zf2 howto GridFS

GridFS is the mongoDB standard for storing and retrieving files.You can find out more information about GridFS here.

This is how I managed to store and retrieve image using zf2, doctrine-odm and mongoDB.

You can setup a Document,

<?php
namespace Course\Document;

use Doctrine\ODM\MongoDB\Mapping\Annotations as ODM;

/** @ODM\Document(collection="course") */
class Course
{
    /** @ODM\Id */
    private $id;

    /** @ODM\File */
    private $thumb;


    public function getId() {
        return $this->id;
    }

    public function getThumb()
    {
        return $this->thumb;
    }

    public function setId($id) {
        $this->id = $id;
    }

     public function setThumb($thumb)
    {
        $this->thumb = $thumb;
    }

    public function exchangeArray($data)
    {
        $this->id               = (isset($data['id']))     ? $data['id']     : null;
        $this->thumb            = (isset($data['thumb'])) ? $data['thumb'] : null;

    }

   public function getArrayCopy()
    {
        return get_object_vars($this);
    }

    public function getObjectAsArray()
    {
        $array = array(
         'thumb' =>$this->thumb,
                      );
        return $array;
    }

}

Then zf2 form with file upload input field, within your function __construct you can add,

$this->setAttribute('method', 'post');
$this->setAttribute('enctype','multipart/form-data');

$this->add(array(
            'name' => 'id',
            'attributes' => array(
                'type'  => 'hidden',
            ),
        ));
$this->add(array(
            'name' => 'thumb',
            'attributes' => array(
                'type'  => 'file',
            ),
            'options' => array(
                'label' => 'Thumbnail',
            ),
        ));

Then create the form,

<?php
$title = 'upload Image';
$this->headTitle($title);
?>
<h1><?php echo $this->escapeHtml($title); ?></h1>
<?php
$form = $this->form;
$form->setAttribute('action', $this->url('image', array('action' => 'add')));
$form->prepare();

echo $this->form()->openTag($form);
echo $this->formRow($form->get('thumb'));
echo $this->formSubmit($form->get('submit'));
echo $this->form()->closeTag();
?>

and finally update your controller with,

$request = $this->getRequest();
        if ($request->isPost()) {

            $data = array_merge_recursive(
            $this->getRequest()->getPost()->toArray(),
            $this->getRequest()->getFiles()->toArray()
             );


     $file_src   = '/tmp/'.$data['thumb']['name'];
         move_uploaded_file($data['thumb']['tmp_name'], $file_src);


    $dm = $this->getServiceLocator()->get('doctrine.documentmanager.odm_default');
    $course = new Course();
    $course->setThumb($file_src);
    $dm->persist($course);
        $dm->flush();

    }

To retrieve image, update controller with

$dm = $this->getServiceLocator()->get('doctrine.documentmanager.odm_default');
        $courses = $dm->createQueryBuilder('Course\Document\Course')
                ->getQuery()
                ->execute();

        return new ViewModel(array(
           'courses' => $courses,
        ));

And your view,

<table class="table">
<tr>
    <th>thumb</th>
    <th>&nbsp;</th>
</tr>
<?php foreach ($courses as $course) : ?>
<tr>
    <td><?php $i= base64_encode($course->getThumb()->getBytes());echo "<img src=\"data:image/jpg;base64,{$i}\">";?></td>
</tr>
<?php endforeach; ?>
</table>

 Make sure you set the correct header image type in order to render the image.

further info :
Storing Files with MongoGridFS
ZF2 form collections

ZF2 skeleton with mongoDB | using doctrine odm

1. git clone the ZF2 Skeleton Application

    git clone git://github.com/zendframework/ZendSkeletonApplication.git

2. cd into the ZendSkeletonApplication directory and open the composer.json in your favourite text editor.

    {
        "name": "zendframework/skeleton-application",
        "description": "Skeleton Application for ZF2",
        "license": "BSD-3-Clause",
        "keywords": [
            "framework",
            "zf2"
        ],
        "homepage": "http://framework.zend.com/",
        "minimum-stability": "dev",
        "require": {
            "php": ">=5.3.3",
            "zendframework/zendframework": "2.*",
            "doctrine/doctrine-mongo-odm-module": "dev-master"
        }
    }

3. Update your composer.json and run

php composer.phar self-update
php composer.phar install

4. If you are success with installing all dependencies using composer follow the official guide here to set up virtual-host and update hosts file.

5. If you are unable to update those dependencies and found something similar to this,

Check your composer.json for any mistakes, or follow my previous blog post.

