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A queue can be rather useful when you want to process a lot of data, but also when I just want to make sure things react quickly. Let’s have a look at a simple case where you might want to send an email.

In a lot of cases people send e-mails right in a controller action. This is okay for a lot of sites, but sometimes if things are mission critical it helps to use a queue. Imagine what happens if there’s a temporary problem with the mail system, since you’re sending it right in your controller you’ll probably show the user an error message telling him that something went wrong. Seeing errors is hardly ever a good thing, with a queue you could use a simple operation to put the action in a queue and process it later. If it fails you could try again a bit later and if it fails permanently put it in a log file you’re monitoring.

There might also be a maintenance task that you can finish before PHP times out. Using a queue would make it more solid, put every object you want to process in a queue and process it piece by piece.

Putting things in the queue

It’s fairly simple to put things the queue. All you need is a queue name to ensure you can keep your tasks apart and the data you need later to process the item from the queue:

use Concrete\Core\Foundation\Queue\Queue;
 
$queue = Queue::get('queue-demo');
$queue->send(1);

With this we are putting the number 1 in a queue called “queue-demo”. Now that we have objects in our queue we need to process them.

Processing queue

When processing a queue we obviously have to use the same queue name.

use Concrete\Core\Foundation\Queue\Queue;
 
$queue = Queue::get('queue-demo');
$queueMessages = $queue->receive(10);
foreach ($queueMessages as $msg) {
   $userId = $msg->body;
   // load the object for the user ID and process it
 
   $queue->deleteMessage($msg);
}

That’s basically all you need to do, but you’ll of course need to put that code somewhere.

concrete5 has an easy to extend CLI API. You derive a class from “Symfony\Component\Console\Command\Command”, implement the “execute” method and handle your queue there. Once you register your command, you can access it by running “./concrete/bin/concrete5”
You can find a complete example here: https://github.com/Remo/concrete5-queue-demo. Here are some of the relevant lines:

• Register CLI command in controller
• Configure command, the name is what you’ll specify when running the command
• Locking and unlocking process. Helps to ensure the command is only running once.
• Getting items from queue and looping through them

You’ll just have to run your command regularly to execute it, a cronjob like this should do the trick: “./concrete/bin/concrete5 queue-demo:process-notifications”.

There’s also a way to handle everything in a job which is especially useful for maintenance tasks as it doesn’t require that you add queue items initiaited by a user action. There’s a good article in the official documentation about this: https://documentation.concrete5.org/developers/jobs/creating-and-scheduling-a-queueable-job.

Benefits

• Non-blocking executing of tasks
• Avoid timeouts when handling a lot of data

Disadvantages

• Adds a bit more complexity to your code
• concrete5 queues require polling on the executing side, adding a delay to your task. Deosn’t apply to queues in general, if you use something like beanstalk you can process tasks immediately

Some of the code was written by Michele Locati. Hope you enjoy working with queues!

concrete5 had an API to add a custom button to the inline editing toolbar. Here’s the article for the older 5.6 version: http://www.codeblog.ch/2012/04/concrete5-custom-toolbar-button/

In 5.7 a few things have changed. The idea is still the same, but you’ll have to use namespaces and loading classes is a bit different too.

Here’s how to get access to the menu helper:

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$menuHelper = Core::make('helper/concrete/ui/menu');

You then have to call the addPageHeaderMenuItem method. Assuming you’ve already got a package, this is how the on_start method could look like:

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public function on_start()
{
    $req = \Request::getInstance();
 
    // Make sure we don't inject our code if it's called by an AJAX request
    if (!$req->isXmlHttpRequest()) {
        /* @var $menuHelper \Concrete\Core\Application\Service\UserInterface\Menu */
        $menuHelper = Core::make('helper/concrete/ui/menu');
 
        $menuHelper->addPageHeaderMenuItem('ortic_btn', $this->pkgHandle, array(
            'icon' => 'question',
            'label' => t('Ortic'),
            'position' => 'right',
            'href' => 'http://www.ortic.com',
            'linkAttributes' => array('id' => 'ortic-button', 'target' => '_blank')
        ));
    }
}

Please note that we’re checking if the request is handled by an AJAX request. This can help to avoid collisions if you inject more things.

After that you’ll only have to create one more file in your package. Within “menu_items”, create a new folder with the button name, in my case “ortic_btn” (the first argument of addPageHeaderMenuItem ) and add a content like this:

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<?php
namespace Concrete\Package\OrticToolbar\MenuItem\OrticBtn;
 
class Controller extends \Concrete\Core\Application\UserInterface\Menu\Item\Controller
{
    /**
     * Return false if you don't want to display the button
     * @return bool
     */
    public function displayItem()
    {
        return true;
    }
}

Please note that “OrticToolbar” refers to my package.

