Reposting old blog entries...

Baru ngerepost postingan lama dari sverdianto.net, banyak yang ilang :(
Tapi gpp deh menuh2in blog :P

Mewarnai OS X Terminal.app :)

Udah cari-cari dari lama gimana caranya bikin Terminal di OS X berwarna kayak di Linux, akhirnya nemu juga

Caranya gamphang :) :

• Pastikan terminal typenya xterm-color, bisa di cek di Terminal -> Preferences
• Edit atau buat file ~/bash_profile.
export CLICOLOR=1 export LSCOLORS=ExFxCxDxBxegedabagacad
• Exit terminal dan…

Ini gambarnya:
[[IMAGE LOST]]

Selamat mencoba…

update:
Ternyata warnanyapun bisa di customize ini detailnya:

Variabel LSCOLORS itu ternyata menyatakan warna yang ditampilkan oleh program ls.
Warna yang bisa digunakan:

a - black
b - red
c - green
d - brown
e - blue
f - magenta
g - cyan
h - light grey
x - default foreground or background
Jika ingin dicetak tebal, lambang warna tersebut bisa dituliskan dengan huruf besar (uppercase).

Warna-warna tersebut dituliskan berdasarkan susunan attribute (setiap attribute terdiri dari foreground diikuti dengan background):

directory
symbolic link
socket
pipe
executable
block special
character special
executable with setuid bit set
executable with setgid bit set
directory writable to others, with sticky bit
directory writable to others, without sticky bit


ref:
- MacTips
- http://www.wikihow.com/Change-Colors-and-Set-Paths-&-Aliases-in-Your-Startup-File

How to prevent non root to execute a perl script

Here is a short script to do that. This help me much...

# check if root
$user = `whoami`;
chomp $user;
if($user ne "root") {
 print "You must be root to execute this command. Please login as root or use sudo command!\n";
 exit;
}

Checkstyle: Custom Inner Class Checker

A week ago, I have successfully installed the Hudson Violation plugin to report our projects Checkstyle result on our Hudson installation. As the first step to force developers not to write a System.out.print/println but instead using Log4J, I only enable module that only reject class having System.out.print/println. Interestingly we caught some developers that have write System.out.print/println function in many classes of our projects :)).

A few days ago, my Boss assigned a new task to also reject any class that have Inner Class. I really agree to this, inner class makes class looks ugly and it would hard to find without a great help of advanced IDE.

I looked at the website and search Google to find if Checkstyle already have Inner Class checker module - but I couldn't find it anywhere. So, I decided to write a simple checker for this. As reference - the Checkstyle "Extending Plugin" page provide everything I need.

Firstly, I need to write the checker implementation class, here it is:

package com.jawasoft.checkstyle.checks;

import java.io.File;

import com.puppycrawl.tools.checkstyle.api.Check;
import com.puppycrawl.tools.checkstyle.api.DetailAST;
import com.puppycrawl.tools.checkstyle.api.SeverityLevel;
import com.puppycrawl.tools.checkstyle.api.TokenTypes;

/**
 * @author sverdianto
 *
 */
public class InnerClassCheck extends Check {

 public InnerClassCheck() {
  // default severity is error
  setSeverity(SeverityLevel.ERROR.getName());
 }
 
 @Override
 public int[] getDefaultTokens() {
  return new int[]{TokenTypes.CLASS_DEF, TokenTypes.INTERFACE_DEF};
 }

 @Override
 public void visitToken(DetailAST aAST) {
  String fileName = this.getFileContents().getFilename();
  File file = new File(fileName);
  String javaName = file.getName().substring(0, file.getName().lastIndexOf(".java")); // remove extension

  if(aAST.branchContains(TokenTypes.IDENT)) {
   DetailAST id = aAST.findFirstToken(TokenTypes.IDENT);
   if(!javaName.equals(id.getText())) {
    log(aAST, "Inner class is not allowed!");
   }
  }
 }

}

The idea is to compare the actual class name with the file name without .java extension which must be a valid public class name. If it doesn't match it would be treated as an inner class even though it is declared in root and as public.

Compile the class (dont forget to also include checkstyle & its dependencies jars to the classpath).
And add new module to the checkstyle configuration file:

Now, try running checkstyle using new configuration, you shoul see some error if you have inner class.

My New Casio Watch

Hehe... I finally bought Casio Edifice 537 (so happy). Actually, this is my first watch I bought with my own money (and select it myself). It is quite simple, the case & the bend are made of stainless steel, black background, and 30 minutes chronograph (sadly no date indicator).

Here are the pictures:

Adding Enum support to CakePHP

CakePHP have been previously support Enum, but it was removed because Enum is actually MySQL specific datatype.

I really need this feature and so I decided to hack the form helper to support Enum type.
It is basically adding new Enum handler to the input() method of form helper which is used by scaffolding or user custom form.

Here is the patch of [CAKE_ROOT]/cake/libs/view/helpers/form.php file:

582c582
< 
---
>   
613a614,625
>     
>  // enum special handling
>  preg_match('/enum\((.*)\)/i', $type, $matches);
>  if(!empty($matches[1])) {
>    $options['type'] = 'select';
>    $enum_options = explode(',', $matches[1]);
>    $options['options'] = array();
>    foreach($enum_options as $_option) {
>      $option = trim($_option, "\"' ");
>      $options['options'][$option] = $option;
>    }
>  }
624c636
< 
---
>    

Once you patched the file, every Enum fields will be displayed as a HTML select instead of a normal text field. Goodluck!

Setting up DomainKeys (DK) and DomainKeys Identified Mail (DKIM) for Sendmail

A short introduction abort DK and DKIM. DK and DKIM is basically an email authentication system to verify the DNS of email sender and message integrity.

