Magento 2: rewrite controller

Question

how can i rewrite a controller (that's actually an action) in Magento 2?
I tried, as instructed here like this:

I have my own module called Namespace_Module with a di.xml file, that is taken into consideration, because the same system works on models and blocks
Example:

<?xml version="1.0"?>
<config xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="../../../../../lib/internal/Magento/Framework/ObjectManager/etc/config.xsd">
    <!-- this one doesn't work for a controller action -->
    <preference for="Magento\Backend\Controller\Adminhtml\Dashboard\RefreshStatistics" 
         type="Namespace\Module\Controller\Adminhtml\Dashboard\RefreshStatistics" />
    <!-- this one works for a model -->
    <preference for="Magento\Customer\Model\Resource\GroupRepository" 
        type="Namespace\Module\Model\Resource\Customer\GroupRepository" />
     <!-- this one works also for a block -->
    <preference for="Magento\Backend\Block\Dashboard" 
        type="Namespace\Module\Block\Backend\Dashboard" />
</config>

I'm trying to replace the dashboard refresh statistics with my own action. Doing it like above, the execute method in the original class still gets called and not my own.
var/cache and var/generation were cleared.

Answer 1

Found it.
Actually what I posted in the question is the correct way of rewriting a controller.

<preference for="Magento\Backend\Controller\Adminhtml\Dashboard\RefreshStatistics" 
     type="Namespace\Module\Controller\Adminhtml\Dashboard\RefreshStatistics" />

works nicely.
The problem for me was this. I forgot to mention that I removed some modules Magento2 and among these it was the Reports module. I didn't state it in the question because I didn't think it was significant.
The method above for rewriting controllers (and maybe other classes) works if all the classes you are trying to change exist and all their parent classes also.
So the original Magento\Backend\Controller\Adminhtml\Dashboard\RefreshStatistics extends Magento\Reports\Controller\Adminhtml\Report\Statistics that I had removed.
In magento 2 the routes are collected by scanning the folders Controller folders for all the enabled modules and they are collected in an array.
So far so good.
I end up with this line among others:

[magento\backend\controller\adminhtml\dashboard\refreshstatistics] => Magento\Backend\Controller\Adminhtml\Dashboard\RefreshStatistics

Then the request is matched to the route magento\backend\controller\adminhtml\dashboard\refreshstatistics and Magento checks if the class corresponding to that route is subclass of Magento\Framework\App\ActionInterface. Since the routes are collected before my class should get identified and instantiated, the old class is validated instead of my own. And the parent class of the class Magento\Backend\Controller\Adminhtml\Dashboard\RefreshStatistics does not exist.

A solution to keep the reports module disabled but still make it work is to create an interceptor for the method that reads all the routes and replace the route mentioned above.

So I added this in di.xml

<type name="Magento\Framework\App\Router\ActionList\Reader">
    <plugin name="namespace-module-route" type="Namespace\Module\Model\Plugin\ActionListReader" sortOrder="100" />
</type>

and my plugin looks like this:

<?php
namespace Namespace\Module\Model\Plugin;

class ActionListReader
{
    public function afterRead(\Magento\Framework\App\Router\ActionList\Reader\Interceptor $subject, $actions)
    {
        $actions['magento\backend\controller\adminhtml\dashboard\refreshstatistics'] = 'Namespace\Module\Controller\Adminhtml\Dashboard\RefreshStatistics';
        return $actions;
    }
}

Answer 2

dont use preference use plugin to extend any core module that is in di.xml

<type name="Magento\Catalog\Controller\Product\View">
    <plugin name="product-cont-test-module" type="Sugarcode\Test\Model\Plugin\Product" sortOrder="10"/>
</type>

and in Product.php

public function aroundExecute(\Magento\Catalog\Controller\Product\View $subject, \Closure $proceed)
{
    echo 'I Am in Local Controller Before <br>';
    $returnValue = $proceed(); // it get you old function return value
    //$name='#'.$returnValue->getName().'#';
    //$returnValue->setName($name);
    echo 'I Am in Local Controller  After <br>';
    return $returnValue;// if its object make sure it return same object which you addition data
}

