framework/rest/Serializer.php
<?php
/**
* @link https://www.yiiframework.com/
* @copyright Copyright (c) 2008 Yii Software LLC
* @license https://www.yiiframework.com/license/
*/
namespace yii\rest;
use Yii;
use yii\base\Arrayable;
use yii\base\Component;
use yii\base\Model;
use yii\data\DataProviderInterface;
use yii\data\Pagination;
use yii\helpers\ArrayHelper;
use yii\web\Link;
use yii\web\Request;
use yii\web\Response;
/**
* Serializer converts resource objects and collections into array representation.
*
* Serializer is mainly used by REST controllers to convert different objects into array representation
* so that they can be further turned into different formats, such as JSON, XML, by response formatters.
*
* The default implementation handles resources as [[Model]] objects and collections as objects
* implementing [[DataProviderInterface]]. You may override [[serialize()]] to handle more types.
*
* @author Qiang Xue <qiang.xue@gmail.com>
* @since 2.0
*/
class Serializer extends Component
{
/**
* @var string the name of the query parameter containing the information about which fields should be returned
* for a [[Model]] object. If the parameter is not provided or empty, the default set of fields as defined
* by [[Model::fields()]] will be returned.
*/
public $fieldsParam = 'fields';
/**
* @var string the name of the query parameter containing the information about which fields should be returned
* in addition to those listed in [[fieldsParam]] for a resource object.
*/
public $expandParam = 'expand';
/**
* @var string the name of the HTTP header containing the information about total number of data items.
* This is used when serving a resource collection with pagination.
*/
public $totalCountHeader = 'X-Pagination-Total-Count';
/**
* @var string the name of the HTTP header containing the information about total number of pages of data.
* This is used when serving a resource collection with pagination.
*/
public $pageCountHeader = 'X-Pagination-Page-Count';
/**
* @var string the name of the HTTP header containing the information about the current page number (1-based).
* This is used when serving a resource collection with pagination.
*/
public $currentPageHeader = 'X-Pagination-Current-Page';
/**
* @var string the name of the HTTP header containing the information about the number of data items in each page.
* This is used when serving a resource collection with pagination.
*/
public $perPageHeader = 'X-Pagination-Per-Page';
/**
* @var string|null the name of the envelope (e.g. `items`) for returning the resource objects in a collection.
* This is used when serving a resource collection. When this is set and pagination is enabled, the serializer
* will return a collection in the following format:
*
* ```php
* [
* 'items' => [...], // assuming collectionEnvelope is "items"
* '_links' => { // pagination links as returned by Pagination::getLinks()
* 'self' => '...',
* 'next' => '...',
* 'last' => '...',
* },
* '_meta' => { // meta information as returned by Pagination::toArray()
* 'totalCount' => 100,
* 'pageCount' => 5,
* 'currentPage' => 1,
* 'perPage' => 20,
* },
* ]
* ```
*
* If this property is not set, the resource arrays will be directly returned without using envelope.
* The pagination information as shown in `_links` and `_meta` can be accessed from the response HTTP headers.
*/
public $collectionEnvelope;
/**
* @var string the name of the envelope (e.g. `_links`) for returning the links objects.
* It takes effect only, if `collectionEnvelope` is set.
* @since 2.0.4
*/
public $linksEnvelope = '_links';
/**
* @var string the name of the envelope (e.g. `_meta`) for returning the pagination object.
* It takes effect only, if `collectionEnvelope` is set.
* @since 2.0.4
*/
public $metaEnvelope = '_meta';
/**
* @var Request|null the current request. If not set, the `request` application component will be used.
*/
public $request;
/**
* @var Response|null the response to be sent. If not set, the `response` application component will be used.
*/
public $response;
/**
* @var bool whether to preserve array keys when serializing collection data.
* Set this to `true` to allow serialization of a collection as a JSON object where array keys are
* used to index the model objects. The default is to serialize all collections as array, regardless
* of how the array is indexed.
* @see serializeDataProvider()
* @since 2.0.10
*/
public $preserveKeys = false;
/**
* {@inheritdoc}
*/
public function init()
{
if ($this->request === null) {
$this->request = Yii::$app->getRequest();
}
if ($this->response === null) {
$this->response = Yii::$app->getResponse();
}
}
/**
* Serializes the given data into a format that can be easily turned into other formats.
* This method mainly converts the objects of recognized types into array representation.
* It will not do conversion for unknown object types or non-object data.