How it works? Let say a user (john@example.org) send an email to other people using Yahoo! account (jen@yahoo.com). The MTA of example.org will sign the message using private key before delivering the email. Once the message received by target server (in this case Yahoo!), they will verify the message using example.org public key published as TXT info by the example.org name server.

DK or DKIM will guarantee that a verified email is coming from the right person or organization.

I will explain how to install DK and DKIM with Sendmail. Why DK and DKIM? some email server might support only DK and some might support advanced DK which is DKIM.

Requirements:

• Sendmail 8.13 or higher (with Milter support)
• OpenSSL
• Bind DNS server (or any other DNS server)

Installation:

1. Install this following packages:
   
   • latest OpenSSL + OpenSSL-devel package from YUM
   • Sendmail, Sendmail-cf and Sendmail-devel for Milter support
2. Download DK-Milter and DKIM-Milter packages:
   
   • http://downloads.sourceforge.net/project/dk-milter/DomainKeys%20Milter/1.0.2/dk-milter-1.0.2.tar.gz?use_mirror=jaist
   • http://downloads.sourceforge.net/project/dkim-milter/DKIM%20Milter/2.8.3/dkim-milter-2.8.3.tar.gz?use_mirror=jaist
3. Build and compilation
   DK-Milter & DKIM-Milter have quite similar installation step configuration.
   
   • DKIM-Milter
     
     • Extract package
     • Copy configuration file from site.config.m4.dist to devtools/Site/site.config.m4 (use default configuration for now)
     • Build & install:
       

       # sh Build
       # sh Build install
       

   • DK-Milter
     
     • Extract package
     • Copy configuration file from site.config.m4.dist to devtools/Site/site.config.m4 (use default configuration for now)
     • Build & install:
       

       # sh Build
       # sh Build install

   
   
   
   • Key generation and DNS setup
     Both DK & DKIM require secure key pair to sign the mail. DKIM comes with tools called dkim-genkey, run it and 2 files will be created, one is the private key and the other one is the DNS TXT entry.
     
     • Copy & rename the default.private to /var/db/dk-dkim/mail
     • Update bind and add this follwoing TXT entry:
       

       mail._domainkey.example.org. IN TXT "v=DKIM1; g=*; k=rsa; p=MIGfMA0GCSqGSIb3DQEBAQUAA4GNADCBiQKBgQDMa7vGwI3zb+y8DL5cI5YU0PrdWhrpOTDLrdwnkGzmj0SEYj4lk7Vsq2f40uiB9qL70OB4HTT+eTeFgL1TNPPcMUkQRj8zKX98BwF+CCQ7wpIbJfoMKGpMQaKbzHcfjWjqWbYGpk4WtM4oj/aSklrIr71w0GpjhONDj+M/QT5w/wIDAQAB"
       _domainkey.example.org.  IN TXT "o=~"
       

       Where p=?, ? is the public key generated by dkim-genkey.
       
     • Restart the DNS service.
   
   
   
4. Sendmail integration
   
   • Configure sendmail milter
     We will run DK on port 8891 and DKIM on port 8892
     
     • Edit /etc/mail/sendmail.mc and add this following lines
       

       INPUT_MAIL_FILTER(`dk-filter', `S=inet:8891@localhost')
       INPUT_MAIL_FILTER(`dkim-filter', `S=inet:8892@localhost')

     • Rebuild sendmail config by running
       

       # make sendmail.cf
       # make restart

   • Start DK and DKIM
     

     # /usr/sbin/useradd -r domainkeys
     # chown -Rf domainkeys /var/db/dk-dkim/
     # /usr/bin/dk-filter -l -p inet:8891@localhost -c simple -b s -h -d example.org -D -s /var/db/dk-dkim/mail -S mail -u domainkeys -m MSA
     # /usr/sbin/dkim-filter -l -p inet:8892@localhost -c simple -b s -h -d example.org -D -k /var/db/dk-dkim/mail -s mail -S rsa-sha256 -u domainkeys -m MSA
     

To test send an email to DK or DKIM aware mail provider (eg: Yahoo!). You should see something like this in mail the header: Signature:

X-DKIM: Sendmail DKIM Filter v2.8.3 host3.example.org n82G7Xwh008144
DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=example.org;
 s=mail; t=1251907653; i=@example.org;
 bh=XgF6uYzcgcROQtd83d1Evx8x2uW+SniFx69skZp5azo=;
 h=Date:From:Message-Id:To:Subject;
 b=d2J8AiWmqecDvFvOva6bahU0TEB+q5RYonPCMh/24UpKBzAIczV7ohhW73LcVJaKw
  xshr0SFRDaOE48iGp6FxC1yfHEFr7nix6vzvhc2Hr5MgwsRy1HwwI36mkPrhrnbMb/
  d2Khy498P9z7qj+yNF99RRxq7NAftRbFFxbVb10s=
X-DomainKeys: Sendmail DomainKeys Filter v1.0.2 host3.example.org n82G7Xwh008144
DomainKey-Signature: a=rsa-sha1; s=mail; d=example.org; c=simple; q=dns;
 b=ndEg7XD5PnWe1/SHdKygFZ9s8ZwwhmFBRVjNwEaPytptgEl5XJ41DWwjspq5+4huj
 6SFBQMmVnEOvRwMPTvL8o9mD+M41vaV0X7dLSNYnC9K3JjFpZiwzLonGNag2TwrQBc3
 zzxZqpol5SSOsi93sZ7j3FMNTPdjVIhcsHdvHVw=

Verification:

Authentication-Results: mta117.mail.re3.yahoo.com  from=mail.example.org; domainkeys=pass (ok); from=example.org; dkim=pass (ok)

Thats all