extension – Aimeos

Steps to configure your TYPO3 extension automatically

aimeos — Wed, 18 Feb 2015 11:16:27 +0000

Simplicity is key! I think nobody would oppose to this little sentence but in the TYPO3 ecosystem, many things are not very simple – at least not for new users. Even the most popular extensions need a deep knowledge of how to configure them before they can be used. And good documentation is most of time a rare thing!

So why not build an extension that works out of the box and configures itself as far as possible to give users an instant feeling of success? The constants.txt or setup.txt TypoScript files of the extensions can contain almost all default settings. But things get difficult if the required configuration depends on dynamic things like page IDs. Then, all hope of simplicity is lost and users have to add the necessary settings themselves again.

Is this really true?

The signal/slot mechanism described in the article about executing scripts after installing an extension provides the tools to get things done. Although, the article is very generic and I would like to go into more detail about how we’ve implemented things in the Aimeos web shop distribution.

The distribution imports some pages from the data.t3d file and the TYPO3 importer cares about avoiding conflicts with existing pages by reassigning the page IDs. Problems arose after we’ve added some required TypoScript settings for access restricted pages like the “MyAccount” page. In order to redirect to the login form when a user isn’t logged in, you have to configure its page ID. That seems to be impossible at the first glance when the page ID will differ in each TYPO3 installation.

The solution is to look up the page ID from the database dynamically after the extension is installed and generate a constants.txt file that will then contain the actual page ID. The constants in this file can be used in the TypoScript setup.txt file afterwards.

But first, you need to make sure your code will be executed automatically after the extension is installed. Remember the steps from the article about executing scripts? The first one was to register your extension for listening to the signal for extension installation:

```
if (TYPO3_MODE === 'BE') {
```

    $class = 'TYPO3\\CMS\\Extbase\\SignalSlot\\Dispatcher';

    $dispatcher = \TYPO3\CMS\Core\Utility\GeneralUtility::makeInstance($class);

```
    $dispatcher-&gt;connect(
```

        'TYPO3\\CMS\\Extensionmanager\\Service\\ExtensionManagementService',

```
        'hasInstalledExtensions',
```
```
        '\\\\',
```
```
        ''
```
```
    );
```
```
}
```

Please replace , , and with the strings that fits for your extension. Afterwards, you must implement the method of your class you’ve registered for listening. We use the name of the Aimeos setup class in our example because you can have a look at it’s implementation for reference.

```
&lt;?php
```
```
 
```
```
namespace \;
```
```
 
```

use \TYPO3\CMS\Core\Utility\GeneralUtility;

use \TYPO3\CMS\Backend\Utility\BackendUtility;

```
 
```
```
class Setup
```
```
{
```

    public function process( $extname = null )

```
    {
```
```
        if( $extname !== '' ) {
```
```
            return;
```
```
        }
```
```
 
```
```
        $data = '';
```
```
        $ds = DIRECTORY_SEPARATOR;
```

        $filename = dirname( __DIR__ ) . $ds . 'Configuration' . $ds . 'TypoScript' . $ds . 'constants.txt';

```
 
```

        $records = BackendUtility::getRecordsByField( 'pages', 'title', 'My account' );

```
 
```
```
	foreach( $records as $record ) {
```

            $data .= 'config.typolinkLinkAccessRestrictedPages = ' . intval( $record['uid'] ) . "\n";

```
        }
```
```
 
```

        GeneralUtility::writeFile( $filename, $data );

```
    }
```
```
}
```

The example contains placeholders for and and you have to replace them with the names from your extension.

First we have to ensure that the constants.txt file is only created if our own extension is installed. Thus, we check for the extension name to filter out all other extension installations.

The TYPO3 backend utilities contains some nice methods to retrieve records from the database with only little effort. For example, you can use the getRecordsByField() method from the BackendUtility class to fetch all records from a table where a field matches a certain value. Here we want to get all records where the “title” equals “My account” from the “pages” table.

Searching for a page with a title only works as long as the page isn’t renamed! In the best case, your extension has added the page including the page name itself, so this won’t be a problem. It’s not bad if somebody renames the page afterwards because the page ID will stay the same in this case. The only problematic situation could be several pages with the same name.

Make sure you generate valid TypoScript afterwards, including new lines and keep an eye on security by enforcing the types you are expecting! The foreach() loop is a great way to deal with no records and several returned records too because both can an will happen sooner or later. Don’t throw an exception if something unexpected happens because it may lead to not being able to install your extension at all! It’s better to drop those records and add a message to the log file.

You don’t have to add all TypoScript statements to your constants.txt that contains a dynamic value. Instead, you can also define them like “page.myaccount.id = 123” and reference the constants in your setup.txt with “{$page.myaccount.id}”. This is especially handy to keep your constants.txt small and if you need the value several times.

