How to change Drupal user password programmatically?

Question

We are going to deploy a Drupal site inside company's intranet. There is a requirement for user to reset password. We have a centralized password reset mechanism (for single sign on):

• user submits a password change request in system
• the request is sent to a password server
• the password server will reset the user's password in all systems with a new password
• the password server will send the new password to user's mobile phone via sms

Now we are going to add the Drupal site to all systems. Please suggest a way to change the Drupal's logon password by an external program (assume the system can run script on the Drupal host and edit Drupal MySQL database).

Answer 1

For Drupal 7 -- Hope this custom function code resolves change password for anonymous user.

function password_reset(){
    global $user;
    $hashthepass = 'password'; /* Your password value*/
    require_once DRUPAL_ROOT . '/' . variable_get('password_inc', 'includes/password.inc');
    $hashthepass = user_hash_password(trim($hashthepass));
    // Abort if the hashing failed and returned FALSE.
    if (!$hashthepass) {
      return FALSE;
    }
    else {
      db_update('users')
        ->fields(array(
          'pass' => $hashthepass
        ))
        ->condition('uid', $user->uid)       
        ->execute();
    }
 }

Answer 2

There are already many nice answers in here, but I believe I add the one which I found easy for me.

// ID of the user whose password you wish to change.
$uid = 1;

// Load the user account.
$account = user_load($uid);

// Load hashing libraries.
// You can use module_load_include() if you want to make it cleaner.
require_once DRUPAL_ROOT . '/' . variable_get('password_inc', 'includes/password.inc');

// Generate new password hash.
$password_hash = user_hash_password('enter-new-password-here');
if (!$password_hash) {
  // Password could not be hashed. Handle the error.
  exit('Password could not be hashed.');
}

$account->pass = $password_hash;
user_save($account);

Given everything is set up correctly, your user's password would be updated.

Note: If you have forgotten your root password, you can safely ignore the error handling, etc. Add these lines in index.php before menu_execute_active_handler(); and open any page to reset your password. Don't forget to remove the lines after you're done though!