Add method 'deleteUserById' and similar methods for email and username

README.md

@@ -58,6 +58,7 @@ Completely framework-agnostic and database-agnostic.
    * [Additional user information](#additional-user-information)
  * [Administration (managing users)](administration-managing-users)
    * [Creating new users](creating-new-users)
+   * [Deleting users](#deleting-users)
  * [Utilities](#utilities)
    * [Creating a random string](#creating-a-random-string)
    * [Creating a UUID v4 as per RFC 4122](#creating-a-uuid-v4-as-per-rfc-4122)
@@ -391,6 +392,42 @@ The username in the third parameter is optional. You can pass `null` there if yo
 
 If you want to enforce unique usernames, on the other hand, simply call `createUserWithUniqueUsername` instead of `createUser`, and be prepared to catch the `DuplicateUsernameException`.
 
+#### Deleting users
+
+```php
+try {
+    $auth->admin()->deleteUserById($_POST['id']);
+}
+catch (\Delight\Auth\UnknownIdException $e) {
+    // unknown ID
+}
+```
+
+or
+
+```php
+try {
+    $auth->admin()->deleteUserByEmail($_POST['email']);
+}
+catch (\Delight\Auth\InvalidEmailException $e) {
+    // unknown email address
+}
+```
+
+or
+
+```php
+try {
+    $auth->admin()->deleteUserByUsername($_POST['username']);
+}
+catch (\Delight\Auth\UnknownUsernameException $e) {
+    // unknown username
+}
+catch (\Delight\Auth\AmbiguousUsernameException $e) {
+    // ambiguous username
+}
+```
+
 ### Utilities
 
 #### Creating a random string

src/Administration.php

@@ -56,6 +56,61 @@ final class Administration extends UserManager {
 		return $this->createUserInternal(true, $email, $password, $username, null);
 	}
 
+	/**
+	 * Deletes the user with the specified ID
+	 *
+	 * This action cannot be undone
+	 *
+	 * @param int $id the ID of the user to delete
+	 * @throws UnknownIdException if no user with the specified ID has been found
+	 * @throws AuthError if an internal problem occurred (do *not* catch)
+	 */
+	public function deleteUserById($id) {
+		$numberOfDeletedUsers = $this->deleteUsersByColumnValue('id', (int) $id);
+
+		if ($numberOfDeletedUsers === 0) {
+			throw new UnknownIdException();
+		}
+	}
+
+	/**
+	 * Deletes the user with the specified email address
+	 *
+	 * This action cannot be undone
+	 *
+	 * @param string $email the email address of the user to delete
+	 * @throws InvalidEmailException if no user with the specified email address has been found
+	 * @throws AuthError if an internal problem occurred (do *not* catch)
+	 */
+	public function deleteUserByEmail($email) {
+		$email = self::validateEmailAddress($email);
+
+		$numberOfDeletedUsers = $this->deleteUsersByColumnValue('email', $email);
+
+		if ($numberOfDeletedUsers === 0) {
+			throw new InvalidEmailException();
+		}
+	}
+
+	/**
+	 * Deletes the user with the specified username
+	 *
+	 * This action cannot be undone
+	 *
+	 * @param string $username the username of the user to delete
+	 * @throws UnknownUsernameException if no user with the specified username has been found
+	 * @throws AmbiguousUsernameException if multiple users with the specified username have been found
+	 * @throws AuthError if an internal problem occurred (do *not* catch)
+	 */
+	public function deleteUserByUsername($username) {
+		$userData = $this->getUserDataByUsername(
+			trim($username),
+			[ 'id' ]
+		);
+
+		$this->deleteUsersByColumnValue('id', (int) $userData['id']);
+	}
+
 	protected function throttle($actionType, $customSelector = null) {}
 
 	/**

src/Exceptions.php

@@ -10,6 +10,8 @@ namespace Delight\Auth;
 
 class AuthException extends \Exception {}
 
+class UnknownIdException extends AuthException {}
+
 class InvalidEmailException extends AuthException {}
 
 class UnknownUsernameException extends AuthException {}