Monthly Archives: September 2013

Multiple Phonegap Push Notifications in the Android’s status bar

Last month I worked within an Android project using Phonegap, jQuery Mobile and Push Notifications. I also wrote one post explaining how to use PHP to send the server side’s part of the push notifications. Today I want to show one small hack, that I’ve done to change the default behaviour of push notifications. Let me explain it a little bit:

When you use the Push Plugin “out of the box” you will see one message in your Android’s status bar everytime we send one push notification (and you application isn’t running at this moment). If you click on the notification you application will start and you can handle this notification. But if you send more than one notifications to the device, only the last one will be shown on the status bar. This behaviour can be suitable for most situations, but within my application I wanted to see all the notifications in the status bar until I click on one (then all must disappear). If we want to do that we need to hack a little bit our Phonegap application. Let me show you what I’ve done.

Basically we need to change com.plugin.gcm.GCMIntentService file. If we open this Java file we can see that there’s one constant called: NOTIFICATION_ID and a public function called createNotification with something like that:

public static final int NOTIFICATION_ID = 237;
...

public void createNotification(Context context, Bundle extras)
{
    ...
    mNotificationManager.notify((String) appName, NOTIFICATION_ID, mBuilder.build());

}

I’m not a Java expert, but I notice that if I change this function to:

public static final int NOTIFICATION_ID = 237;
public static int MY_NOTIFICATION_ID = 237;
...

public void createNotification(Context context, Bundle extras)
{
    ...
    MY_NOTIFICATION_ID++;
    mNotificationManager.notify((String) appName, MY_NOTIFICATION_ID, mBuilder.build());

}

Now my android device will show multiple notifications, exactly as I need.

If we need to handle properly the way that our notifications are cancelled we also need to modify the public function cancelNotification

public static void cancelNotification(Context context)
{
    NotificationManager mNotificationManager = (NotificationManager) context.getSystemService(Context.NOTIFICATION_SERVICE);
    //mNotificationManager.cancel((String)getAppName(context), MY_NOTIFICATION_ID);
    mNotificationManager.cancelAll();
    MY_NOTIFICATION_ID = NOTIFICATION_ID;
}

And that’s all. Multiple notifications as I needed.

Sending automated emails with PHP, Swiftmailer and Twig

I’m the one of hosts of a Coding Dojo in my city called Katayunos. Katayunos is the mix of the word Kata (coding kata) and “Desayuno” (breakfast in Spanish). A group of brave programmers meet together one Saturday morning and after having breakfast we pick one coding kata and we practise TDD and pair programming. It’s something difficult to explain to non-geek people (why the hell we wake up early one Saturday morning to do this) but if you are reading this post probably it sounds good:).

My work as host is basically pick the place and encourage people to join to the Coding Dojo. One way of doing this (besides twitter buzz) is take my address book and send one bulk email to all of them inviting to join us. I don’t like this kind of mails. They look like spam, so I prefer to send a personalized email. This email has a common part (the place location, the hour, the event description, …) and the personalized part. I can do it manually, the list isn’t so huge, but definitely that’s not cool. Because of that I have done a little script to perform this operation. I can do a simple PHP script but we are speaking about announcing a event about TDD, SOLID and things like that, so I must use the “right way”. Let’s start.

I manage my list of contacts within a spreadsheet. In this spreadsheet I have the name, the email and a one paragraph with the personalized part to each one of my contact. I can easily export this spreadsheet to a csv document like this:

Peter Parker, spiderman@gmail.com, "Lorem ipsum dolor sit amet, ..."
Clark Kent, superman@gmail.com, "consectetur adipisicing elit, ..."
Juan López Fernández, superlopez@gmail.com, "sed do eiusmod tempor incididunt .."

