J3.x

Didacticiel : Liste de Contrôle d'Accès (ACL)

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This page is a translated version of the page J3.x:Access Control List Tutorial and the translation is 53% complete.

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Joomla! 
3.x
série

Résumé des ACL pour la Version Joomla 3.x

Cette section décrit les changements majeurs d'ACL entre les versions 2.5 et la série 3.x (incluant les futures versions). Le tableau ci-dessous résume les changements depuis la version 2.5.

Version 2.5 Version 3.9
Groupes Nombre illimité de groupes d'utilisateurs définis La même chose que pour 2.5
Utilisateurs & Groupes Un utilisateur peut être assigné à plusieurs groupes La même chose que pour 2.5
Niveaux d'accès Niveaux d'accès illimités pour les utilisateurs définis La même chose que pour 2.5
Niveaux d'accès & groupes Les groupes sont assignés à des niveaux d'accès. Toute combinaison de groupes peut être assignée à n'importe quel niveau d'accès. La même chose que pour 2.5

Des ACL séparées pour Voir et pour Faire

Le système ACL de Joomla! peut être appréhendé comme étant divisé en deux systèmes distincts. Un système de contrôle de ce que les utilisateurs peuvent "voir". Un autre système permettant le contrôle de ce que les utilisateurs peuvent "faire" (les actions qu'un utilisateur peut entreprendre). Les ACL pour chacun des systèmes sont configurées différemment.

Contrôler ce que les utilisateurs peuvent voir

Les réglages permettant de contrôler ce que les utilisateurs peuvent voir se font de la manière suivante :

  • Créer un ensemble de Niveaux d'accès selon les Catégories et/ou la combinaison de catégories que vous souhaitez rendre visibles aux utilisateurs connectés. Note : à ce stade, n'assignez aucun groupe d'utilisateurs à ces nouveaux Niveaux d'accès.
  • Créer un Groupe d'utilisateurs avec la qualité de 'Registered' en tant que parent, pour chaque Niveau d'accès. Utiliser les mêmes noms pour les Groupes d'utilisateurs et les Niveaux d'accès permettra d'éviter plus tard toute confusion.
  • Editer vos nouveaux niveaux d'accès et assigner le bon (nouveau) groupe d'utilisateur à chacun. Vous pouvez également souhaiter assigner le Groupe de Super User (et/ou d'autres groupes d'utilisateurs par défaut mais pas le groupe d'utilisateur 'Guest') à tous vos nouveaux niveaux d'accès.
  • Attribuer à chaque élément un niveau d'Accès. Les éléments comprennent les éléments de contenu (articles, contacts et ainsi de suite), les éléments de menu et les modules.

Chaque fois qu'un utilisateur est sur le point de voir un élément sur une page Joomla, le programme vérifie si l'utilisateur a accès à cet élément, comme suit:

  1. Il crée une liste de tous les niveaux d'accès auxquels l'utilisateur a accès, basé sur tous les groupes auxquels appartient l'utilisateur. De plus, si un groupe possède un groupe parent, les niveaux d'accès du groupe parent sont également inclus à la liste.
  2. Il vérifie si le niveau d'accès à l'élément (article, module, élément de menu et ainsi de suite) est sur cette liste. Si oui, l'élément est affiché à l'utilisateur. Si non, l'élément n'est pas affiché.

Notez que les niveaux d'accès sont définis séparément pour chaque groupe et ne sont pas hérités d'un groupe parent du groupe.

Contrôler ce que les utilisateurs peuvent faire

Le système pour déterminer ce que les utilisateurs d'un groupe d'utilisateurs peuvent faire - les actions qu'ils peuvent faire sur un élément donné -- se paramètre dans l'onglet des droits de l'écran de configuration et dans l'onglet des droits dans chaque composant. Des droits peuvent également être paramétré au niveau de la catégorie pour les composants natifs et au niveau article pour les articles.

