Saturday, December 26, 2015

Ready for freelancing?

I’ve been a professional software/web developer for more than a decade, and up until now I mostly worked as full time employee in several companies and one contracting project as freelancer, where I gained expertise in many technologies and Scrum Master management skills. Latest technologies were mostly web development oriented.

After a decade of my professional life I could say that full time corporate job is right choice if you don't have much experience or you just got out of school. After gaining initial experience in corporate jobs, you will want to make portfolio populated with projects you have worked on. You will need a portfolio to show to future clients that you are right choice for them. Experience proves both client and you that you are capable of finishing projects.

After that you could try yourself working by contract or as freelancer, having flexible working hours, where the end result counts. You need to have self-discipline to work when needed and be reliable and responsible while communicating to clients. This will also help you make time to stay sharp and in step with technology edge, because you are in control of your availability. All this is just what I always wanted so I decided that it is time to dive into freelance world.

In corporate culture, if you think in terms of financial part of software and its price, then of course you would like to finish it ASAP to reduce its cost. Companies driven by that notion only, will often threat its developers as necessary evil. For those companies, it is not the product that is in focus and value it brings to client, but rather the points of contracted work and its unreasonable deadlines.

Often under management pressure to follow deadlines, developers reduce products quality to gain speed. Not the career plan you would like to follow, because you don't have time to improve and work is not fun in such stressed environments.

Then I searched for freelance market sites. And I found sites like UpWork and Elance which are great but they don't guarantee you constant work because first you need to build your reputation and even than you have to compete with some very low unreasonable offers.

If only there could be some intermediate which will connect self-organizing teams of professionals with right customers, willing to pay for good quality product along with reasonable deadlines (so we don't need to compete with immoral offers to jobs like to make a copy of popular social network for 30$, or less, in couple of days). With financial aspect covered, team job is to handle time and quality aspect and gets job done. Team than incrementally develops software and brings value to customer so they together can steer product in right direction.

And then I heard of TopTal while attending presentation with freelancing as topic. It was scheduled at gathering of developer community of Banja Luka. Ines Avdic Zekic from Sarajevo held informative presentation about TopTal. Less than 3% passes screening process, she said. Nobody likes to be tested, but if this is what I have to pass to put financial aspect in background than by all means, let’s do this.

Why join TopTal?

If you pass TopTal screening process, then TopTal stands for you. TopTal takes care of finding jobs and paying you upon completed work, even in such cases where the customer refuses to pay. Take worries about not being paid away, and just commit yourself to finish your job.
Yours is to get job done. Money should be just a side effect of your work.
You can set higher or lower price per hour and frequency of jobs you receive will depend on that. Higher the price per hour, lower frequency of jobs.
It enables you to connect with other freelance professionals and do work together for TopTal trusted customers and companies.
You are not tied to location, as long as you have reliable internet connection.
Market is dictating new technologies, and that technology edge is exactly what you want to learn and contribute in. TopTal enables you to grow as IT professional. It provides you with courses and webinars to learn technologies with highest demand on market. 
It enables you to grow your software using edge technologies to bring better value to its users. You don’t wont to end up in companies just to maintain some piece of software until time and new technologies overrun them.
Availability and commitment can be changed. Your availability varies and you can reduce your availability while you are travelling or on vacation, and also increase it when you are eager to work.
Working 9-5 is not necessary what will bring the most out of developer. I want to use morning hours for work because I'm well rested. Then after lunch I could take a nap, do some physical activities and then go back to work and finish work refreshed and sharp minded.

In Banja Luka, there is still no developers working for TopTal. This would be a great opportunity to make a first step to connect TopTal with talented developers from this region and Banja Luka developer’s community. What I’ve heard so far, convinced me more that TopTal is right fit for me. I’m eager to learn new technologies and improve myself through active communication with TopTal clients and deliver them good piece of useful software. Later on my ambitions would be to gather people around me so we could provide TopTal services in a wide range of technologies as a self-organized team.

Now I'm heading back to Codility for some more practice. TopTal is also providing guide for interviewing PHP developers.

Wish me luck!

