Form action/link to render a plugin in WordPress front-end

Question

I am new to WordPress and I'm wondering if anyone could help me understand how I should go for rendering the output of a plugin when a form of a widget is submitted in the front-end.

I'm developing a plugin that has two "views" and one widget. The widget is just a form with a dropdown menu to select a value from a list. When a value is selected, the form should submit this value to a page where the first view of the plugin is rendered. This first view should print links that take the visitor to the second view. It's like if the first view was a list of rows, and the second view was the details of the row selected from the first view. My widget's form should know to which URL the data should be posted. This is the goal.

I've been reading the Plugin API, but I don't seem to have found a proper solution. My question is: should I only rely on the Shortcodes, previously put on certain pages, to render the plugin in the front-end? Is this the only way?

I tried to submit a custom action with the form of my widget (with action get_admin_url().'admin-post.php'), and hook it in the plugin with:

add_action('admin_post_customaction', 'handle_customaction');
add_action('admin_post_nopriv_customaction', 'handle_customaction');
function (handle_customaction) {
    //do something
}

but the page admin-post.php truncates the execution, so I guess this practice is only for executing certain tasks and then redirect, not to display content within a page in the front-end.

Is there a solution beside using Shortcodes? Because then my question would be "which action attribute should I use in the form of the widget?", like how do I know which pages use the Shortcode I need?

Maybe by creating a custom post type within the plugin? I do not need anything special in the admin section of the website. However, at least there, my plugin is called by WordPress with the link wp-admin/admin.php?page=myplugin and my main callback is called. But what about the front-end?

Am I missing something? I would like to not rely on the theme's code. Any hints would be much appreciated! Thanks

Answer 1

I think you are complicating it more than it needs to be. You don't really need a widget at all. You need just a shortcode that outputs the form with the select, and also the data if there has been something selected. That data would be either the first view or the second view, depending on the parameters that you embed in the links and your form. So the page the shortcode is on is controlling the whole thing. This way it is not limited to one use on a site, although you should probably include a define in the shortcode that you check, so that it can't be used more than once per page.

The form would not need an action attribute, so it will be handled by the current page it is on. It would need to have the current value of which view is shown, and the links of the first view would need to have the value of the second view. That makes it have to use GET instead of POST, which looks messier in the address bar. So if you can change the first view to use buttons or something instead of links, you could use POST.