Duplicate code is one of the most pungent code smells. A rule that is often used is to re-structure code once it is duplicated in three or more places.
Common duplication problems, and corresponding solutions are:
| 1 | <?php  | 
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| 17 | abstract class CMB2_REST_Controller extends WP_REST_Controller { | 
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| 18 | |||
| 19 | /**  | 
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| 20 | * The current request object  | 
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| 21 | * @var WP_REST_Request $request  | 
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| 22 | * @since 2.2.0  | 
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| 23 | */  | 
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| 24 | public $request;  | 
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| 25 | |||
| 26 | /**  | 
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| 27 | * The current server object  | 
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| 28 | * @var WP_REST_Server $server  | 
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| 29 | * @since 2.2.0  | 
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| 30 | */  | 
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| 31 | public $server;  | 
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| 32 | |||
| 33 | /**  | 
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| 34 | * Box object id  | 
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| 35 | * @var mixed  | 
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| 36 | * @since 2.2.0  | 
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| 37 | */  | 
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| 38 | public $object_id = null;  | 
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| 39 | |||
| 40 | /**  | 
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| 41 | * Box object type  | 
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| 42 | * @var string  | 
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| 43 | * @since 2.2.0  | 
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| 44 | */  | 
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| 45 | public $object_type = '';  | 
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| 46 | |||
| 47 | /**  | 
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| 48 | * The initial route  | 
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| 49 | * @var string  | 
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| 50 | * @since 2.2.0  | 
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| 51 | */  | 
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| 52 | protected static $route = '';  | 
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| 53 | |||
| 54 | /**  | 
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| 55 | * Defines which endpoint the initial request is.  | 
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| 56 | * @var string $request_type  | 
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| 57 | * @since 2.2.0  | 
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| 58 | */  | 
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| 59 | protected static $request_type = '';  | 
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| 60 | |||
| 61 | /**  | 
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| 62 | * Constructor  | 
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| 63 | * @since 2.2.0  | 
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| 64 | */  | 
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| 65 | 	public function __construct( WP_REST_Server $wp_rest_server ) { | 
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| 68 | |||
| 69 | /**  | 
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| 70 | * Check if a given request has access to a field or box.  | 
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| 71 | * By default, no special permissions needed, but filtering return value.  | 
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| 72 | *  | 
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| 73 | * @since 2.2.0  | 
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| 74 | *  | 
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| 75 | * @param WP_REST_Request $request Full details about the request.  | 
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| 76 | * @return bool  | 
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| 77 | */  | 
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| 78 | 	public function get_item_permissions_check( $request ) { | 
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| 91 | |||
| 92 | /**  | 
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| 93 | * Prepare a CMB2 object for serialization  | 
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| 94 | *  | 
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| 95 | * @since 2.2.0  | 
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| 96 | *  | 
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| 97 | * @param mixed $data  | 
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| 98 | * @return array $data  | 
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| 99 | */  | 
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| 100 | 	public function prepare_item( $post ) { | 
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| 103 | |||
| 104 | /**  | 
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| 105 | * Output buffers a callback and returns the results.  | 
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| 106 | *  | 
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| 107 | * @since 2.2.0  | 
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| 108 | *  | 
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| 109 | * @param mixed $cb Callable function/method.  | 
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| 110 | * @return mixed Results of output buffer after calling function/method.  | 
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| 111 | */  | 
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| 112 | 	public function get_cb_results( $cb ) { | 
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| 120 | |||
| 121 | /**  | 
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| 122 | * Prepare a CMB2 object for serialization  | 
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| 123 | *  | 
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| 124 | * @since 2.2.0  | 
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| 125 | *  | 
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| 126 | * @param mixed $data  | 
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| 127 | * @param WP_REST_Request $request Request object  | 
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| 128 | * @return array $data  | 
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| 129 | */  | 
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| 130 | 	public function prepare_item_for_response( $data, $request = null ) { | 
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| 144 | |||
| 145 | View Code Duplication | 	protected function initiate_rest_read_box( $request, $request_type ) { | 
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| 152 | |||
| 153 | View Code Duplication | 	protected function initiate_rest_write_box( $request, $request_type ) { | 
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| 160 | |||
| 161 | 	protected function initiate_rest_box( $request, $request_type ) { | 
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| 170 | |||
| 171 | 	public function initiate_request( $request, $request_type ) { | 
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| 188 | |||
| 189 | 	public static function get_intial_request_type() { | 
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| 192 | |||
| 193 | 	public static function get_intial_route() { | 
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| 196 | |||
| 197 | /**  | 
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| 198 | * Get CMB2 fields schema, conforming to JSON Schema  | 
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| 199 | *  | 
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| 200 | * @since 2.2.0  | 
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| 201 | *  | 
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| 202 | * @return array  | 
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| 203 | */  | 
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| 204 | 	public function get_item_schema() { | 
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| 230 | |||
| 231 | /**  | 
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| 232 | * Return an array of contextual links for endpoint/object  | 
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| 233 | * @link http://v2.wp-api.org/extending/linking/  | 
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| 234 | * @link http://www.iana.org/assignments/link-relations/link-relations.xhtml  | 
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| 235 | *  | 
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| 236 | * @since 2.2.0  | 
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| 237 | *  | 
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| 238 | * @param mixed $object Object to build links from.  | 
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| 239 | *  | 
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| 240 | * @return array Array of links  | 
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| 241 | */  | 
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| 242 | abstract protected function prepare_links( $object );  | 
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| 243 | |||
| 244 | }  | 
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| 245 | 
You can fix this by adding a namespace to your class:
When choosing a vendor namespace, try to pick something that is not too generic to avoid conflicts with other libraries.