User Object Framework

This plugin creates a user-object relationship table and a user-object relationship metadata
table. Relationships between a user (logged-in or IP) are created and added to the relationship
table; metadata (ex. votes, flags, and ratings) is attached to that particular relationship
via the metadata table. This is a framework; it is intended for use in voting, flagging,
and similar user applications where a user-affiliated metadata is attached to an object.
Supported object tables include wp_posts, wp_comments, wp_users, and wp_bp_activity.

Functions are provided to add/get/delete relationships; metadata is added via the native WordPress
metadata-handling functions.
Functions provided by this framework include:

• ucc_uof_object_reference() returns an array of object-integer assignments. Use this to look up the
  appropriate value for $object_ref based on the object table (wp_posts, wp_comments, wp_users,
  wp_bp_activity are currently supported) to which you are attaching a user relationship.
• ucc_uof_add_relationship( $user_id = 0, $user_ip = 0, $object_id, $object_ref ) adds a relationship
  to the relationship table if none exists and returns the relationship id for that user/object pairing.
• ucc_uof_delete_relationship( $user_id = 0, $user_ip = 0, $object_id, $object_ref ) will delete a
  relationship if there are no metadata entries left for that relationship.
• ucc_uof_get_relationship() returns the relationship id for that user/object pairing.
• ucc_uof_get_user_id() returns the current user id or 0 if not logged in.
• ucc_uof_get_user_ip() returns 0 if the current user is logged in, or an ip2long() if anonymous.

Example code:

// Create or get the user-object relationship.
$relationship = ucc_uof_get_relationship( $user_id, $user_ip, $object_id, $object_ref );
if ( empty( $relationship ) )
    $relationship = ucc_uof_add_relationship( $user_id, $user_ip, $object_id, $object_ref );

// Add user_object_meta.
if ( $mode == 'delete' )
    delete_metadata( 'uof_user_object', $relationship, '_your_meta_key' );
else
    update_metadata( 'uof_user_object', $relationship, '_your_meta_key', 'your meta key value' );