Installing Apache, Php5, MySql in Ubuntu:

You can install Apache, Php, Mysql and other applications from Synaptic Package Manager. Go to System > Administration > Synaptic Package Manager and search with your desired application name. When found, double-click on package name. The package will be marked for installation along with it’s dependences. Now click on apply button to install the package. In this post, the red+bold texts are the name of software package which can be installed from Synaptic Package Manager.

To make your system ready for PHP development, you have to install more or less this packages: apache2.2-common, apache2-utils, php5, mysql-server-5.0, mysql-client-5.0, mysql-query-browser etc. You may also require some common php extensions which may not installed automatically with PHP installation. Most of them also will be found in Synaptic Package Manager as php5-gd, php5-curl, php5-mysql, php-pear etc.

Paths of important directories

One of the major differences I find here is the file system. All the directory paths I’ve been using in windows are changed here. I m listing here some PHP-MySql related paths here. But they may differ on your installation.

• Apache configation files: /etc/apache2/
• localhost root directory: /var/www/
• PHP ini file: /etc/php5/apache2/
• PHP extensions configuration files : /etc/php5/conf.d
• MySql Data files: /var/lib/mysql/mysql
• MySql Configuration files: /etc/mysql/

PHP Editors for Ubuntu

Gedit is the default text editor of Ubuntu and it support syntax coloring for many languages including PHP. But If you want an advanced editor for programming, you can try Geany or Screem. But, I am sure, who’ve been using advanced IDEs like PHPEd or PHPDesigner in windows, none of this can satisfy him. Don’t worry, the great open source IDE eclips has PHP-Development-Tool. It’s surely one of the best PHP IDE.

Subversion in Ubuntu

Subversion maintains current and historical versions of source code and documentation. It’s very important for distributed application development. RapidSVN is a graphical client for the subversion revision control system (svn) for linux. If you want to use svn from command line, install subversion.

File Difference and Merging Tools for Ubuntu

I have been using WinMerge in windows as file comparison and merging tool along with TortoiseSVN. Now using TkDiff as it’s alternative in linux. TkDiff has advanced functionalities and graphical interface. It provides file-merge and change-summary facilities, line number toggling (for easier cut & paste) and support for Subversion, RCS, CVS and SCCS. To use from command line, diff is may be the simplest file comparison tool.

Ftp and SSH

Ubuntu installs its default programs for FTP, SSH and many other internet applications. But, I’ve liked gFTP as FTP application because of it’s interface is similar to SmartFTP. And for working with SSH, required nothing. Just open the terminal and use ssh command. Write something like ssh username@example.com and press ENTER.

Testing in IE

One of the important (and painful to me) issue of web development is testing the output in IE. Though IE has no version for Linux, you can install it through wine. Wine is a application that crates a virtual environment for installing windows applications in Linux. After installing wine, you can install any available version of IE from http://www.tatanka.com.br/ies4linux/page/Installation:Ubuntu.

When witting this post, my aim was to help a developer who is thinking to switch to Ubuntu Linux or a newcomer here. You are welcome to add your valuable comment/suggestion for the same purpose.

UPDATE(15th May, 2008) : cURL support added. Where url fopen() is disabled, the class will use cURL to load the RSS/ATOM content.

Features:

• Parses all channels and feed item tags and sub tags.
• Serve the parsed data as associative array.
• Enough documented and easy to understand code.
• Many ways to get parsed information.
• Parsing includes attributes too.
• No regular expression used.
• Parsed by XML Parser extension of PHP.
• Pure PHP5 objected oriented.
• Enable to parse all commonly used feed versions.

Supported versions: I tried to include all stable and commonly used feed versions. Currently it’s being used to parse the following versions:

• RSS 1.0
• RSS 2.0
• ATOM 1.0

Download:

• Click Here to get the class file with example. (downloaded 481 times)
• Download from phpclasses.org.

How to use:

It’s dead simple to use this class. Just follow this 3 steps:

1. Include the file

include(’FeedParser.php’);

2. Create an object of FeedParser class

$Parser = new FeedParser();

3. Parse the URL you want to featch

$Parser->parse(’http://www.sitepoint.com/rss.php’);

Done.

