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TWiki Access ControlRestricting read and write access to topics and webs, by Users and groups TWiki Access Control allows you restrict access to single topics and entire webs, by individual user and by user Groups. Access control, combined with TWikiUserAuthentication, lets you easily create and manage an extremely flexible, fine-grained privilege system. Tip: TWiki:TWiki.TWikiAccessControlSupplement on TWiki.org has additional documentation on access control.
An Important Control ConsiderationOpen, freeform editing is the essence of WikiCulture - what makes TWiki different and often more effective than other collaboration tools. For that reason, it is strongly recommended that decisions to restrict read or write access to a web or a topic are made with great care - the more restrictions, the less Wiki in the mix. Experience shows that unrestricted write access works very well because:
Permissions settings of the webs on this TWiki site
Authentication vs. Access ControlAuthentication: Identifies who a user is based on a login procedure. See TWikiUserAuthentication. Access control: Restrict access to content based on users and groups once a user is identified.Users and GroupsAccess control is based on the familiar concept of Users and Groups. Users are defined by their WikiNames. They can then be organized in unlimited combinations by inclusion in one or more user Groups. For convenience, Groups can also be included in other Groups.Managing UsersA user can create an account in TWikiRegistration. The following actions are performed:
Managing GroupsGroups are defined by group topics located in theMain web, such as the TWikiAdminGroup. To create a new group, visit TWikiGroups and enter the name of the new group ending in Group into the "new group" form field. This will create a new group topic with two important settings:
 Note: TWiki has strict formatting rules. Make sure you have three spaces, an asterisk, and an extra space in front of any access control rule.
The Super Admin GroupBy mistyping a user or group name in the settings, it's possible to lock a topic so that no-one can edit it from a browser. To avoid this, add the WikiNames of registered administrators to the super admin group topic calledTWikiAdminGroup. The name of this topic is defined by the {SuperAdminGroup} configure setting. Example group setting:
Restricting AccessYou can define who is allowed to read or write to a web or a topic. Note that some plugins may not respect access permissions.
Controlling access to a WebYou can define restrictions on who is allowed to view a TWiki web. You can restrict access to certain webs to selected Users and Groups, by:
Controlling access to a Topic
Controlling access to AttachmentsAttachments are referred to directly, and are not normally indirected via TWiki scripts. This means that the above instructions for access control will not apply to attachments. It is possible that someone may inadvertently publicise a URL that they expected to be access-controlled. The easiest way to apply the same access control rules for attachments as apply to topics is to use the Apachemod_rewrite module, and configure your webserver to redirect accesses to attachments to the TWiki viewfile script. For example,
ScriptAlias /twiki/bin/ /filesystem/path/to/twiki/bin/
Alias /twiki/pub/ /filesystem/path/to/twiki/pub/
RewriteEngine on
RewriteCond %{REQUEST_URI} !^/+twiki/+pub/+TWiki/+.+
RewriteRule ^/+twiki/+pub/+([^/]+)/+((([^/]+)/+)+)(.+) /twiki/bin/viewfile/$1/$4?filename=$5 [L,PT]
That way all the controls that apply to the topic also apply to attachments to the topic. Other types of webserver have similar support.
Note: Images embedded in topics will load much slower since each image will be delivered by the viewfile script.
Controlling who can create top-level websTop level webs are a special case, because they don't have a parent web with a WebPreferences. So there has to be a special control just for the root level.
ROOTCHANGE access to rename an existing top-level web. You just need WEBCHANGE in the web itself.
How TWiki evaluates ALLOW/DENY settingsWhen deciding whether to grant access, TWiki evaluates the following rules in order (read from the top of the list; if the logic arrives at PERMITTED or DENIED that applies immediately and no more rules are applied). You need to read the rules bearing in mind that VIEW and CHANGE access may be granted/denied separately.
Access Control quick recipesObfuscating WebsAnother way of hiding webs is to keep them hidden by not publishing the URL and by preventing theall webs search option from accessing obfuscated webs. Do so by enabling the NOSEARCHALL variable in WebPreferences:
Note: Obfuscating a web without view access control is very insecure, as anyone who knows the URL can access the web.
Authenticate all Webs and Restrict Selected WebsUse the following setup to authenticate users for topic viewing in all webs and to restrict access to selected webs. Requires TWikiUserAuthentication to be enabled.
Authenticate and Restrict Selected Webs OnlyUse the following setup to provide unrestricted viewing access to open webs, with authentication only on selected webs. Requires TWikiUserAuthentication to be enabled.
Hide Control Settings Tip: To hide access control settings from normal browser viewing, you can put them into the topic-local settings. You can access those settings via the "More" screen, as explained in TWikiVariables.
Alternatively, place them in HTML comment markers, but this exposes the access setting during ordinary editing.
Related Topics: AdminDocumentationCategory, TWikiUserAuthentication, TWiki:TWiki.TWikiAccessControlSupplement -- Contributors: TWiki:Main.PeterThoeny, TWiki:Main.MikeMannix, TWiki:Main.CrawfordCurrie |
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