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phprecursionmenuparent-childarrayofarrays

Building a parent/child array menu structure from SQL query result


I need to build a complex menu structure dinamically using a MySQL DB query. The query allows to define the menu items the user is entitled to use and see. The Menu structure is stored into a results set in a classic parent/child relation where each element has its own id and rely on its parent id. Parent id = 0 means there are no parents above that element (it's a root):

MNU_ID    MNU_FUNC    MNU_PARENT    MNU_ICON    MNU_TITLE_IT    MNU_TITLE_EN
----------------------------------------------------------------------------
  1       FLTMGR      0             home        STATO FLOTTA    FLEET STATUS
  2       PSTN        0             map-marker  POSIZIONI       POSITIONS
  3       RTS         0             road        PERCORSI        ROUTES
  4       CHRTS       0             line-charts DIAGRAMMI       CHARTS
  ...
  13      MNLS        0             book        MANUALI         MANUALS
  14      RGLTNS      0             bank        NORMATIVE       REGULATIONS
  16      SPD         4             tachometer  VELOCITA'       SPEED
  17      ALT         4             area-chart  ALTITUDINE      ALTITUDE
  18      DST         4             exchange    DISTANZA        DISTANCE
  ...
  32      INSTL       13            book        INSTALLAZIONE   SETUP
  33      BASE        32            wrench      BASE            BASE
  34      FLPR        32            wrench      SONDA CARB.     FUAL PROBE

So as you can see the element 33 and 34 is under element 32, while element 32 is under element 13 and finally element 13 is has no parent as it's a root element (it's MNU_PARENT is 0). Well having said that I've developed my code to return the following:

Array(
[FLTMGR] => Array(
    [icon] => fa fa-home
    [title] => STATO FLOTTA
    ),
[PSTN] => Array(
    [icon] => fa fa-map-marker
    [title] => POSIZIONI
    ),
[RTS] => Array(
    [icon] => fa fa-road
    [title] => PERCORSI
    ),
[CHRTS] => Array(
    [icon] => fa fa-line-charts
    [title] => DIAGRAMMI
    [sub] => Array(
            [SPD] => Array(
                [icon] => fa fa-tachometer
                [title] => VELOCITÁ
                ),
            [ALT] => Array(
                [icon] => fa fa-area-chart
                [title] => ALTITUDINE
                ),
            [DST] => Array(
                [icon] => fa fa-exchange
                [title] => DISTANZA
                ),
            [GSLN] => Array(
                [icon] => fa fa-tint blink
                [title] => CARBURANTE
                )
            )
        ),
...
[MNLS] => Array(
    [icon] => fa fa-book
    [title] => MANUALI
    [sub] => Array(
        [INSTL] => Array(
            [MNU_ID] => 32
            [MNU_FUNC] => INSTL
            [MNU_PARENT] => 13
            [icon] => fa fa-book
            [title] => INSTALLAZIONE
            [sub] => Array(
                [0] => Array(
                    [MNU_ID] => 33
                    [MNU_FUNC] => BASE
                    [MNU_PARENT] => 32
                    [icon] => fa fa-wrench
                    [title] => BASE
                    ),
                [1] => Array(
                    [MNU_ID] => 34
                    [MNU_FUNC] => FLPR
                    [MNU_PARENT] => 32
                    [icon] => fa fa-wrench
                    [title] => SONDA CARB.
                    )
                )
            )
        )
    ),
[RGLTNS] => Array( 
    [icon] => fa fa-bank
    [title] => NORMATIVE
    )
)

However as you can see I'm unable to produce the correct structure over the fisrt level. In other words if you look at INSTL element under MNLS there are the following errors:

  1. The item MNU_ID,MNU_FUNC,MNU_PARENT should not be there (see the others)
  2. The items under 'sub' have the same errors in 1.
  3. The items under 'sub' should be identified by BASE, FLPR and not by 0 and 1

So the expected structure should be the following:

