John Davidson

Message:

I'm struggling with the following situation:

I have an object of type Category with several private properties I want to extract into a separate data structure / array through its available getters: getId(), getTitle(), getLink(),.
It stores any nested subcategories as a property as well, which can be accessed through getter getSubCats() which will return an associative array of Categories with the corresponding ID's as keys.

I need to extract some properties and create a nested array (for use with json_encode) which fits the following structure:

<ID> => array(

  'title'    => <title>,

  'url'      => <url>,

  'parent'   => <parentID>,

  'children' => array(

    <ID> => array(

      'title'    => <title>,

      'url'      => <url>,

      'parent'   => <parentID>,

      'children' => array(

        ...

    ),

    <ID> => array(

      'title'    => <title>,

      'url'      => <url>,

      'parent'   => <parentID>,

      'children' => array(

      ...

    ),

    ...

  )

)

Maybe this can be done by using RecursiveIteratorIterator?
Below are my last two approaches:

function buildTree_v1(&$oCat, &$aOutput = [], &$oParent = null) {

  $actId = $oCat->getId();

  $aOutput [$actId]['title'] = $oCat->getTitle();

  $aOutput [$actId]['url'] = $oCat->getLink();

  $aOutput [$actId]['parent'] = $oCat->getParentCategory()->getId() ?? null;

  if ( $oCat->getHasVisibleSubCats() ) {

    foreach ( $oCat->getSubCats() as $sId => &$oSubCat ) {

      $aOutput [$actId][$sId] = [];

      foreach ( $oSubCat as &$oSubChild ) {

        buildTree_v1($oCat, $aOutput, $oSubChild);

      }

    }

  }

}





// Try to split - only build the nested object structure as first step

function buildTree_v2(&$oCat) {

  $return = [];

  if ( $oCat->getHasVisibleSubCats() ) {

    foreach ( $oCat->getSubCats() as &$oSubCat) {

      if ( $oSubCat->getHasVisibleSubCats() ) {

        $return[$oSubCat->getId()] = buildTree_v2($oSubCat);

      } else {

        $return[] = $oSubCat->getId();

      }

    }

  }

  return empty($return) ? null : $return;

}

Thanks in advance for any advice!

//Edit:

Input structure (relevant parts):

class Category {

  protected $_aSubCats = array();

  protected $_blHasVisibleSubCats;

  protected $_aSeoUrls = array();

  protected $_oParent = null;

  protected $_sId;

  protected $_sTitle;



  public function getSubCats(): array<Category>;

  public function getHasVisibleSubCats(): bool;

  public function getLink($iLang = null): string;

  public function getParentCategory(): ?Category;

  public function getId(): string;

  public function getTitle(): string;



}

An concrete example input object might look like:

$oInputCat = {Category}

-> $_aSubCats = array(

     '316' => {Category},

     '23'  => {Category},

     '262' => {Category}

   )

-> $_blHasVisibleSubCats = true

-> $_aSeoUrl = 'https://example.com/Hardware'

-> $_oParent = {Category}

-> $_sId = '5068'

-> $_sTitle = 'Hardware'





/* Entries of $_aSubCats */



// '316' = {Category}

-> $_aSubCats = array()

-> $_blHasVisibleSubCats = false

-> $_aSeoUrl = 'https://example.com/Hardware/3D-Googles'

-> $_oParent = {Category}

-> $_sId = '316'

-> $_sTitle = '3D Googles'



// '23' = {Category}

-> $_aSubCats = array(

     '26'  => {Category}

   )

-> $_blHasVisibleSubCats = true

-> $_aSeoUrl = 'https://example.com/Hardware/CPUs-and-Cooler'

-> $_oParent = {Category}

-> $_sId = '23'

-> $_sTitle = 'CPUs & Cooler'



// '262' = {Category}

-> $_aSubCats = array()

-> $_blHasVisibleSubCats = false

-> $_aSeoUrl = 'https://example.com/Hardware/Sound-Cards'

-> $_oParent = {Category}

-> $_sId = '262'

-> $_sTitle = 'Sound Cards'



// '26' = {Category}  <-- example for a 2nd level subcategory

-> $_aSubCats = array()

-> $_blHasVisibleSubCats = false

-> $_aSeoUrl = 'https://example.com/Hardware/CPUs-and-Cooler/Cooler'

-> $_oParent = {Category}

-> $_sId = '26'

-> $_sTitle = 'Cooler'

The desired result would look like:

array(

  '5068' => array(

    'title'    => 'Hardware',

    'url'      => 'https://example.com/Hardware',

    'parent'   => '12',  // not listed - parent of the input category

    'children' => array(

      '316' => array(

        'title'    => '3D Googles',

        'url'      => 'https://example.com/Hardware/3D-Googles',

        'parent'   => '5068',

        'children' => array(),

      '23' => array(

        'title'    => 'CPUs & Cooler',

        'url'      => 'https://example.com/Hardware/CPUs-and-Cooler',

        'parent'   => '5068',

        'children' => array(

          '26' => array(

          'title'    => 'Cooler',

          'url'      => 'https://example.com/Hardware/CPUs-and-Cooler/Cooler',

          'parent'   => '23',

          'children' => array(),

        ),

      '262' => array(

        'title'    => 'Sound Cards',

        'url'      => 'https://example.com/Hardware/Sound-Cards',

        'parent'   => '5068',

        'children' => array(),

    )

  )

)

The real object tree has an arbitrary number of branches and dimensions, but I think this should be enough to understand, what I want to do.

As you can see, the desired target could be described as "convert the objects to arrays while filtering some specific properties".
I hope this will make things easier to understand.

---

My Answer:
You can achieve the desired result by recursively traversing the nested Category objects and extracting the required properties. Here's an updated version of your code that should work:

php
function buildTree($oCat) {
$output = [];

$output[$oCat->getId()] = [
'title' => $oCat->getTitle(),
'url' => $oCat->getLink(),
'parent' => $oCat->getParentCategory() ? $oCat->getParentCategory()->getId() : null,
'children' => []
];

if ($oCat->getHasVisibleSubCats()) {
foreach ($oCat->getSubCats() as $subCat) {
$output[$oCat->getId()]['children'][$subCat->getId()] = buildTree($subCat);
}
}

return $output;
}

// Example usage
$oInputCat = new Category(); // Assuming you have instantiated the Category object
$result = buildTree($oInputCat);

// Convert the result to JSON
$jsonResult = json_encode($result);
echo $jsonResult;


In this code snippet, the `buildTree` function recursively traverses the nested Category objects and builds the desired nested array structure. The function returns the nested array, which can then be converted to JSON using `json_encode`.

Make sure to replace `Category` with the actual class name of your Category object in the code above. Also, ensure that the getters (`getId()`, `getTitle()`, `getLink()`, `getSubCats()`, `getHasVisibleSubCats()`, `getParentCategory()`) return the correct values as per your object structure.

I hope this helps! Let me know if you have any further questions.