Tuesday, July 14, 2015

Simple blog using Laravel - Part I

Migrations

Create articles migration:
$ php artisan make:migration create_articles_table --create="articles"
Inside database/migrations find created migration and edit:
2015_07_13_192755_create_articles_table.php
and add these lines to up() method:
Schema::create('articles', function (Blueprint $table) {
    $table->increments('id');
    $table->string('title');
    $table->text('body');
    $table->text('excerpt')->nullable();
    $table->timestamp('published_at');
    $table->timestamps();
});
To execute created migration do:
$ php artisan migrate

Routes

Edit
app\Http\routes.php
and add this line:
Route::resource('articles', 'ArticlesController');
Which is easier way and equal to manually supply all CRUD routes following REST convention like so:
Route::get('articles', 'ArticlesController@index');
Route::get('articles/create', 'ArticlesController@create');
Route::get('articles/{id}', 'ArticlesController@show');
Route::post('articles', 'ArticlesController@store');
Route::get('articles/{id}/edit', 'ArticlesController@edit');

Model

We have articles table, so lets create Article model:
$ php artisan make:model Article
Edit our model app\Article.php and add $fillable fields so we can mass assign them while creating article. Also specify published_at field inside $dates so Laravel threat this field as Carbon date object instead of simple string representation.
class Article extends Model
{
    protected $dates = ['published_at'];
    protected $fillable = [
    'title',
    'body',
    'published_at'
    ];
}

Add two rows to article table using Laravel interactive tinker tool:
$ php artisan tinker;
$ App\Article::create(['title' => 'My first article', 'body' => 'Article body', 'published_at' => Carbon\Carbon::now()]);
$ App\Article::create(['title' => 'New article', 'body' => 'New body', 'published_at' => Carbon\Carbon::now()]);
$ App\Article::all();
Update first article:
$article = App\Article::find(1);
$article->body = 'Lorem ipsum';
$article->save();
App\Article::all();
Get collection of articles:
$articles = App\Article::where('body','Lorem ipsum')->get();
Get first article:
$article = App\Article::where('body','Lorem ipsum')->first();

Controller

Let's create plain ArticlesController:
$ php artisan make:controller ArticlesController --plain
So now we will create index action to fetch list of articles.
Edit app\Http\Controllers\ArticlesController.php:
public function index()
{
    $articles = Article::latest('published_at')->published()->get();
    return view('articles.index', compact('articles'));
}
We want to use published() scope while fetching articles to get only those published until today and sort them descending from newest to oldest by published_at using latest(). So let's create published() scope in app\Article.php model. Notation is keyword scope followed by scope name, like this:
use Carbon\Carbon;
public function scopePublished($query)
{
    $query->where('published_at', '<=', Carbon::now());
}
To show details of selected article we need show() action. Edit app\Http\Controllers\ArticlesController.php:
public function show($id)
{
    $article = Article::findOrFail($id);
    return view('articles.show', compact('article'));
}

View

Inside resources folder create app.blade.php:
<!doctype html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Document</title>
<link rel="stylesheet" href="//maxcdn.bootstrapcdn.com/bootstrap/3.2.0/css/bootstrap.min.css">
</head>
<body>
<div class="container">
@yield('content')
</div>
@yield('footer')
</body>
</html>
Inside resources\articles create index.blade.php:
@extends('app')
@section('content')
<div class="col-md-12 staff-header">
<h5>Articles</h5>
</div>
<div class="col-xs-12 col-md-12">
@foreach( $articles as $article)
<article>
<h4>
<a href="{{ action('ArticlesController@show', [$article->id]) }}">{{ $article->title }}</a>
</h4>
<h6>{{ $article->body }}</h6>
<br/>
</article>
@endforeach
</div>
@stop
Inside resources\articles create show.blade.php:
@extends('app')
@section('content')
<div class="col-md-12 staff-header">
<h5>{{ $article->title }}</h5>
</div>
<div class="col-xs-12 col-md-12">
<article>
<h6>{{ $article->body }}</h6>
</article>
</div>
@stop

Tuesday, June 30, 2015

Laravel on Debian Wheezy

LAMP

First we need LAMP packages installed.
Laravel requires PHP >= 5.5.9 so we will install php56.

