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:DataExtension]`
(see below).
</div>

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

	:::php
	class MyMember extends Member {
		private 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 public 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:FieldList]` object.  You should generally start by calling
parent::getCMSFields() and manipulate the `[api:FieldList]` from there.

	:::php
	public 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 Extension

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 extensions to add this behaviour. Add the following to your
`[config.yml](/topics/configuration)`.

	:::yml
	Member:
	  extensions:
	    - MyMemberExtension

A role extension is simply a subclass of `[api:DataExtension]` 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 MyMemberExtension extends DataExtension {
	  /**
	
	   * Modify the field set to be displayed in the CMS detail pop-up
	   */
	  public function updateCMSFields(FieldList $currentFields) {
	    // Only show the additional fields on an appropriate kind of use 
	    if(Permission::checkMember($this->owner->ID, "VIEW_FORUM")) {
	      // Edit the FieldList passed, adding or removing fields as necessary
	    }
	  }
	
		// define additional properties
		private static $db = array(); 
		private static $has_one = array(); 
		private static $has_many = array(); 
		private static $many_many = array(); 
		private static $belongs_many_many = array(); 
	
	  public function somethingElse() {
	    // You can add any other methods you like, which you can call directly on the member object.
	  }
	}


## API Documentation

`[api:Member]`