  • Si vous souhaitez pour des catégories spécifiques que les utilisateurs se connectent pour créer, supprimer, modifier un statut ou modifier le leur, alors :
    • Créez un groupe d'utilisateurs avec comme parent un de vos groupes d'utilisateurs disposant d'un accès à la catégorie (ou aux catégories) à laquelle vous souhaitez que ce nouveau groupe d'utilisateurs puisse apporter des modifications.
    • Affectez à votre nouveau groupe d'utilisateurs le(s) niveau(x) d'accès approprié(s). Puis modifiez les autorisations requises pour votre nouveau groupe d'utilisateurs soit globalement, soit par catégorie/article.
      • Lors de la création d'un groupe d'utilisateurs, il est conseillé de sélectionner un groupe parent ayant moins de droits que ceux nécessaires au nouveau groupe. Il est en effet plus facile d'augmenter les droits par composant/catégorie/article plutôt que d'avoir plus de droits que nécessaire et de devoir supprimer des droits dans les autres composants/catégories/articles.
        • (exemple: vous avez 10 catégories, mais vous voulez créer des droits pour une seule. Si vous définissez les droits globaux sur 'Créer - Autoriser' pour ce groupe vous devrez alors retirer le droit Créer pour toutes ces catégories. Et vous devrez supprimer le droit Créer pour ce groupe pour toute nouvelle catégorie que vous ajouterez ultérieurement.)
    • Créer un groupe d'utilisateurs avec un des groupes d'utilisateurs par défaut en tant que parent uniquement si aucun d'eux n'a exactement les droits dont vous avez besoin ou que vous souhaitez pour toutes les catégories.

Notez que cette configuration est indépendante de la configuration pour l'affichage et un groupe d'utilisateurs doit être assigné à des niveaux d'accès appropriés pour que les utilisateurs de ce groupe puissent utiliser ces autorisations.

Lorsqu'un utilisateur veut lancer une action spécifique pour l'élément d'un composant (par exemple, éditer un article), le système (après avoir vérifié que l'utilisateur appartient à un groupe y ayant accès) vérifie l'autorisation pour cette combinaison d'utilisateur, d'objet et d'action. Si elle est autorisée, l'utilisateur peut agir. Sinon, l'action n'est pas autorisée.

La suite de ce didacticiel explique comment il est possible de contrôler ce que les utilisateurs peuvent faire -- de quelles autorisations ils disposent.

Actions, groupes et héritage

Un autre intérêt des ACL est l'octroi, aux utilisateurs, des autorisations d'effectuer des actions sur les objets.

Séries 3.x
Groupes et actions Les actions autorisées pour chaque groupe sont définies par l'administrateur du site.
Portée des droits Les droits peuvent être définis à plusieurs niveaux de la hiérarchie : site, composent, catégorie, objet.
Héritage des droits Les autorisations peuvent être héritées de groupes parents et de catégories mères.

Comment fonctionnent les droits

Il existe quatre droits possibles pour les actions, comme indiqué ci-dessous :

  • Non défini : "refuser" par défaut, mais à la différence de la permission "Refuser", cette autorisation peut être substituée dans la hiérarchie des autorisations par les paramètres "Autoriser" des groupes enfants ou d'un niveaux inférieurs. Cette autorisation s'applique uniquement à la configuration globale des autorisations.
  • Hériter : hérite de la valeur d'un groupe parent ou d'un niveau supérieur dans la hiérarchie des autorisations. Cette autorisation s'applique à tous les niveaux à l'exception de la configuration globale.
  • Refuser : refuse cette action pour ce niveau de groupe. IMPORTANT : cela refuse également cette action pour tous les groupes enfants et tous les niveaux inférieurs dans la hiérarchie des autorisations. Paramétrer un groupe enfant ou un niveau inférieur sur Autoriser n'aura aucun effet. L'action sera toujours refusée pour tous les membres du groupe enfant ou d'un niveau inférieur dans la hiérarchie des autorisations.
  • Autoriser : permet cette action pour ce niveau et ce groupe et pour les niveaux inférieurs et les groupes enfants. Cela n'a aucun effet si un groupe ou niveau supérieur est paramétré sur 'Refuser' ou 'Autoriser'. Si un groupe ou niveau supérieur est paramétré sur 'Refuser', alors cette permission sera toujours refusée. Si un groupe ou niveau supérieur est défini sur 'Autoriser', alors cette permission est déjà autorisée.

