Code Diary

How to get User's IP adress using Perl

2012-01-24T02:14:00.000-08:00

In a server environment there several servers are involved in an architecture with load balancer for example the user's IP-address are retrieved using HTTP_X_FORWARDED_FOR environment parameter in PERL:

my @ip_address = split(/,/, $ENV{'HTTP_X_FORWARDED_FOR'});
print $ip_address[0] ;

In all other language you should be able to access to HTTP_X_FORWARDED_FOR:

Ruby:

@remote_ip = request.env["HTTP_X_FORWARDED_FOR"]

Using Emacs instead of Eclipse

2012-01-18T23:50:00.000-08:00

One of the selling points in using Eclipse or other IDE is code completion, but this can be as well in Emacs.
With Emacs you can be more effective using only keyborads as all is textbased.
As a developer you will be more effective. I would recommend that you begin using Emacs instead of IDE for scripting languages like Scala. Here is an excellent instruction how to use Emacs on Scala:
http://www.scala-lang.org/node/354

The server principal "user" is not able to access the database "Database" under the current security context.

2012-01-18T03:28:00.000-08:00

If you get the following error message in MS SQL 2008:
The server principal "yourUser" is not able to access the database "yourDB" under the current security context

This issue arise due to cross ownership chaining restriction that comes after SQL 2000 SP3.
If cross database ownership chaining is required for your application to work, you must enable it.

How you see if this uis enabled ?
exec sp_dboption ' yourDB ', 'db chaining'

You should get:
OptionName CurrentSetting
db chaining OFF

If you are using views to see data in tables owned by different users SQL server check the permissions on the table.

Resources:
Using Ownership Chainshttp://msdn.microsoft.com/en-us/library/aa905173%28SQL.80%29.aspx

Solution
http://blogs.technet.com/b/mdegre/archive/2010/08/29/the-server-principal-quot-sqlloginname-quot-is-not-able-to-access-the-database-quot-mydatabasename-quot-under-the-current-security-context.aspx

Troubleshooting Orphaned Users
http://msdn.microsoft.com/en-us/library/ms175475.aspx

PRB: "Troubleshooting Orphaned Users" Topic in Books Online is Incomplete
http://support.microsoft.com/kb/274188/

sp_addlogin (Transact-SQL)
http://msdn.microsoft.com/en-us/library/ms173768.aspx

Webmaster's gold mine

2012-01-12T04:43:00.001-08:00

This is the Google blog :
http://googlewebmastercentral.blogspot.com/

"Access is denied." when you run "./RedistMaker.bat y 32 y"

2011-12-31T04:53:00.001-08:00

When you run

$ ./RedistMaker.bat y 32 y

You may see "Access is denied" in the output as follows:

*******************************************

*** Running the Redist OpenNI script... ***

*******************************************

Access is denied.

This is due to the Windows is unable to run Python program Redist_OpenNi.py. How to solve it?

List of shorter link servers

2011-12-29T16:15:00.000-08:00

https://bitly.com/

Ping your Blog, website and RSS feed to get more traffic

2011-12-29T15:59:00.000-08:00

List of Ping sites:

1) http://www.blogpingtool.com

Google, Google FeedBurner, Yahoo!, Pingomatic, Weblogs.com, Blo.gs, Syndic8, NewsGator, PubSub.com, Blogdigger, BlogStreet, Moreover, Weblogalot, Icerocket, News Is Free, Topic Exchange, Spinn3r, Audio.Weblogs, RubHub, GeoURL, A2B GeoLocation, BlogShares, PostRank, SkyGrid, Collecta, Superfeedr, blo.gs, pingoat.com, longrank.com, ipodder.org, freshpodcats.com, memigo.com, BlogMatcher, bulkfeeds.net, Weblogs.se, coreblog.org, feedster.com, BlogPeople, catapings.com.

