Thoughts on bitweaver Database Permissions and Content Access Control

Created by: William Leibzon, Last modification: 29 Jan 2005 (23:42 UTC)

Current Problems

The table's primary key is permissoin name itself which is often long text. Having primary key that is often referenced to be non-numerical value is considered a bad design and slows database access as well as increases size of database tables and indices. So it is best to untroduce new numerical id for each permission.

In order to not make it necessary to lookup the id for each access to page and for use of the permission name in php pages (where its all done by name), it might be good to add php id and configurations file for each package that can be updated whenever permissions are added. Then php function will convert from real name to numerical id without requirying database access based on that configuration file.

Also it might be good idea to rename this table from user_permissions to tiki_permissions as in reality it represents tiki-specific information and not user-specific data

This table needs to be replaced to allow permissions control on per-content (rather then per object) and per group

Relevent Tables with Some Schema Changes

tiki_permissions (primary key is perm_id, unique constraint on perm_name):

This table is used to hold information about each permission

perm_id - integer - Numerical ID of the permission, assigned when package is added
perm_name - varchar - Actual name of the permission
perm_desc - varchar - Full description
level= - varchar - This is might have been better if it was called "permission type". It specifies appropriate control level needed to use this permission, typical values are "admin", "editors", "basic". This closely corresponds to what group is typically this permission assigned to.
package - varchar - Name of the package which uses this permission
maintainer_url - varchar - This is used to point to whoever supports use of this permission. Normally this would be "", but for custom permissions the value would be something else

users_groups (primary key is group_id):

This table holds information about each group

group_id - ingeger - Numeric id of the group
user_id - integer - This is an id of the user that added the group and can change it
is_default varchar(1) - not 100% sure but it seems to be a pointer to which group new users are added to. NOTE: If this is so, it has no place in users_group table as you might expect only one group to have this property, the actual default group_id should instead be entered in some general bitweaver config table like tiki_defaults.
group_name - varchar - This is the actual name of the group as seen by end-users
group_desc - varchar - Longer description of what kind of users are going to be in the group
access_question - varchar - Additional question to ask before granting user access as member of this group
access_answer - varchar - Expected answer to access question (i.e. password). Note that it might be good idea to have this be MD5 hash of actual answer

users_group_permissions_ (primary key is combination of group_id and perm_id)

This table has information on what kind of permissions does a group member has by default

group_id - integer - Which user
perm_id - integer - Which permission
value - varchar(1) - Unsure what this is for....


This table has information about each specific access type. Access is a grouping of one or more permissions as it applies to the content that certain group can use

perm_id - integer - what permission is in this access
group_id - integer -
content_id - integer -

Thoughts regarding "hidden" access.

Its been thought that it would be good idea to have special way to designate some page as hidden so that it does not show up on pages and that should be property of the access_type (is_hidden tag in access table). After thingking about it more, I believe this actually more closely corresponds to permission. In fact the permission should be "tiki_p_searchable_content" and represents that given user/group can in fact do searches for particular object and view it as part of the list of objects of its type. Normally this would be standard permission that is enabled (like tiki_p_view) but it might be disabled for some content or for some groups of users

Statements to be supported:

GROUP A has default View access on ALL Tiki Pages
GROUP B has View access on Tiki Page2 but not on Tiki Page 3
GROUP C has View and Search Access for Tiki Page2 and View only access on Tiki Page3 and password-protected View Access on Tiki Page 4


PHP id configuration file for each package?

by Jan Lindåker, 31 Jan 2005 (10:08 UTC)

I do not support the idea that there should be a special
php id file. It is better to have an Id - name mapping table, that is only accessed when permission are granted/revoked. In all other situation the numeric Id's
are used (and no extra DB hit is incurred).

In this way you can keep all information in the database and only get decreased in performance when fiddling with permission.

(Ther emigt be a reason to have a DB config script for each module that sets up permission, but that is a completely different story)

This discussion also applies to RSS id's and Menu Id's, which currently are numerical. It would be very convenient
to have textual, easy to remember names, here too and coding, decoding would only be done when the user is configuring these entitites.
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