Now you can use this functions to get various information of parsed feed:

• $Parser->getChannels() - To get all channel elements as array
• $Parser->getItems() - To get all feed elements as array
• $Parser->getChannel($name) - To get a channel element by name
• $Parser->getItem($index) - To get a feed element as array by it’s index
• $Parser->getTotalItems() - To get the number of total feed elements
• $Parser->getFeedVersion() - To get the detected version of parsed feed
• $Parser->getParsedUrl() - To get the parsed feed URL

A simple example:

Here is a simple example of using this Feed Parser class. Click here to see is the output of this example.

<?php 

include(‘FeedParser.php’); 

$Parser     = new FeedParser();

$Parser->parse(’http://www.sitepoint.com/rss.php’);

$channels   = $Parser->getChannels();     

$items      = $Parser->getItems();        

?>

<h1 id=”title”><a href=”<?php echo $channels[‘LINK’]; ?>“><?php echo $channels[‘TITLE’]; ?></a></h1>

<p id=”description”><?php echo $channels[‘DESCRIPTION’]; ?> </p>

<?php foreach($items as $item): ?>

    <a class=”feed-title” href=”<?php echo $item[‘LINK’]; ?>“><?php echo $item[‘TITLE’]; ?></a>

    <p class=”feed-description”><?php echo $item[‘DESCRIPTION’]; ?></p>

<?php endforeach;?>

I hope, this class is so easy that, anyone who have general knowledge about PHP5 can use it. Whatever it is, Feel free to ask me anything, anytime.

Supported versions:

• RSS 1.0 (which officially obsoleted RSS 0.90)
• RSS 2.0 (which officially obsoleted RSS 0.91, 0.92, 0.93 and 0.94)
• ATOM 1.0

Download: 

• Download it from here (downloaded 2510 times).
• Download from phpclasses.org.

Features:

• Generates RSS 1.0, RSS 2.0 and ATOM 1.0 feeds
• All feeds are are validated by feed validator.
• Supports all possible feed elements.
• Simple and easy to define channel and feed items
• Implements appropriate namespaces for different versions.
• Automatically converts date formats.
• Generates UUID for ATOM feeds.
• Enables usage of subtags and attributes. (example: image and encloser tags)
• Completely Object oriented in PHP5 class structure.
• Handles CDATA encoding for required tags.
• Nearly same code for generating all kinds of feed

A minimum example

It’s a minimum example of using this class. I am generating a RSS 2.0 feed from retrieved data from a MySQL database. There are more examples in the download package for different versions.

<?php

  // This is a minimum example of using the Universal Feed Generator Class

  include("FeedWriter.php");

  //Creating an instance of FeedWriter class. 

  $TestFeed = new FeedWriter(RSS2);

  //Setting the channel elements

  //Use wrapper functions for common channel elements

  $TestFeed->setTitle(‘Testing & Checking the RSS writer class’);

  $TestFeed->setLink(‘http://www.ajaxray.com/projects/rss’);

  $TestFeed->setDescription(‘This is test of creating a RSS 2.0 feed Universal Feed Writer’);

  //Image title and link must match with the ‘title’ and ‘link’ channel elements for valid RSS 2.0

  $TestFeed->setImage(‘Testing the RSS writer class’,‘http://www.ajaxray.com/projects/rss’,‘http://www.rightbrainsolution.com/images/logo.gif’);

    //Retriving informations from database

    mysql_connect("server", "mysql_user", "mysql_password");

    mysql_select_db("my_database");

    $result = mysql_query("Your query here");

 

    while($row = mysql_fetch_array($result, MYSQL_ASSOC))

    {

        //Create an empty FeedItem

        $newItem = $TestFeed->createNewItem();

        //Add elements to the feed item    

        $newItem->setTitle($row[‘title’]);

        $newItem->setLink($row[‘link’]);

        $newItem->setDate($row[‘create_date’]);

        $newItem->setDescription($row[‘description’]);

        //Now add the feed item

        $TestFeed->addItem($newItem);

    }

  //OK. Everything is done. Now genarate the feed.

  $TestFeed->genarateFeed();

?>

Shhhh….a universal feed reader is on the way

Let’s take a look what Wikipedia has to say about the format of UUID :

A UUID is a 16-byte (128-bit) number. The number of theoretically possible UUIDs is therefore 216*8 = 2128 = 25616 or about 3.4 × 1038. This means that 1 trillion UUIDs would have to be created every nanosecond for 10 billion years to exhaust the number of UUIDs.

In its canonical form, a UUID consists of 32 hexadecimal digits, displayed in 5 groups separated by hyphens, in the form 8-4-4-4-12 for a total of 36 characters.

Enough said. Here is the function.

