Start Class 0830

New Template, New Theme and New Territory

2011-01-13T22:47:00.000-08:00

Thank you for visiting this blog and your support. It has found a new place. If you are following this blog, please update your blogs list. Thank you very much.

Sudoku Game

2010-12-17T00:39:00.000-08:00

This game has found a new home here.

Project Euler, Python and Notepad++

2010-12-02T23:34:00.000-08:00

This article has been move to here.

Bubble, Selection and Insertion Sorts Demonstration

2010-10-28T07:57:00.000-07:00

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JavaFX and Google Maps

2009-06-11T22:29:00.000-07:00

This article was move to here.

Java Compile and Run in Notepad++

2009-03-31T08:30:00.000-07:00

This article has been moved to here.

App_Code Folder in ASP .NET 3.5

2009-03-18T22:47:00.000-07:00

This article has been moved to here.

Using IronPython in ASP .NET VS 2008

2009-03-16T22:31:00.000-07:00

Download Microsoft ASP.NET Futures (July 2007) from Microsoft and follow the instructions for installation closely in the download page especially you are installing it on Windows Vista. The installation should work for Visual Studio 2005, Visual Web Developer 2005 Express Edition, Visual Studio 2008 or Visual Web Developer 2008 Express Edition. Start up Visual Studio, create a new website. You should see IronPython in the Language drop down box.

Storing Passwords in MS SQL

2009-03-11T20:37:00.001-07:00

In MySQL, storing users' passwords is easily done by the function SHA1. Assuming a table usertable exists with two columns userid and passwrd.

INSERT INTO usertable(userid, passwrd) 
VALUES('johnlim', SHA1('SECRET'));

To retrieve the user's record,

SELECT * FROM usertable
 WHERE userid = 'johnlim'
   AND passwrd = SHA1('SECRET');

Is there an equivalent in MS SQL Server? Yes! Recently, MS SQL Server 2005 has nicely built-in support for hashing and the function is called HASHBYTES. This function takes in two string parameters. The first determines the algorithm used to provide the hash. Possible values for the algorithm are MD2, MD4, MD5, SHA and SHA1. The second takes in the value to be hashed. Hence the equivalent SQL statements for MS SQL are

INSERT INTO usertable(userid, passwrd) 
VALUES('johnlim', HASHBYTES('SHA1', 'SECRET'));

SELECT * FROM usertable
 WHERE userid = 'johnlim'
   AND passwrd = HASHBYTES('SHA1', 'SECRET');

The only difference is that the passwrd column in MySQL is VARCHAR while in MS SQL is VARBINARY.

Changing Template in Blogger

2009-03-01T19:09:00.000-08:00

I had been a casual blogger until of late when I am seriously exploring how Blogger works. One of the things which I sought to do was to change the template to something more professional. I have tried many templates without success. The cryptic errors reported by Blogger on various occasions were bX-si9ejx, bX-aoj9qb, bX-hq2u5m and etc.

Many other bloggers also experienced these problems and the solution commonly suggested was to delete all browser cookies and temporary files, and then upload the template again. This solution didn't work for me. I also tried changing browsers from FireFox to IE to Chrome and even Opera.

After many hours of research and experimentation, I've finally understood the problem. I came to the understanding that the template not only defines the skin and the layout of the blog, it also stores information about the widgets which I've created. The definition for each created widget is stored in this template. And along with this definition, Blogger also automatically assigns an id with each created widget. By the way, for the uninitiated, widgets are page elements which make up a blog. These are your blog archives, labels, feeds, links and etc. Basically, they are different sections of your blog.

For each template downloaded from popular sites such as Our BLOGGER Template, the template also consists of pre-defined widgets . As mentioned above, each widget is defined by its id. Most of the time unfortunately, the ids of these widgets clash with your existing widgets. In another words, they have the same name. This is where the problem lies!

To overcome this problem, before you upload the template, you should resolve these name conflicts. Common names of widgets are blog1, feed1, label1, etc. You probably need to rename all these other names, (such as blog111, feed111 and label111 etc) in order to avoid the problem altogether.

Take for example the Professional Template downloaded from http://www.ourblogtemplates.com/2008/11/blogger-template-professional-template.html. These are the lines in the template which should be changed. You can open this file using WordPad and search for "widget id". You need not rename every instance. Only those instances that have name conflicts with your existing widgets need to be renamed. But for simplicity, just rename every widget id.