Yet another list:

http://rpc.technorati.com/rpc/ping
http://rpc.pingomatic.com/
http://api.feedster.com/ping
http://api.moreover.com/RPC2
http://api.my.yahoo.com/RPC2
http://xping.pubsub.com/ping/
http://ping.blo.gs/
http://ping.feedburner.com
http://ping.syndic8.com/xmlrpc.php
http://ping.weblogalot.com/rpc.php
http://rpc.blogrolling.com/pinger/
http://rpc.icerocket.com:10080/
http://rpc.newsgator.com/
http://rpc.weblogs.com/RPC2
http://topicexchange.com/RPC2
http://www.blogdigger.com/RPC2
http://www.blogstreet.com/xrbin/xmlrpc.cgi
http://www.newsisfree.com/RPCCloud
http://ping.weblogs.se/
http://blogmatcher.com/u.php
http://coreblog.org/ping/
http://www.blogpeople.net/servlet/weblogUpdates
http://bulkfeeds.net/rpc
http://trackback.bakeinu.jp/bakeping.php
http://ping.myblog.jp
http://ping.bitacoras.com
http://ping.bloggers.jp/rpc/
http://ping.blogmura.jp/rpc/
http://xmlrpc.blogg.de
http://1470.net/api/ping
http://bblog.com/ping.php
http://blog.goo.ne.jp/XMLRPC
http://api.feedster.com/ping.php
http://api.moreover.com/ping
http://api.my.yahoo.com/rss/ping
http://bitacoras.net/ping
http://blogdb.jp/xmlrpc
http://mod-pubsub.org/kn_apps/blogchatt
https://phobos.apple.com/WebObjects/MZFinance.woa/wa/pingPodcast
http://ping.amagle.com/
http://ping.cocolog-nifty.com/xmlrpc
http://pinger.blogflux.com/rpc/
http://ping.exblog.jp/xmlrpc
http://pingqueue.com/rpc/
http://ping.blogg.de/
http://ping.rootblog.com/rpc.php
http://rcs.datashed.net/RPC2/
http://rpc.blogbuzzmachine.com/RPC2
http://rpc.britblog.com/
http://rpc.tailrank.com/feedburner/RPC2
http://rpc.wpkeys.com/
http://services.newsgator.com/ngws/xmlrpcping.aspx
http://signup.alerts.msn.com/alerts-PREP/submitPingExtended.doz
http://www.a2b.cc/setloc/bp.a2b
http://www.bitacoles.net/ping.php
http://www.blogoole.com/ping/
http://www.blogoon.net/ping/
http://www.blogroots.com/tb_populi.blog?id=1
http://www.blogshares.com/rpc.php
http://www.blogsnow.com/ping
http://www.holycowdude.com/rpc/ping/
http://www.lasermemory.com/lsrpc/
http://www.imblogs.net/ping/
http://www.mod-pubsub.org/kn_apps/blogchatter/ping.php
http://www.newsisfree.com/xmlrpctest.php
http://www.popdex.com/addsite.php
http://www.snipsnap.org/RPC2
http://www.weblogues.com/RPC/
http://bulkfeeds.net
http://thingamablog.sourceforge.net/ping.php
http://pingoat.com/goat/RPC2
http://xmlrpc.blogg.de/
http://zing.zingfast.com
http://blogbot.dk/io/xml-rpc.php
http://www.catapings.com/ping.php
http://effbot.org/rpc/ping.cgi
http://rpc.wpkeys.com
http://rpc.britblog.com
http://ping.fakapster.com/rpc
http://pinger.blogflux.com/rpc
http://blogsearch.google.com/ping/RPC2
http://rpc.icerocket.com:10080
http://rpc.pingomatic.com
http://blogupdate.org/ping/
http://www.feedsky.com/api/RPC2
http://bitacoras.net/ping/
http://rcs.datashed.net/RPC2
http://euro.weblogs.com
http://www.bitacoles.net/notificacio.php
http://ping.blogoon.net/
http://www.weblogues.com/ping/
http://blo.gs/ping.php
http://www.weblogalot.com/Ping/
http://www.packetmonster.net/xmlrpc.php
http://blogsearch.google.com/ping
http://www.blogupdate.org/ping/
http://blogupdate.org/sverige/ping/
http://rcs.datashed.net/RPC2
http://ping.feeds.yahoo.com/RPC2/
http://www.syndic8.com/xmlrpc.php
http://pingoat.com/
http://www.mod-pubsub.org/ping.php
http://www.weblogues.com/RPC
http://rpc.odiogo.com/ping/
http://www.bloglines.com/ping/
http://api.feedset.com/ping
http://rpc.pingomatic.com/RPC2

How to create QR code recognition in Processing

2011-12-27T16:02:00.000-08:00

For a start you need a library that can be used in Processing.
There is a library implemented in Java at http://qrcode.sourceforge.jp/.
But for our purpose we use library from http://www.shiffman.net/p5/pqrcode/ in processing.
Why use QR Code that is widely used in Japan? The advantage is larger data capacity can be stored and have error correction than well-known barcode.
You can generate an QR code image online at http://qrcode.kaywa.com

