Multi-Store Fix Module for Magento 2

Fix redirect loops when using multiple storeviews in Magento 2 with MAGE_RUN_CODE environment variables combined with the locale switcher.

Description

Magento 2 has a built-in store switcher (language switcher / locale switcher) that visitors can use to choose their preferred language.

If a language is chosen, the visitor will be redirected to the same page in one of the other store views (languages). The store switcher uses a cookie to remember the selected store code between requests. This makes sense when multiple store views share the same base url, because otherwise the selected store view could not be determined.

It's common for a web shop to have multiple domain names, with each hostname showing a translated version of the same content. When a visitor selects another language, he can simple be redirected to the same page on one of the other domain names: the request hostname is used to determine the selected store view. The recommended way to set this up is by configuring the web server to set the environment variable MAGE_RUN_TYPE to store and MAGE_RUN_CODE to the correct store code depending on the requested hostname.

If a store code is found in both the store switcher cookie and the server environment variable, Magento uses the one from the cookie. This doesn't make sense. It breaks store switching and can even cause a redirect loop.

Example

Imagine the following Magento 2 web shop with two store views:

Base URL	Store Code	Store Name
http://myshop.com/	default	English
http://myshop.nl/	nl	Dutch

1. Visitor opens http://myshop.com/. While processing the request, Magento finds no cookie, but the environment variable is set to default so the English store view is shown.
2. Visitor selects Dutch from the locale switcher.
3. Magento sets the cookie for myshop.com to nl and redirects the visitor to http://myshop.nl/.
4. Visitor's browser requests http://myshop.nl/. Magento finds no cookie (as it was set for the other domain), but the environment variable is set to nl so the Dutch store view is shown. So far, no problems.
5. Now, the visitor tries to switch back to English using the locale switcher.
6. Magento sets the cookie for myshop.nl to default and redirects the visitor to http://myshop.com/.
7. Visitor's browser requests http://myshop.com/. Magento finds the cookie (from step 3) is set to nl and ignores the environment variable. It loads the Dutch store view, but because the hostnames do not match it redirects to http://myshop.nl/.
8. Visitor's browser requests http://myshop.nl/. Magento finds the cookie (from step 6) set to default and ignores the environment variable. It loads the English store view, but because the hostnames do not match it redirects to http://myshop.com/.
9. Steps 7 and 8 will be repeated until the browser gives up and shows a Too many redirects error message:

Solution

This module uses a plugin for Magento's StoreCookieManager::getStoreCodeFromCookie method which is responsible for reading the store code from the locale switcher cookie. It gets called by StoreResolver::getCurrentStoreId which looks up the store code in the database and returns its ID.

If a store code is set by the webserver using an environment variable, the plugin will not read the cookie but return the store code as defined by the webserver instead. This way a cookie can never override the environment variable.

The plugin checks to see if MAGE_RUN_TYPE is set to store and MAGE_RUN_CODE contains a string value. This way, it will not break other setups. For instance, when MAGE_RUN_TYPE is set to website, the problem as described above does not occur and there's no need for a fix.

Installation

The preferred way of installing this module is through Composer. Simply add metmeer/magento2-multi-store-fix as a dependency, and Composer will take care of downloading and extracting the files to the correct locations:

composer require metmeer/magento2-multi-store-fix

Optionally you can download the latest version of the module here and copy the archive's contents to your project under directory app/code/METMEER/MultiStoreFix.

After the files are installed, the module can be enabled with this command:

bin/magento module:enable METMEER_MultiStoreFix

Each time a new module is enabled, Magento needs to upgrade the database. This is done with the following command:

bin/magento setup:upgrade

If the deployment mode is set to production, the dependency injection compiler needs to be run. This is not necessary for the developer mode. To start the compiler, use this command:

bin/magento setup:di:compile

At last, the caches should be cleared with this command:

bin/magento cache:flush

Configuration

No further configuration is required. The fix is applied automatically when needed.

Contribution

Feel free to contribute to this module by reporting issues or creating pull requests for improvements.

License

This project is licensed under the MIT License - see the LICENSE file for details.

Copyright

Copyright (c) 2017 METMEER - All rights reserved.