<b:widget id='Header1' locked='true' title='The Professional Template (Header)' type='Header'>
<b:widget id='Blog1' locked='true' title='Blog Posts' type='Blog'>
<b:widget id='Profile1' locked='false' title='About Me' type='Profile'>
<b:widget id='Label2' locked='false' title='Labels' type='Label'>
<b:widget id='Image1' locked='false' title='' type='Image'>
<b:widget id='Text2' locked='false' title='About This Blog' type='Text'>
<b:widget id='Text3' locked='false' title='Lorem Ipsum' type='Text'>
<b:widget id='Text4' locked='false' title='Lorem Ipsum' type='Text'>
<b:widget id='Text5' locked='false' title='Lorem' type='Text'>
<b:widget id='LinkList1' locked='true' title='Linkbar' type='LinkList'>
<b:widget id='LinkList2' locked='false' title='Links' type='LinkList'>
<b:widget id='BlogArchive1' locked='false' title='Blog Archive' type='BlogArchive'>
<b:widget id='Feed1' locked='false' title='Our Blogger Templates' type='Feed'>

The following lines show the renamed ids. E.g. Header1 → Header111.

<b:widget id='Header111' locked='true' title='The Professional Template (Header)' type='Header'>
<b:widget id='Blog111' locked='true' title='Blog Posts' type='Blog'>
<b:widget id='Profile111' locked='false' title='About Me' type='Profile'>
<b:widget id='Label222' locked='false' title='Labels' type='Label'>
<b:widget id='Image111' locked='false' title='' type='Image'>
<b:widget id='Text222' locked='false' title='About This Blog' type='Text'>
<b:widget id='Text333' locked='false' title='Lorem Ipsum' type='Text'>
<b:widget id='Text444' locked='false' title='Lorem Ipsum' type='Text'>
<b:widget id='Text555' locked='false' title='Lorem' type='Text'>
<b:widget id='LinkList111' locked='true' title='Linkbar' type='LinkList'>
<b:widget id='LinkList222' locked='false' title='Links' type='LinkList'>
<b:widget id='BlogArchive111' locked='false' title='Blog Archive' type='BlogArchive'>
<b:widget id='Feed111' locked='false' title='Our Blogger Templates' type='Feed'>

Have a productive time changing your blogger templates!

Python 3.0 and New Books

2009-01-25T08:30:00.000-08:00

The Python 3.0 or Python 3000 final was released on 3 Dec 2009. I welcome the changes as highlighted by Guido van Rossum in http://docs.python.org/3.0/whatsnew/3.0.html. These changes make Python more suitable for teaching programming to students. I did a quick search in Amazon and I spotted these books covering Python 3.0.

It is exciting to see so many books are published with this release. Does it point to the beginning of a new wave?

Setting Default Folder in Windows Explorer

2009-01-17T08:30:00.000-08:00

When Windows Explorer is started, the Documents folder of the current user will be selected. Suppose you want it to select another folder, say the Work folder in D:, can this be done easily? Yes!

Right click on the Windows Explorer icon and click Properties. In the Target textbox, you will see "%SystemRoot%\explorer.exe". Replace this with

%SystemRoot%\explorer.exe /n, /e, /select, D:\Work

The above tip works for Windows XP, Vista and Seven.

Keyboard Shortcuts for Eclipse

2008-12-06T19:14:00.000-08:00

My favourite keyboard shortcuts for Eclipse 3.4 Gandymede. Try the following when you are editing Java codes.

[Ctrl][Shift] + [F] - Reformat your source code with indentation.
[Alt] + [Up] or [Down] - Move a line or selected block of code up or down. Better than cut & paste.
[Ctrl] + [/] - Comment or uncomment current line or selected block of code.
[Alt][Shift] + [R] - Rename all instances of the selected variable.

Resequencing Photos from more than one Camera

2008-12-05T18:26:00.000-08:00

This is a python script which I have written to resequence photos taken from two cameras. The script makes use of the date and time of the photos to sequence the filenames.

import os, glob, time

fprefix = "Beijing"        # Name to prefix photos
folder  = "D:/Beijing2008" # Folder to look for photos
ext     = "jpg"            # Extension of photos
sno     = 1                # Serial number to start

print "Folder = ", folder
print '-' * 60
date_file_list = []
for file in glob.glob(folder + "/*." + ext):
  stats = os.stat(file)
  lastmod_date = time.localtime(stats[8])
  date_file_tuple = lastmod_date, file
  date_file_list.append(date_file_tuple)
  #print date_file_list  # test

date_file_list.sort()
#date_file_list.reverse()  # newest mod date now first

import string
print "%-40s %s" % ("filename:", "last modified:")
for file in date_file_list:
  folder, file_name = os.path.split(file[1])

  # Rename File
  ext = os.path.splitext(file_name)
  file_name = fprefix + ("%03d" % sno) + string.lower(ext[1])
  sno = sno + 1
  newfile = folder + "/" + file_name

  os.rename(file[1], newfile)

  # convert date tuple to MM/DD/YYYY HH:MM:SS format
  file_date = time.strftime("%m/%d/%y %H:%M:%S", file[0])
  print "%-40s %-20s %s" % (folder, file_name, file_date)

Autoexec with Windows Vista

2008-06-17T08:30:00.000-07:00

In the days of Windows 98, commands which you wish to execute when the system starts up are placed in the autoexec.bat file. One of the useful things to do is to remove all temporary files in the temp folder. For example, we could issue these commands in the autoexec.bat file.