So first of all I need to parse this file.

class Parser
{
    private $data;

    public function createFromCsvFile($path)
    {
        $handle = fopen($path, "r");
        while (($data = fgetcsv($handle)) !== false) {
            $this->data[] = [
                'name'  => trim($data[0]),
                'email' => trim($data[1]),
                'body'  => isset($data[2]) ? trim($data[2]) : null,
            ];
        }
    }

    public function getData()
    {
        return $this->data;
    }
}

Easy. Now I want to send this parsed array by email. Because of that I will include Swiftmailer in my composer.json file.

My email will also be one template and one personalized part. We will use Twig to manage the template.

"require": {
        "swiftmailer/swiftmailer": "v5.0.2",
        "twig/twig": "v1.13.2",
}

Now we will create a class to wrap the needed code to send emails

class Mailer
{
    private $swiftMailer;
    private $swiftMessage;

    function __construct(Swift_Mailer $swiftMailer, Swift_Message $swiftMessage)
    {
        $this->swiftMailer  = $swiftMailer;
        $this->swiftMessage = $swiftMessage;
    }

    public function sendMessage($to, $body)
    {
        $this->swiftMessage->setTo($to);
        $this->swiftMessage->setBody(strip_tags($body));
        $this->swiftMessage->addPart($body, 'text/html');

        return $this->swiftMailer->send($this->swiftMessage);
    }
}

Our Mailer class sends mails. Our Parser class parses one csv file. Now we need something to join those two classes: the Spammer class. Spammer class will take one parsed array and it will send one by one the mails using Mailer class.

class Spammer
{
    private $twig;
    private $mailer;

    function __construct(Twig_Environment $twig, Mailer $mailer)
    {
        $this->twig       = $twig;
        $this->mailer     = $mailer;
    }

    public function sendEmails($data)
    {
        foreach ($data as $item) {
            $to = $item['email'];
            $this->mailer->sendMessage($to, $this->twig->render('mail.twig', $item));
        }
    }
}

Ok with this three classes I can easily send my emails. This script is a console script and we also want pretty console colours and this kind of stuff. symfony/console to the rescue. But I’ve a problem now. I want to write one message when one mail is sent and another one when something wrong happens. If I want to do that I need to change my Spammer class. But my Spammer class does’t know anything about my console Command. If I inject the console command into my Spammer class I will violate the Demeter law, and that’s a sin. What can we do? Easy: The mediator pattern. We can write one implementation of mediator pattern but we also can use symfony/event-dispatcher, a well done implementation of this pattern. We change our Spammer class to:

use Symfony\Component\EventDispatcher\EventDispatcher;

class Spammer
{
    private $twig;
    private $mailer;
    private $dispatcher;

    function __construct(Twig_Environment $twig, Mailer $mailer, EventDispatcher $dispatcher)
    {
        $this->twig       = $twig;
        $this->mailer     = $mailer;
        $this->dispatcher = $dispatcher;
    }

    public function sendEmails($data)
    {
        foreach ($data as $item) {
            $to = $item['email'];
            try {
                $this->mailer->sendMessage($to, $this->twig->render('mail.twig', $item));
                $this->dispatcher->dispatch(MailEvent::EVENT_MAIL_SENT, new MailEvent\Sent($to));
            } catch (\Exception $e) {
                $this->dispatcher->dispatch(MailEvent::EVENT_SENT_ERROR, new MailEvent\Error($to, $e));
            }
        }
    }
}

Now can easily build of console command class:

use Symfony\Component\Console\Command\Command;
use Symfony\Component\Console\Input\InputArgument;
use Symfony\Component\Console\Input\InputInterface;
use Symfony\Component\Console\Input\InputOption;
use Symfony\Component\Console\Output\OutputInterface;
use Symfony\Component\EventDispatcher\EventDispatcher;

class SpamCommand extends Command
{
    private $parser;
    private $dispatcher;

    protected function configure()
    {
        $this->setName('spam:run')
            ->setDescription('Send Emails');
    }

    protected function execute(InputInterface $input, OutputInterface $output)
    {
        $output->writeln("Sending mails ...");
        $this->dispatcher->addListener(MailEvent::EVENT_MAIL_SENT, function (MailEvent\Sent $event) use ($output) {
                $output->writeln("<info>Mail sent to</info>: <fg=black;bg=cyan>{$event->getTo()}</fg=black;bg=cyan>");
            }
        );