Niveaux hiérarchiques des permissions

Les permissions d'action dans la version 2.5 et supérieure, peuvent être définies jusqu'à quatre niveaux et comme suit :

  1. Configuration globale : détermine les autorisations par défaut pour chaque action et chaque groupe.
  2. Options de composants    Droits : vous permet de remplacer les autorisations par défaut pour ce composant (par exemple pour les articles, menus, utilisateurs, bannières, et ainsi de suite).
  3. Catégorie : permet de se substituer aux permissions par défaut pour des éléments d'une ou plusieurs catégories. S'applique à tous les composants utilisant des catégories y compris ceux pour les Articles, Bannières, Contacts, Fils d'actualité et de Liens web.
  4. Article : permet de remplacer les permissions pour un article spécifique. Ce niveau s'applique uniquement aux articles. Les autres composants autorisent uniquement les trois premiers niveaux.

Configuration

Allez dans Système → Configuration → Droits. Cet écran vous permet de régler le niveau supérieur des droits de chaque groupe et de chaque action, tel qu'indiqué sur la capture d'écran ci-dessous.

Screenshot global acl J3 tutorial-fr.png

Les options pour chaque valeur sont Hérité, Autorisé ou Refusé. La colonne de paramètre indique le réglage en vigueur. Autorisé (par défaut).

Vous pouvez travailler sur un groupe à la fois en ouvrant le panneau pour ce groupe. Vous modifiez les autorisations dans la liste déroulante Modifier un droit.

Notez que la colonne des paramètres appliqués ne sera mise à jour qu'après avoir cliqué sur le bouton Enregistrer de la barre d'outils. Pour vérifier que les paramètres sont ce que vous souhaitez, appuyez sur le bouton Enregistrer et vérifier dans la colonne.

Options de composant  Droits

Accessible pour chaque composant en cliquant sur l'icône Options de la barre d'outils. Cet écran est similaire à l'écran de Configuration ci-dessus. Par exemple, en cliquant sur l'icône des options dans le gestionnaire de menu, vous trouverez l'écran de configuration des menus comme ci-dessous. Screenshot menu acl J3 tutorial-fr.jpg

Access to Options is only available to members of groups who have permission for the Configure action in for each component. In the example above, the Administrator group has Allowed permission for the Configure option, so members of this group can access this screen.

Category

Category permissions are accessed in the Category Manager: Edit Category screen, in a tab at the top of the screen. This screen has five permissions, as shown below.

Screenshot category acl j3 tutorial-fr.png

In these screens, you work on the permissions for one User Group at a time. In the example above, we are editing the permissions for the Administrator group.

Note that the Configure and Access Component actions do not apply at the category level, so those actions are not included.

Note also that Categories can be arranged in a hierarchy. If so, then action permissions in a parent category are inherited automatically by a child category. For example, if you had a category hierarchy of Animals → Pets → Dogs, then the full permission level hierarchy for an article in the Dogs category would be as follows:

  • Global Configuration
  • Article Manager → Options → Permission
  • Animals Category
  • Pets Category
  • Dogs Category
  • specific article

Article

Les droits attribués pour un article unique sont accessibles depuis le gestionnaire des articles. Modifiez l'écran des articles dans le panneau en bas de l'écran. Cet écran propose trois actions comme montré ci-dessous.

J3x acl tutorial article manager article permissions-fr.png

Again, you edit each group by clicking on it to open the slider for that group. You can then change the permissions under the Select New Setting column. To see the effect of any changes, press the Save button to update the Calculated Setting column.

Note that the Configure, Access Component, and Create actions do not apply at the article level, so these actions are not included. Permission to create an article is set at one of the higher levels in the hierarchy.

