SSH Login without password

Posted on October 12, 2009 by Marvin

This is actually a repost from the tutorial I often ran onto when working with servers. Lately, the sys-ad I was working with changed users home directory and also changed their passwords, but gave me the root pass. However, I don’t want to bother him for new passwords, and I guess he setup new ones from password generator apps/scripts, which are of course, really really recommended nowadays. Since I have the root pass, and I don’t want to go back to chmod-chown each and every files/folders I created via root, I thought I can automate logging in with each account I need to work ‘as’ their respective users. Or I can use cat /etc/passwd to know their home directories.

First log in on A as user a and generate a pair of authentication keys. Do not enter a passphrase:

a@A:~> ssh-keygen -t rsa
Generating public/private rsa key pair.
Enter file in which to save the key (/home/a/.ssh/id_rsa):
Created directory '/home/a/.ssh'.
Enter passphrase (empty for no passphrase):
Enter same passphrase again:
Your identification has been saved in /home/a/.ssh/id_rsa.
Your public key has been saved in /home/a/.ssh/id_rsa.pub.
The key fingerprint is:
3e:4f:05:79:3a:9f:96:7c:3b:ad:e9:58:37:bc:37:e4 a@A

Now use ssh to create a directory ~/.ssh as user b on B. (The directory may already exist, which is fine):

a@A:~> ssh b@B mkdir -p .ssh
b@B's password:

Finally append a’s new public key to b@B:.ssh/authorized_keys and enter b’s password one last time:

a@A:~> cat .ssh/id_rsa.pub | ssh b@B 'cat >> .ssh/authorized_keys'
b@B's password:

Now I can work as ‘owner’ and ‘user’ within each user home directory.

a@A:~> ssh b@B hostname
B

Some notes, depending on your version of SSH you might also have to do the following changes:

Put the public key in .ssh/authorized_keys2
Change the permissions of .ssh to 700
Change the permissions of .ssh/authorized_keys2 to 640

Source: http://linuxproblem.org/art_9.html

PHP code block – bringing order to chaos

Posted on September 25, 2009 by Marvin

I had to come up with this post because I’ve been working on an old CMS about 3 years old (or even more) and I had been wondering why the calendar links cuts off from 2001 to 2003.

Task: List a year/month links from the present to the oldest published image sets.

Sounds easy, and I believe it is.

But when I checked on the existing script, this is what I got.

 $month_array = array("1"=>'January',"2"=>'February',"3"=>'March',"4"=>'April',"5"=>'May',"6"=>'June',"7"=>'July',"8"=>'August',"9"=>'September',"10"=>'October',"11"=>'November',"12"=>'December');
	$smarty->assign('y2day',$y2day); $y=0;
	for ($q=12; $q >= 1; $q--){
			$month = $month_array[$q];
			if( ($_GET[year] < '2000') && ($m2day ==$q ) ) $w_string = $week_string; else  $w_string ='';
			if( ($_GET[year] == '2007') && ($_GET[month] == $q) ) $w_string = $week_string;
 
		  if($m2day >= $q){
			$tmp_cal_month_now_array = array(
					'month' => $month,
					'string' => $w_string,
					'link' => $q
					); $date_month_now_array[$y++] =  $tmp_cal_month_now_array;	 }
		} //for
 
	 $smarty->assign('calendar_now_month',$date_month_now_array);
 
	$y=0;	$c_yeartoday = date("Y") -1; //echo $c_yeartoday;
	for($q=0; $q < = 5; $q++){
			$tmp =$c_yeartoday - $q; //echo $tmp;
 
		 $tmp_cal_date_array = array(
					  'year' => $tmp
 
				 );  $date_year_array[$y++] =  $tmp_cal_date_array;
	 } //for
 
	$smarty->assign('calendar_year',$date_year_array);
 
	    $y=0;
		for($q=12; $q >= 1; $q--)
		{
			$month = $month_array[$q];
			if( $_GET[month] == $q ) $w_string = $week_string; else $w_string='';
			$tmp_cal_month_array = array(
					'month' => $month,
					'string' => $w_string,
					'link' => $q
					); $date_month_array[$y++] =  $tmp_cal_month_array;
 
		}//for
	 $smarty->assign('calendar_month',$date_month_array);
 
	 $y=0;
		for($q=12; $q >= 10; $q--)
		{
			$month = $month_array[$q];
			if( ($_GET[year] == '2000') && ($_GET[month] == $q) ) $w_string = $week_string; else $w_string='';
			$tmp_cal_month_old_array = array(
					'month' => $month,
					'string' => $w_string,
					'link' => $q
					); $date_month_old_array[$y++] =  $tmp_cal_month_old_array;
 
		}//for
	 $smarty->assign('calendar_month_old',$date_month_old_array);

Continue reading →

Variable, variables and lots of variables

Posted on September 11, 2009 by Marvin

List of variable names, oddly named and other stuff I’m glad I bumped into . Found them in project about 5 or 6 yrs old that needs modification and I believe optimization too, yes really. So why glad? Because I realized the way I named my variables isn’t that bad at all.