How to handle thousands of simultaneous standing connections

2011-12-25T16:19:00.000-08:00

Interesting articles how to handle thousands of simultaneous standing connections, which means it is ideal for real-time web services.
http://www.tornadoweb.org/ used in http://friendfeed.com/

http://www.kegel.com/c10k.html

How to convert a scanned image text to text

2011-12-25T16:17:00.000-08:00

Use open source Optical Character Recognition OCR Tesseract. This use Leptonica Image Processing Library to read a wide range of image formats.
See this blog about how to use in Android or on a Cloud.
Tresseract is hosted on Google and you can find it at http://code.google.com/p/tesseract-ocr/
This is among 3 best engines in accuracy test done in 1990 and supposed to be still accurate.
The challenge to make a Cloud version of this.

How to Install a Contributed Library in Processing

2011-12-24T16:09:00.001-08:00

http://wiki.processing.org/w/How_to_Install_a_Contributed_Library

Maven Integration for Eclipse warning

2011-12-20T04:50:00.000-08:00

The above warning is a result of conflicting Java version in your environments.

"The Maven Integration requires that Exlipse be running in a JDK, because a number of Maven core plugins are using from the JDK.

Please make sure the -vm option in eclipse.ini isn pointing to a JDK and verify that Installed JREs are also using JDK installs."

My first PHP app to Openshift Express

2011-12-20T01:42:00.000-08:00

Start with the following if you are starting to use OpenShift:
$ssh-keygen

$rhc-create-domain -d  -n mynamespace -l mymail@mailserver.com

Alter the namespace if you regret and want to change an existing one. Be aware that the name should not conflict with other namespaces !

$rhc-create-domain -d  -n mynamespace -l mymail@mailserver.com --alter

My first PHP app on Openshift:

 rhc-create-app -a App01 -t php-5.3 --enable-jenkins

Next add MySql support:

$ rhc-ctl-app -a myapp -e add-mysql-5.1

Password:

RESULT:

Mysql 5.1 database added. Please make note of these credentials:

Root User: admin

Root Password: WE4GWEHJASDJSDKLSDJSDFJKFHSDJFHSDJFHSDJKFSD

Database Name: myapp

Connection URL: mysql://127.1.XX.XXX:XXX/

You can manage your new Mysql database by also embedding phpmyadmin-3.4.

You will find a directory named myapp with a php directory created.

Set up and unzip your osCommerce under php-directory:

git commit -a -m 'My first version php version '

git push

To manage your MySQL using phpmyadmin use the following command:
$rhc-ctl-app -a redmine -e add-phpmyadmin-3.4

Exit Code: 97 at Redhat OpenShift

2011-12-20T00:42:00.000-08:00

I got the following error:

Contacting https://openshift.redhat.com
Problem reported from server. Response code was 401.
JSON response:
DEBUG:

Exit Code: 97
broker_c: namespacerhloginsshapp_uuiddebugaltercartridgecart_typeactionapp_nameapi
api_c: placeholder
API version: 1.1.1
Broker version: 1.1.1

RESULT:
Invalid user credentials

This is baecause I had have used only user name instead of e-mail address to the following account:

$ rhc-create-domain -d -n prylindex -l myUserName

butb this should be

$ rhc-create-domain -d -n prylindex -l myUserName@domain.com

ruby 3304 fork: child 2132 - died waiting for dll loading, errno 11

2011-12-18T15:35:00.001-08:00

I had the following problems
ruby 3304 fork: child 2132 - died waiting for dll loading, errno 11

when I tryed to run OpenShift
rhc-create-domain -n mydomainname -l rhlogin

I resolved this following the steps below:

1)Shutdown cygserver (if running): net stop cygserver.
2)Close all cygwin windows.
3)Open Start->Run
4)rebase has to be run from an ash shell, so type C:\path\to\cygwin\bin\ash.exe
5)Once the shell window run the following:
$ /bin/rebaseall
6) $ exit to close the window

Try to open again Cygwin terminal. Voila this is solved !

If you get the following message, try to close all Cygwin terminals before you run the following:

rebaseall: only ash or dash processes are allowed during rebasing
Exit all Cygwin processes and stop all Cygwin services.
Execute ash (or dash) from Start/Run... or a cmd or command window.
Execute '/bin/rebaseall' from ash (or dash).