* The default implementation will handle [[Model]], [[DataProviderInterface]] and [\JsonSerializable](https://www.php.net/manual/en/class.jsonserializable.php).
* You may override this method to support more object types.
* @param mixed $data the data to be serialized.
* @return mixed the converted data.
*/
public function serialize($data)
{
if ($data instanceof Model && $data->hasErrors()) {
return $this->serializeModelErrors($data);
} elseif ($data instanceof Arrayable) {
return $this->serializeModel($data);
} elseif ($data instanceof \JsonSerializable) {
return $data->jsonSerialize();
} elseif ($data instanceof DataProviderInterface) {
return $this->serializeDataProvider($data);
} elseif (is_array($data)) {
$serializedArray = [];
foreach ($data as $key => $value) {
$serializedArray[$key] = $this->serialize($value);
}
return $serializedArray;
}
return $data;
}
/**
* @return array the names of the requested fields. The first element is an array
* representing the list of default fields requested, while the second element is
* an array of the extra fields requested in addition to the default fields.
* @see Model::fields()
* @see Model::extraFields()
*/
protected function getRequestedFields()
{
$fields = $this->request->get($this->fieldsParam);
$expand = $this->request->get($this->expandParam);
return [
is_string($fields) ? preg_split('/\s*,\s*/', $fields, -1, PREG_SPLIT_NO_EMPTY) : [],
is_string($expand) ? preg_split('/\s*,\s*/', $expand, -1, PREG_SPLIT_NO_EMPTY) : [],
];
}
/**
* Serializes a data provider.
* @param DataProviderInterface $dataProvider
* @return array the array representation of the data provider.
*/
protected function serializeDataProvider($dataProvider)
{
if (($pagination = $dataProvider->getPagination()) !== false) {
$this->addPaginationHeaders($pagination);
}
if ($this->request->getIsHead()) {
return null;
}
if ($this->preserveKeys) {
$models = $dataProvider->getModels();
} else {
$models = array_values($dataProvider->getModels());
}
$models = $this->serializeModels($models);
if ($this->collectionEnvelope === null) {
return $models;
}
$result = [
$this->collectionEnvelope => $models,
];
if ($pagination !== false) {
return array_merge($result, $this->serializePagination($pagination));
}
return $result;
}
/**
* Serializes a pagination into an array.
* @param Pagination $pagination
* @return array the array representation of the pagination
* @see addPaginationHeaders()
*/
protected function serializePagination($pagination)
{
return [
$this->linksEnvelope => Link::serialize($pagination->getLinks(true)),
$this->metaEnvelope => [
'totalCount' => $pagination->totalCount,
'pageCount' => $pagination->getPageCount(),
'currentPage' => $pagination->getPage() + 1,
'perPage' => $pagination->getPageSize(),
],
];
}
/**
* Adds HTTP headers about the pagination to the response.
* @param Pagination $pagination
*/
protected function addPaginationHeaders($pagination)
{
$links = [];
foreach ($pagination->getLinks(true) as $rel => $url) {
$links[] = "<$url>; rel=$rel";
}
$this->response->getHeaders()
->set($this->totalCountHeader, $pagination->totalCount)
->set($this->pageCountHeader, $pagination->getPageCount())
->set($this->currentPageHeader, $pagination->getPage() + 1)
->set($this->perPageHeader, $pagination->pageSize)
->set('Link', implode(', ', $links));
}
/**
* Serializes a model object.
* @param Arrayable $model
* @return array the array representation of the model
*/
protected function serializeModel($model)
{
if ($this->request->getIsHead()) {
return null;
}
list($fields, $expand) = $this->getRequestedFields();
return $model->toArray($fields, $expand);
}
/**
* Serializes the validation errors in a model.
* @param Model $model
* @return array the array representation of the errors
*/
protected function serializeModelErrors($model)
{
$this->response->setStatusCode(422, 'Data Validation Failed.');
$result = [];
foreach ($model->getFirstErrors() as $name => $message) {
$result[] = [
'field' => $name,
'message' => $message,
];
}
return $result;
}
/**
* Serializes a set of models.
* @param array $models
* @return array the array representation of the models
*/
protected function serializeModels(array $models)
{
foreach ($models as $i => $model) {
if ($model instanceof Arrayable) {
$models[$i] = $this->serializeModel($model);
} elseif (is_array($model)) {
$models[$i] = ArrayHelper::toArray($model);
}
}
return $models;
}
}