array( 'authManager'=>array( 'class'=>'CPhpAuthManager', // 'authFile' => 'path' // only if necessary ), ...
This basically activates the authorization Manager of the application and tells Yii that we want to use CPhpAuthManager class to take care of our accessControll. When you login Yii will assign a role to your user id. After you login open up the auth.php file and see that Yii has re-arranged it in the appropriate way.
For the sake of testing our functionality we should now add some RBAC check to our views/post/view.php:
if(Yii::app()->user->checkAccess('commentor')): <h3>Leave a Comment</h3> .........//your /commnet/_form here <?php endif;
Place the above code around your comments form section in the view file to check if the user has enough access privileges to post a comment.
You should now have a working privilege based system. One more thing left for our cookbook to be complete.
Info: When the user logs out we need to delete the assigned role otherwise if you change that user's role while he is offline and when he comes back and logs in again he will end up with two roles: the old one and the new one! So we place the below code in our logout action in the SiteController:
// protected/controllers/SiteController.php public function actionLogout() { $assigned_roles = Yii::app()->authManager->getRoles(Yii::app()->user->id); //obtains all assigned roles for this user id if(!empty($assigned_roles)) //checks that there are assigned roles { $auth=Yii::app()->authManager; //initializes the authManager foreach($assigned_roles as $n=>$role) { if($auth->revoke($n,Yii::app()->user->id)) //remove each assigned role for this user Yii::app()->authManager->save(); //again always save the result } } Yii::app()->user->logout(); //logout the user $this->redirect(Yii::app()->homeUrl); //redirect the user }
In your auth.php file you can use the following parameters:
- type => role,task,operation
- description => describe the type
- bizRule => apply business rule
- data => used in the business rule
- children => inherit other roles/tasks/operations
The 'type' is represented by the following constants in the CAuthItem class:
const TYPE_OPERATION=0; const TYPE_TASK=1; const TYPE_ROLE=2;
Role-Based Access Control
CModel::rules()
CAuthManager
RBAC clarification
another related rbac approach
CPhpAuthManager - how it works, and when to use it
Disclaimer: The above code works for me. I do not guarantee that it will work in all situations. If you need more complex RBAC structure use the DB one. I've read all posts in the forum re: RBAC but none of them helped me so the above code has been discovered through trial & error. Use it on your own responsibility.
Total 12 comments
USERiDENTITY.PHP public function authenticate() { $record = RRegister::model()->findByAttributes(array('username'=>$this->username)); if($record===null) $this->errorCode=self::ERROR_USERNAME_INVALID;
else if($record->password!==$this->password) $this->errorCode=self::ERROR_PASSWORD_INVALID; else { $this->id=$record->id; echo $this->setState('role', $record->role); $this->errorCode=self::ERROR_NONE; } return !$this->errorCode; } public function getId(){ return $this->id; }MAIN.PHP
'user'=>array( // enable cookie-based authentication 'allowAutoLogin'=>true, //set user role class 'class' => 'WebUser', ),
components/webuser.php
<?php /* * To change this template, choose Tools | Templates * and open the template in the editor. */ class WebUser extends CWebUser { /** * Overrides a Yii method that is used for roles in controllers (accessRules). * * @param string $operation Name of the operation required (here, a role). * @param mixed $params (opt) Parameters for this operation, usually the object to access. * @return bool Permission granted? */ public function checkAccess($operation, $params=array()) { if (empty($this->id)) { // Not identified => no rights return false; } $role = $this->getState("role"); if ($role === 'admin') { return true; // admin role has access to everything } // allow access if the operation request is the current user's role return ($operation === $role); } } ?>VIEW FORM:
<div id="mainmenu"> <?php $user = Yii::app()->user; $this->widget('zii.widgets.CMenu',array( 'items'=>array( array('label'=>'Home', 'url'=>array('/site/index')), //array('label'=>'About', 'url'=>array('/site/page', 'view'=>'about')), //array('label'=>'Contact', 'url'=>array('/site/contact')), array('label'=>'Create Account', 'url'=>array('/RRegister/create'),'visible'=>$user->checkAccess('admin')), array('label'=>'Amount Deposit', 'url'=>array('/RDEposit/create'),'visible'=>$user->checkAccess('staff')), array('label'=>'Amount Transaction', 'url'=>array('/RTransaction/create'),'visible'=>$user->checkAccess('staff')), array('label'=>'Amount Withdraw', 'url'=>array('/RWithdraw/create'),'visible'=>$user->checkAccess('normal')), array('label'=>'Login', 'url'=>array('/site/login'), 'visible'=>Yii::app()->user->isGuest), array('label'=>'Logout ('.Yii::app()->user->name.')', 'url'=>array('/site/logout'), 'visible'=>!Yii::app()->user->isGuest) ), )); ?> </div><!-- mainmenu -->USERiDENTITY.PHP [code] public function authenticate() { $record = RRegister::model()->findByAttributes(array('username'=>$this->username)); if($record===null) $this->errorCode=self::ERROR_USERNAME_INVALID;