Add package repositories to apt sources.
Edit sources.list
$ vi /etc/apt/sources.list
and add these two lines:
deb http://packages.dotdeb.org wheezy-php56 all
deb-src http://packages.dotdeb.org wheezy-php56 all

Add dotdeb.gpg key so apt can authenticate packages from added sources.
$ cd
$ wget http://www.dotdeb.org/dotdeb.gpg
$ apt-key add dotdeb.gpg
$ apt-get update

Install Apache, MySQL and PHP
$ apt-get install mysql-server mysql-client
$ apt-get install apache2
$ apt-get install php5 libapache2-mod-php5 php5-mcrypt

Enable rewrite apache modul
$ a2enmod rewrite
$ /etc/init.d/apache2 restart

Confirm that php is working well with apache by creating info.php file:
$ vi /var/www/info.php
add this line:
<?php phpinfo(); ?>
Access inside browser: http://localhost/info.php

Laravel

# To install laravel we need composer:
$ sudo curl -sS https://getcomposer.org/installer | php -- --install-dir=/usr/local/bin --filename=composer

* Use composer to install laravel:
$ composer global require "laravel/installer=~1.1"

* Add laravel bin to your PATH so you can use laravel executable from any location. Edit bash_profile file:
$ vi ~/.bash_profile
and add these lines:
PATH=$PATH:~/.composer/vendor/bin
export PATH

* Create new base for web application
$ cd ~/NetBeansProjects
$ laravel new LaravelDemo

# Or we could skip installing laravel and using it's executable to create base for web application (steps marked with asterisk *), and go ahead do all that with composer directly:
$ rm -rf ~/NetBeansProjects/LaravelDemo
$ cd ~/NetBeansProjects
$ composer create-project laravel/laravel LaravelDemo --prefer-dist

# Create Apache VirtualHost by:
$ vi /etc/apache2/sites-available/laraveldemo.org
and add these lines:
ServerAdmin webmaster@laraveldemo.org
ServerName  laraveldemo.org
ServerAlias *.laraveldemo.org

DocumentRoot /home/{user}/NetBeansProjects/LaravelDemo/public

        Options Indexes FollowSymLinks MultiViews
        AllowOverride All
        Order allow,deny
        allow from all

ErrorLog ${APACHE_LOG_DIR}/laraveldemo_error.log

# Possible values include: debug, info, notice, warn, error, crit,
# alert, emerg.
LogLevel warn

CustomLog ${APACHE_LOG_DIR}/laraveldemo_access.log combined

# Enable virtual host:
$ a2ensite laraveldemo.org

# Add virtual host to hosts file by editing:
$ vi /etc/hosts
add this line:
127.0.0.1 laraveldemo.org

# Restart apache
$ service apache2 restart

# Create simple /about route and appropriate controller, action and view
$ cd ~/NetBeansProjects/LaravelDemo
$ vi app/Http/routes.php 
add this line to routes.php:
Route::get('about', 'PagesController@about');

# Create PagesController by:
$ php artisan make:controller PagesController --plain
$ vi app/Http/Controllers/PagesController.php
 
add about() method to PagesController.php:
    public function about() {
    return view('about');
    }

# Create about view by editing about.blade.php:
$ vi resouces/views/about.blade.php
add this line:
    Hello World

# Make local configuration
$ copy .env.example to .env

# Generate app key
$ php artisan key:generate

# Set Directory Permissions
$ cd ~/NetBeansProjects/LaravelDemo
$ chgrp www-data -Rv storage/
$ chmod g+w -Rv storage/
$ cd bootstrap/
$ chgrp www-data -Rv cache
$ chmod g+w -Rv cache

Test it by pointing browser to:
http://laraveldemo.org/about

Create database
mysql> create database laraveldemo;
mysql> CREATE USER 'laraveldemouser'@'localhost' IDENTIFIED BY 'laraveldemopass';
mysql> GRANT ALL ON laraveldemo.* TO 'laraveldemouser'@'localhost';

# Add mysql authentication data to .env
$ vi .env
change these lines:
DB_HOST=localhost
DB_DATABASE=laraveldemo
DB_USERNAME=laraveldemouser
DB_PASSWORD=laraveldemopass

Monday, August 9, 2010

How to load/write XML using JAXB?

