Page on save:: copy field value into (hidden) field

[matjash]

I need some help.

I have fields price and priceBefore

I want to copy price value on save to priceBefore field.

    public function init() {
        $this->pages->addHookAfter('save', $this, 'hookSave');
        //$this->pages->addHookAfter('added', $this, 'hookAdded');
    }
    public function hookSave(HookEvent $event) {
        // this function called any time a page is saved (whether new or not)
        //$page = $event->object;
        $page = $event->arguments[0];
        // now you can access anything from the $page
        if ($page->template == "nepremicnine-vnos") {
            // get value from price field and copy to priceBefore/cenaStara
            $page->cenaStara = $page->cena;
            $page->save("cenaStara");
            
        }
    }

I 've read some examples but I just can't make it work.

Is it maybe better to put it in InputField::render? 

    public function init() {
            // add before-hook to the inputfield render method
            $this->addHookBefore("Inputfield::render", $this, "renderField");
        }

    public function renderField(HookEvent $event) {
        // // get the current field
        $field = $event->object;
        if($field->name == 'cenaStara' && $field->value == '' ) {
            $field->cenaStara = $field->cena; 
            $oldPrice = $field->cenaStara          
            $field->set('value', $oldPrice);
        }
    }

[horst]

You cannot (simply) save within the hook that is called after save. You need to avoid endless loop.

Add a temporary property to the page object you have altered and check for this in the beginning of the hook method:

    if (page->imAlreadyDone) return;  // is already altered
    if ($page->template != "nepremicnine-vnos") return;  // is the wrong page type
    
    $page->cenaStara = $page->cena;   // alter data
    $page->imAlreadyDone = true;      // flag page as altered
    $page->save("cenaStara");         // save

[renobird]

Untested, but you could use trackChange.

public function init() {
    $this->addHookAfter('Pages::saveReady', $this, 'hookPageSave');
}

public function hookPageSave($event) {

    $page = $event->arguments[0];
    
    // check template
    if ($page->template == "nepremicnine-vnos") {

        // If there was a change to the price field
        if ($page->trackChange('price')) {
            
            // get the old page from the DB (contains the previous value of 'price');
            $old = $this->pages->get($page->id);
            
            // set the value of priceBefore to previous value of price.
            $page->priceBefore = $oldPage->price;

        }
    }
}

There is no need to do a save(), as the hook is just editing the values of the page object right before it's saved.

[horst]

@renobird: ah, now I see what was the real problem. Haven't realized it before.

[renobird]

There's also this handy little module that some dude made — keeps a log of changes made to fields on a per-template basis.

[matjash]

Thank you guys. In the meantime I found another solution which suits my need:

    public function init() {
        $this->addHookAfter('Pages::saveReady', $this, 'afterSaveReady');
    }

    public function afterSaveReady($event) {
        // Get the soon to be saved page object from the given event
        $page = $event->arguments[0];

        // Sample condition and changes
        if($page->template == "nepremicnine-vnos" && !$page->isTrash()){
            //Price
            $cena = $page->cena;
            //Old price
            $stara = $page->cenaStara;
            $znizano = $page->znizano;

            //Checkbox to display old price, if not checked on save copy price to oldPrice
            if($znizano == 0) {
                $page->set("cenaStara", $cena);
                $page->save("cenaStara");
            }
        }
    }
}

I will look into the way of track field changes. It seems usefull for future development.