Ruby: No such file to load -- ubygems (LoadError)

2011-12-17T03:45:00.000-08:00

If you get the following error message from Cygwin in Windows this is due to the problem with setting RUBYOPT option. Unset it and you will not get the

List of open latform as a service PaaS

2011-12-16T05:42:00.000-08:00

Here is a list of open source clouds that you should consider if you are starting a new project:
1) Cloud Foundry from VMware
Cloud Foundry is an open platform as a service and makes it faster and easier to build, test, deploy and scale Java and .Net applications.
It is an open source project and is available through a variety of private cloud distributions and public cloud instances, including CloudFoundry.com. See more about what is PaaS in my blog.

2) OpenShift is a free, auto-scaling platform-as-a-service for Java, Ruby, PHP, Perl and Python applications. If the time is important for you you can just upload the code in production. Openshift is Scalable and you do not need any additional coding to scale your code up. OpenShift has support for open source Java, PHP, Ruby, Python, Perl and much more.

3) CloudBees.com

This is another Platform as a service that lets you build, test and deploy Java web applications in the cloud. The price is reasonable however I suppose that this is more affordable to rey CloudFoundry and OpenShift. This is not Open Platform as a service. You can only deply Java web applications.

4) Google App Engine - you can develope, build, maintain, scale your web applications in Java, Python and Go. You can set up a daily budget to manage your billing. The App Engine have some restriction that you can visit this page

5) Amazon Web Services AWS EC2 - there is less restrictions on Amazon in comparison to Google App Engine however watch up for the increasing costs if you use any sources.

6) Microsoft Azure - You can try Windows Azure however their pricing is horrible and this is not an alternative to innovative developers. Just for companies that heavily invested in Windows products and would like to skip their infrastructure.

What is Platform as a service PaaS?

2011-12-16T05:27:00.000-08:00

PaaS make it easy to develop, build, test and deploy applications written in some language. Not all PaaS offers support for all languagse and there are restrictions in choice of frameworks and language. Some restricts deployment to a signle cloud. The key and reason to use PaaS is developers agility. There is nothing between your idea and the application to be implemented and you should develop and implement your idea to application fast. Then idea is to write your application once and test , scale and deploy to production.

Gaia: Open Source Flash

2011-12-16T04:53:00.000-08:00

Gaia is an open-source front-end Flash Framework for AS3 and AS2 designed to reduce development time.
With Gaia's scaffolding engine, you can build a fully functional Flash site in less than 10 minutes without writing a single line of Actionscript!

http://www.gaiaflashframework.com

Working with Openshift in Windows

2011-12-16T04:49:00.000-08:00

Redhat come with exciting news about Openshift, as Platform as a service PaaS. Unfortunetaly for a new beginner the information can be too much and difficult to get start quickly. Below is an attempt to gather all information in one place if you are working with Openshift in Windows

1) Install Cygwin in windows
2) Deploying Scala/Lift to Openshift - unfortunaley Openshift does not support deployment for Scala/Lift - see here
3) About attempts to deploy Play from http://www.playframework.org on Openshift Express , see here and follow the excelennt guide to Play on Red Hat Cloud using the Play Framework on Openshift Express with JBoss AS7

Installing OpenShift Express client tools in Windows

2011-12-16T04:37:00.000-08:00

1) Install Cygwin. See my blog how to install Cygwin in Windows
2) Download and extract rubygems from http://rubyforge.org/frs/download.php/75574/rubygems-1.8.12.zip
2) Write the following command in your Cygwin terminal

$ruby <path_to_extracted_rubygems>/setup.rb

In my example I am writing

$ruby "E:\tools\rubygems\setup.rb" install

There E:\tools\rubygems\setup.rb is my local path to extracted rubygem. Please note that the path must be quoted if you want to use DOS-style path instead of Unix-style, something like the folliwng:

$ruby /cygdrive/e/tools/rubygems/setup.rb install

Where /cygdrive is mounted to Windows C:. You can see the list of mounted as follows:

$mount
C:/cygwin/bin on /usr/bin type ntfs (binary,auto)
C:/cygwin/lib on /usr/lib type ntfs (binary,auto)
C:/cygwin on / type ntfs (binary,auto)
C: on /cygdrive/c type ntfs (binary,posix=0,user,noumount,auto)
E: on /cygdrive/e type ntfs (binary,posix=0,user,noumount,auto)
G: on /cygdrive/g type ntfs (binary,posix=0,user,noumount,auto)
I: on /cygdrive/i type ntfs (binary,posix=0,user,noumount,auto)
M: on /cygdrive/m type mvfs (binary,posix=0,user,noumount,auto)
U: on /cygdrive/u type ntfs (binary,posix=0,user,noumount,auto)

