Returning JSON after a query in yii - php

Question

I'm new to yii framework. I'm just trying to implement Restful APIs. In the simple case scenario (after following some tutorial) I've succeeded with this:
$result = [];
foreach($this->getData() as $record) {
$result[] = $record->getAttributes();
}
return $result;
Note that getData() is a built-in method. Where when trying to use queries for more advanced scenarios, it's done this way:
$attributeNames = 'udid,model,appverionid';
$connection = Yii::app()->db;
$command = $connection->createCommand('select ' . $attributeNames . ' from device');
$models = $command->queryAll();
$attributeNames = explode(',', $attributeNames);
$rows = array();
foreach ($models as $model) {
$row = array();
foreach ($attributeNames as $name) {
$row[$name] = CHtml::value($model, $name);
}
$rows[] = $row;
}
return $rows;
Is that the best practice to return get JSON from queries results, or maybe it can be done in a better way?
Update:
The final response is returned from the following method:
private function sendAjaxResponse(AjaxResponseInterface $interface)
{
$success = count($interface->getErrors()) === 0;
$responseCode = $success ? 200 : 404;
header("content-type: application/json", true, $responseCode);
echo json_encode([
'success' => $success,
'data' => $interface -> getResponseData(),
'errors' => $interface -> getErrors()
]);
Yii::app()->end();
}
And I found out that only these lines are sufficient:
$attributeNames = 'udid,model,appverionid';
$connection = Yii::app()->db;
$command = $connection->createCommand('select ' . $attributeNames . ' from device');
$models = $command->queryAll();
return $models;
The other part (the nested loop) seems for encoding with relations (see here) Then my question is what is encoding with relations and when it is helpful?

Answer 1

The Yii way of creating JSOn data is using CJson library
$query = "'select ' . $attributeNames . ' from device'";
$command = Yii::app()->db->createCommand($query);
$result = $command->queryAll();
$ret = array_values($result);
/* or ...
$ret = array();
foreach ($models as $model) {
$ret = array();
foreach ($attributeNames as $name) {
$row[$name] = CHtml::value($model, $name);
}
$ret[] = $row;
}
*/
echo CJSON::encode($ret);
Yii::app()->end();

Answer 2

I think you simply need to encode the value before return
foreach ($models as $model) {
$row = array();
foreach ($attributeNames as $name) {
$row[$name] = CHtml::value($model, $name);
}
$rows[] = $row;
}
return json_encode($rows);

Answer 3

Very Simple! Just add this line - \Yii::$app->response->format = \yii\web\Response:: FORMAT_JSON; in your method at start and do other code
normally.
for example,
public function actionHospitals()
{
\Yii::$app->response->format = \yii\web\Response:: FORMAT_JSON;
$hospitals = Hospitals::find()->select('speciality')->distinct()->all();
return ['hospitals' => $hospitals];
}