/**

  * Generates an UUID

  * 

  * @author     Anis uddin Ahmad <admin@ajaxray.com>

  * @param      string  an optional prefix

  * @return     string  the formatted uuid

  */

  function uuid($prefix = ”) 

  {

    $chars = md5(uniqid(rand()));

    $uuid  = substr($chars,0,8) . ‘-’;

    $uuid .= substr($chars,8,4) . ‘-’;

    $uuid .= substr($chars,12,4) . ‘-’;

    $uuid .= substr($chars,16,4) . ‘-’;

    $uuid .= substr($chars,20,12);

    return $prefix . $uuid;

  }

Example of using the function -

//Using without prefix.

echo uuid(); //Returns like ‘1225c695-cfb8-4ebb-aaaa-80da344e8352′ 

//Using with prefix

echo uuid(‘urn:uuid:’);//Returns like ‘urn:uuid:1225c695-cfb8-4ebb-aaaa-80da344e8352′

See you.

UPDATE : The PHP Universal Feed Generator class, for which I wrote this function is released.

About the problem :

We see this warning when we try to revisit a page that has accepted POSTDATA using browser’s history mechanism. Usually we do it by browser’s BACK button or refreshing a page. When a page in browser history requested with POST method, the browser thinks this POSTDATA is important to process this page. So, it asks the user if he wants to send the POSTDATA again or not. Different browsers show this warning differently. For example, the images below shows how Firefox and Internet Explorer show this warning.

POSTDATA resend warning in Mozilla Firefox

POSTDATA resend warning in Internet Explorer

Now, If the user accepts the confirmation, the page is reloaded with previously sent data using POST method; otherwise some browsers don’t take any action and some shows a "Webpage has expired" message. In some situations, this re-submitting is useful, but most of the times it’s not expected. It’s more harmful when user accepts it without understanding and causes multiple entries of previously entered data in database.

The easy solution :

The easy solution is simply redirecting. When we redirect a page, the target page is loaded without any POST data that comes with request.

Let’s solve this problem by hand. Say we have 2 pages - A and B. A has a feedback form which submits data by POST request method to B. B inserts the information into database and shows a success message.

Now, if the user try to reload the page by refresh, back button or any other way, browser will show the confirmation message. If user accepts this, the message will inserted again. But after inserting to database, If we redirect to another page C and C shows the success message, the problem will not occur. Because, in the final output to the browser will come from C which didn’t use any POST request data. The code should be something like this:

<?php

if($_POST)

{

  /* Form validation, Inserting to database or anything you want goes here */

  /* Now redirect to another page */

  header(‘Location: http://yoursite.com/success.php’);

}

?>

Extending the solution :

The solution I explained above can show just an static message like "Thanks for your feedback" or "Registration completed successfully" etc. But usually we like to include some information about sender or submitted information in the success of failure message. For example:

Hi Andrew, your registration is successfully completed. An email is sent to you at andy001@yahoo.com with more information.

In the above message, the purple colored information has to be taken from POST data. But the POST data will be lost when redirecting. So, it’s not possible by the above solution.

What we can do to solve this is that we can use SESSION to store those data which we want to display with message in redirected page. Just like this:

<?php

session_start();

if($_POST)

{

  /* Form validatio, Inserting to database or anything you want goes here */

  //Store data to session

  $_SESSION[‘name’]   = $_POST[‘name’];

  $_SESSION[‘email’]  = $_POST[‘email’];

  //Now redirect to another page 

  header(‘Location: http://yoursite.com/success.php’);

}

?>

Let’s look an example of this interactive solution here. 

OK. Now we will make this in 2 easy steps.

1. Import your jQuery file and write the function "limitChars(textid, limit, infodiv)" in the head section of your page.

This function takes 3 parameters. They are:

• textid : (string) The ID of your textarea.
• limit : (num) The number of character you allow to write.
• infodiv : (string) The ID of a div, in which limit information will be shown .