3) Install the gem:

$gem install rhc

Installing Cygwin in Windows step for step

2011-12-16T04:07:00.000-08:00

1) Download Cygwin setup-package from http://cygwin.com/setup.exe or http://cygwin.com/install.html and choose setup.exe

2) Choose Installation Directory

3) Select Local Package Directory

4)Select your Internet Connection

5) Choose A Download site. I usually choose ftp://ftp.sunet.se but you can choose any reliable site near to your area. You should same the same site otherwise version conflicts can arise. But for most of the time choosing other sites that your original coice should work without problem.

6) Select packages you need. I choose the following git, make, gcc, ruby, perl, vim as a minumum. Use Serach to get required packages to install:

7)You may see something like the following for resolving dependencies. Just clik next:

8) Just relax and let the Cygwin setup things. This may take many minutes.

9) Choose to create Cygwin icon on desktop

8) Click on the icon created Cygwin Terminal

9) You will see a black terminal. Test to write the command vim in the black terminal:

$vim

9) Done!

3 different ways to convert existing web project to WTP project

2011-12-14T05:05:00.000-08:00

1) Using Maven

If you created an application using maven you can use the folliwng command line to convert it to support Eclipse's wtp:

$ mvn eclipse:eclipse -Dwtpversion=2.0

This will create .wtpscomudules that Eclipse require to eneble WTP support.

2) Using Eclipse WTP tool

Standard Eclipse’s “.classpath” and “.project” files are created. And you will noticed a new “.setting” folder is created and inside contains “org.eclipse.wst.common.component” and “org.eclipse.wst.common.project.facet.core.xml“, both files for WTP or Faces support in Eclipse.
File : org.eclipse.wst.common.project.facet.core.xml

<faceted-project>
  <fixed facet="jst.java"/>
  <fixed facet="jst.web"/>
  <installed facet="jst.web" version="2.4"/>
  <installed facet="jst.java" version="1.4"/>
</faceted-project>

Note
Maven 2.x generated web application with JDK1.4 (see above), which is rather outdated, you may need to upgrade it to latest JDK version.

File : org.eclipse.wst.common.component

<project-modules id="moduleCoreId" project-version="2.0">
  <wb-module deploy-name="mkyongweb-core">
    <property name="context-root" value="mkyongweb-core"/>
    <wb-resource deploy-path="/" source-path="src/main/webapp"/>
    <property name="java-output-path" value="/target/classes"/>
    <wb-resource deploy-path="/WEB-INF/classes" source-path="src/main/resources"/>
  </wb-module>
</project-modules>

3)Import into Eclipse IDE

Now, you have everything what a Eclipse web application want, so, you
 can start import your Maven based web application into Eclipse IDE.
Steps :

 In Eclipse IDE, menu bar , File -> Import… -> General -> 
Existing Projects into Workspace -> select root directory (select 
your project folder) -> Done.

Git Tutorial: How to download facebook php-sdk from git repository

2011-12-09T01:47:00.000-08:00

To create a copy php-sdk from of remote repository on Facebook you can use the following in Linux:
$ git clone git://github.com/facebook/php-sdk.git

Cloning into php-sdk...
github.com[0: 207.97.227.239]: errno=Connection timed out
fatal: unable to connect a socket (Connection timed out)

$git clone git://github.com/facebook/php-sdk.git

Cloning into php-sdk...
error: SSL certificate problem, verify that the CA cert is OK. Details:
error:14090086:SSL routines:SSL3_GET_SERVER_CERTIFICATE:certificate verify failed while accessing https://github.com/facebook/php-sdk.git/info/refs

fatal: HTTP request failed

Resources:

http://cheat.errtheblog.com/s/git

What is Xtext?

2011-12-02T00:11:00.000-08:00

XText is a language development framwwork supported by Eclipse.You can create a small textual domain-specific language (DSL) or a full-blown general purpose programming language in a very short time.

XText can also be used to create an Eclipse-based development environment.

XText is an example of how the lightweight dependency injection (DI) framework Google Guice is used to wire up the language and the IDE infrastructure.

XText is used for code generator, game developementn etc. Xtext-based languages is used to drive code generators that target Java, C, C++, C#, Objective C, Python, or Ruby code.
XText can be used instead of XML. XText is a very powerfil tool, if you use it correct, you will make the life far easy for many developers.