        $this->dispatcher->addListener(MailEvent::EVENT_SENT_ERROR, function (MailEvent\Error $event) use ($output) {
                $output->writeln("<error>Error sending mail to</error>: <fg=black;bg=cyan>{$event->getTo()}</fg=black;bg=cyan> Error: " . $event->getException()->getMessage());
            }
        );

        $this->spammer->sendEmails($this->parser->getData());
        $output->writeln("End");
    }

    public function setSpammer(Spammer $spammer)
    {
        $this->spammer = $spammer;
    }

    public function setParser(Parser $parser)
    {
        $this->parser = $parser;
    }

    public function setDispatcher(EventDispatcher $dispatcher)
    {
        $this->dispatcher = $dispatcher;
    }
}

With all this parts we can build our script. Our classes are decoupled. That’s good but setting up the dependencies properly can be hard. Because of that we will use symfony/dependency-injection. With symfony DIC we can set up our dependency tree within a yaml file:

Our main services.yml

imports:
  - resource: conf.yml
  - resource: mail.yml
  - resource: twig.yml

parameters:
  base.path: .

services:
  parser:
    class: Parser
    calls:
      - [createFromCsvFile, [%mail.list%]]

  mailer:
    class: Mailer
    arguments: [@swift.mailer, @swift.message]

  spam.command:
    class: SpamCommand
    calls:
      - [setParser, [@parser]]
      - [setDispatcher, [@dispatcher]]
      - [setSpammer, [@spammer]]

  spammer:
    class: Spammer
    arguments: [@twig, @mailer, @dispatcher]

  dispatcher:
    class: Symfony\Component\EventDispatcher\EventDispatcher

I like to separate the configuration files to reuse those files between projects and to make them more readable.

One for twig:

parameters:
  twig.path: %base.path%/templates
  twig.conf:
    auto_reload: true

services:
  twigLoader:
    class: Twig_Loader_Filesystem
    arguments: [%twig.path%]

  twig:
    class: Twig_Environment
    arguments: [@twigLoader, %twig.conf%]

another one for swiftmailer:

services:
  swift.message:
    class: Swift_Message
    calls:
      - [setSubject, [%mail.subject%]]
      - [setFrom, [%mail.from.mail%: %mail.from.name%]]

  swift.transport:
    class: Swift_SmtpTransport
    arguments: [%mail.smtp.host%, %mail.smtp.port%, %mail.smtp.encryption%]
    calls:
      - [setUsername, [%mail.smtp.username%]]
      - [setPassword, [%mail.smtp.password%]]

  swift.mailer:
    class: Swift_Mailer
    arguments: [@swift.transport]

and the last one for the configuration parameters:

parameters:
  mail.do.not.send.mails: false

  mail.list: %base.path%/mailList.csv
  mail.subject: mail subject
  mail.from.name: My Name
  mail.from.mail: my_email@mail.com

  mail.smtp.username: my_smtp_username
  mail.smtp.password: my_smtp_password
  mail.smtp.host: smtp.gmail.com
  mail.smtp.port: 465
  mail.smtp.encryption: ssl

Now we can build our script.

use Symfony\Component\Console\Application;
use Symfony\Component\DependencyInjection\ContainerBuilder;
use Symfony\Component\Config\FileLocator;
use Symfony\Component\DependencyInjection\Loader\YamlFileLoader;

$container = new ContainerBuilder();
$loader = new YamlFileLoader($container, new FileLocator(__DIR__ . '/conf'));
$loader->load('services.yml');

$container->setParameter('base.path', __DIR__);

$application = new Application();
$application->add($container->get('spam.command'));
$application->run();

n

And that’s all. My colleagues of the next Katayuno will be invited in a “SOLID” way :).
Source code is available in my github account.

BTW: Do you want to organize one Katayuno in your city? It’s very easy. Feel free to contact me for further information.

