---+ Package =TWiki::Users=

This package provides services for the lookup and manipulation of login and
wiki names of users, and their authentication.

It is a Facade that presents a common interface to the User Mapping
and Password modules. The rest of the core should *only* use the methods
of this package, and should *never* call the mapping or password managers
directly.

TWiki uses the concept of a _login name_ which is used to authenticate a
user. A login name maps to a _wiki name_ that is used to identify the user
for display. Each login name is unique to a single user, though several
login names may map to the same wiki name.

Using this module (and the associated plug-in user mapper) TWiki supports
the concept of _groups_. Groups are sets of login names that are treated
equally for the purposes of access control. Group names do not have to be
wiki names, though it is helpful for display if they are.

Internally in the code TWiki uses something referred to as a _canonical user
id_ or just _user id_. The user id is also used externally to uniquely identify
the user when (for example) recording topic histories. The user id is *usually*
just the login name, but it doesn't need to be. It just has to be a unique
7-bit alphanumeric and underscore string that can be mapped to/from login
and wiki names by the user mapper.

The canonical user id should *never* be seen by a user. On the other hand,
core code should never use anything *but* a canonical user id to refer
to a user.

*Terminology*
   * A *login name* is the name used to log in to TWiki. Each login name is
     assumed to be unique to a human. The Password module is responsible for
     authenticating and manipulating login names.
   * A *canonical user id* is an internal TWiki representation of a user. Each
     canonical user id maps 1:1 to a login name.
   * A *wikiname* is how a user is displayed. Many user ids may map to a
     single wikiname. The user mapping module is responsible for mapping
     the user id to a wikiname.
   * A *group id* represents a group of users and other groups.
     The user mapping module is responsible for mapping from a group id to
     a list of canonical user ids for the users in that group.
   * An *email* is an email address asscoiated with a *login name*. A single
     login name may have many emails.
	 
*NOTE:* 
   * wherever the code references $user, its a canonical_id
   * wherever the code references $group, its a group_name


%TOC%

---++ ClassMethod *new* <tt>($session)</tt>

Construct the user management object



---++ ObjectMethod *finish* <tt>()</tt>
Break circular references.



---++ ObjectMethod *loginTemplateName* <tt>() -> templateFile</tt>

allows UserMappings to come with customised login screens - that should preffereably only over-ride the UI function



---++ ObjectMethod *supportsRegistration* <tt>() -> boolean</tt>

#return 1 if the  main UserMapper supports registration (ie can create new users)



---++ ObjectMethod *initialiseUser* <tt>($login) -> cUID</tt>





---++ randomPassword()
Static function that returns a random password


---++ ObjectMethod *addUser* <tt>($login,$wikiname,$password,$emails) -> $user</tt>

   * =$login= - user login name. If =undef=, =$wikiname= will be used as the login name.
   * =$wikiname= - user wikiname. If =undef=, the user mapper will be asked
     to provide it.
   * =$password= - password. If undef, a password will be generated.

Add a new TWiki user identity, returning the canonical user id for the new
user. Used ONLY for user registration.

The user is added to the password system (if there is one, and if it accepts
changes). If the user already exists in the password system, then the password
is checked and an exception thrown if it doesn't match. If there is no
existing user, and no password is given, a random password is generated.

$login can be undef; $wikiname must always have a value.

The return value is the canonical user id that is used
by TWiki to identify the user.



---++ ObjectMethod *getCanonicalUserID* <tt>($login) -> $user</tt>

Works out the unique TWiki identifier for the user who logs in with the
given login. The canonical user ID is an alphanumeric string that is unique
to the login name, and can be mapped back to a login name and the
corresponding wiki name using the methods of this class.

returns undef if the user does not exist.



---++ ObjectMethod *findUserByWikiName* <tt>($wn) -> \@users</tt>
   * =$wn= - wikiname to look up
Return a list of canonical user names for the users that have this wikiname.
Since a single wikiname might be used by multiple login ids, we need a list.

If $wn is the name of a group, the group will *not* be expanded.



---++ ObjectMethod *findUserByEmail* <tt>($email) -> \@users</tt>
   * =$email= - email address to look up
Return a list of canonical user names for the users that have this email
registered with the password manager or the user mapping manager.

The password manager is asked first for whether it maps emails.
If it doesn't, then the user mapping manager is asked instead.



---++ ObjectMethod *getEmails* <tt>($user) -> @emailAddress</tt>

If this is a user, return their email addresses. If it is a group,
return the addresses of everyone in the group.

