Mohamed Faramawi Blog

iPhone 3G/4G tester - online website test emulator with flip

2011-09-09T00:17:00.000-07:00

Test how your website will look when viewed with iPhone

iPhone 3G/4G tester - online website test emulator with flip

Implement Inheritance in NodeJs

2011-08-22T21:31:00.000-07:00

I'm learning Nodejs these days , and coming from an OOP background, i tend to get things done closer to how i'm doing there.

So I wanted all my Nodejs objects to inherit from a base object , that provide utilities common to every other thing .. this is in OOP known as inheritance.

In JavaScript world class/inheritance isn't officially a feature of the language, but its doable, for example the following JavaScript method copies the prototype of one object to another,

function inherit (parent, descendant) {
                var sConstructor = parent.toString();
		var aMatch = sConstructor.match(/\s*function (.*)\(/);
		if(aMatch != null) {
			descendant.prototype[aMatch[1]] = parent;
		}
		for(var m in parent.prototype) {
			descendant.prototype[m] = parent.prototype[m];
		}

The result of this method is, all functions implemented by the parent will now be added to the descendant.

Fine so far, now how to get this done in Nodejs.

NodeJs combine/organize code into what so called "Modules" , and each module should export (the term used by Nodejs) an object that reference the methods defined in the module.

So for example, we will have a module named "baseObject" defined as follows :

var util = require('util');
var base = function() {}

base.prototype = {
	asString : function() {
		return util.inspect(this, true, null);
	}
}
module.exports = base;

This module defined an object called base, that have a single method called "asString()" which simply dumps a string representation of the object using Nodejs "util.inspect" method , and we export this object .

And we have another object called "settings" that also needs to define a method "asString()" to dump the string representation of that object , defiantly the proper way to do this in Java is to have "settings" inherit from "base" , but how to do so in Nodejs , here is how :

var obj = require("./utils/objectUtils.js");// Defines "inherit" method
var base = require("./utils/baseObject.js");// Holds "asString()" method that we want "settings" to inherit it.
var settings = function() {
	this.x=1;
        this.y=2
}
// Inheirt from the base object 
obj.inherit(base,settings);
module.exports = new settings();

So what did we do is , before we export the module , we called the method "inherit" to copy the prototype of "base" class into "settings" class.

This will result having the following code simply works :

var settings=require('./settings.js');
console.log(settings.asString());

7 Free E-Books and Tutorials for Learning and Mastering Node.js

2011-08-22T20:57:00.000-07:00

7 Free E-Books and Tutorials for Learning and Mastering Node.js

The Node Beginner Book » A comprehensive Node.js tutorial

2011-08-19T18:34:00.000-07:00

The Node Beginner Book » A comprehensive Node.js tutorial

Nagstamon : Nagios Windows Desktop Integration/ Status Monitor Utility

2011-07-15T09:09:00.000-07:00

Nagstamon is a utility that sets at your system tray in Windows listening for your Nagios alerts , incredibly helpful if you don't want to set looking at your Email all the time.

http://nagstamon.ifw-dresden.de/

Getting full process name in Linux

2011-07-14T17:48:00.000-07:00

"ps: commands doesn't display the full name of the process with command line run arguments to get over this you can either :

1- Get it from /proc//cmdline
2- using either htop (required to be installed) , and scroll horizontally.

Fixing "Your system or network configuration does not allow Drupal to access web pages" on Windows

2011-07-13T03:15:00.000-07:00

I've installed Durpal for the first time today , and the status report was showing this message

"Your system or network configuration does not allow Drupal to access web pages"

Fixing that requires editing /system32/drivers/etc/hosts to like :

# localhost name resolution is handled within DNS itself.
127.0.0.1 localhost
# ::1 localhost

The default was

# localhost name resolution is handled within DNS itself.
# 127.0.0.1 localhost
# ::1 localhost

This also caused the website to sped up dramatically .

For more possible solutions check out

http://drupal.org/node/222454

What is the difference between Git Commit and Git Push

2011-07-06T09:39:00.000-07:00

Git Commit , is used to push your changes to your local repository.

Git Push, is used to push changes from your local repository to the remote repositories.