Releasing unmanaged resources (a PHP port from C#’s “using” statement)

Sometimes we work with instances that needs to released even when exceptions happens. Something typical when we work with resources (Files, Database connections, …) Let me show you with an example:

Imagine this class for handling file resources:

class File
{
    private $resource;
    private $logger;

    public function __construct($filename, Loger $logger)
    {
        $this->logger = $logger;
        $this->resource = fopen($filename);
    }

    public function write($string)
    {
        fwrite($this->resource, $string);
    }

    public function close()
    {
        $this->logger->log("file closed")   
        fclose($this->resource);
    }
}

We can use this class:

$file = new File(__DIR__ . "/file.txt", 'w');
$file->write("Hello\n");
// ...
// some other things
// ...
$file->write("Hello\n");
$file->close();

OK. What happens if one exception happens inside “some other things”? Simple answer: close() function isn’t called. This can be a problem. We can face this problem with a try/catch block like this:

try {
    $file->write("Hello\n");
    // ...
    // some other things
    // ...
    $file->write("Hello\n");
    $file->close();
} catch (\Exception $e) {
    $file->close();
}

Or even if we’re using PHP5.5 we can use “finally” keyword

try {
    $file->write("Hello\n");
    // ...
    // some other things
    // ...
    $file->write("Hello\n");
} catch (\Exception $e) {
} finally {
    $file->close();
}

Sometimes I need collaborate with C# projects. C# is a great language. I really like it. It has a really cool feature to solve this problem: the “using” statement. Because of that we are going to build today one small library to implement something similar in PHP.

First we will add G\IDisposable interface to our File class

namespace G;

interface IDisposable
{
    public function dispose();
}

Now our File class looks like this:

use G\IDisposable;

class File implements IDisposable
{
    private $resource;

    public function __construct($filename, $mode)
    {
        $this->resource = fopen($filename, $mode);
    }

    public function write($string)
    {
        fwrite($this->resource, $string);
    }

    public function close()
    {
        fclose($this->resource);
    }

    public function dispose()
    {
        $this->close();
    }
}

And we can use our “using” function in PHP:

using(new File(__DIR__ . "/file.txt", 'w'), function (File $file) {
        $file->write("Hello\n");
        $file->write("Hello\n");
        $file->write("Hello\n");
    });

As we can see we can forget to close() our file instance. “using” will do it for us, even if one exception is triggered inside. We need to take into account that “using” is not a way to handle exceptions. If you want to handle them you need to do it. The only responsibility of “using” is to ensure that dispose() is been called.

We also can use an array of instances (implementing the IDisposable interface of course)

using([new Bar, new Foo], function (Bar $bar, Foo $foo) {
        echo $bar->hello("Gonzalo");
        echo $foo->hello("Gonzalo");
    });

And that’s all. Library is available in github and also you can use it with composer.

Update!
I’ve changed the Example. The first example wasn’t a good one. Now File::close() closes the resource and also write a log. With the first example (without the logger) it wasn’t important to close the resorce (PHP closes it).

Creating QR codes with PHP and Silex

Today we’re going to play with QR codes and how to use them within a Silex application using one Service Provider. First we need a QR code generator. If we find in Packagist we can see various libraries. We are going to use the library: endroid/qrcode.

We are not going to modify endroid/qrcode, because of that we will create a wrapper. This wrapper will receive in the constructor one instance of endroid/qrcode. It’s responsability will be to take one QrCode object and generate a Symfony\Component\HttpFoundation\Response with our QR code and the properly headers. Here you can see the unit tests of our QrWrapper:

use Symfony\Component\HttpFoundation\Response;
use G\QrWrapper;

class QrWrapperTest extends PHPUnit_Framework_TestCase
{
    public function testObjectInit()
    {
        $qrCode = $this->getMockBuilder('Endroid\QrCode\QrCode')
                ->disableOriginalConstructor()
                ->getMock();

        $wrapper = new QrWrapper($qrCode);