Niveaux d'accès

Les niveaux d'accès pour la série 3.x de Joomla! sont simples et flexibles. L'écran ci-dessous vous montre le niveau d'accès Special.

J3x acl tutorial viewing levels-fr.png

Simply check the box for each group you want included in that level. The Special Access Level includes the Manager, Author, and Super Users groups. It also includes child groups of those groups. So, Administrator group is included, since it is a child group of the Manager group. The Editor, Publisher, and Shop Suppliers groups are included, since they are child groups of Author. (Note that we could check all of the child groups if we wanted and it wouldn't hurt anything).

Once Access Levels are created, they are used in the same way as in version 1.5. Each object in the front end is assigned an Access Level. If the level is Public, then anyone may access that object. Otherwise, only members of groups assigned to that access level may access that object. Access levels are assigned to Menu Items and to Modules. Each one can only be assigned to one access level.

For example, the screen below shows the Edit Menu Item screen with the list of available access levels.

J3x acl tutorial edit menu item level dropdown-fr.png

Paramétrage par défaut des ACL

When Joomla! is installed, these are set to their initial default settings. We will discuss these initial settings as a way to understand how the ACL works.

Groupes par défaut

Version 3.x allows you to define your own Groups. When you install version 3.x, it includes a set of default groups, shown below are the basic default user groups. (Additional default user groups are installed with sample data)

Screenshot usergroupsl acl J3 tutorial-fr.png

The arrows indicate the child-parent relationships. As discussed above, when you set a permission for a parent group, this permission is automatically inherited by all child groups. The Inherited, and Allowed permissions can be overridden for a child group. The Denied permission cannot be overridden and will always deny an action for all child groups.

Configuration globale

Joomla! version 2.5 will install with the same familiar back-end permissions as that of version 1.5. However, with 2.5, you can easily change these to suit the needs of your site.

As discussed earlier, the permissions for each action are inherited from the level above in the permission hierarchy and from a group's parent group. Let's see how this works. The top level for this is the entire site. This is set up in the Site->Global Configuration->Permissions, as shown below.

Screenshot global acl J3 tutorial-fr.png

The first thing to notice are the ten Actions: Site Login, Admin Login, Offline Access, Super User, Access Administration Interface, Create, Delete, Edit, Edit State. and Edit Own. These are the actions that a user can perform on an object in Joomla. The specific meaning of each action depends on the context. For the Global Configuration screen, they are defined as follows:

Connexion 
Connexion en frontend du site.
Connexion à l'administration 
Connexion à l'interface d'administration du site.
Offline Access 
Login to the front end of the site when the website site is offline (when Global Configuration setting "Site Offline" is set to Yes)
Super User 
Grants the user "super user" status. Users with this permission can do anything on the site. Only users with this permission can change Global Configuration settings (this screen). These permissions cannot be restricted. It is important to understand that, if a user is a member of a Super Admin group, any other permissions assigned to this user are irrelevant. The user can do any action on the site. However, Access Levels can still be assigned to control what this group sees on the site. (Obviously, a Super Admin user can change Access Levels if they want to, so Access Levels do not totally restrict what a Super Admin user can see.)
Access Component
Open the component manager screens (User Manager, Menu Manager, Article Manager, and so on)
Créer 
créer de nouveaux objets (par exemple, des utilisateurs, des éléments de menu, des articles, des liens web, et ainsi de suite)
Supprimer 
permet de supprimer des objets existants
Modifier 
modifier les éléments existants
Edit State 
Change object state (Publish, Unpublish, Archive, and Trash)
Edit Own 
Edit objects that you have created.

Each Group for the site has its own slider which is opened by clicking on the group name. In this case (with the sample data installed), we have the standard 7 groups that we had in version 1.5 plus two additional groups called "Shop Suppliers" and "Customer Group". Notice that our groups are set up with the same permissions as they had in version 1.5. Keep in mind that we can change any of these permissions to make the security work the way we want. Let's go through this to see how it works.

