TWiki Access Control

TWiki allows you to define restrictions of who is allowed to view a TWiki web, make changes to topics or attach files.

• DENYTOPICCHANGE (in topic) overrides DENYWEBCHANGE (in WebPreferences)
• ALLOWTOPICCHANGE (in topic) overrides ALLOWWEBCHANGE (in WebPreferences)

Read Access Restriction for a Whole TWiki Web

You can define restrictions of who is allowed to view a TWiki web.

• • Leave the view script non authenticated in the .htaccess file.
  • Enable the $doRememberRemoteUser flag in wikicfg.pm as described in TWiki Authentication. TWiki will now remember the IP address of an authenticated user.
  • Copy the view script to viewauth (or better, create a symbolic link)

• • When a user accesses a web where you enabled view restriction, TWiki will redirect from the view script to the viewauth script once (this hapens only if the user has never edited a topic). Doing so will ask for authentication. The viewauth script shows the requested topic if the user could log on and if the user is authorized to see that web.
• If you enable view restriction for a web, it is recommended to restrict search "all webs" from searching this web. Enable this restriction with the NOSEARCHALL variable in its WebPreferences, like:
  • Set NOSEARCHALL = on

IMPORTANT NOTE: Think twice before restricting read or write access to a web or a topic, because an open system where everybody can contribute is the essence of the WikiCulture. Experience shows that unrestricted write access works very well because:

• A topic revision can be undone by a member of the TWikiAdminGroup in case needed.

• ALLOWTOPICCHANGE defines who is allowed to change the group topic; it is a comma delimited list of users and groups. You typically want to restrict that to the members of the group itself, so it should contain the name of the topic, i.e.
      * Set ALLOWTOPICCHANGE = Main.TWikiAdminGroup
  for the TWikiAdminGroup topic. (This is to prevent users not in the group from editing the topic and gaining unauthorized membership to the group.)

• DENYTOPICCHANGE (in topic) overrides DENYWEBCHANGE (in WebPreferences)
• ALLOWTOPICCHANGE (in topic) overrides ALLOWWEBCHANGE (in WebPreferences)

• Set ALLOWWEBVIEW = < list of users and groups >

Notes for read access restriction:

• Read access restriction only works if the view script is authenticated, that means that users need to log on also just to read topics. TWiki Installation has more on basic authentication based on the .htaccess file.
• There is a workaround if you prefer to to have unrestricted access to view topics located in normal webs, and to authenticate users only for webs where view restriction is enabled:
  • Leave the view script non authenticated in the .htaccess file.