authhttp DokuWiki HTTP authentication plugin
       Copyright (c) 2013-2023 Pieter Hollants <pieter@hollants.com>
           Licensed under the GNU Public License (GPL) version 3


Last successfully tested: 2023-09-20 with PHP 8.0.30 and
                          DokuWiki 2023-04-04a "Jack Jackrum"


DESCRIPTION

This auth plugin is for you if you don't want your users to have to login
through the login form all the time when you have instead already configured
your webserver to perform some sort of authentication (eg. HTTP Basic or
NTLM authentication). In that case, the Webserver provides a user's
credentials to PHP scripts through the superglobal variables
$_SERVER['PHP_AUTH_USER'] and $_SERVER['PHP_AUTH_PW'].

Out of the box DokuWiki will already pick these up and pretend the user
supplied those through the login form. It will perform authentication using
the configured auth plugin (usually authplain) and, if successful, show the
user (and the admin) options depending on the auth plugin's capabilities.

This all works out as long as
- EITHER DokuWiki's auth plugin does NOT report capabilities such as "change
  login name", "change password", "add user", "edit user", "delete user"
  so that DokuWiki consequently does not expose these controls to the user
- OR the Webserver and DokuWiki's auth plugin use the SAME source for their
  authentication.

If the first condition is not true, ie. the plugin DOES provide the named
capabilities, the user could attempt to change his password through the
"User profile" function. The admin, through the "User manager", could also
change his login name, delete him or add him with a different login name.

Now if the second condition is ALSO not true, there can be inconsistencies
between the HTTP authentication (which might eg. use an old password) and
DokuWiki's auth plugin (which might have stored a new password somewhere
else), causing Single Sign-On to break and errors to be displayed.

Note that this is not a bug in DokuWiki - DokuWiki can't in any way know how
your Webserver's HTTP authentication has been set up.

For example, if you configure your Webserver to display the username/password
prompt but not to actually validate them, there is no problem at all since
DokuWiki (without this plugin) is the only entity doing actual authentication.
This might actually be a considerable setup since there is not much point in
authenticating twice. https://www.dokuwiki.org/tips:httpauth-passthru
describes this.

This plugin does it the other way round. It assumes that the web server already
did the authentication and essentially annuls DokuWiki's own authentication by
providing a minimalistic checkPass() method which does not really authenticate.
It merely checks that DokuWiki's idea of username/password equals the HTTP
authentication credentials which should always be the case (except if you did
not enable HTTP authentication in your Webserver).

Note however that DokuWiki expects information that HTTP authentication does
not provide and where the plugin, when used on its own, thus has to improvise:
- the user's real name: authhttp will simply return the user's login name here.
- the user's email address: authhttp makes one up by appending a configurable
  domain part to the user's login name. This will generate email addresses that
  will probably not work. There is not really a way around this, so you might
  want to disable email-related functions in DokuWiki.
- the user's groups: authhttp will simply put all users in DokuWiki's
  "defaultgroup". Users whose login names are listed in "specialusers" will
  also be reported to be member of "specialgroup". If you did not modify
  DokuWiki's "superuser" configuration setting default of "@admin", you should
  leave this setting at "admin" as well and put users supposed to be admins in
  "specialusers".

If these limitations are not acceptable, you might want to combine authhttp
with another plugin, authsplit (https://www.dokuwiki.org/plugin:authsplit).
authhttp comes with an action plugin that improves integration with authsplit:
- When authhttp is the primary auth plugin for authsplit, there could be the
  case that while users are known to authhttp, they aren't to the secondary auth
  plugin yet, so they'd have to register (unless authsplit's "autocreate_users"
  feature is used). In this scenario, the username for registration should match
  the HTTP authentication username. Also, the login form should be hidden
  because there is not much sense in offering a form-based login when HTTP
  authentication is used. authhttp's action plugin takes care of all that.
- When authhttp is used on its own, ie. without authsplit, users are ALWAYS
  logged in and "registered", so authhttp's action plugin won't have a visible
  effect.


INSTALLATION

Download the latest version from https://github.com/pief/authhttp/zipball/master
and rename the extracted directory to "authhttp", otherwise the plugin won't
work.

Please refer to http://www.dokuwiki.org/plugins for additional info
on how to install plugins in DokuWiki.


CONFIGURATION AND SETTINGS

- usernameregex: A regular expression specifying the actual user name part of
  the HTTP authentication login name (the string in $_SERVER['PHP_AUTH_USER']).
  Examples:
  .+           for UNIX/passwd environments (ie. user name = login name)
  ^[^@]+       for Kerberos environments with user@domain login names,
               uses everything before the @ character as user name
  \\[^\\]+$    for Windows domain environments with DOMAIN\USER login names,
               uses everything after the \ character as user name
- emaildomain: The domain to append to login names to generate email addresses.
- specialusers: The login names of users to be put in the special group. You
  can list multiple login names separated by Space.
- specialgroup: The name of the special group.

Note: when authhttp is used together with authsplit and authhttp is the primary
auth plugin for authsplit, the last three configuration settings above will
have no effect any longer due to the way authsplit works.


REFERENCES

Visit the DokuWiki plugin page at

  https://www.dokuwiki.org/plugin:authhttp

To follow development more closely, clone the GitHub repo at

  https://github.com/pief/authhttp.git


CREDITS

This plugin is based on ideas in the "ggauth" auth backend by Grant Gardner
<grant@lastweekend.com.au>. Grant has not been maintaining ggauth for
DokuWiki versions after "WeatherWax". Also, his "http" auth backend uses
trustExternal() which eg. does not support group memberships if used on
its own, ie. without the ggauth "split" auth backend.