  • Public has everything set to "Not set", as shown below.
    File:Screenshot global acl public J3 tutorial-fr.png
    • This can be a bit confusing. Basically, "Not Set" is the same as "Inherited". Because Public is our top-level group, and because Global Configuration is the top level of the component hierarchy, there is nothing to inherit from. So "Not Set" is used instead of "Inherit".
    • The default in this case is for no permissions. So, as you would expect, the Public group has no special permissions. Also, it is important to note that, since nothing is set to Denied, all of these permissions may be overridden by child groups or by lower levels in the permission hierarchy.
  • Guest is a 'child' group of the Public group has everything set to 'Inherited'
    File:Screenshot global acl guest J3 tutorial-fr.png
    • This is the default 'Guest User Group' in the User Manager options and the Group that (non logged in) visitors to your site are placed in.
  • Manager is a "child" group of the Public group. It has Allowed permissions for everything except Access Component and Super Admin. So a member of this group can do everything in the front and back end of the site except change Global Permissions and Component Options.
    File:Screenshot global acl manager J3 tutorial-fr.png
  • Registered is the same a Public except for the Allow permission for the Site Login action. This means that members of the Registered group can login to the site. Since default permissions are inherited, this means that, unless a child group overrides this permission, all child groups of the Registered group will be able to login as well.
    File:Screenshot global acl registered J3 tutorial-fr.png
  • Author is a child of the Registered group and inherits its permissions and also adds Create and Edit Own. Since Author, Editor, and Publisher have no back-end permissions, we will discuss them below, when we discuss front-end permissions.
    File:Screenshot global acl author J3 tutorial-fr.png
  • Shop Suppliers is an example group that is installed if you install the sample data. It is a child group of Author.
  • Customer Group is an example group that is installed if you install the sample data. It is a child group of Registered.
  • Super Users group has the Allow permission for the Super Admin action. Because of this, members of this group have super user permissions throughout the site. They are the only users who can access and edit values on the Global Configuration screen. Users with permission for the Super Admin action have some special characteristics:
  • If a user has Super Admin permissions, no other permissions for this user matter. The user can perform any action on the site.
  • Only Super Admin users can create, edit, or delete other Super Admin users or groups.

There are two very important points to understand from this screen. The first is to see how the permissions can be inherited from the parent Group. The second is to see how you can control the default permissions by Group and by Action.

This provides a lot of flexibility. For example, if you wanted Shop Suppliers to be able to have the ability to login to the back end, you could just change their Admin Login value to "Allowed". If you wanted to not allow members of Administrator group to delete objects or change their state, you would change their permissions in these columns to Inherited (or Denied).

It is also important to understand that the ability to have child groups is completely optional. It allows you to save some time when setting up new groups. However, if you like, you can set up all groups to have Public as the parent and not inherit any permissions from a parent group.

Options des composants & droits

Now, let's continue to see how the default back-end permissions for version 2.5 mimic the permissions for version 1.5. The Super Users group in 2.5 is equivalent to the Super Administrator group in 1.5.

Just looking at the Global Configuration screen above, it would appear that the Administrator group and the Manager group have identical permissions. However, in version 1.5 Administrators can do everything except Global Configuration, whereas Managers are not permitted to add users or work with menu items. That is also true in the default version 2.5 configuration. Let's see how this is accomplished.

If we navigate to Users->User Manager and click the Options button in the toolbar, we see the screen below:

This screen is the same as the Global Configuration Permissions screen, except that these values only affect working with Users. Let's look at how this works.

First, notice that the Administrator group has Allow permission for the Admin action and the Manager group has Deny permission for this action. Remember that the Admin action in the Global Configuration screen gives the group "super user" permissions. In this screen, the Admin action allows you to edit the Options values. So, the Administrator group can do this but the Manager group cannot.

Next, notice that the Administrator has Inherit for the Manage action and the Manager group has Deny permission. In this screen, the Manage action gives a group access to the User Manager. Since the Administrator has Allow for the Manage action by default, then the Inherit permission here means they inherit the Allow permission for the Manage action. Since the Manager group has Deny permission for the Manage action, members of the Manager group cannot access the User Manager and therefore cannot do any of the other user-related actions.