/**
 * This one is on top of a movie player page. Maybe 'he' wasn't so sure 
 * that the parameters passed on to this page is for a 'video'. Just making
 * sure for the nth time I guess.
 */
$videoistrue=0;
/**
 * I think 'he' hate lines. And this one is good, page title is saved 
 * in a session variable, so if another programmer writes a new page
 * and forgot to assign $_SESSION['pagetitle'] a new value for an FAQ
 * page, say faq.php, it'd show up <title>Show Series</title>
 */
session_start();$_SESSION['pagetitle'] = "Show Series";
/**
 * ... and it went on and on
 * $_SESSION['pagetitle'] = "Calendar";
 * session_start();$_SESSION['pagetitle'] = "Browse Model";
 *
 * Hmmmm, $ii as iteration variable, struggling with names? I often 
 * use $i, $n or $x, sometime $c, hehehe! I've seen $i for many. And 
 * have you noticed the class name 'smalleditnoline', can it be any 
 * longer? Yes! and if he had enough time, it may have look like 
 * 'smalleditnolinewitharialbold' or 'smalleditnolineFFFbgcolor333fgcolor'
 * crazy! This is CSS anyway, will surely post one for that, hahaha!
 */
for ($ii=1;$ii< =$totalpages;$ii++)
{
  if ($ii==$page) {
    echo "<font class='smallediton'>[$ii]";
  }
  else {
    echo "<a href='?sort=" . $_GET['sort'] . "&page=$ii' class='smalleditnoline'>[$ii]</a>";
  }
}
/**
 * more variables with default values, note that this is set just
 * before a loop starts
 */
$thisCat = "";
$firstrun = true;
$firstrow = 0;
$rowcount = 0;
/**
 * "NO QUOTES" for key names in square brackets :( 
 * if only my IDE could complain
 */
$GLOBALS[catadded] = false;
$GLOBALS[keywordadded] = false;
$GLOBALS[modeladded] = false;
/**
 * Consistent! Maybe 'He' doesn't want anybody to easily understand 
 * the script that's why no new lines after semi-colon at least.
 */
if ($seriesRow[seriesNo] < 10) $seriesNoTxt = "0".$seriesRow[seriesNo]; else $seriesNoTxt = $seriesRow[seriesNo];

Ok, enough of grumbling here. I have released my frustration for today, going back to work. But if I am to start a project or even a simple script, I follow formatting conventions, consistent quotes and escapes, logical variable names and useful comments with links and samples. It doesn't only make your code readable, it helps a lot for the next programmer to just add-in the stuff he needs to and keeping his sanity.

Smarty Gravatar plugin

Posted on August 26, 2009 by Marvin

I realize the need for this when working on an MVC based CMS especially with Smarty engine in it.

Oh and in case you’re wondering why its sounds like the upcoming movie Avatar by James Cameron, I don’t know. What it has to do with internet term ‘avatar‘? I really don’t know. But in ‘www’, Gravatar is a short term for “Globally Recognized Avatar” assigned by a user as his/her default avatar in every places of the internet, same people behind WordPress. There are other similar services too.

So, this plugin is based from its documentation

/**
 * Gravatar
 *
 * @link http://www.marvinmarcelo.com
 *
 * @param array $params
 * @param Smarty $smarty
 */
function smarty_function_gravatar($params, &$smarty)
{
  /**
   * constant $gravatar_host
   */
  $gravatar_host = "http://www.gravatar.com/avatar/";
 
  if ( !isset($params['email']) )
  {
    $smarty->trigger_error("gravatar: email parameter not set");
    return;
  }
 
  if ( !eregi("^[_a-z0-9-]+(\.[_a-z0-9-]+)*@[a-z0-9-]+(\.[a-z0-9-]+)*(\.[a-z]{2,3})$", $params['email']) )
  {
    $smarty->trigger_error("gravatar: {$params['email']} is not a valid email.");
    return;
  }
  /**
   * @link http://en.gravatar.com/site/implement/url
   */
  $hash = strtolower(md5(trim($params["email"])));
  $src = $gravatar_host . $hash . ".jpg?";
 
  if ( !isset($params["size"]) || !($params["size"] >= 1 && $params["size"] < =512 ))
  {
    $params["size"] = 32;
  }
  $src .= "s={$params["size"]}";
 
  if ( !isset($params["default"]) )
  {
    $params["default"] = "identicon";
  }
  $src .= "d={$params["default"]}";
 
  if ( !isset($params["rating"]) )
  {
    $params["rating"] = "G";
  }
  $src .= "r={$params["rating"]}";
 
  $extras = "";
 
  if ( isset($params["class"]) )
  {
    $extras .= " class=\"{$params["class"]}\"";
  }
 
  if ( isset($params["id"]) )
  {
    $extras .= " id=\"{$params["id"]}\"";
  }
  /**
   * @example http://www.gravatar.com/avatar/7023218434f12aee57f4b03454dadcaa?s=32&d=identicon&r=G
   */
  print "<img src=\"$src\" alt=\"{$params["alt"]}\"$extras />";
}

Simply extract function.gravatar.zip into your Smarty plugin directory. And use it in your template file like this

{gravatar email='someemail@domain.com'}

You’re done!