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XAO-Web-1.04
River stage one • 2 direct dependents • 2 total dependents
/ XAO::DO::Web::IdentifyUser

NAME

XAO::DO::Web::IdentifyUser - class for user identification and verification

SYNOPSYS

Currently is only useful in XAO::Web site context.

DESCRIPTION

IdentifyUser class is used for user identification and verification purposes. In 'login' mode it logs a user in while in 'logout' mode, it logs a user out. In 'check' mode it determines the identification status of the user using cookies.

Possible user identification status are:

  • anonymous - user cannot be identified

  • identified - user has been identified

  • verified - user has recently been positively identified

The 'IdentifyUser' class takes the following parameters:

  • mode

    Indicates how 'IdentifyUser' will be used. Possible values are

    - check: (default) check the identification status
    - login: log user in
    - logout: Log current user out

  • anonymous.path

    Template to display if user has not been identified.

  • identified.path

    Template to display if user has been identified, but not verified.

  • verified.path

    Template to display if user has been identified.

  • hard_logout

    If 'true' in logout mode, this parameter not only unverifies the user, but erases identification cookies too. The default is to retain identified status.

  • stop

    Directive indicating that if a specified template is displayed, the remainder of the current template must not be displayed.

The 'IdentifyUser' class relies on some site configuration values. These values are available in the form of a reference to a hash obtained as follows:

 my $config=$page->siteconfig->get('identify_user');

where $page is a 'Page' object. The keys of such a hash correspond to the 'type' parameter of the 'IdentifyUser' class. An example of a $config hash with all required parameters is presented below:

 customer => { 
    list_uri            => '/Customers', 
    id_cookie           => 'id_customer',    
    id_cookie_expire    => 126230400,       # (seconds) optional,
                                            # default is 10 years
    user_prop           => 'email',         # optional, see below    
    pass_prop           => 'password', 
    pass_encrypt        =>  'md5',          # optional, see below
    vf_key_prop         => 'verify_key',    # optional, see below 
    vf_key_cookie       => 'key_customer',  # optional, see below
    vf_time_prop        => 'verify_time',   # time of last verification
    vf_expire_time      => '600',           # seconds
    cb_uri              => 'IdentifyUser/customer' # optional
 }
list_uri

URI of users list (see XAO::FS and XAO::DO::FS::List).

Name of cookie that IdentifyUser sets to identificate the user in the future

Expiration time for the identification cookie (default is 4 years).

user_prop

Name attribute of a user object. If there is no 'user_prop' parameter in the configuration it is assumed that user ID is the key for the given list.

An interesting capability is to specify name as a URI style path, for instance if a member has many alternative names that all can be used to log-in and these names are stored in a list called Nicknames on each member object, then the following might be used:

 user_prop => 'Nicknames/nickname'
pass_prop

Password attribute of user object.

pass_encrypt

Encryption method for the password. Available values are 'plaintext' (not encrypted at all, default) and 'md5' (MD5 one way hash encryption.

vf_key_prop

The purpose of two optional parameters 'vf_key_cookie' and 'vf_key_prop' is to limit verification to just one computer at a time. When these parameters are present in the configuration on login success 'IdentifyUser' object generates random key and store it into user's profile anf create a cookie named according to 'vf_key_cookie' with the value of the generated key.

Temporary verifiction key cookie.

vf_time_prop

Attribute of user object which stores the time of latest verified access.

vf_expire_time

Time period for which user remains verified.

Please note, that the cookie with the customer key will be set to expire in 10 years and actual expiration will only be checked using the content of 'vf_time_prop' field value. The reason for such behavior is that many (if not all) versions of Microsoft IE have what can be considered a serious bug -- they compare the cookie expiration time to the local time on the computer. And therefore if customer computer is accidentally set to some future date the cookie might expire immediately and prevent this customer from logging into the system at all. Most (if not all) versions of Netscape and Mozilla do not have this problem.

Therefore, when possible we do not trust customer's computer to measure time for us and do that ourselves.

cb_uri

URI of clipboard where IdentifyUser stores identification and verification information about user and makes it globally available.

EXAMPLE

Now, let us look at some examples that show how each mode works.

LOGIN MODE

 <%IdentifyUser mode="login"
   type="customer"
   username="<%CgiParam param="username" %>
   password="<%CgiParam param="password" %>
   anonymous.path="/bits/login.html"
   verified.path="/bits/thankyou.html"
 %>

LOGOUT MODE

 <%IdentifyUser mode="logout"
   type="customer"
   anonymous.path="/bits/thankyou.html"
   identified.path="/bits/thankyou.html"
   hard_logout="<%CgiParam param="hard_logout" %>"
 %>

CHECK MODE

 <%IdentifyUser mode="check"
   type="customer"
   anonymous.path="/bits/login.html"
   identified.path="/bits/order.html"
   verified.path="/bits/order.html"
 %>

METHODS

check_mode (%)

Checks operation mode and redirects to a method accordingly.

check ()

Checks identification/verification status of the user.

To determine identification status, first check clipboard to determine if there is such object present. If so, then that object identifies the user. If not, then check whether there is a identification cookie and if so, perform a search for object in database. If this search yields a positive result, the user's status is 'identified' and an attempt to verify user is made, otherwise the status is 'anonymous'.

Once identity is established, to determine verification status, first check the clipboard to determine if there is a 'verified' flag set. If so, then the user's status is 'verified'. If not, check whether the difference between the current time and the time of the latest visit is less than vf_expire_time property. If so, the user status considered 'verified', a new time is stored.

If optional 'vf_key_prop' and 'vf_key_cookie' parameters are present in the configuration then one additional check must be performed before changing status to 'verified' - the content of the key cookie and apropriate field in the user profile must match.

display_results ($$;$)

Displays template according to the given status. Third optinal parameter may include the content of 'ERRSTR'.

find_user ($;$)

Searches for the user in the list according to the configuration:

 my $user=$self->find_user($config,$username);
login ()

Logs in user. Saves current time to vf_time_prop database field. Generates pseudo unique key and saves it value to vf_key_prop (optional). Sets identification cookies.

login_check ()

A method that can be overriden in a derived object to check addition conditions for letting a user in. Get the following arguments as its input:

 name       => name of user object
 password   => password
 object     => reference to a database object containing user info
 type       => user type

This method is called after all standard checks - it is guaranteed that user object exists and password matches its database record.

Must return empty string on success or suggested error message on failure. That error message will be passed in ERRSTR argument to the templates.

logout ()

Logs out user. Resetting vf_time_prop database field and clearing identification cookie (for hard logout mode). Set user status to 'anonymous' (hard logout mode) or 'identified'.

EXPORTS

Nothing

AUTHOR

Copyright (c) 2001 XAO, Inc.

Andrew Maltsev <am@xao.com>, Marcos Alves <alves@xao.com>, Ilya Lityuga <ilya@boksoft.com>.

SEE ALSO

Recommended reading:

XAO::Web, XAO::DO::Web::Page, XAO::FS.