The password manager and user mapping manager are both consulted for emails
for each user (where they are actually found is implementation defined).

Duplicates are removed from the list.



---++ ObjectMethod *setEmails* <tt>($user,@emails)</tt>

Set the email address(es) for the given user.
The password manager is tried first, and if it doesn't want to know the
user mapping manager is tried.



---++ ObjectMethod *isAdmin* <tt>($cUID) -> $boolean</tt>

True if the user is an admin
   * is $TWiki::cfg{SuperAdminGroup}
   * is a member of the $TWiki::cfg{SuperAdminGroup}



---++ ObjectMethod *isInList* <tt>($user,$list) -> $boolean</tt>

Return true if $user is in a list of user *wikinames* and group ids.

$list is a comma-separated wikiname and group list. The list may contain the
conventional web specifiers (which are ignored).



---++ ObjectMethod *getLoginName* <tt>($cUID) -> $string</tt>

Get the login name of a user.



---++ ObjectMethod *getWikiName* <tt>($cUID) -> $wikiName</tt>

Get the wikiname to display for a canonical user identifier.



---++ ObjectMethod *webDotWikiName* <tt>($user) -> $webDotWiki</tt>

Return the fully qualified wikiname of the user



---++ ObjectMethod *userExists* <tt>($cUID) -> $boolean</tt>

Determine if the user already exists or not. A user exists if they are
known to to the user mapper.



---++ ObjectMethod *eachUser* <tt>() -> $iterator</tt>

Get an iterator over the list of all the registered users *not* including
groups.

list of canonical_ids ???

Use it as follows:
<verbatim>
    my $iterator = $umm->eachUser();
    while ($iterator->hasNext()) {
        my $user = $iterator->next();
        ...
    }
</verbatim>



---++ ObjectMethod *eachGroup* <tt>() -> $iterator</tt>

Get an iterator over the list of all the groups.



---++ ObjectMethod *eachGroupMember* <tt>($group) -> $iterator</tt>

Return a iterator of user ids that are members of this group.
Should only be called on groups.

Note that groups may be defined recursively, so a group may contain other
groups. This method should *only* return users i.e. all contained groups
should be fully expanded.



---++ ObjectMethod *isGroup* <tt>($user) -> boolean</tt>

Establish if a user refers to a group or not.

The default implementation is to check if the wikiname of the user ends with
'Group'. Subclasses may override this behaviour to provide alternative
interpretations. The $TWiki::cfg{SuperAdminGroup} is recognized as a
group no matter what it's name is.

QUESTION: is the $user parameter here a string, or a canonical_id??



---++ ObjectMethod *isInGroup* <tt>($user,$group) -> $boolean</tt>

Test if user is in the given group.



---++ ObjectMethod *eachMembership* <tt>($user) -> $iterator</tt>

Return an iterator over the groups that $user (an object)
is a member of.



---++ ObjectMethod *checkPassword* <tt>($userName,$passwordU) -> $boolean</tt>

Finds if the password is valid for the given user.

Returns 1 on success, undef on failure.

TODO: add special check for BaseMapping admin user's login, and if its there (and we're in sudo_context?) use that..



---++ ObjectMethod *setPassword* <tt>($user,$newPassU,$oldPassU) -> $boolean</tt>

If the $oldPassU matches matches the user's password, then it will
replace it with $newPassU.

If $oldPassU is not correct and not 1, will return 0.

If $oldPassU is 1, will force the change irrespective of
the existing password, adding the user if necessary.

Otherwise returns 1 on success, undef on failure.



---++ ObjectMethod *passwordError* <tt>() -> $string</tt>

returns a string indicating the error that happened in the password handlers
TODO: these delayed error's should be replaced with Exceptions.

returns undef if no error



---++ ObjectMethod *removeUser* <tt>($user) -> $boolean</tt>

Delete the users entry. Removes the user from the password
manager and user mapping manager. Does *not* remove their personal
topics, which may still be linked.



---++ ObjectMethod *ASSERT_IS_CANONICAL_USER_ID* <tt>($user_id) -> $boolean</tt>

used for debugging to ensure we are actually passing a canonical_id



---++ ObjectMethod *ASSERT_IS_USER_LOGIN_ID* <tt>($user_login) -> $boolean</tt>

used for debugging to ensure we are actually passing a user login



---++ ObjectMethod *ASSERT_IS_USER_DISPLAY_NAME* <tt>($user_display) -> $boolean</tt>

used for debugging to ensure we are actually passing a user display_name (commonly a WikiWord Name)