You can find the complete example on github: https://github.com/ortic/ortic-button

concrete5 version 5.7 is out for a couple of month and as always with a major version, old stuff might is broken and it takes a while to find new packages, resources and information. I tried to assemble a list of open source packages for 5.7 which you can use in your project or learn from to build your own packages. Please note that some packages aren’t stable yet, it’s not a list for end-users but rather a list for concrete5 developers eager to learn about building add-ons.

Please let me know if I have missed a package, I’ll happily update my list.

As you might have heard, a major release of concrete5 has been published. If you haven’t, here’s a list of things that have changed http://www.concrete5.org/documentation/background/version_history/5-7-0/.

In this post, I’m going to look at the process of upgrading an existing package which worked for version 5.6. I’m doing this step by step to show to show you possible error messages which might help you convert you own packages, but please note that I’m aiming at concrete5 developers knowing version 5.6 and will thus skip a few things which haven’t changed.

I’m going to use a simple package I wrote a while ago, it’s the zoom image block which allows you to zoom into a single image. Much like lightbox, but limited to a single picture. The code can be found here https://github.com/Remo/concrete5-zoom-image.

The Directory Structure of concrete5.7

Once you’ve downloaded and installed concrete5.7 you’ll probably see that the directory structure has changed quite a bit:

• The root directory
  • There are only four directories left
  • application – this is where your overrides for your own site should be placed
  • concrete – this is still the core and should never be touched unless
  • packages – this is obviously the place where you have to add your own packages
  • updates – still the same, here’s where you can find an updated core
• What new directories are there
  • authentication – there’s a pretty neat authentication system you can extend, by default there’s a built-in concrete5 system and one supporting facebook
  • bootstrap – as the name tells you, here’s where things get started, loaded etc.
  • src – this is where you can find the PSR4 auto-loaded classes, have a look at this directory to get acquainted with the new things in concrete5
  • vendor – version 5.7 partially uses composer.json to manage dependencies, this is where you can find the libraries installed by composer

Installing the zoom image package

Before you install anything, make sure you’ve got a database dump you can easily restore, it might make things easier.

I simply downloaded the latest version from github and placed it in a directory called zoom_image in the packages directory. In concrete5, type add functionality in the search box and select the first item. You’ll already see your first exception at this point:

.

We can’t see any details about the error, now what? You can either look at your database and check the content of the Logs table or go back and type debug in the search box. Navigate to debug settings and check Show errors in page.. If you then to back to install your package, you’ll see a nice output produces by https://github.com/filp/whoops. It tells use, that we can’t redeclare the class ZoomImagePackage. That’s because concrete5.7 uses namespaces for pretty much everything. To get around this problem, we have to update the controller in our package. The first few lines have to look like this:

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<?php
 
namespace Concrete\Package\ZoomImage;
 
defined('C5_EXECUTE') or die('Access Denied.');
 
class Controller extends \Concrete\Core\Package\Package {
 
    protected $pkgHandle = 'zoom_image';
    protected $appVersionRequired = '5.7.0';
    protected $pkgVersion = '2.0.0';

• A package controller class is always called Controller.
• It derives from \Concrete\Core\Package\Package
• The namespace of your package controller has to start with Concrete\Package\ and must then be append with the camelcased name of your package.
• I also updated the number to be 2.0.0, that’s not necessary, but probably make sense

When you reload the add functionality page again, you’ll finally see our package. Let’s try and install it! Next error:
Class 'Concrete\Package\ZoomImage\BlockType' not found. As I’ve mentioned above, the src directory contains some rather useful classes. We’re looking for something related to blocks and no surprise, there’s a Block directory. If you look at src/Block/BlockType/BlockType.php you can see where the missing class is. Open the file and you’ll know the namespace we have to import.

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<?php
 
namespace Concrete\Package\ZoomImage;
 
use Concrete\Core\Block\BlockType\BlockType;

Unfortunately the package got installed anyway and uninstalling can be tricky if parts of your code haven’t been upgraded for 5.7. Let’s just restore that dump file we’ve created and try to install the package again. Guess what, the next exception. The zoom image block uses an old out-dated method called Loader::block. Remove it, restore the dump file and try again. Next, you’ll get an exception because BlockController isn’t defined. Namespaces again! While we do this, we can also make the class name change like we did with the package controller.

• The class is simply called Controller too.
• You’ll have to derive it from \Concrete\Core\Block\BlockController. If you look at the code below, you can see that I didn’t specify the fully qualifier name when deriving the class but rather added another statement to use.
• Your namespace has to be Concrete\Package\[camel-case-package-handle]\Block\[camel-case-block-handle]

After making these changes, restore the dump file and install the package again – the installation process works! Now let’s try to add a zoom image block. Go back to the website and hit the plus icon:

Drag your block into the page and release it. The block interface shows up, but after adding the block, nothing happens. That’s because the AJAX magic hid the error message, reload the page and you’ll get your next exception to work with Class 'Concrete\Package\ZoomImage\Block\ZoomImage\File' not found. As you can see, it tries to load the class File in our own namespace where it can’t be found. We forgot to add another use statement. Let’s add \Concrete\Core\File\File and reload the page.