If you look at the Options for Menus->Menu Manager, you will see the same default settings as for the User Manager. Again, the Administrator group can manage and set default permissions for Menu Manager objects whereas the Manager group cannot.

In short, we can see that the different permissions for the Administrator and Manager groups are set using the Options->Permissions forms on the User Manager and Menu Manager screens.

It is also important to understand that this same Options->Permissions form for setting default permissions is available for all Joomla! objects, including Media Manager, Banners, Contacts, Newsfeeds, Redirect, Search Statistics, Web Links, Extensions, Modules, Plugins, Templates, and Language. So you now have the option to create user groups with fine-tuned sets of back-end permissions.

Droits pour le frontend

Default permissions for the front end are also set using the Options form. Let's look at Content->Article Manager->Options->Permissions. First, let's look at the permissions for Manager, as shown below.

Manager has allowed permission for all actions except Configure. So members of the Manager group can do everything with Articles except open the Options screen.

Now let's look at Administrator, as shown below.

Administrator has Allowed for Configure, so Administrators can edit this Options screen.

Both groups can create, delete, edit, and change the state of articles.

Now, let's look at the groups Publisher, Editor, and Author and see how their permissions are set.

Authors only have Create and Edit Own permissions, as shown below.

This means that Authors can create articles and can edit articles they have created. They may not delete articles, change the published state of articles, or edit articles created by others.

Editors have the same permissions as Authors with the addition of permission for the Edit action, as shown below.

So Editors can edit articles written by anyone.

Publishers can do everything Editors can do plus they have permission for the Edit State action, as shown below.

So Publishers can change the published state of an article. The possible states include Published, Unpublished, Archived, and Trashed.

All of these groups have Inherit permission for Configure and Access Component. Remember that Author is a child of the Registered group, and Registered does not have any default permissions except for Login. Since Registered does not have permission for Configure and Access Component, and since Author's permission for these actions is "Inherited", then Author does not have these permissions either. This same permission is passed from Author to Editor and from Editor to Publisher. So, by default, none of these groups are allowed to work with articles in the back end.

It is important to remember that these permissions are only default settings for categories and articles and for any child groups that are created. So they can be overridden for child groups, for categories, and for specific articles.

Also, note that there are no Denied permissions for any actions in the default settings. This allows you to add Allowed permissions at any level. Remember, once you have an action set for Denied, this action will be denied at all lower levels in the hierarchy. For example, if you set the Admin Login for Registered to Denied (instead of Inherited), you could not grant Publishers Allowed permissions for this action.

Article Manager & Actions Diagram

The diagram below shows how each action in the permissions form relates to the various options on the Article Manager screen.

  • Configure allows you to view and change the Options for the component.
  • Access Component allows you to navigate to the Article Manager. Without this permission, no other actions are possible.
  • Créer vous permet d'ajouter de nouveaux articles.
  • Delete allows you to delete trashed articles. Note that the Delete icon only shows in the toolbar when you have the "Select State" filter set to "Trash".
  • Edit allows you to edit existing articles.
  • Edit State allows to you Publish, Unpublish, Archive, or Trash articles.
  • Edit Own is the same as Edit except that it only applies to articles written by you.

Allowing Guest-Only Access to Menu Items and Modules

Version 1.6 introduced the ability to create a View Access Level that is only for guests of the site (meaning a user who is not logged in). The example below shows how you can set up this new feature. (N.B. Steps 1 to 3 are not needed for Joomla! 3.x as they exist in the default install)

  1. Create a new user group called Guest. Make it a child of the Public group as shown below.
  2. Create a new access level called Guest and grant only the Guest group access to this level, as shown below.
  3. Navigate to User Manager→Options→Component and change the Guest User Group from the default value of "Public" to "Guest", as shown below.

