Language switcher on the login screen

[johnbillion]

Since [41692] it's possible to control the language of the login screen using the wp_lang query variable (eg. wp-login.php?wp_lang=it_IT). This is a hidden feature that's only used by the interim login modal.

A language switcher should be introduced on the login screen that makes use of this so users can use the login screen, the password reset screens, and the registration screen in their own language. The behaviour would be the same as the language choosers that are used elsewhere in core, for example on the General Settings screen and on the Multisite registration screens.

One thing that needs to be considered is how the language persists between screens, how to persist POSTed values such as redirect_to, and whether it should persist in user meta once the user successfully logs in. Suggestions welcome.

[swissspidy]

How has this been implemented on WordPress.org?

[netweb]

Replying to swissspidy:

How has this been implemented on WordPress.org?

I've not looked at it personally but the code is here: ​https://meta.trac.wordpress.org/browser/sites/trunk/wordpress.org/public_html/wp-content/themes/pub/wporg-login

[Nikschavan]

Seems this was the main commit for adding this to WordPress.org - ​https://meta.trac.wordpress.org/changeset/6677

[Nikschavan]

Patch 43700.1.diff​ is the first pass at adding the language switcher to the login window.

One thing that needs to be considered is how the language persists between screens, how to persist POSTed values such as redirect_to, and whether it should persist in user meta once the user successfully logs in. Suggestions welcome.

This attached patch adds the $_GET parameters to hidden variables so that they are retained after the page is reloaded.
Currently three $_GET parameters are handled interim-login, redirect_to, action.

[johnbillion]

43700.diff​ is a work in progress patch that continues the work of @Nikschavan. Changes:

• Ensure the language switcher only appears when there are language choices available
• Store the selected language in a cookie so it persists between all of the possible login screens and actions
• Take the cookie into account when determining the user's locale
• Allow the user to switch to en_US when it's not the site's default language

[Nikschavan]

43700.2.diff​ Refreshes @johnbillion's patch with latest trunk and fixes 2 PHP notices.

• Set default value of explicit_option_en_us as false in wp_dropdown_languages() to avoid PHP notice for undefined index on Line 1511 in src/wp-includes/l10n.php
• Use esc_url_raw() instead of sanitize_url() to remove depracation warning in wp-login.php

@johnbillion, @swissspidy - Can this ticket be considered for the 5.3 release cycle?

[Nikschavan]

Another question would be - should the value of wp_lang be set to user locale after successful login, If user locale is currently empty?