How do I change the value of a select box field of a certain entry through the front-end?

Question

So I'm having this entry (a product) that contains a selectbox field with two values:

• Reserved
• Available

By default this field is set to 'Available', but when the user lands on a certain page (a thank you page after "ordering" this product with the entry id as a querystring in the URL), I'd like to change the value of that selectbox to 'Reserved'.

Anyone can put me in the right direction on this one?

Thanks in advance!

Answer 1

Twig

You can check for certain URL parameters via

{% set param = craft.app.getRequest().getParam('id') %}
{% if param is not null %}
    {% set entry = craft.app.getElements().getElementById(param) %}
    {# insert your new field value! not the label, the value/handle
    {% do entry.setFieldValue('fieldHandle', 'Reserved') %}
    {% do craft.app.getElements().saveElement(entry) %}
{% endif %}

However I would not recommend doing this in Twig

PHP

You can see how to use Template Variables and create your boilerplate at pluginfactory.io

{% do craft.myAwesomePlugin.saveEntry(entry, {fieldHandle: 'yourValue'}) %}

And your function could be

public function saveEntry($entry, $attributes = []){
    $entry->getContent()->setAttributes($attributes);
    craft()->entries->saveEntry($entry);
}

That's just a "quick" version, I suggest you to take a look at EntriesController to see how Craft handles it in detail