Every now and then you need to load or write some XML files. It is very effective way to put data in machine-readable form. XML is text format file which is well formatted using standardized rules.

So to demonstrate use of JAXB we will:
1) create XML file with some data (bookmarks.xml)
2) create XML schema file to validate our XML file (bookmarks.xsd)
3) create XML object model using xjc utility (xjc.txt)
4) load that XML file into JAXB object (XMLUnmarshall.java)
5) write JAXB object back over original XML file (XMLMarshaller.java)
6) create main java class to call these functions in appropriate order (JAXBLoader,java)

Create XML file
Lets create a simple xml file for storing bookmark data organized through sets. It will contain root element bookmarks with bookmark elements inside and list of attribute elements for storing href values. Also for every bookmark element there will be a attribute set which will identify current bookmark set. Example of this xml can be found here: bookmarks.xml.

Create XML schema file
To validate bookmark.xml we need to create schema file. Example for this example can be found here: bookmarks.xsd.

Create object model
To create object model for our xml we need to run xjc utility and supply it with xsd schema file as argument at command line.

zlaja@orion:~/NetBeansProjects/JAXBLoader> xjc ./data/bookmarks.xsd -p com.blogspot.zetaorionis.bookmarks.model -d ./src
parsing a schema...
compiling a schema...
com/blogspot/zetaorionis/bookmarks/model/AttributeType.java
com/blogspot/zetaorionis/bookmarks/model/Bookmark.java
com/blogspot/zetaorionis/bookmarks/model/Bookmarks.java
com/blogspot/zetaorionis/bookmarks/model/ObjectFactory.java
com/blogspot/zetaorionis/bookmarks/model/package-info.java
zlaja@orion:~/NetBeansProjects/JAXBLoader>

Unmarshalling / loading XML data to object model instance
This utility class will help you read xml file into it's object representation. It will work with every xml file. You just need to supply it with uri path to xml file:
data/bookmarks.xml

and root element class of object model:
Bookmarks.class

Here is XMLUnmarshaller.java utility class:

package com.blogspot.zetaorionis.util.xml;

import java.io.FileNotFoundException;
import java.io.InputStream;
import java.io.IOException;
import java.net.URI;

import javax.xml.bind.JAXBContext;
import javax.xml.bind.JAXBElement;
import javax.xml.bind.JAXBException;
import javax.xml.bind.Unmarshaller;
import javax.xml.transform.stream.StreamSource;

import org.apache.log4j.Logger;

/**
*
* @author zlaja
*/
public class XMLUnmarshaller {

private static final Logger logger = Logger.getLogger(XMLUnmarshaller.class);
/**
* The bookmark file.
*/
protected URI uri;

/**
* Create an xml based loader of bookmarks.
* @param uri the bookmark file
*/
public XMLUnmarshaller(final URI uri) {
this.uri = uri;
}

//
// BookmarksXMLLoader
//
/**
* Load bookmarks into a action list.
*
* @throws IOException
* If an I/O error occurred.
* @throws FileNotFoundException
* If the resource was not found.
*/
public T load(Class docClass) throws IOException {
final InputStream in = getClass().getResourceAsStream("/" + uri.getPath());

if (in == null) {
throw new FileNotFoundException("Cannot find resource: " + uri);
}

try {
return load(docClass, in);
} finally {
in.close();
}
}

protected T load(Class docClass, final InputStream in) {
T o = null;
try {
o = unmarshal(docClass, in);
} catch (JAXBException ex) {
logger.error("Error while unmarshalling.", ex);
}
return o;
}

public T unmarshal(Class docClass, InputStream inputStream)
throws JAXBException {
String packageName = docClass.getPackage().getName();
JAXBContext jc = JAXBContext.newInstance(packageName);
Unmarshaller u = jc.createUnmarshaller();
JAXBElement doc = u.unmarshal(new StreamSource(inputStream), docClass);
return doc.getValue();
}
}