REM *** inside autoexec.bat ***
cd C:\temp
del *.tmp

Each time when the system reboots, those files with extension tmp will be removed in the temp folder of C: drive.

How to do this in Windows Vista? The autoexec.bat concept is not used in Vista. However, we can tell Vista to do this by specifying a Local Group Policy on the script to execute during Windows startup. We can do this by using the Local Group Policy Editor.

Open the Run... Dialog Box from the Windows Start menu. Key in "gpedit.msc" to start the Local Group Policy Editor.

When the Local Group Policy Editor appears, expand on the left pane, Local Computer Policy → Computer Configuration → Windows Settings → Scripts (Startup/Shutdown).

Double click on the right pane, Startup. Click on the Add button and specify the script you want Windows to execute during startup. In this case, I placed the delete commands in a script called cleartemp.bat.

Click OK and we are done! Exit the editor. Test out the script by restarting Windows Vista.

Vista and Command Prompt Here

2008-05-16T08:30:00.000-07:00

Those of us who were using Windows XP and Microsoft PowerToys Command Prompt Here would miss this feature in Windows Vista. You will find that there is no equivalent of such a utility by Microsoft for Vista. This is so because of an obvious reason. Vista has already this feature built-in.

Open up Windows Explorer, hold the [Shift] key down, right-click on any folder on the details pane on the right, you will see "Open Command Window Here" menu item third in the pop-up menu. However, if you do this on the folder pane on the left of the Windows Explorer, this will not work. Disappointed?

Another way is to modify Vista's registry. Here is how this can be done. Navigate in your Registry to HKEY_LOCAL_MACHINE/Software/Classes/Folder/Shell and create a key called Open Command Prompt Here. Set the default string to whatever text you want to appear in the right-click menu. Create a new key within your newly created command prompt named "command," and set the default string to cmd.exe /k pushd %L. You may need to add %SystemRoot%\system32\ before the cmd.exe if the executable can't be found.

The changes should take place immediately. Right click a folder in both the right and left panes of your Windows Explorer and your new menu item should appear.

Python and .NET

2008-04-16T20:28:00.000-07:00

I was asked to explore using Python with .NET. Here are three possibilities. Configuration A – Plain IronPython This is the most straightforward and plain vanilla installation. Download IronPython-1.1.1-Bin.zip (975KB) from http://www.codeplex.com/IronPython. Unzip the files into a folder, say C:\IronPython-1.1.1 and set the PATH. Voila! Type ipy helloworld.py or ipyw helloworld.py Configuration B – IronPython Studio IronPython Studio is based on the Visual Studio 2008 Shell runtime (royalty free) and can be installed without requiring any version of Visual Studio. It provides the following templates for projects using IronPython. Need to first install Visual Studio 2008 Shell (Isolated) (390MB) from http://www.microsoft.com/downloads/details.aspx?familyid=aca38719-f449-4937-9bac-45a9f8a73822&displaylang=en. Make sure you execute the vs_shell_isolated.enu.exe file in C:\VS 2008 Shell Redist\Isolated Mode. If you missed this step, the Iron Python Studio will not work. Download IronPythonStudio.msi (1127KB) from http://www.codeplex.com/IronPythonStudio. Double click on the above msi file and the installation will start. IronPython is also included in the msi. Configuration C – Visual Studio 2008 with IronPython For those who already have VS2008 installed and are working in VS2008 for VB and C# projects, this would be the best configuration. Download Visual Studio 2008 SDK (98MB) from http://www.microsoft.com/downloads/details.aspx?familyid=30402623-93ca-479a-867c-04dc45164f5b&displaylang=en and install it on top of Visual Studio 2008. Run VS2008 under “Visual Studio 2008 SDK --> Tools --> Start Visual Studio 2008 Under Experimental Hive”. On top of VB, C#, C++ and all the project types in IronPython Studio, it also allows ASP.NET web applications and services to be developed using IronPython!

It is difficult to develop GUI Applications without IDE. Since I am a DOTNET guy, I go with Configuration C. Configuration B would be good for those of us who are not using VB and C#. Configuration A in my opinion is not productive, but nonetheless a very convenient way to pick up the basics of Python in .NET. After some hours of experimentation, there are some serious bugs in IronPython. My colleague reported this problem, create a Button and define a button_click event for the button. However, when a new Label is created, the button_click function is overwritten. Any change made directly to the codes in the code view will most likely mess up the designer view. The Designer View can also be easily "corrupted" even with incorrect indentation.