For more understand read,

git ready » pushing and pulling

Git, SSH, PuTTY, GitHub, Unfuddle, Getting Them To Work on Windows

2011-07-05T22:30:00.000-07:00

Git, SSH, PuTTY, GitHub, Unfuddle, the kitchen sink - Sergio Pereira - Devlicio.us - Just the Tasty Bits

Installing Both Python 2.5 And Python 2.6 on Windows Box

2011-07-05T20:51:00.000-07:00

I needed to have both python 2.5 and python 2.6 installed on my development box (windows 7) , both to be used , and to simplify things for my self , i wanted to be able to run from command line

python26 xyz.py to run a python script with Python 2.6
python25 xyz.py to run a python script with Python 2.5

So here is what i've done :
1- Installed Python 2.6 , and on the installation wizard i unchecked the "Register Extensions" option.

2- Installed Python 2.5 , and did the same for the "Register Extensions" option.

3- Created a new folder called it "PythonRunner".

4- Added Symlinks for both python 2.6 , and python 2.5 , called them python26, python25.
mklink python26.exe D:\python26\python.exe
mklink python25.exe D:\python25\python.exe

5- Added the folder "PythonRunner" to my system "PATH".

And i'm done, now opening the command line , and typing python25 , opens the python 2.5 interpreter, and typing python26 opens the python 2.6 interpreter.

There might be something else needed to be done, or maybe there is a better way, i'll update this post if any of that happened.

SVN Equivalent Commands in Git

2011-07-05T20:28:00.000-07:00

Commands mapping between SVN and Git

Git - SVN Crash Course

Changing Windows Program Files Directory Path

2011-07-03T00:26:00.000-07:00

Great tip for how to change the path of windows program files directory

Change Default Installation Directory In Windows 7 & Vista

Checking schema differences between two MySQL database

2011-07-01T06:46:00.000-07:00

My @hubspot colleague @katzj recently asked me to get one of our QA/Prod MySQL dbs synchornized , he used the MySQL "checksum" command to check if there are differences between the QA/Prod MySQL.

The time consuming part is figuring out the differences so you can correct them , luckily someone worked on this area and gave us "Schema Sync" , a python script that takes MySQL URL's of 2 MySQL source,target databases, and compares them , the output of the script are 2 SQL files, the first is changes to be applied to the target database to get it synched with the source, second file is a revert of commands you ran from the first output file.

For more info go to http://schemasync.org/ , but there is no much to figure out, its pretty straight forward.

Update :
If you happened to be using Toad for MySQL you can compare schema between 2 databases, from Toad's menu : Advanced > Schema Compare.

Its much like the "Schema Sync" takes a source and a target , and gives you direct pointer to what the difference is, and a script to fix it (even if the table has data , which is a win over schema sync) , but this is a GUI option if you got a GUI , but if you just have command line, then schema sync is your way.

Collection of python tips and hacks

2011-06-27T16:18:00.001-07:00

Found this nice article containing bunch of Python tips and hacks for your every day python coding

http://www.siafoo.net/article/52

Python: Remove items from a list that occur in another list

2011-06-12T22:13:00.000-07:00

>>> x = [1, 2, 3, 4, 5, 6, 7, 8]

>>> y = [4, 7, 9]
>>> list(set(x) - set(y))
[1, 2, 3, 5, 6, 8]

My new blogging policy

2011-06-12T22:09:00.000-07:00

1-You don't need to blog about a super fancy new things, or hard complicated technical problems to solve only, Just blog about every thing, no matter if its trivial , already known to experts, because as long as the internet is available someone at somewhere at sometime might be looking for that simple, trivial thing.

2- If you googled for it , then Blog It.

That's it, share what you know every day , makes you memorize it , and you might be helping someone .

Why i decided to take this path , simple because i'm still a "thank you comments" about posts i posted years ago about what might look simple to experts.. and yeah it feel good when someone thank you about sharing a piece of info.

Ok , starting with the next post , how to subtract 2 lists in python ... !!

Overriding class methods without inheritance in Java

2010-08-31T07:08:00.000-07:00

So imagine that there is some class , and you want to override a method from that class , but on the same time you do not want to create a new class to inherit from that class, you just want to use the same class, but alter a method definition when that method is used in some context.

