WP_REST_Request

Last updated: February 12, 2026

Core class implementing a REST request object. Contains request data passed to endpoint callbacks.

Source: wp-includes/rest-api/class-wp-rest-request.php
Since: 4.4.0

Implements ArrayAccess for parameter access: $request['param'] is equivalent to $request->get_param('param').

Properties

Property	Type	Visibility	Description
`$method`	string	protected	HTTP method
`$params`	array	protected	Parameters by source (URL, GET, POST, FILES, JSON, defaults)
`$headers`	array	protected	Request headers (lowercase keys)
`$body`	string	protected	Request body data
`$route`	string	protected	Matched route pattern
`$attributes`	array	protected	Route handler attributes
`$parsed_json`	bool	protected	Whether JSON has been parsed
`$parsed_body`	bool	protected	Whether body has been parsed

Methods

__construct()

Creates a new request object.

public function __construct( string $method = '', string $route = '', array $attributes = array() )

Parameter	Type	Description
`$method`	string	HTTP method
`$route`	string	Request route
`$attributes`	array	Route attributes

HTTP Method

get_method()

Retrieves the HTTP method.

public function get_method(): string

Returns: HTTP method (uppercase).

set_method()

Sets the HTTP method.

public function set_method( string $method ): void

Parameter	Type	Description
`$method`	string	HTTP method

is_method()

Checks if request uses a specific method.

public function is_method( string $method ): bool

Parameter	Type	Description
`$method`	string	Method to check

Returns: true if method matches.

Since: 6.8.0

Headers

get_headers()

Retrieves all headers.

public function get_headers(): array

Returns: Map of lowercase header name to values array.

get_header()

Retrieves a single header value.

public function get_header( string $key ): string|null

Parameter	Type	Description
`$key`	string	Header name (case-insensitive)

Returns: Comma-joined values, or null if not set.

get_header_as_array()

Retrieves header values as array.

public function get_header_as_array( string $key ): array|null

Parameter	Type	Description
`$key`	string	Header name

Returns: Array of values, or null if not set.

set_header()

Sets a header value.

public function set_header( string $key, string $value ): void

Parameter	Type	Description
`$key`	string	Header name
`$value`	string	Header value

add_header()

Appends a value to a header.

public function add_header( string $key, string $value ): void

Parameter	Type	Description
`$key`	string	Header name
`$value`	string	Value to append

remove_header()

Removes a header.

public function remove_header( string $key ): void

Parameter	Type	Description
`$key`	string	Header name

set_headers()

Sets multiple headers.

public function set_headers( array $headers, bool $override = true ): void

Parameter	Type	Description
`$headers`	array	Map of header name to value
`$override`	bool	Replace existing headers

canonicalize_header_name() (static)

Normalizes header name to lowercase with underscores.

public static function canonicalize_header_name( string $key ): string

Parameter	Type	Description
`$key`	string	Header name

Returns: Normalized name.

Note: Treats - and _ as equivalent per Apache/nginx behavior.

Content Type

get_content_type()

Retrieves parsed Content-Type header.

public function get_content_type(): array|null

Returns: Array with keys:

value — Full content type
type — Main type (e.g., application)
subtype — Subtype (e.g., json)
parameters — Extra parameters

Or null if not set/invalid.

is_json_content_type()

Checks if request has JSON Content-Type.

public function is_json_content_type(): bool

Returns: true if application/json or similar.

Since: 5.6.0

Parameters

get_param()

Retrieves a parameter from any source.

public function get_param( string $key ): mixed|null

Parameter	Type	Description
`$key`	string	Parameter name

Returns: Parameter value or null.

Priority Order: JSON → POST → GET → URL → defaults

has_param()

Checks if a parameter exists.

public function has_param( string $key ): bool

Parameter	Type	Description
`$key`	string	Parameter name

Returns: true if parameter exists (even if null).