At last, your extension has to write the TypoScript statements to the constants.txt file. The GeneralUtiltiy class from the TYPO3 core contains a little writeFile() helper function to get this done within one line.

Simple, isn’t it?

These few additional lines can make the difference between an easy installable extension and hours of frustrations bugging your users. I think the little effort during the development of your extension is worth the hours saved later on. Your users will thank you for your work by using your extension more often!

A special thanks for the inspiration to this tutorial goes to Stephan Schuler from netlogix.

How to execute scripts after installing TYPO3 extensions

aimeos — Thu, 12 Feb 2015 09:58:19 +0000

Extensions are a great way to add features to the TYPO3 CMS and there are extension for virtually everything! Simply download them from the TYPO3 extension repository and install them via the Extension Manager in the TYPO3 back-end. So far so good …

Often, the remaining tasks of configuring the extension, adding new pages with the plug-ins from the extension or importing required data into the database becomes much more cumbersome. Why can’t life be not as easy as in other CMS? Just click and everything works?

Yes, we can!

The infrastructure for performing additional tasks after installing extensions is part of TYPO3 since some time. At least since TYPO3 6.2 it works flawlessly, before your way may vary. The trick is to utilize the signal/slot mechanism to connect to the Extension Management service and listen for signals emitted after an extension was installed.

In the Aimeos TYPO3 web shop extension we’ve added the following code to the ext_localconf.php:

```
if (TYPO3_MODE === 'BE') {
```

    $class = 'TYPO3\\CMS\\Extbase\\SignalSlot\\Dispatcher';

    $dispatcher = \TYPO3\CMS\Core\Utility\GeneralUtility::makeInstance($class);

```
    $dispatcher-&gt;connect(
```

        'TYPO3\\CMS\\Extensionmanager\\Service\\ExtensionManagementService',

```
        'hasInstalledExtensions',
```
```
        'Aimeos\\Aimeos\\Setup',
```
```
        'executeOnSignal'
```
```
    );
```
```
}
```

The first line ensures that we are connecting only to the Extension Management service if we are in the back-end. If you leave this line out, your script would connect at every front-end request too, which would only slow down response times. The next two lines instantiates the signal/slot dispatcher class and the makeInstance() method of the GeneralUtility class does a good job.

Don’t use the PHP “new” operator for creating the class instance! This would create one instance each time the code is executed instead of sharing a common instance during the request.

The remaining lines connect your method executeOnSignal() of your namespaced class Aimeos\Aimeos\Setup to the Extension Management service whose class name is handed over as first parameter. Here we are listening to the hasInstalledExtensions signal, that is emitted by the service after an extension has been installed. The key of the installed extension will be passed as first parameter to our method.

There’s another signal that is emitted by the Extension Management service named willInstallExtensions. By listening to this signal, your script can be informed about which extensions are going to be installed next. An array of extension keys is given in this case.

Do what you need

At last, you need to create a class that contains the code to be executed after an extension is installed. The Aimeos TYPO3 extension contains a Setup class in the Classes/ directory of the extension with a method named executeOnSignal() to care about this. The basic code of this class is:

```
&lt;?php
```
```
 
```
```
namespace Aimeos\Aimeos;
```
```
 
```
```
class Setup
```
```
{
```

    public function executeOnSignal( $extname = null )

```
    {
```
```
        if( $extname !== 'aimeos' ) {
```
```
            return;
```
```
        }
```
```
 
```
```
        // your code
```
```
    }
```
```
}
```

The namespace declaration is important but must be adapted to your extension. The first namespace part is the vendor name, e.g. the name of your company. The second part is the extension key with the first letter uppercased. If your extension key contains an underscore, then the underscore is removed and the next character transformed to uppercase as well, e.g. the boostrap_package uses BootstrapPackage as the second namespace part.

You are free to use any valid class and method name in your extension. Only make sure that the third and fourth parameter of the connect() method call are named appropriately. Also, ensure that your class and method are neither abstract nor static so an instance can be created. Like said above, the key name of the extension that has been installed is given as first parameter to your method. For compatibility reasons, you should make that parameter optional by assigning a default value of null.

Use the given extension key name to filter for your one! The Extension Management service will inform your script about every extension that is installed, not only your own one. Otherwise, you would execute your script code for every installed extension and this may slow down the installation process depending on how much your code does.

What’s next?

Pretty simple, isn’t it? Now it’s time to pimp your TYPO3 extension to remove as much burden as possible from the user! In a second article we will go into more detail how this can save your users day when your extension imports pages and depending TypoScript configuration.

A special thanks goes to Benjamin Kott for his bootstrap_package because it was the first that provided a working example that the signal/slot infrastructure can be used for these kind of use cases.