Now, if we assign a menu item, module, or other object to the Guest access level, only non-logged in users will have access. For example, if we create a new menu item with access level of Guest, as shown below,

this menu item will only be visible to non-logged-in visitors to the site.

If required other user groups like Author can be granted access in the Guest access level, this would allow Authors to view articles in the front end for editing.

N.B. Login/logout in front end (for changing data in session) to see the change.

Using Permission and Group Levels Together

As discussed above, it is possible to define groups in a hierarchy, where each child group inherits action permissions (for example, the create permission) from its parent group. Action permissions are also be inherited from the permission level above. For example, a permission in the Article Manager is inherited from the same permission in the Global Configuration, and a permission in a child Category is inherited from the parent Category permission.

This dual inheritance can be confusing, but it can also be useful. Let's consider an example as follows. We have a school with a group hierarchy of Teachers → History Teachers → Assistant History Teachers. We also have a category hierarchy of Assignments → History Assignments. We want History Teachers and Assistant History Teachers to have the following permissions:

  • both groups can create new articles only in the History Assignments category.
  • only History Teachers (not Assistant History Teachers) can Publish or otherwise have Edit State permission.

This ACL scheme is very easy to implement. The diagram below shows how this would be set up for the Create Action.

In the diagram, the Permission Hierarchy is shown down the left side and the Group hierarchy is shown across the top. Permissions are inherited down and to the right, as shown by the arrows. To implement the desired permissions, we leave the Global Configuration blank (Not Set) for all three groups. Similarly, in the Article Manager and Assignments Category, we leave the Create permission to Inherit for all the groups. As shown in the diagram, this means that these groups do not have Create permission for articles in general or for articles in the Assignments group.

To sum up so far, we have not set any special permissions to get to this point. Now, in the History Assignments category permissions screen, we set the Create permission to Allow for the History Teachers group. This setting overrides the Soft (Implicit) Deny that we had by default and gives members of this group permission to create content (articles and child categories) for this category. This Allow setting also is inherited by the Assistant History Teachers group.

Next, we need to grant History Teachers the Edit State permission while denying this permission to Assistant History Teachers. This is done as shown in the diagram below.

This configuration is the same as the one above except that this time we set the Edit State permission in the History Assignments category to Deny for the Assistant History Teachers group. This means that Assistant History Teachers will not be able to Publish or Unpublish articles in this category.

Note that this was accomplished by setting just two permissions in the History Assignments category: Allow for the History Teachers group and Deny for the Assistant History Teachers group.

ACL Action Permission Examples

Here are some examples of how you might set up the ACL for some specific situations.

Back-end Article Administrator

Problème :

We want to create a group called "Article Administrator" with back-end permissions only for articles and not for any other back-end menu options. Members of this group should be able to use all of the features of the article manager, including setting article permissions.

Solution :

  1. Create a new group called Article Administrator and make its parent group Public, as shown below. Because its parent group is Public, it won't have any permissions by default.
  2. In Users → Access Levels, edit the Special Access level to add the new group. That way they can get access to the back end menu items and modules (This assumes that the modules for the admin menu and quickicons have the Special Access level assigned to them, which is the default.) By default, the back-end menu items and modules are set to Special access, so if you forget to add the new group to the Special access level, you won't see any modules or menu items when you log in as a user of the new group.
  3. In Site → Global Configuration → Permissions, click on the Article Administrator group and change the permissions to Allowed for the following actions: Admin Login, Create, Delete, Edit, Edit State, and Edit Own. The screen below shows what will show before you press Save. After you save, the Calculated Permissions should show as shown below. Note that the permission for the Access Component is Inherited, which translates to Not Allowed. This is important. This means that this group will only be able to access components if we give the group "Allowed" permission for Access Component. So we only have to change the one component we want to give them access to and don't have to change any settings for the components where we don't want them to have access. If we had a case where we wanted to give a group access to everything except for one component, we could set the default to Allowed and then set the one component to Denied. Also note that we did not give the group Site Login permission, so users in this group will not be able to log into the front end. (If we wanted to allow that, we would just change the permission to Allowed for Site Login.)
  4. In Article Manager → Options → Permissions, change permissions to Allowed for this group for the Access Component action, as shown below. All of the other desired permissions are inherited.

