TYPO3 7.3 - Extending the backend login form by using the new backend login form API

Back in january 2015 I added support for TYPO3 7.1 to the YubiKey TYPO3 extension and raised the extension compatibility level to be compatible with TYPO3 version 6.2.0 up to 7.99.99. When TYPO3 7.2 was released, I found out, that the YubiKey extension did’nt work any more with the new TYPO3 version, because the TYPO3 backend login has been rewritten. I debugged into the issue and found out, that the new backend login did not respect the template set in $TBE_STYLES[‘htmlTemplates’][$tmplPath].

It seemed I was not the only one having this problem, as another user already reported the same issue on forge. So with TYPO3 7.2+, you can’t use $TBE_STYLES[‘htmlTemplates’][$tmplPath] to add own fields to the backend login form, since it is not supported any more.

In this article I describe, how the new backend login form API is integrated in the OpenID extension and I also describe, how I extended the username/passwors login provider to add an additional field to the default backend login form.

The new login form API in TYPO3 7.3

In order to get the missing functionality of extending the backend login form back, the TYPO3 core developers added the backend login form API and also did a lot of great work refactoring the backend login. The backend login form API uses login providers to enable extension developers to add an own backend login form for e.g. an own ** authentication service. As an example, lets have a look at how the **OpenID authentication service is integrated.

The OpenID authentication service registers a new login provider by adding the following code in the file ext_localconf.php

New login providers must add a new key to the array $GLOBALS[‘TYPO3_CONF_VARS’][‘EXTCONF’][‘backend’ ][‘loginProviders’]. The new key must be an unix timestamp (unique for all login providers). The following array has the following keys:

• provider: The name of the login provider
• sorting: Defines the sorting order in case of there are multiple login providers
• icon-class: A class which defines the icon for the login provider
• label: the label for the login provider

Having the OpenID authentication service installed, the login provider of the OpenID extension adds a link to the backend login (see screenshot below).

When you follow the “Login with OpenID” link, you come to an own login form showing the OpenID field (screenshot below).

From there, you have the possibility to switch back to the username and password login. This is, because also the username and password login has an own login provider.

Lets have a look at the contents of the login provider class.

As you can see, there is not much magic there. The OpenidLoginProvider implements the LoginProviderInterface and has only one method (render), which is called in the LoginController of the TYPO3 backend login form. In case of the OpenID extension, you see that setTemplatePathAndFilename is used to set the Fluid template for the OpenID login form.

The template is kept really simple. It uses the layout “Login” (this is required) and has a section called “loginFormFields” (also required), which contains the OpenID login field.

Integration of the backend login form API to the YubiKey extension

For the YubiKey extension, I could have used the same technique as the OpenID extension does, but since some TYPO3 installations may require each user to use YubiKey two-factor authentication, it would be not very user-friendly to let a user manually switch to the YubiKey backend login provider when opening the TYPO3 backend login form.

In order to add the YubiKey field to the backend login, I extended the existing username and password login provider with my own login form. In the ext_localconf.php, I added the following code.

Next I created the YubiKey login provider, which calls the parent login provider (username and password) and sets the path to the Fluid template which contains the both the username and password fields and the YubiKey login field.

Note, that I do not implement the LoginProviderInterface, but extend the UsernamePasswordLoginProvider.

Finally, after the YubiKey extension is installed and activated, the TYPO3 backend login now again has an additional field for the YubiKey two factor authentication (screenshot below)

As TYPO3 7.3 has been released yesterday, extension authors ,who created own authentication providers for the TYPO3 backend, can now start to implement the new backend login API to their extensions.

The latest version 1.1.0 of the TYPO3 YubiKey extension uses the new backend login form API and is compatible with TYPO3 6.2 and TYPO3 7.x (except 7.2)