Marshalling / writing data to xml from object model instance
This utility class will help you write data from object representation to xml file. It will work with every xml file. You just need to supply it with uri path to xml file:
data/bookmarks.xml

and root element class of object model:
Bookmarks.class

Here is XMLMarshaller.java utility class:
package com.blogspot.zetaorionis.util.xml;

import java.io.FileNotFoundException;
import java.io.OutputStream;
import java.io.FileOutputStream;
import java.net.URI;
import java.io.IOException;

import javax.xml.bind.JAXBContext;
import javax.xml.bind.JAXBElement;
import javax.xml.bind.JAXBException;
import javax.xml.bind.Marshaller;

import org.apache.log4j.Logger;

/**
*
* @author zlaja
*/
public class XMLMarshaller {

private static final Logger logger = Logger.getLogger(XMLUnmarshaller.class);
/**
* The output XML file.
*/
protected URI uri;

/**
* Create an xml based writer for specified jaxbObject.
* @param uri - uri for output XML file
*/
public XMLMarshaller(final URI uri) {
this.uri = uri;
}

//
// XMLMarshaller
//
/**
* Write JAXBElement representation of object to XML file.
*
* @param jaxbObject - object for marshalling to xml, converted to JAXBElement.
* Conversion is done using function inside ObjectFactory.java which is
* created with xjc utility
* @param docClass - class for object that is going to be marshalled to XML
*
* @throws IOException
* If an I/O error occurred.
* @throws FileNotFoundException
* If the resource was not found.
*/
public void write(final JAXBElement jaxbObject, Class docClass) throws IOException {
final OutputStream os = new FileOutputStream(uri.getPath());

if (os == null) {
throw new FileNotFoundException("Cannot create resource: " + uri);
}

try {
write(jaxbObject, docClass, os);
} finally {
os.close();
}
}

protected void write(final JAXBElement jaxbObject, Class docClass, final OutputStream os) {
try {
marshall(jaxbObject, docClass, os);
} catch (JAXBException ex) {
logger.error("Error in marshalling to XML.", ex);
}
}

private void marshall(final JAXBElement jaxbObject, Class docClass, final OutputStream os)
throws JAXBException {
String packageName = docClass.getPackage().getName();
JAXBContext context = JAXBContext.newInstance(packageName);
Marshaller m = context.createMarshaller();
m.setProperty(Marshaller.JAXB_FORMATTED_OUTPUT, Boolean.TRUE);
m.marshal(jaxbObject, os);
}
}

Call utility classes inside main class
package com.blogspot.zetaorionis.jaxbloader;

import com.blogspot.zetaorionis.bookmarks.model.Bookmarks;
import com.blogspot.zetaorionis.bookmarks.model.ObjectFactory;
import com.blogspot.zetaorionis.util.xml.XMLMarshaller;
import com.blogspot.zetaorionis.util.xml.XMLUnmarshaller;
import java.net.URI;
import org.apache.log4j.Logger;

/**
*
* @author zlaja
*/
public class JAXBLoader {

private static final String LOG4J_PROPERTIES = "data/log4j.properties";
private static final Logger logger = Logger.getLogger(JAXBLoader.class);
private Bookmarks bookmarks = new Bookmarks();

public JAXBLoader() {
Log4J.init(LOG4J_PROPERTIES);
}

/**
* Loads XML data to object
*/
private void loadBookmarks() {
try {
final String path = "data/bookmarks.xml";
final URI uri = new URI(path);

final XMLUnmarshaller xmlBookmarks = new XMLUnmarshaller(uri);
this.bookmarks = xmlBookmarks.load(Bookmarks.class);
logger.info("Info: Bookmarks loaded successfuly.");
} catch (Exception ex) {
logger.error("Error: Loading bookmarks XML file failed", ex);
}
}

