Magento 2 Plugin for Contact Form Post Controller

Question

I have added google recaptcha in my contact form. Also, I have added a contact form on CMS page.

I have to validate the captcha when post contact form.

I have to create a plugin for this, but not much idea how doing this. In plugin have to check condition with captcha. I fail to then add error, otherwise default success message from Magento.

Answer 1

At this,case you have to use around method (aroundExecute()).

First, create di.xml at app/code/{VendorName}/{Modulename}/etc/frontend/ for define plugin class.

<?xml version="1.0"?>
<config xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="urn:magento:framework:ObjectManager/etc/config.xsd">
    <type  name="Magento\Contact\Controller\Index\Post">
           <plugin name="add_new_item" sortOrder="1"  disabled="false"
           type="StackExchange\Magentodemo\Plugin\ContactPostPlugin"/>
    </type> 
</config>

Now, you have to create a plugin where you have to check captcha is valid or not at app/code/{VendorName}/{Modulename}/Plugin/

<?php

namespace StackExchange\Magentodemo\Plugin;


class ContactPostPlugin {

    /**
     * @var \Magento\Framework\UrlInterface
     */
    protected $urlInterface;

    /**
     * @var \Magento\Framework\Message\ManagerInterface
     */
    protected $messageManager;


    public function __construct(
        \Magento\Framework\Message\ManagerInterface $messageManager,
        \Magento\Framework\UrlInterface $urlInterface   
    ) {
        $this->messageManager = $messageManager;
        $this->urlInterface = $urlInterface;
    }
    public function aroundExecute(
        \Magento\Contact\Controller\Index\Post $subject,
        \Closure $proceed          
    )
    {
        if({CapctheIsNOtValdated}) // condition for not valdate captcha
        {
           $url = $this->urlInterface->getUrl('contact/index');
           $this->messageManager->addErrorMessage('Captcha is not valid');
           return $subject->getResponse()->setRedirect($url);            
        }
        return $proceed();
    }
}