I have made a module to override Magento\Catalog\Block\Product\View. I want to add some standard things to the MetaTitle and MetaDescription on the product page. Specifically for empty descriptions.


I alter the title string and save with


The same goes for the description



The MetaTitle and MetaDescription on the product page stay the same.

Possible causes and solutions

I have investigated and ruled out the following:

  • Cache
  • Third party modules
  • Module related problems (magento setup:upgrade,...)


When I echo the string I want to set I get the following error:

a:4:{i:0;s:282:"Warning: Cannot modify header information - headers already sent by (output started at /app/code/[MyVendor]/[MyModule]/Block/Product/View.php:61) in /www/vendor/magento/framework/Stdlib/Cookie/PhpCookieManager.php on line 125";i:1;s:1702:"#0 [internal function]: Magento\Framework\App\ErrorHandler->handler(2, 'Cannot modify h...', '/data/sites/web...', 125, Array)
#1 /www/vendor/magento/framework/Stdlib/Cookie/PhpCookieManager.php(125): setcookie('mage-messages', '[]', 1533729078, '/', '', false, false)
#2 /www/vendor/magento/framework/Stdlib/Cookie/PhpCookieManager.php(98): Magento\Framework\Stdlib\Cookie\PhpCookieManager->setCookie('mage-messages', '[]', Array)
#3 /www/vendor/magento/module-theme/Controller/Result/MessagePlugin.php(85): Magento\Framework\Stdlib\Cookie\PhpCookieManager->setPublicCookie('mage-messages', '[]', Object(Magento\Framework\Stdlib\Cookie\PublicCookieMetadata))
#4 /www/vendor/magento/framework/Interception/Interceptor.php(152): Magento\Theme\Controller\Result\MessagePlugin->afterRenderResult(Object(Magento\Framework\View\Result\Page\Interceptor), Object(Magento\Framework\View\Result\Page\Interceptor))
#5 /www/var/generation/Magento/Framework/View/Result/Page/Interceptor.php(26): Magento\Framework\View\Result\Page\Interceptor->___callPlugins('renderResult', Array, Array)
#6 /www/vendor/magento/framework/App/Http.php(139): Magento\Framework\View\Result\Page\Interceptor->renderResult(Object(Magento\Framework\App\Response\Http\Interceptor))
#7 /www/vendor/magento/framework/App/Bootstrap.php(258): Magento\Framework\App\Http->launch()
#8 /www/index.php(39): Magento\Framework\App\Bootstrap->run(Object(Magento\Framework\App\Http))

But I think this is more an issue of the echo than error due to code error.

I mainly followed this logic. Is there another logic I should follow or does anyone have an idea of why the metainfo does not change?

Thanks for your time!

  • You cant override View.php file you have to create plugin for your changes. Commented Aug 8, 2017 at 12:16
  • Thanks Rakesh. Is it possible to get a specific example of a plugin for metadata? Commented Aug 8, 2017 at 14:12
  • I've studied Plugins but are too limiting for my purposes. eg. I want to be able to call the current product. Plugins don't seem suitable to do that Commented Aug 9, 2017 at 12:18

1 Answer 1


create di.xml file and called plugin function,

<?xml version="1.0"?>
<config xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="urn:magento:framework:Event/etc/events.xsd">
    <type name="Magento\Catalog\Block\Product\View">
        <plugin name="block_product_view_plugin" type="Vendor\Modulename\Plugin\Productview"/>

Create plugin file inside your module,

namespace Vendor\Modulename\Plugin;

use Closure;

class Productview
    public function aroundGetProduct( 
        \Magento\Catalog\Block\Product\View $subject,
        Closure $proceed
        $newdata = $proceed();        

            $metaTitle = $newdata->getMetaTitle(); 
            return $newdata; 
        return $newdata;
  • Thanks for your effort. But this acts on the product itself. I want to change the metadescription according to the product page. It would be nice to include the current category in the metadescription Commented Aug 10, 2017 at 9:10

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