Add users from SSO server database to Drupal

Question

I am trying to implement an SSO system for Drupal system. The detailed description of the scenario can be seen in "Understanding Drupal's session management and user authentication".

I did implement the authentication part, as per the using the suggestions provided (thanks to Pierre Buyle). Now, I have a requirement to add the users to Drupal database which are already present in SSO database.
The IT team of SSO will create a form which will post this values to a URL on the Drupal site.

This URL have to catch the request and create a user in Drupal. I'll be using the method user_save() to achieve this.

My questions are:

1. How do I create this URL in Drupal? (Thought of using hook_menu and use $items to create the URL, but I don't want it to be accessible to users except admin.
2. How could I read the data from that URL?

I'm not asking for the complete code. Just pointers to which hooks or methods should I use for the use cases would be enough.

Answer 1

IMHO, integration of different system through form POSting is at the hack level. To let external system inject data into Drupal, the Services module let you easily build HTTP REST API in Drupal. It comes out of the box with a user API that allow external system to easily create new Drupal users.

Off course, you can create your own page to receive POSTed data from a form build outside Drupal. You simply have to declare it through a hook_menu() implementation. For access control to the page, you can either use the 'access arguments' to restrict access with Drupal permission system. you can also use your own 'access callback' to implement your own access control logic (ie. for instance, using a secret token based access control).

Answer 2

Used hook_menu() to create an URL, and got the values which were POSTed on this URL (as per @Pierre 's suggestion)

function MYMODULE_menu() {
    $items['add-new-user'] = array (
        'title' => '',
        'type' => 'MENU_CALLBACK',
        'page callback' => 'MYMODULE_add_new_custom_user',
        'page arguments' => array($_POST),
        'access arguments' => array('access administration pages'), //Admin access only
    );
    return $items;
}

In the function to create user, used user_save() to save the user.

function MYMODULE_add_new_custom_user($post_value) {
    $account = new stdClass();
    $account->is_new = TRUE; //This is a new account
    $edit = array (     
        'roles' => array(
          //left empty because only needed to create authenticated users
        ),
        'administer_users' => FALSE,
        'name' => $post_values['username'],
        'mail' => $post_values['mail'],
        'status' => FALSE,   //newly created user would have STATUS as blocked.
        'notify' => 0,
        'timezone' => 'America/Chicago',
        'signature' => '',
        'picture' => '',
        'picture_delete' => '',
        'picture_upload' => '',
        'signature_format' => 'filtered_html',
        'pass' => $post_values['pass'],
        'init' => $post_values['mail'],     
    );

    $user_obj = user_save($account, $edit, 'account');
    if(isset($user_obj->uid)) { //as $user_obj will be an object of stdClass and not an array.
      //user created
    }
    else {
      //some error occurred, handled seperately;
      //user_save returns FALSE if saving a users returns any error. 
    }
}