6. Add the doctrine modules to your config file, config/application.config.php. Update the modules array similar to this, here im adding zend module named course as well.

        'modules' => array(
            'Application',
            'Course',
            'DoctrineModule',
            'DoctrineMongoODMModule',
        ),

7.  Copy the doctrine-odm config file to your config directory, and update according to your environment.This is where you set your server hosts, ports, username, and passwords etc.

    cp vendor/doctrine/doctrine-mongo-odm-module/config/module.doctrine-mongo-odm.local.php.dist config/module.doctrine-mongo-odm.local.php

 and update,

8. You can try the course module I have created here with course add and retrieve course data.

Installing doctrine ODM through composer

I tried to install doctrine/doctrine-mongo-odm-module through composer with ZF2, but I keep getting an error stating that PHP mango extension is missing from my computer.This is the require section of my composer.json file,

"require": {
        "php": ">=5.3.3",
        "zendframework/zendframework": "2.*",
        "doctrine/doctrine-mongo-odm-module": "dev-master"
    }

 Im getting this after I run  "php composer.phar install"

Correct version of MongoDB driver shows up in phpinfo() as well.

And THE PROBLEM is, Composer runs on PHP-CLI I do have two php.ini files.

/etc/php5/apache2/php.ini
/etc/php5/cli/php.ini

But I only updated MongoDB extension "extension=mongo.so" in /etc/php5/apache2/php.ini.Composer in the other hand is looking for mongo extension in the php.ini located in the /etc/php5/cli/php.ini directory. So by adding mongo extension in /etc/php5/cli/php.ini  file and apache restart solved my problem.

Event driven, asynchronous callbacks and Node.js

Node's approach of code execution isn't unique, but back end execution model is different from environments like PHP or Java.

Node.js core provides methods to reading content of a file in the file-system. fs module provides variety of file system methods.The easiest way to read the entire contents of a file is as follows.

fs = require('fs');
fs.readFile('/home/udara/docs/users.txt');
console.log("Hello Users !!");

Let's assume that the time taken to read users.txt is really long, JavaScript interpreter of Node.js first has to complete reading the users.txt file, and then only it execute the console.log() function. Same as in PHP if this code would be part of a webpage, the user have to wait until it read whole file at once and load the page.

Unlike PHP, Node.js there is only one single process. If there is something happen like above example this will effect the whole process and each and every user would be affected. But in PHP only user who request that web page feel slow page load, but other users requesting other pages would not be affected. 

So where is asynchronous of Node.js ????

fs = require('fs');
fs.readFile('/home/udara/docs/users.txt', function (error,data) {
console.log(data);
});
console.log("Hello Users !!");

Here, without expecting fs.readFile() to directly return a file content to us we pass second parameter an anonymous function.Now Node.js can handle fileread request asynchronously.Only when fileread is done then it will execute anonymous function that was passed to fs.readFile().

Without waiting for the fileread output system will out put Hello Users !! to the console.

 

How to move apps from phone memory to SD card in android

You may find many apps on google play which can use to move apps from phone memory to SD card, but for this to work developers need to enable this option in their apps.Following method is valuable if you do have a phone with small internal memory plus loads of apps which you cant move to SD card using apps like APP 2 SD.

• Download latest version of Android SDK.
• Connect the phone using USB cable and enable USB debugging mode.Settings -> Applications -> Development and enable USB debugging
• Open terminal and navigate to android SDK directory, in my instance cd /home/udara/private/android-sdk-linux/platform-tools/
• Add that directory to path using, export PATH=$PATH:/home/udara/private/android-sdk-linux/platform-tools/
• Now by typing adb devices command you will get something similar to,

• Type adb shell and then run command pm setInstallLocation 2.
• Now on your phone go to Settings->Applications->Manage Applications and you will find most of the applications are now available to move from phone memory to SD card.

I have tested this on a rooted huawei U8160 running android 2.2(froyo) using UBUNTU 12.04. 

browscap to JS navigator

Browscap facilitate to identify what a visitor's browser is capable of, an improved version of native php function get_browser(). You need to update browscap.ini which resides on your server periodically in order to get the correct browser capabilities.

In the recent past with rise of the JS world, you can detect HTML5, CSS3 browser capabilities with the use of JS libraries like modernizr or even with simple JS navigator.

browscap output,

JS navigator output,

Password Protecting with .htaccess

1. create password file with encrypted password. Save password file as .ht{something} outside web root if possible.

for example .htukrpass file contain following
username:password

2. create .htaccess file with following content


AuthUserFile {fullpath to .htukrpass file}
AuthType Basic
AuthName "our test source dir"
Require valid-user
require user {username}