29.2.2. User authentication and access control

This section gives an overview of user authentication and how groups, roles and projects are used for access control to items.

Figure 29.3. User authentication and access control

User authentication and access control

Users and passwords

The UserData class holds information about users. We keep the passwords in a separate table and use proxies to avoid loading password data each time a user is loaded to minimize security risks. It is only if the password needs to be changed that the PasswordData object is loaded. The one-to-one mapping between user and password is controlled by the password class, but a cascade attribute on the user class makes sure that the password is deleted when a user is deleted.

Groups, roles, projects and permission template

The GroupData, RoleData and ProjectData classes holds information about groups, roles and projects respectively. A user may be a member of any number of groups, roles and/or projects. New users are automatically added as members of all groups and roles that has the default property set.

The membership in a project comes with an attached permission values. This is the highest permission the user has in the project. No matter what permission an item has been shared with the user will not get higher permission. Groups may be members of other groups and also in projects. A PermissionTemplateData is just a holder for permissions that users can use when sharing items. The template is never part of the actual permission control mechanism.

Group membership is always accounted for, but the core only allows one project at a time to be use, this is the active project. When a project is active new items that are created are automatically shared according to the settings for the project. There are two cases. If the project has a permission template, the new item is given the same permissions as the template has. If the project doesn't have a permission template, the new item is shared to the active project with the permission given by the autoPermission property. Note that in the first case the new item may or may not be shared to the active project depending on if the template is shared to the project or not.

Note that the permission template is only used (by the core) when creating new items. The permissions held by the template are copied and when the new item has been saved to the database there is no longer any reference back to the template that was used to create it. This means that changes to the template does not affect already existing items and that the template can be deleted without problems.


The KeyData class and it's subclasses ItemKeyData, ProjectKeyData and RoleKeyData, are used to store information about access permissions to items. To get permission to manipulate an item a user must have access to a key giving that permission. There are three types of keys:


Is used to give a user or group access to a specific item. The item must be a ShareableData item. The permissions are usually set by the owner of the item. Once created an item key cannot be changed. This allows the core to reuse a key if the permissions match exactly, ie. for a given set of users/groups/permissions there can be only one item key object.


Is used to give members of a project access to a specific item. The item must be a ShareableData item. Once created a project key cannot be changed. This allows the core to reuse a key if the permissions match exactly, ie. for a given set of projects/permissions there can be only one project key object.


Is used to give a user access to all items of a specific type, ie. READ all SAMPLES. The installation will make sure that there already exists a role key for each type of item, and it is not possible to add new or delete existing keys. Unlike the other two types this key can be modified.

A role key is also used to assign permissions to plug-ins. If a plug-in has been specified to use permissions the default is to deny everything. The mapping to the role key is used to grant permissions to the plugin. The granted value gives the plugin access to all items of the related item type regardless of if the user that is running the plug-in has the permission or not. The denied values denies access to all items of the related item type even if the logged in user has the permission. Permissions that are not granted nor denied are checked against the logged in users regular permissions. Permissions to items that are not linked are always denied.


The permission property appearing in many classes is an integer values describing the permission:

Value Permission
1 Read
3 Use
7 Restricted write
15 Write
31 Delete
47 (=32+15) Set owner
79 (=64+15) Set permissions
128 Create
256 Denied

The values are constructed so that READ -> USE -> RESTRICTED_WRITE -> WRITE -> DELETE are chained in the sense that a higher permission always implies the lower permissions also. The SET_OWNER and SET_PERMISSION both implies WRITE permission. The DENIED permission is only valid for role keys, and if specified it overrides all other permissions.

When combining permission for a single item the permission codes for the different paths are OR-ed together. For example a user has a role key with READ permission for SAMPLES, but also an item key with USE permission for a specific sample. Of course, the resulting permission for that sample is USE. For other samples the resulting permission is READ.

If the user is also a member of a project which has WRITE permission for the same sample, the user will have WRITE permission when working with that project.

The RESTRICTED_WRITE permission is in most cases the same as the WRITE permission. So far the RESTRICTED_WRITE permission is only given to users to their own UserData object so they can change their address and other contact information, but not quota, expiration date and other administrative information.