get nested json object containing all the related data in yii2 - yii2

Question

I am writing an api to fetch data. I have three models Page , Section and Question.This is image of the erd diagram showing relationship between different entities .
I have defined there relationships in respective models.
Page Model
class CmsPage extends ActiveRecord
{
public static function tableName()
{
return '{{%cms_page}}';
}
public function getCmsSection()
{
/*Page and Section has many to many relation having a junction table*/
return $this->hasMany(CmsSection::className(),['id'=>'section_id'])->viaTable('tbl_cms_page_section',['page_id'=>'id']);
}
}
Section Model
class CmsSection extends ActiveRecord
{
public static function tableName()
{
return '{{%cms_section}}';
}
public function getCmsQuestion()
{
return $this->hasMany(CmsQuestion::className(),['id'=>'section_id']);
}
}
Question Model
class CmsQuestion extends ActiveRecord
{
public static function tableName()
{
return '{{%cms_question}}';
}
public function getCmsSection()
{
return $this->hasOne(CmsSection::className(),['section_id'=>'id']);
}
}
I want to fetch data as a json object like below
{
"id": "1",
"name": "Lorem Ipsom",
"title": "Eiusmod voluptate Lorem aute tempor fugiat eiusmod ex ipsum enim magna consequat cupidatat.",
"short_summary": "Will ContentsQuis consequat occaecat consequat aliquip adipisicing aute sunt pariatur culpa sint consectetur reprehenderit eu aliquip.",
"summary": "Officia eu fugiat quis laboris voluptate sunt sint cupidatat eu consequat et deserunt sint eu.",
"section": [
{
"id": 1,
"title": "Advanced Planning",
"short_summary": "Advanced Planning",
"summary": "Summary ",
"question": [
{
"id": 1,
"question_type_id": 1,
"show_relations": "true",
"title": "Family Members",
"place_holder_text": "Your faimly list is currently empty.",
"label_name": "Name",
"label_email": "Email",
"label_phone": "Mobile number",
"select_1": "url:test-data/dashboard-relationship.json",
"label": "Remarks"
},
{
"id": 2,
"question_type_id": 2,
"title": "Close Friends",
"place_holder_text": "Your list is close friends currently empty.",
"label_name": "Name",
"label_email": "Email",
"label_phone": "Mobile number",
"label_address": "Address",
"help_text": "<b>Close Friends<b><ul><li>1</</li><li>2</</li></ul>"
},
{
"id": 3,
"question_type_id": 3,
"title": "Designated Executors",
"place_holder_text": "It is vital you nominate an Executor",
"label_name": "Name",
"label_email": "Email",
"label_phone": "Mobile number",
"label_address": "Address"
},
{
"id": 4,
"question_type_id": 4,
"question_type": {},
"title": "Witnesses",
"place_holder_text": " It is vital you nominate an Executor",
"label_1": "Name",
"opption_2": "Email",
"label_3": "Phone",
"label_4": "Occupation",
"label": "Address"
}
]
},
{
"id": 2,
"title": "Labore proident cupidatat ex dolore occaecat in tempor sit proident sint labore minim cillum.",
"summary": "Dolor cupidatat consequat cillum deserunt laborum aliqua commodo occaecat sint aute cillum exercitation.",
"short_summary": "Ullamco Lorem incididunt dolore ipsum.",
"question": [
{
"id": 5,
"question_type_id": 5,
"title": "Last Words",
"short_summary": "Plan, the way you want!",
"summary": "Start by writing down.",
"label": "Write your last words here"
},
{
"id": 6,
"question_type_id": 5,
"title": "Venue",
"short_summary": "Plan, the way you want!",
"summary": "Start by writing down.",
"label": "Mention"
}
]
}
]
}
I have followed yii2 docs to come this far but not been able to get data in the json format. How to do that?

Answer 1

HI in API there a function call fields you can override that function :
Please check below code which will help you to get idea or for more detail
you read yii2 doc here
Yii 2 fields doc
public function fields()
{
return [
'id',
"name"
'title',
'short_summary',
'summary',
'section'=> function ($model) {
return $model->cmsSection;
},
];
}
if you want to go more nested then you can use array store first nested data and again use loop for inner data:
'section'=> function ($model) {
$sections = $model->cmsSection;
//store section data in array
//forloop of $sections
$sections->question;
//Again store question data in first array and return it
},
Aplly it you will understand what i am trying to tell you.