For example ,
We have a class "HtmlTable" and we have "render()" method implemented to print an HTML table .

public class HtmlTable{
  public String toString(){
  }
}

Normal uses cases for that object is like
HtmlTable myTable=new HtmlTable();
myTable.render();

Now suppose we have a special use case that requires us to use "
" tags when rendering the table as HTML , the way to do so is inheriting from HtmlTable and provide an override to the render() method and use that new object.

public class HtmlTableWithTheadTfoot extends HtmlTable{
  public String render(){
  }
}

But this is not the only way, we can achieve the same thing using anonymous inner class as follows ,

HtmlTable myTable=new HtmlTable() { public String render(){}};

In the above statement we've created an anonymous inner class that inherits from HtmlTable and ovrriden the method "render()" only for that instance.

More references about this type of overriding found here,

http://stackoverflow.com/questions/1542410/what-is-this-type-of-method-overriding-called-in-java

What version of .NET framework do i have ?

2010-08-04T11:06:00.000-07:00

If you end up on forgetting what is the version of the .NET framework currently installed on your machine, you can find out by visiting the following link on using Internet Explorer browser

http://www.hanselman.com/smallestdotnet/

Convert Java Date object Long value to .NET DateTime object

2010-07-12T17:21:00.000-07:00

From Java Date Long value to .NET DateTime object :

DateTime origin = new DateTime(1970, 1, 1, 0, 0, 0, 0);

return origin.AddSeconds(timestamp);

To convert a .NET DateTime object to Java date Long value :

DateTime origin = new DateTime(1970, 1, 1, 0, 0, 0, 0);
TimeSpan diff = date - origin;
return Math.Floor(diff.TotalSeconds);
To test what you are doing is correct, check it out here , 
http://www.epochconverter.com/

CouchDB vs MongoDB benchmarks for Insert time

2010-03-08T06:21:00.000-08:00

Found the following links for insert time benchmarks for CouchDB and MongoDB

CouchDB Insert Benchmarks

CouchDB vs. MongoDB Benchmark

Update 09/21/2011
Cassandra vs MongoDB vs CouchDB vs Redis vs Riak vs HBase vs Membase vs Neo4j comparison

"No Computers" day policy

2010-03-07T00:47:00.000-08:00

Last week i was thinking about something that is , i don't really take a weekend, day off, vacation if im using a computer.

I work with computer every day its my only mate, even when i'm thinking this is my day off, or a "not working" time, But computer is what my work all about , how can i consider my self in a time off if i'm still using the thing that i work with every day !.

I compared my self to other kinds of workers , civil engineers, teachers, doctors, they can get time off from what they work on daily , and i need to do the same.

Getting into that i came up with 2 options :
1- Have 2 computers, one to be used during work days, it have every thing related to what im working on , and another computer to be used during day offs, weekends, that have nothing related to my work.

2- Don't use a computer completely during weekend, and to check my email i can do that from my cell phone.

I chosen #2 , it sounds more like where i want to be,i tried that yesterday it wasn't easy though, but it happened , my computer was off all the day, i didn't stay at the office (where i work as i work from home) , and done a bunch of stuff , weather was good so i went our running, got out at the night, watched a movie on TV , and i used my cell phone to check my email , thankfully there was nothing serious that needed me to turn my computer on and do work .

It was a good experience and i developed this must follow policy "There must be a day during the weekend where i don't use the computer at all ,calling it a No Computer day ".

Acquired By Oracle

2010-02-18T05:08:00.000-08:00

I was looking for something in MySQL docs , and at the bottom of the page found this silly remainder that MySQL is now a property of Oracle !

Well its not that only , www.sun.com now takes you to www.oracle.com , though http://www.sun.com/software/ still works ;) , But actually any page that had anything related to sun, will show be now having Oracle badge somewhere on the page , bottom, top, anywhere it doesn't matter as long as it shows that SUN IS ACQUIRED BY ORACLE.

Google Social Search In Action

2010-02-17T01:19:00.000-08:00

I was googeling for something yesterday and when scrolling down through the results i found this near at the bottom

Looking at the marked text in the above image "Results from people in your social circle for " , this is something new , googling for it , its turned to be a new feature from google , that is called "Social Search" that allows you to search content added, edited, written by people your trust !

Looking at how the people i trust socially list is figured out by Google , it turns out to be your gmail contacts, your google reader subscription , google profile, and with the release of Google Buzz, it come from your buzz followers/following , this includes people you have on Twitter, Facebook, Flicker , Blogger, if you have these connections added to your Buzz profile , this is all based on Google's Social Graph API.

Two things more :
1- As you guessed , you need to be logged-in to your google account to see this new feature.
2- Its not avilable yet for international Google domains check , google.com vs www.google.com.eg

And a new SSO ( Social Search Optimization) tip : Blog more, tweet more, you will get high ranked in social search results.