  Here is the function:

 1: <script language="javascript" src="Jquery.js"></script>

 2: <script language="javascript">

 3: function limitChars(textid, limit, infodiv)

 4: {

 5: var text = $(‘#’+textid).val(); 

 6: var textlength = text.length;

 7: if(textlength > limit)

 8: {

 9: $(‘#’ + infodiv).html(‘You cannot write more then ‘+limit+‘ characters!’);

 10: $(‘#’+textid).val(text.substr(0,limit));

 11: return false;

 12: }

 13: else

 14: {

 15: $(‘#’ + infodiv).html(‘You have ‘+ (limit - textlength) +‘ characters left.’);

 16: return true;

 17: }

 18: }

 19: </script>

 1: $(function(){

 2: $(‘#comment’).keyup(function(){

 3: limitChars(‘comment’, 20, ‘charlimitinfo’);

 4: })

 5: });

 1: function limitChars(textarea, limit, infodiv)

 2: {

 3: var text = textarea.value; 

 4: var textlength = text.length;

 5: var info = document.getElementById(infodiv);

 6:  

 7: if(textlength > limit)

 8: {

 9: info.innerHTML = ‘You cannot write more then ‘+limit+‘ characters!’;

 10: textarea.value = text.substr(0,limit);

 11: return false;

 12: }

 13: else

 14: {

 15: info.innerHTML = ‘You have ‘+ (limit - textlength) +‘ characters left.’;

 16: return true;

 17: }

 18: }

 1: <textarea name="comment" id="comment" onkeyup="limitChars(this, 20, ‘charlimitinfo’)">

 2: </textarea>

Please let me know if you have an idea to make it better. 

I am getting a lots of request and questions from visitors about adding some features and some other problems. Sometimes I faced some problem when using this script myself. So, I have made some changes here. I hope, this change will help you to overcome some problems of previous version of this script. The main features added in this version are:

1. It will keep in child list box only sub items of selected parent value when initializing.
2. Added a 4th parameter to input a selected value for child list box.
3. When "isSubselectOptional" is true, add a default value ‘none’ for ‘– Select –’ option of child list box.
4. Automatically focus the child list box when a value is selected from parent list box.
5. More effective for multilevel association.

Click here to see a demo of multilevel association using this function.

Here is the modified function:

 1: function makeSublist(parent,child,isSubselectOptional,childVal)

 2: {

 3: $("body").append("<select style=’display:none’ id=’"+parent+child+"’></select>");

 4: $(‘#’+parent+child).html($("#"+child+" option"));

 5: 

 6: var parentValue = $(‘#’+parent).attr(‘value’);

 7: $(‘#’+child).html($("#"+parent+child+" .sub_"+parentValue).clone());

 8: 

 9: childVal = (typeof childVal == "undefined")? "" : childVal ;

 10: $("#"+child+‘ option[@value="’+ childVal +‘"]’).attr(’selected’,’selected’);

 11: 

 12: $(‘#’+parent).change( 

 13: function()

 14: {

 15: var parentValue = $(‘#’+parent).attr(‘value’);

 16: $(‘#’+child).html($("#"+parent+child+" .sub_"+parentValue).clone());

 17: if(isSubselectOptional) 

 18: $(‘#’+child).prepend("<option value=’none’> — Select — </option>");

 19: $(‘#’+child).trigger("change"); 

 20: $(‘#’+child).focus();

 21: }

 22: );

 23: }

And initialize the association on ‘$(document).ready’, as following example:

 1: $(document).ready(function()

 2: {

 3: makeSublist(’parentID’,‘childID’, true, ‘selected_val_of_child’);

 4: });

If you want to create multilevel association, start the initialization from child most order. such as:

 1: $(document).ready(function()

 2: {

 3: makeSublist(‘child’,‘grandson’, true, ”); 

 4: makeSublist(‘parent’,‘child’, false, ‘3′); 

 5: });

For details instruction and example of using this script, please visit the previous version. Feel free to ask me if any problem with using this script or any bug you found.

part-1 : Rolling with Ruby on Rails

part-2 : Rolling with Ruby on Rails, Part 2

Ok. It’s confirming your successful starting. For the next step, I am listing here some essentials of learning Ruby on Rails.

1. http://tryruby.hobix.com/ : This is an interactive interface for learning Ruby. They said,"Got 15 minutes? Give Ruby a shot right now!".
2. What is ruby on Rails - This is another tutorial from http://www.onlamp.com/ describing amazing features of Ruby on Rails.
3. Four Days on Rails (PDF) : This PDF goes through building a "To-Do List" Application. The steps of building a ruby applications are explained here excellently.
4. http://wiki.rubyonrails.com/rails : Ruby on Rails Wiki : The community-driven Rails documentation! A place where you will get everything about Ruby on Rails.
5. http://api.rubyonrails.com/ : The details documentation of Rails API.
6. http://rubyforge.org/ and http://raa.ruby-lang.org/index.html: These are the world’s richest  collection of open source ruby proj