---+ Package =TWiki::Users::Password=

Base class of all password handlers. Default behaviour is no passwords,
so anyone can be anyone they like.

The methods of this class should be overridded by subclasses that want
to implement other password handling methods.


%TOC%

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

Constructs a new password handler of this type, referring to $session
for any required TWiki services.



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



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

returns true if the password database is not currently modifyable
also needs to call
$this->{session}->enter_context('passwords_modifyable');
if you want to be able to use the existing TWikiUserMappingContrib ChangePassword topics



---++ ObjectMethod *fetchPass* <tt>($login) -> $passwordE</tt>

Implements TWiki::Password

Returns encrypted password if succeeds.
Returns 0 if login is invalid.
Returns undef otherwise.



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

Finds if the password is valid for the given user.

Returns 1 on success, undef on failure.



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

Delete the users entry.



---++ ObjectMethod *setPassword* <tt>($login,$newPassU,$oldPassU,$mcp) -> $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.

If $mcp is true, the "must change password" flag is set

Otherwise returns 1 on success, undef on failure.



---++ encrypt( $login, $passwordU, $fresh ) -> $passwordE

Will return an encrypted password. Repeated calls
to encrypt with the same login/passU will return the same passE.

However if the passU is changed, and subsequently changed _back_
to the old login/passU pair, then the old passE is no longer valid.

If $fresh is true, then a new password not based on any pre-existing
salt will be used. Set this if you are generating a completely
new password.


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

Return any error raised by the last method call, or undef if the last
method call succeeded.



---++ ObjectMethod *isManagingEmails* <tt>() -> $boolean</tt>
Determines if this manager can store and retrieve emails. The password
manager is used in preference to the user mapping manager for storing
emails, on the basis that emails need to be secure, and the password
database is the most secure place. If a password manager does not
manage emails, then TWiki will fall back to using the user mapping
manager (which by default will store emails in user topics)

The default ('none') password manager does *not* manage emails.



---++ ObjectMethod *getEmails* <tt>($login) -> @emails</tt>
Fetch the email address(es) for the given login. Default
behaviour is to return an empty list. Called by Users.pm.
Only used if =isManagingEmails= -> =true=.



---++ ObjectMethod *setEmails* <tt>($login,@emails) -> $boolean</tt>
Set the email address(es) for the given login name. Returns true if
the emails were set successfully.
Default behaviour is a nop, which will result in the user mapping manager
taking over. Called by Users.pm.
Only used if =isManagingEmails= -> =true=.



---++ ObjectMethod *findUserByEmail* <tt>($email) -> \@users</tt>
Returns an array of login names that relate to a email address.
Defaut behaviour is a nop, which will result in the user mapping manager
being asked for its opinion. If subclass implementations return a value for
this, then the user mapping manager will *not* be asked.
Only used if =isManagingEmails= -> =true=.

Called by Users.pm.



---++ ObjectMethod *getMustChangePassword* <tt>($cUID) -> $flag</tt>

Returns 1 if the $cUID must change the password, else 0. Returns undef if $cUID not found.



---++ ObjectMethod *getUserData* <tt>($cUID) -> $dataRef</tt>

Return a reference to an array of hashes with user data, used to manage 
users. Each item is a hash with:

   * ={name}= - name of field, such as "email"
   * ={title}= - title of field, such as "E-mail"
   * ={value}= - value of field, such as "jimmy@example.com"
   * ={type}= - type of field: =text=, =password=, =checkbox=, =label=
   * ={size}= - size of field, such as =40=
   * ={note}= - comment note, if any

User management forms can be build dynamically from this data structure.
Each password manager may return a different set of fields.



---++ ObjectMethod *setUserData* <tt>($cUID,$dataRef)</tt>

Set the user data of a user. Same array of hashes as getUserData is 
assumed, although only ={name}= and ={value}= are used.

Sub classes should return an empty string if save action is OK, or an 
error string starting with 'Error: '.



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

returns true if the fetchUsers method is implemented and can return an iterator of users.
returns undef / nothing in this case, as we are unable to generate a list of users



---++ ObjectMethod *fetchUsers* <tt>() -> newTWiki::ListIterator(\@users)</tt>

returns a TWikiIterator of loginnames from the password source. If AllowLoginNames is false
this is used to remove the need for a TWikiUsers topic.