        $this->assertInstanceOf('G\QrWrapper', $wrapper);
    }

    public function testGetResponseWithDefaultParameters()
    {
        $qrCode = $this->getMockBuilder('Endroid\QrCode\QrCode')
                ->disableOriginalConstructor()
                ->getMock();

        $qrCode->expects($this->any())->method('get')->will($this->returnValue("hello"));
        $wrapper = new QrWrapper($qrCode);

        $response = $wrapper->getResponse();

        $this->assertInstanceOf('Symfony\Component\HttpFoundation\Response', $response);
        $this->assertEquals("hello", $response->getContent());
        $this->assertEquals("image/png", $response->headers->get('Content-Type'));
    }

    public function testGetResponseForJpg()
    {
        $qrCode = $this->getMockBuilder('Endroid\QrCode\QrCode')
                ->disableOriginalConstructor()
                ->getMock();

        $qrCode->expects($this->any())->method('get')->will($this->returnValue("hello"));
        $wrapper = new QrWrapper($qrCode);
        $wrapper->setImageType('jpg');

        $response = $wrapper->getResponse();

        $this->assertInstanceOf('Symfony\Component\HttpFoundation\Response', $response);
        $this->assertEquals("hello", $response->getContent());
        $this->assertEquals("image/jpeg", $response->headers->get('Content-Type'));
    }

    public function testGetResponseForJpeg()
    {
        $qrCode = $this->getMockBuilder('Endroid\QrCode\QrCode')
                ->disableOriginalConstructor()
                ->getMock();

        $qrCode->expects($this->any())->method('get')->will($this->returnValue("hello"));
        $wrapper = new QrWrapper($qrCode);
        $wrapper->setImageType('jpeg');

        $response = $wrapper->getResponse();

        $this->assertInstanceOf('Symfony\Component\HttpFoundation\Response', $response);
        $this->assertEquals("hello", $response->getContent());
        $this->assertEquals("image/jpeg", $response->headers->get('Content-Type'));
    }

    public function testReusingResponse()
    {
        $qrCode = $this->getMockBuilder('Endroid\QrCode\QrCode')
                ->disableOriginalConstructor()
                ->getMock();

        $qrCode->expects($this->any())->method('get')->will($this->returnValue("hello"));
        $wrapper = new QrWrapper($qrCode);

        $response = new Response('foo');
        $response->headers->set('xxx', 'gonzalo');

        $response = $wrapper->getResponse($response);

        $this->assertEquals("hello", $response->getContent());
        $this->assertEquals("image/png", $response->headers->get('Content-Type'));
        $this->assertEquals("gonzalo", $response->headers->get('xxx'));
    }
}

Now we will create the ServiceProvider. We only need to implement ServiceProviderInterface

use Silex\Application;
use Silex\ServiceProviderInterface;
use Endroid\QrCode\QrCode;

class QrServiceProvider implements ServiceProviderInterface
{
    public function register(Application $app)
    {
        $app['qrCode'] = $app->protect(function ($text, $size = null) use ($app) {
            $default = $app['qr.defaults'];

            $qr = new QrWrapper(new QrCode());
            $qr->setText($text);
            $qr->setPadding($default['padding']);
            $qr->setSize(is_null($size) ? $default['size'] : $size);
            $qr->setImageType($default['imageType']);

            return $qr;
        });
    }

    public function boot(Application $app)
    {
    }
}

And that’s all. Now we can use our service provider within one Silex Application:

use Silex\Application;
use G\QrServiceProvider;

$app = new Application();

$app->register(new QrServiceProvider(), [
    'qr.defaults' => [
        'padding'   => 5, // default: 0
        'size'      => 200,
        'imageType' => 'png', // png, gif, jpeg, wbmp (default: png)
    ]
]);

$app->get("/qr/base64/{text}", function($text) use ($app) {
    return $app['qrCode'](base64_decode($text))->getResponse();
});

$app->get("/qr/{text}", function($text) use ($app) {
    return $app['qrCode']($text)->getResponse();
});

$app->run();

You can fetch the full code in github and also use it with composer