Since: 5.3.0

set_param()

Sets a parameter value.

public function set_param( string $key, mixed $value ): void

Parameter	Type	Description
`$key`	string	Parameter name
`$value`	mixed	Parameter value

Updates existing parameter in its original source, or adds to primary source.

get_params()

Retrieves all merged parameters.

public function get_params(): array

Returns: Map of parameter name to value.

get_url_params()

Retrieves URL (route regex) parameters.

public function get_url_params(): array

Returns: Parameters parsed from URL path.

set_url_params()

Sets URL parameters.

public function set_url_params( array $params ): void

Parameter	Type	Description
`$params`	array	Parameter map

get_query_params()

Retrieves query string parameters ($_GET).

public function get_query_params(): array

Returns: Query parameters.

set_query_params()

Sets query parameters.

public function set_query_params( array $params ): void

Parameter	Type	Description
`$params`	array	Parameter map

get_body_params()

Retrieves body parameters ($_POST).

public function get_body_params(): array

Returns: Body parameters.

set_body_params()

Sets body parameters.

public function set_body_params( array $params ): void

Parameter	Type	Description
`$params`	array	Parameter map

get_file_params()

Retrieves file parameters ($_FILES).

public function get_file_params(): array

Returns: File upload data.

set_file_params()

Sets file parameters.

public function set_file_params( array $params ): void

Parameter	Type	Description
`$params`	array	File parameter map

get_default_params()

Retrieves default parameters from route registration.

public function get_default_params(): array

Returns: Default parameter values.

set_default_params()

Sets default parameters.

public function set_default_params( array $params ): void

Parameter	Type	Description
`$params`	array	Default values

get_json_params()

Retrieves JSON body parameters.

public function get_json_params(): array

Returns: Parsed JSON data.

Body

get_body()

Retrieves raw request body.

public function get_body(): string

Returns: Request body content.

set_body()

Sets request body.

public function set_body( string $data ): void

Parameter	Type	Description
`$data`	string	Body content

Resets JSON parsing state.

Route

get_route()

Retrieves matched route pattern.

public function get_route(): string

Returns: Route regex pattern.

set_route()

Sets the matched route.

public function set_route( string $route ): void

Parameter	Type	Description
`$route`	string	Route pattern

get_attributes()

Retrieves route handler attributes.

public function get_attributes(): array

Returns: Handler options from registration.

set_attributes()

Sets route attributes.

public function set_attributes( array $attributes ): void

Parameter	Type	Description
`$attributes`	array	Handler attributes

Validation

sanitize_params()

Sanitizes all parameters.

public function sanitize_params(): true|WP_Error

Returns: true if all valid, WP_Error with invalid params.

Uses sanitize_callback from route args, or rest_parse_request_arg for typed params.

Error Codes:

rest_invalid_param — One or more parameters failed sanitization

has_valid_params()

Validates parameters against route requirements.

public function has_valid_params(): true|WP_Error

Returns: true if valid, WP_Error if missing/invalid params.

Checks:

JSON parsing errors
Required parameters
validate_callback for each arg
Global validate_callback on route

Error Codes:

rest_invalid_json — Invalid JSON body
rest_missing_callback_param — Required parameter missing
rest_invalid_param — Parameter failed validation

ArrayAccess Implementation

offsetExists()

Checks if parameter exists.

public function offsetExists( string $offset ): bool

Parameter	Type	Description
`$offset`	string	Parameter name

offsetGet()

Retrieves a parameter.

public function offsetGet( string $offset ): mixed|null

Parameter	Type	Description
`$offset`	string	Parameter name

offsetSet()

Sets a parameter.

public function offsetSet( string $offset, mixed $value ): void

Parameter	Type	Description
`$offset`	string	Parameter name
`$value`	mixed	Parameter value

offsetUnset()

Removes a parameter from all sources.

public function offsetUnset( string $offset ): void

Parameter	Type	Description
`$offset`	string	Parameter name

Static Methods

from_url()

Creates request from a full URL.

public static function from_url( string $url ): WP_REST_Request|false

Parameter	Type	Description
`$url`	string	Full URL with query string

Returns: Request object or false if URL couldn’t be parsed.

Since: 4.5.0

Example:

$request = WP_REST_Request::from_url( 'https://example.com/wp-json/wp/v2/posts?per_page=5' );
// Creates GET request to /wp/v2/posts with per_page=5

Protected Methods

get_parameter_order()

Gets priority order for parameter sources.

protected function get_parameter_order(): string[]

Returns: ['JSON', 'POST', 'GET', 'URL', 'defaults'] (varies by method).

Filterable via rest_request_parameter_order.

parse_json_params()

Parses JSON body into parameters.

protected function parse_json_params(): true|WP_Error

Returns: true if parsed or not JSON, WP_Error if invalid JSON.

parse_body_params()

Parses URL-encoded body.

protected function parse_body_params(): void

Called automatically for non-POST requests with body.