We now get the message Call to a member function getFileObject() on a non-object.

Accessing the controller from view.php was a bit of a habit when you looked at code back from version 5.0 and a bit later. Before we worry about the message, let’s make sure we properly forward data from the controller to the view and not the other way round.

Let’s add the following method to the block controller:

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public function view() {
    $ih = Loader::helper('image');
 
    $fileObject = $this->getFileObject();
 
    $fileName = $fileObject->getRelativePath();
    $thumbnail = $ih->getThumbnail($fileObject, intval($this->thumbnailWidth), intval($this->thumbnailHeight));
 
    $this->set('fileName', $fileName);
    $this->set('thumbnail', $thumbnail);
}

Use those variables in your view.php and then try to reload the page. No error messages for a change, but when you publish the page changes and try to click on the thumbnail of your block, nothing happens. If we check the error console of the browser, we can see a problem due to undefined jQuery variables. At the time when our javascript gets executed, jQuery isn’t loaded. We don’t think too much about it and simply use addFooterItem instead of addHeaderItem.

Reload and still no luck, msie isn’t defined. But luckily that’s just because of our JavaScript which isn’t happy with the new jQuery version. Update the script to get around that.

That’s it! JavaScript fixed and no more problems, everything working! While this article is a bit long, what we actually did isn’t that much. In short:

• Namespaced all of our controllers, the package and block controller
• Made sure we properly forwarded our variables from the controller to the view (something I should have done before)
• Fixed a problem because of the new jQuery version in concrete5.7

You can find the commit I’ve made on github, a proper diff file might help https://github.com/Remo/concrete5-zoom-image/commit/fa0895081b62fbbb53d8e79c00858619fcec1fd4.

Have fun with 5.7!

If you built a couple of block templates, you’ll probably have had some nasty CSS code. Quite often you’ll have block specific options, a background color for example, which has to change the CSS file. You can easily do that, no doubt, just use addHeaderItem or put a style tag in your view.php. The block controller code might look like this:

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public function on_page_view() {
   $this->addHeaderItem('<style type="text/css">#my-block-' . $this->bID . ' { background: ' . $this->backgroundColor . '; }</style>');
}

In most cases you’ll find situations where the developer mixed a code like shown above with an external CSS file.

That certainly works but it’s usually much more elegant to keep all the block related CSS rules in a single file. We can use the great LESS language to achieve a much more elegant solution. Wouldn’t it be great if you could put all the CSS rules in a file like this:

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#my-block@{bID} {
   background: @backgroundColor;
   display: block;
   width: 100px;
   height: 100px;
}

That’s possible, it just takes a bit more code. You’ll need lessphp available here http://leafo.net/lessphp/. In your block controller, you can use a method like this to compile a LESS file like the one shown above into a static CSS with all variables replaced on the fly if required. Here’s the code:

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public function on_page_view() {
    // get current block template
    $template = $this->getCurrentTemplate();
 
    $bv = new BlockView();
    $bv->setController($this);
    $bv->setBlockObject($this->getBlockObject());
 
    // build path to less file
    $blockPath = $bv->getBlockPath();
    if ($template == '') {
        $blockTemplateLessPath = $blockPath . DIRECTORY_SEPARATOR . 'view.less';
    } else {
        $blockTemplateLessPath = $blockPath . DIRECTORY_SEPARATOR . 'templates' . DIRECTORY_SEPARATOR . $template . DIRECTORY_SEPARATOR . 'view.less';
    }
 
    // there's a less file, check if we have to rebuild it
    if (file_exists($blockTemplateLessPath)) {
        $lessFileHash = md5($blockTemplateLessPath . $this->bID . filemtime($blockTemplateLessPath));
        $cacheFile = DIR_FILES_CACHE . '/my-block-' . $lessFileHash . '.css';
 
        // cache file doesn't exist, rebuild it
        if (!file_exists($cacheFile)) {
            $lessc = Loader::library('3rdparty/lessc.inc', 'my_block');
            $lessc = new lessc();
            $lessc->setVariables(
                    array(
                        'backgroundColor' => $this->backgroundColor,
                        'bID' => $this->bID
                    )
            );
            $lessc->compileFile($blockTemplateLessPath, $cacheFile);
        }
 
        // include generated css file
        $this->addHeaderItem('<link rel="stylesheet type="text/css" href="' . REL_DIR_FILES_CACHE . '/cover-picture-' . $lessFileHash . '.css' . '"/>');
    }

If these instructions were a bit short, you can find a working example in one of my github repositories, check this: https://github.com/Remo/concrete5-cover-picture/blob/master/blocks/cover_picture/controller.php#L43-L81.

I hope this helps you to clean up your code!