/**
* Writes object data to XML
*/
private void writeBookmarks() {
try {
final String path = "data/bookmarks.xml";
final URI uri = new URI(path);

final XMLMarshaller xmlBookmarks = new XMLMarshaller(uri);
ObjectFactory of = new ObjectFactory();
xmlBookmarks.write(of.createBookmarks(this.bookmarks), Bookmarks.class);
logger.info("Info: Bookmarks written successfuly.");
} catch (Exception ex) {
logger.error("Error: Writing bookmarks XML file failed", ex);
}
}

/**
* @param args the command line arguments
*/
public static void main(String[] args) {
JAXBLoader loader = new JAXBLoader();
loader.loadBookmarks();
loader.writeBookmarks();
}
}

Saturday, February 20, 2010

Use yubikey for safer and less painful browsing

What is yubikey?
Yubikey is usb powered piece of hardware with one action button to generate OTP (one time passwords).

Main advantages:
- There is no need to remember credentials for different sites on the web. Just plug in the yubikey and press action button which will create random OTP password with unique header number of that particular yubikey.
- It will guarantee user inviolability and thus disable fishing attacks and credential information interception.

Main disadvantages:
- You have to carry it with you :), but you can access your web portals without using it in old fashion way by typing your credentials.

Settings things up:
You need to register your account at KeyGenius:
http://kg.yubico.com/

You can use basic or standard account type. Basic will not ask you for any password when logging and all you need is one touch on your yubikey for every login on the web. You are released of typing. Standard account is more secure. It will ask you on first access for your KeyGenius credentials, and after supplying it you can use yubikey like in basic account for every other portal on the web.

Under your account you need to supply information like username, passsword and domain for every domain and credential information.

So it's like this. You want to login on e.g. facebook.com. You will open facebook in browser. Your username will be remembered by your browser. Instead of typing passwords you plug your yubikey and touch button. Login process will continue automatically. First it will send request to KeyGenius to return real password for facebook and after receiving password browser will log you to facebook.

Browser will need to know how to get password from KeyGenius. That is accomplished with java script which can be installed to browser using GreasyMonkey addon. Script can be found here:
http://kg.yubico.com/keygenius.user.js

And thats it. Enjoy your safe browsing... :)

Database synchronization using TableSyncer

Prerequisites:
ruby
ruby-devel
ruby-mysql
rubygems
libmysqlclient
libmysqlclient-devel
libopenssl-devel
zlib-devel

Installation:
sudo gem install mysql
sudo gem install table_syncer

Settings:
cd /usr/lib64/ruby/gems/1.8/gems/table_syncer-0.3.1/lib
cp table_syncer.rb table_syncer.rb.orig
vi table_syncer.rb

Add and change these lines:
local_source_db = {:host => '127.0.0.1', :user => 'user', :password => 'password', :db => 'SourceDatabase'}
local_test_db = {:host => '127.0.0.1', :user => 'user', :password => 'password', :db => 'test'}

Executing
table_syncer --from=local_source_db --to=local_test_db --tables=account

Reference:
http://code.google.com/p/ruby-roger-useful-functions/wiki/TableSyncer
http://www.freelinuxtutorials.com/quick-tips-and-tricks/sync-mysql-tables-via-ruby-gem-tablesyncer/
http://forums.mysql.com/read.php?116,178217,198518#msg-198518

SCP & SSH

At local machine:
ssh-keygen -t rsa
cd ~/.ssh
cp id_rsa.pub authorized_keys
scp -p ~/.ssh/authorized_keys username@remoteMachine:.ssh/

Note that before executing scp you need to make sure there is ~/.ssh at remote machine also and create it if neccecery with
mkdir ~/.ssh

At remote machine:
cd
ls -ld . .ssh .ssh/authorized_keys
drwxr-xr-x 36 username username 4096 Jul 25 02:24 .
drwxr-xr-x 2 username username 512 Apr 10 02:30 .ssh
-rw-r--r-- 1 username username 1674 Apr 10 02:29 .ssh/authorized_keys

cd
chmod go-w . .ssh .ssh/authorized_keys

At local machine:
scp -p file username@remoteMachine:path/to/file

Reference:
http://kimmo.suominen.com/docs/ssh/