If your module needs to store data along with a Phorum user, you can make use of custom profile fields. These fields will be accessible from within the user data. E.g. if you create a custom profile field named "foobar", the value of that field will be stored in $user["foobar"] (so right next to the standard fields like $user["username"] and $user["email"]).

Creating custom profile fields can be done from the admin interface, under "Custom Profiles". It is also possible to let your module create the custom profile field fully automatical, by using the Custom Profile Fields API. If you choose to let the user of your module create the field by hand, then please include a thorough description of what configuration the user has to do. A lot of problems with modules that require manual configuration come from using wrong options for a custom profile field.

Using a separate field for each piece of data

When using a custom profile field for storing module information, you can use a separate field for each piece of data you want to store. The advantage of doing this, is that you can then use the option "Disable HTML" for the fields that you will be sending to the user's browser. In fields with this option enabled, characters that have a special meaning in HTML will be escaped after loading the user from the database. This prevents the field from being vulnerable to XSS attacks. Recommended settings for storing a single value in a profile field are:

Using a single field for storing a complex data structure

Instead, you can also create a single field for storing a complete array of information. Phorum will automatically take care of storing this information (serialized) in the database. You only should make sure that the custom profile field is large enough to store all the data and that HTML is allowed for the field, so the special PHP serialization code will not be broken by escaping special characters. When your module needs to store multiple fields, this is the preferred way. Recommended settings for storing a full array in a profile field are:

There are some hooks that send a full message structure to the hook functions. These can change the message structure before returning it to Phorum. An example is the hook "???". For these kind of hooks, you can update the custom profile field data in the user structure and be done with it. Here's an example of what this could look like in your hook function:

function phorum_mod_foo_user_save ($user)
{
    // Some data to store in the "mod_foo" custom field.
    $data = array(
        "user_id" => $user_id,
        "mod_foo" => array (
            "foodata" => "Some user data",
            "bardata" => "Some more user data"
        )
    );

    // Put the data in the user sructure.
    $user["mod_foo"] = $data;

    // Return the updated user. Phorum will take care of
    // storing the "mod_foo" array in the database.
    return $user;
} 

For storing data in the custom profile field, you can make use of the phorum_api_user_save() function. This function needs the user_id of the user and all fields that need to be updated. Below are two pieces of code which show how our example module might store data for a user (asuming $user_id is the id of the user that must be changed).

  // When using multiple fields "mod_foo_foodata" and "mod_foo_bardata".

  $userdata = array(
      "user_id"         => $user_id,
      "mod_foo_foodata" => "Some user data",
      "mod_foo_bardata" => "Some more user data"
  );
  phorum_api_user_save($userdata);

  // When using a single custom field "mod_foo" for this module:

  $userdata = array(
      "user_id" => $user_id,
      "mod_foo" => array (
          "foodata" => "Some user data",
          "bardata" => "Some more user data"
      )
  );
  phorum_api_user_save($userdata);