silverstripe-framework/docs/en/reference/member.md

# Member

## Introduction

The [api:Member] class is used to represent user accounts on a SilverStripe site (including newsletter recipients).
 
## Testing For Logged In Users

The [api:Member] class comes with 2 static methods for getting information about the current logged in user.

**Member::currentUserID()**

Retrieves the ID (int) of the current logged in member.  Returns *0* if user is not logged in.  Much lighter than the
next method for testing if you just need to test.

	:::php
	// Is a member logged in?
	if( Member::currentUserID() ) {
		// Yes!
	} else {
		// No!
	}


**Member::currentUser()**

Returns the full *Member* Object for the current user, returns *null* if user is not logged in.

	:::php
	if( $member = Member::currentUser() ) {
		// Work with $member
	} else {
		// Do non-member stuff
	}



## Subclassing

<div class="warning" markdown="1">
This is the least desirable way of extending the [api:Member] class. It's better to use [api:DataObjectDecorator]
(see below).
</div>

You can defined subclasses of [api:Member] to add extra fields or functionality to the built-in membership system.

	:::php
	class MyMember extends Member {
		static $db = array(
			"Age" => "Int",
			"Address" => "Text",
		);
	}


To ensure that all new members are created using this class, put a call to [api:Object::useCustomClass()] in
(project)/_config.php:

	:::php
	Object::useCustomClass("Member", "MyMember");

Note that if you want to look this class-name up, you can call Object::getCustomClass("Member")

## Overloading getCMSFields()

If you overload the built-in function getCMSFields(), then you can change the form that is used to view & edit member
details in the newsletter system.  This function returns a [api:FieldSet] object.  You should generally start by calling
parent::getCMSFields() and manipulate the [api:FieldSet] from there.

	:::php
	function getCMSFields() {
		$fields = parent::getCMSFields();
		$fields->insertBefore(new TextField("Age"), "HTMLEmail");
		$fields->removeByName("JobTitle");
		$fields->removeByName("Organisation");
		return $fields;
	}


## Extending Member or DataObject?

Basic rule: Class [api:Member] should just be extended for entities who have some kind of login.
If you have different types of [api:Member]s in the system, you have to make sure that those with login-capabilities have
unique email-addresses (as this is used for login-credentials). 
For persons without login-capabilities (e.g. for an address-database), you shouldn't extend [api:Member] to avoid conflicts
with the Member-database. This enables us to have a different subclass of [api:Member] for an email-address with login-data,
and another subclass for the same email-address in the address-database.

## Member Role Decorator

Using inheritance to add extra behaviour or data fields to a member is limiting, because you can only inherit from 1
class.  A better way is to use role decorators to add this behaviour.

	:::php
	DataObject::add_extension('Member', 'ForumRole');
	// OR
	Member::add_role('ForumRole');

A role decorator is simply a subclass of [api:DataObjectDecorator] that is designed to be used to add behaviour to [api:Member]. 
The roles affect the entire class - all members will get the additional behaviour.  However, if you want to restrict
things, you should add appropriate [api:Permission::checkMember()] calls to the role's methods.

	:::php
	class ForumRole extends DataObjectDecorator {
	  /**
	
	   * Modify the field set to be displayed in the CMS detail pop-up
	   */
	  function updateCMSFields(FieldSet $currentFields) {
	    // Only show the additional fields on an appropriate kind of use 
	    if(Permission::checkMember($this->owner->ID, "VIEW_FORUM")) {
	      // Edit the fieldset passed, adding or removing fields as necessary
	    }
	  }
	
	  function extraStatics() {
	    // Return an array containing keys 'db', 'has_one', 'many_many', 'belongs_many_many',
	  }
	
	  function somethingElse() {
	    // You can add any other methods you like, which you can call directly on the member object.
	  }
	}


## API Documentation

[api:Member]