Returning Stream result using Struts2 REST plug-in

2010-02-05T04:18:00.000-08:00

As this information is fresh on my head, i wanted to document it , If you are using Java Struts2 with the REST plug-in to build RESTFul web services, and wanted for example provide a RESTFul URL for a binary file (image, excel sheet, anything that is downloadable) , the way to do it is as follows (assuming you want to show an image) :

1- Add the annotation "@Result" to your controller.

@Result(name = "image", type = "stream",params={"contentType","image/png","bufferSize","1024"})
public class MyController extends HubSpotObject implements ModelDriven{
  // Controller Implementation
}

2-The result annotation takes 3 parameters :
1- name : This is the name of your result , which will be returned from your controller.
2- type : The Struts2 result type name, in our case its "stream" similar to how we refer to it in the struts.xml.
3- params : This a list of parameters you want to set for your result , the format is like this "key","value","key","value"..etc.
In case of our image result, we need to set the "contentType" and "bufferSize", and optionally we can set "inputName" name, but if this is omitted you will need to declare an object of type "InputStream" in your controller and call it "inputStream", or anything else, as the REST will look for any input stream object.
If you are not using the REST plugin you would this in struts.xml as follows

<action name="getImage" class="example.ImageAction">
   <result name="success" type="stream">
   <param name="contentType">image/png</param>
   <param name="inputName">imageStream</param>
   <param name="bufferSize">1024</param>
   </result>
   </action>

So we are just giving our result the same parameters we give in the struts.xml.

3- Inside your controller , you will need to make sure you define an InputStream object and have it read the image you want to show .
private InputStream inputStream;

4- Inside your controller "show()" method, you will initialize your InputStream method, and return the result named "image" as we called it when we added the "@Result" annotation.

   public HttpHeaders show() {
   // Make sure your input stream is initialized
   return new DefaultHttpHeaders("image");
   }

And thats it, you can now show images using a RESTFul URL , eg "http://my.app.com/profileImages/1"

Quick tips from my recent REST plug-in experiment:

1- If you want to use "string" ids with your URLS , make sure you set the default extension constants in struts.xml to empty , and this way you can have URLS like "http://my.app.com/profileImages/m.mawi" , without doing so, struts was going to use "m" as the ID , and ".mawi" as the result type and throws an exception about there is no handler for the result type ".mawi".

2- You can not use "/" in your IDs , so if you are thinking of passing URLS as your controllers ID's this will fail, as struts REST plug-in will consider whatever comes after the last slash "/" as a method in your controller and will throw an exception telling you there is no method defined
eg. http://my.app.com/profilerUrl/users.app/profile10 , im not sure if there is a way to disable this behavior.

3- It didn't work for me when i tried to have normal struts actions on the same app as REST struts controllers.

4- The wiki page of the REST plug-in SUX , so google will be your friend here.

5- Make sure you read and get how the Struts 2 Convention plug-in works.

XML to object de-serialization will fail if your object changed

2010-01-26T10:01:00.000-08:00

Today i was doing a code cleanup in a project that uses XStream for object serialization into XML and de-serialization back into.

I deleted some fields from the object that are not used anymore, and this caused the de-serialization of old serialized objects to fail , because they still contains the removed fields. "com.thoughtworks.xstream.mapper.CannotResolveClassException".

XStream states this problem clearly in their FAQs, and also provide possible fixes for it,
"If a field is removed from the class, deserializing an old version that contains the field will cause an exception. Leaving the field in place but declaring it as transient will avoid the exception, but XStream will not try to deserialize it.".

The fix i tried and worked perfectly for me was using a Custom Mapper
"implement a custom mapper to ignore unknown fields automatically (see acceptance test CustomMapperTest.testCanBeUsedToOmitUnexpectedElements())".

I had to grap the source code of XStream to get the test mentioned there, and the fix is simply is adding couple line of code to the XStream object initialization
xstream = new XStream(new DomDriver()){

   protected MapperWrapper wrapMapper(MapperWrapper next) {
   return new MapperWrapper(next) {
   public boolean shouldSerializeMember(Class definedIn, String fieldName) {
   return definedIn != Object.class ? super.shouldSerializeMember(definedIn, fieldName) : false;
   }
   };
   }
   };

Thats it.