How to Override Core Block, Model and controller in Magento2

Answer 3

I have rewrite controller for review model. composer.json file:

{
        "name": "apple/module-review",
        "description": "N/A",
        "require": {
            "php": "~5.5.0|~5.6.0|~7.0.0",
            "magento/framework": "100.0.*"
        },
        "type": "magento2-module",
        "version": "100.0.2",
        "license": [
            "OSL-3.0",
            "AFL-3.0"
        ],
        "autoload": {
            "files": [
                "registration.php"
            ],
            "psr-4": {
                "Apple\\Review\\": ""
            }
        }
    }

registration.php file

    \Magento\Framework\Component\ComponentRegistrar::register(
        \Magento\Framework\Component\ComponentRegistrar::MODULE,
        'Apple_Review',
        __DIR__
    );

app/code/Apple/Review/etc/module.xml file:

    app/code/Apple/Review/etc/di.xml file for override review controller.
    <?xml version="1.0"?>
    <!--
    /**
     * Copyright © 2015 Magento. All rights reserved.
     * See COPYING.txt for license details.
     */
    -->
    <config xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="urn:magento:framework:ObjectManager/etc/config.xsd">
        <preference for="Magento\Review\Controller\Product\Post" type="Apple\Review\Controller\Post" />   
    </config>

In controller file for review model,

app/code/Apple/Review/Controller/Post.php

    use Magento\Review\Controller\Product as ProductController;
    use Magento\Framework\Controller\ResultFactory;
    use Magento\Review\Model\Review;

    class Post extends \Magento\Review\Controller\Product\Post
    {
        public function execute()
        {
           $resultRedirect = $this->resultFactory->create(ResultFactory::TYPE_REDIRECT);
            if (!$this->formKeyValidator->validate($this->getRequest())) {
                $resultRedirect->setUrl($this->_redirect->getRefererUrl());
                return $resultRedirect;
            }

            $data = $this->reviewSession->getFormData(true);
            if ($data) {
                $rating = [];
                if (isset($data['ratings']) && is_array($data['ratings'])) {
                    $rating = $data['ratings'];
                }
            } else {
                $data = $this->getRequest()->getPostValue();
                $rating = $this->getRequest()->getParam('ratings', []);
            }

            if (($product = $this->initProduct()) && !empty($data)) {
                /** @var \Magento\Review\Model\Review $review */
                $review = $this->reviewFactory->create()->setData($data);

                $validate = $review->validate();
                if ($validate === true) {
                    try {
                        $review->setEntityId($review->getEntityIdByCode(Review::ENTITY_PRODUCT_CODE))
                            ->setEntityPkValue($product->getId())
                            ->setStatusId(Review::STATUS_PENDING)
                            ->setCustomerId($this->customerSession->getCustomerId())
                            ->setStoreId($this->storeManager->getStore()->getId())
                            ->setStores([$this->storeManager->getStore()->getId()])
                            ->save();

                        foreach ($rating as $ratingId => $optionId) {
                            $this->ratingFactory->create()
                                ->setRatingId($ratingId)
                                ->setReviewId($review->getId())
                                ->setCustomerId($this->customerSession->getCustomerId())
                                ->addOptionVote($optionId, $product->getId());
                        }

                        $review->aggregate();
                        $this->messageManager->addSuccess(__('You submitted your review for moderation.Thanks'));
                    } catch (\Exception $e) {
                        $this->reviewSession->setFormData($data);
                        $this->messageManager->addError(__('We can\'t post your review right now.'));
                    }
                } else {
                    $this->reviewSession->setFormData($data);
                    if (is_array($validate)) {
                        foreach ($validate as $errorMessage) {
                            $this->messageManager->addError($errorMessage);
                        }
                    } else {
                        $this->messageManager->addError(__('We can\'t post your review right now.'));
                    }
                }
            }
            $redirectUrl = $this->reviewSession->getRedirectUrl(true);
            $resultRedirect->setUrl($redirectUrl ?: $this->_redirect->getRedirectUrl());
            return $resultRedirect;
        }
    }

This is working code for review controller override in magento2. Thanks.