Array(
[FLTMGR] => Array(
    [icon] => fa fa-home
    [title] => STATO FLOTTA
    ),
[PSTN] => Array(
    [icon] => fa fa-map-marker
    [title] => POSIZIONI
[RTS] => Array(
    [icon] => fa fa-road
    [title] => PERCORSI
    ),
[CHRTS] => Array(
    [icon] => fa fa-line-charts
    [title] => DIAGRAMMI
    [sub] => Array(
            [SPD] => Array(
                [icon] => fa fa-tachometer
                [title] => VELOCITÁ
                ),
            [ALT] => Array(
                [icon] => fa fa-area-chart
                [title] => ALTITUDINE
                ),
            [DST] => Array(
                [icon] => fa fa-exchange
                [title] => DISTANZA
                ),
            [GSLN] => Array(
                [icon] => fa fa-tint blink
                [title] => CARBURANTE
                )
            )
        ),
...
[MNLS] => Array(
    [icon] => fa fa-book
    [title] => MANUALI
    [sub] => Array(
        [INSTL] => Array(
            [icon] => fa fa-book
            [title] => INSTALLAZIONE
            [sub] => Array(
                [BASE] => Array(
                    [icon] => fa fa-wrench
                    [title] => BASE
                    ),
                [FLPR] => Array( 
                    [icon] => fa fa-wrench
                    [title] => SONDA CARB.
                    )
                )
            )
        )
    ),
[RGLTNS] => Array(
    [icon] => fa fa-bank
    [title] => NORMATIVE
    )
)

And now the code:

// $MenuDB contains the Menu structure returned by the DB

// Build the basic structure
$new = array();
foreach ($MenuDB as $a){
    $new[$a['MNU_PARENT']][] = $a;
    }

// Calls the recursive function CreateTree 
$tree = createTree($new, $new[0]);  

// Make final correction (remove unwanted items and replace index with keys)
$b=replaceKeys($tree);

print_r($b);
exit();

function replaceKeys(array $input) {    
    foreach($input as $key => &$val){                   // Scan the input array, each element will go in $val, the key will be $key
        $input[$val['MNU_FUNC']]=$input[$key];          // Replace index with key, the key is the value of the field MNU_FUNC
        if(is_numeric($key)) unset($input[$key]);       // Remove the item with numeric key (index) and leave the item with non-numeric index (key)
        unset($val['MNU_ID']);                          // Remove ID
        unset($val['MNU_PARENT']);                      // Remove Parent
        unset($val['MNU_FUNC']);                        // Remove Function
        if(isset($val['sub'])) {                        // avoid to work with undefined items
            if (is_array($val['sub'])) {                // check if there are childs inside the 'sub' item
                $val['sub'] = replaceKeys($val['sub']); // if we have childs, do it again recursively
                unset($val['url']);                     // remove url element if we have childs
                unset($val['url_target']);              // remove url_target element if we have childs
                }
            }
        }
    return $input;
    }

function createTree(&$list, $parent){
    $tree = array();
    foreach ($parent as $k=>$l){
        if(isset($list[$l['MNU_ID']])){
            $l['sub'] = createTree($list, $list[$l['MNU_ID']]);
            }
        $tree[] = $l;
        } 
    return $tree;
    }

Despite my efforts I cannot figure out where is the error. Is there any alternaive to my workflow?


Solution

  • You may use only one recursive function:

    function makeTree($array, $parent) {
        $return = [];
        foreach ($array as $key => $value) {
            if ($value['MNU_PARENT'] == $parent) {
                $return[$value['MNU_FUNC']] = [
                    'icon' => 'fa fa-' . $value['MNU_ICON'],
                    'title' => $value['MNU_TITLE_IT'],
                ];
                $subs = false;
                foreach ($array as $search) {
                    if ($search['MNU_PARENT'] == $value['MNU_ID']) {
                        $subs = true;
                    }
                }
                if ($subs === true) {
                    $return[$value['MNU_FUNC']]['subs'] = makeTree($array, $value['MNU_ID']);
                }
            }
        }
        return $return;
    }
    
    $new = makeTree($arr, 0);