That's all you need to do. Members of this group can login to the back end and do everything in Article Manager but can't do anything else in the back end. For example, the screen below shows what a user in the Article Manager will see when they login to the back end.

ACL View Access Levels Examples

A basic concept of using Access Levels is that all items with the same Access will be viewable by the same group of users. In other words, if two items have the same Access, you can't have one viewable by one user and not viewable by another user. On the other hand, it is easy to have one Group view any number of items with different Access levels.

Similarly, each Group has exactly the same combination of Access levels, but one User can be a member of more than one group. Depending on the situation, you may want to have users only in one Group or you may need to have a User in more than one Group.

This means that we may need to group our items so that items so that all items in a group have the same level of sensitivity. Here are some examples.

Exemple hiérarchique

In this example, Access levels are hierarchical, for example, like government security clearance codes. Say for example we have the following sets of classified documents: Classified, Secret, and Top Secret. Users have corresponding clearence codes. Users with Classified clearance can only see Classified documents and cannot see Secret or Top Secret. Users with Secret clearance can see Classified and Secret documents but not Top Secret. Users with Top Secret can see all documents.

In this case, you would create three Access levels: Classified, Secret, and Top Secret and the same three Groups. Users would only be members of one group, as follows:

Utilisateur Groupe Niveaux d'accès
C1, C2, C3 Classé Classé
S1, S2, S3 Secret Classé, Secret
TS1, TS2, TS3 Top Secret Classified, Secret, Top Secret

In this case, all users are in exactly one group, but some groups have access to more than one Access Level of items. In other words, we have a one-to-one relationship between users and groups, but a one-to-many relationship between Groups and Access Levels.

Exemple pour une équipe de sécurité

Another possible use case is a set of non-hierarchical teams. Let's say we have three teams, T1, T2, and T3. Some users are only on one team, but others might be on two or more teams. In this case, we could set up our Access Levels and Groups by team. Documents for each team have the access level for that team, and the Group for the team has only the one access level. When a User is on more than one team, they get added to the group for each team, as follows:

Utilisateur Description Groupe Niveaux d'accès
U1 Membre de l'équipe 1 T1 T1
U2 Membre de l'équipe 2 T2 T2
U3 Membre de l'équipe 3 T3 T3
U1-2 Membre des équipes 1 et 2 T1, T2 T1, T2
U1-3 Membre des équipes 1 et 3 T1, T3 T1, T3
U1-2-3 Membre des équipes 1, 2 et 3 T1,T2, T3 T1, T2, T3


Exemple hybride

In a real-world situation, you might have a combination of these two arrangements. Say for example we have Managers and Staff. Staff can only see Staff documents and Managers can see Manager and Staff documents. Both types of users can be assigned to teams as well, in which case they can see all of the documents for that team. In addition, say that Managers can access some, but not all, team documents. Staff can only access team documents if they are members of that team.

In this example, we could set up the following Access Levels:

Niveaux d'accès Description Groupes
Manager Non-team manager documents Manager
Staff Non-team staff documents Manager, Staff
Equipe1 Sensitive Team1 documents (no access outside team) Equipe1
Team1-Manager Team1 documents that can be accessed by all managers Team1, Manager
Equipe2 Sensitive Team2 documents (no access outside team) Equipe2
Team2-Manager Team2 documents that can be accessed by all managers Team2, Manager

Ainsi, les utilisateurs peuvent être assignés à des groupes comme suit :

Type d'utilisateur Groupe
Dirigeant dans aucune des équipes Dirigeant
Staff on no teams Staff
Dirigeant de l'équipe 1 Dirigeant, Équipe 1
Équipier de l'équipe 1 Équipier, Équipe 1
Dirigeant des équipes 1 et 2 Dirigeant, Équipe 1, Équipe 2
Équipier des équipes 1 et 2 Équipier, Équipe 1, Équipe 2