else if($record->password!==$this->password) $this->errorCode=self::ERROR_PASSWORD_INVALID; else { $this->id=$record->id; echo $this->setState('role', $record->role); $this->errorCode=self::ERROR_NONE; } return !$this->errorCode; } public function getId(){ return $this->id; }[/code] MAIN.PHP [code] 'user'=>array( // enable cookie-based authentication 'allowAutoLogin'=>true, //set user role class 'class' => 'WebUser', ),
[/code] components/webuser.php [code] <?php /* * To change this template, choose Tools | Templates * and open the template in the editor. */ class WebUser extends CWebUser { /** * Overrides a Yii method that is used for roles in controllers (accessRules). * * @param string $operation Name of the operation required (here, a role). * @param mixed $params (opt) Parameters for this operation, usually the object to access. * @return bool Permission granted? */ public function checkAccess($operation, $params=array()) { if (empty($this->id)) { // Not identified => no rights return false; } $role = $this->getState("role"); if ($role === 'admin') { return true; // admin role has access to everything } // allow access if the operation request is the current user's role return ($operation === $role); } } ?> [/code]
VIEW FORM: [code]
[/code]
@emix @fsb You're both right to say that this subverts the intention of having authManager keep the role assignments in permanent storage. However, I find a variation of this technique very useful in a particular use case I've encountered.
The generalized use case is a site where some users (call them "account administrators") can create and modify other users with fewer privileges (less full-featured roles). Rather than a complex integration with authManager, it makes sense to define a small set of roles in a lookup table tied to a column in the user profile table (not the user table, as suggested in this article). The lookup table has a column for the role's common description (seen by the account admins) and one for the corresponding role name in authManager.
Now in implementing this technique, we can let the account admins modify the role column in the user profiles of people they've created. When this occurs, the next time that user logs in, he or she will have a new set of permissions.
In this use case, the reassignment at login is not such an outlandish way to handle roles. You can argue that with the same set-up, the best place to reassign a user's role is in the profile model when the role column value is altered. Sure. That's probably better. But this article's technique isn't so very terrible either.
I thought this was ok after having looked at several RBAC extensions... these days I use the methods outlined here: http://www.yiiframework.com/doc/guide/1.1/en/topics.auth
Much better!
This wiki demonstrates a fundamental misunderstanding of
CAuthManager.Yii's RBAC stores user role assignments in its own persistent store. But this wiki proposes storing role assignments in the application's
tbl_user.This creates a disconnect: without a role assignments in the RBAC store,
CAuthManagercannot do anything useful. The wiki closes the disconnect by copying the user's role assignment from the app'stbl_userinto RBAC on every page load and saving it.That's just wrong. In Yii RBAC, you store the definition of auth items, the auth item hierarchy AND the user auth assignments in RBAC, not in your app's table of users.
The copy and save of auth assignments causes needless server load but that may nor may not be a problem. What is certainly a problem is a tutorial teaching incorrect use of Yii RBAC.
Sorry, but I think you misunderstood the concept of PhpAuthManager and you are making other people repeat your mistakes..
Imagine having 1.000.000 users, hundreds of them logging in and out every second, haven't it occurred to you that this approach is just wrong?
You should only define roles, task and operations inside auth.php file and assign the user to his role each time he logs in to the system and store his roles inside a cookie or in the session, that's dead simple, never call save() too.
CPhpAuthManager ovewrites the auth.txt file every time save() is called. It means with thousands of users logging in/out a day, that would take up a lot of time to execute this.
Haven't tried the code, but the above code shouldn't be changed to something this?
Hi, In your example I don't really understand why you are using this auth.php to save the role of a user. You load the role of the user from the database, then you save this role in the auth.php. And when the user logout you remove the role from the auth.php. Why?? In this case, why just not use session?
When I saw this way of storing roles and so on, I was thinking that should not have interaction at all with the database. The file should keep the roles all the time, and give us the possibility to make the relation between a userId and roles.
This method makes a lot more sense to me that what I see around as database centered RBAC managers:
Sure, its a little more work, but so what?
Just as a side note here: for anyone doing this; please check and make sure that you have the getID() function in your UserIdentity component... without it, this method fails.
Thanks for this! Made my life a million times easier this morning... got through the whole of RBAC just by reading this and a few other snippets around the site.
Thanks! :)
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