Lifetime's Weblog

Mysql Order / Sort by before Group by

2012-02-19T18:26:00.002+02:00

Every developer knows the horror of mysql sort/order by or select distinct using with group by. Mysql does group by before order by and you get mixed results not what you expected. This is a small solution with less performance problem:

SELECT * FROM 

(
select * from `my_table` order by timestamp desc
) as my_table_tmp

group by catid

order by nid desc

In this example we get latest news in each category. We create a temp table by sorting by timestamp and group by after it. It worked for me.

How to Resize an Animated GIF Without Losing the Animation in PHP

2012-02-18T22:22:00.002+02:00

Source: http://blog.oskoui-oskoui.com/?p=404

One question that you may ask yourself when you work with images is if it is possible to resize an animated GIF and keep the animation. We will see here the different steps to do that in PHP, without using any special library like ImageMagick or something else.

Required libraries

First, to manipulate our image files, we will need the GD library from PHP. If you don’t have it already installed on your server, here is the link which explains how to proceed: click to link to the page.
Here is the animated GIF that we would like to resize:

The following steps explain the process.
Step 1: Extraction of the GIF’s frames

The first step is to extract each frame, each individual image of the GIF, to modify them.

For this, we will use the PHP class GIFDecoder.class.php that is available on the web. This class allows us to retrieve each frame from the GIF and the delay between each frame.
Here is the part of the code which shows how to extract and reduce each frame of the GIF:

$animation ="../gif_upload/animated_image.gif; // link to the file
$gifDecoder = new GIFDecoder ( fread ( fopen ( $animation, "rb" ), filesize ($animation) ) );
$delay = $gifDecoder->GIFGetDelays ( ); // get the delay between each frame
// treatment of the reduced images 225x127
$i = 1;
foreach ( $gifDecoder -> GIFGetFrames ( ) as $frame ) {
   fwrite ( fopen ( "resizeGif/tmp_reduced/image$i.gif" , "wb" ), $frame );  // write each frame in a temporary file
   $img = "resizeGif/tmp_reduced/image$i.gif"; // File image location
   $newfilename = "resizeGif/tmp_reduced/image$i.gif"; // New file name
   $w = 225;  // new width
   $h = 127;  // new height
   resize($img, $w, $h, $newfilename);  // function to reduce the image
 
   $i++;
}

Step 2: Reduction of the Frames

The “resize” function used in Step 1 used the GD library, and resizes the image to the given width and height:

function resize($img, $w, $h, $newfilename) {
 
 //Check if GD extension is loaded
 if (!extension_loaded('gd') && !extension_loaded('gd2')) {
  trigger_error("GD is not loaded", E_USER_WARNING);
  return false;
 }
 
 //Get Image size info
 $imgInfo = getimagesize($img);
 switch ($imgInfo[2]) {
   case 1: $im = imagecreatefromgif($img); break;
   case 2: $im = imagecreatefromjpeg($img);  break;
   case 3: $im = imagecreatefrompng($img); break;
   default:  trigger_error('Unsupported filetype!', E_USER_WARNING);  break;
 }
 
 //If image dimension is smaller, do not resize
 if ($imgInfo[0] <= $w && $imgInfo[1]  $h/$imgInfo[1]) {
   $nWidth = $w;
   $nHeight = $imgInfo[1]*($w/$imgInfo[0]);
  }else{
   $nWidth = $imgInfo[0]*($h/$imgInfo[1]);
   $nHeight = $h;
  }
 }
 $nWidth = round($nWidth);
 $nHeight = round($nHeight);
 
 $newImg = imagecreatetruecolor($nWidth, $nHeight);
 
 // Check if this image is PNG or GIF, then set if Transparent
 if(($imgInfo[2] == 1) OR ($imgInfo[2]==3)){
  imagealphablending($newImg, false);
  imagesavealpha($newImg,true);
  $transparent = imagecolorallocatealpha($newImg, 255, 255, 255, 127);
  imagefilledrectangle($newImg, 0, 0, $nWidth, $nHeight, $transparent);
 }
 imagecopyresampled($newImg, $im, 0, 0, 0, 0, $nWidth, $nHeight, $imgInfo[0], $imgInfo[1]);
 
 //Generate the file, and rename it to $newfilename
 switch ($imgInfo[2]) {
  case 1: imagegif($newImg,$newfilename); break;
  case 2: imagejpeg($newImg,$newfilename);  break;
  case 3: imagepng($newImg,$newfilename); break;
  default:  trigger_error(&#039;Failed resize image!&#039;, E_USER_WARNING);  break;
 }
 
   return $newfilename;
}

We now have on the folder “tmp_reduced” the temporary reduced images. The next step will consist of assembling all the frames to construct the new resized GIF image.
Step 3: Fusion of the Frames to Create the New Resized GIF

Now that we have reduced all the frames, the last step will consist of retrieving each reduced frame, and then building the new resized GIF.

For this, we will use the PHP class GIFEncoder.class.php, also available on the web. This class lets us retrieve each frame from the GIF contained in an array and reconstruct the GIF with the same delay between each frame.

//Build a frames array from sources
$i = 1;
if ( $dh = opendir ( "resizeGif/tmp_thumbnail/" ) ) {
 while ( false !== ( $dat = readdir ( $dh ) ) ) {
    if ( $dat != "." && $dat != ".." ) {
          $framesThumb [ ] = "resizeGif/tmp_thumbnail/image$i.gif";
          $i++;
     }
  }
  closedir ( $dh );
}
 
$gifThumb = new GIFEncoder (
        $framesThumb,
        $delay,
        0,
        2,
        0, 0, 0,
        "url"
);
 
// save the new gif file
$fpThumb = fopen('../gif_upload/thumb_image.gif', 'w');
fwrite($fpThumb, $gifThumb->GetAnimation());
fclose($fpThumb);

The parameters of the GIFEncoder constructor are, in order:

the images
the delay time
the animation are played n times (0 = infinite)
disposal
transparent red, green and blue colors
source type

With the “GetAnimation” function of GIFEncoder, we are now able to construct the new GIF image.

We can now use our resized animated GIF!
Image before resizing:

Image after resizing:

Extract tar.gz File

2011-12-28T16:07:00.001+02:00

tar is used to create a Tape ARchive. The resulting file is known as a tarball. It's pretty much the same concept as a ZIP file, if you know what they are, but without the compression. To get the files out of a tarball, you can use the following commands:

tar xvf something.tar

If the tarball has also been gzipped (compressed), you can use the following command:

tar xvfz something.tar.gz

If you only want certain directories from the tarball, do this:

tar xvzf something.tar.gz */dir.you.want/*

If you have a .tar.bz2 file, then you need bzip2 installed (/usr/ports/archivers/bzip2), and you issue this command:

tar yxf something.tar.bz2

tar

To tar up *.db in the current directory into a tarball called blah.tar.gz, issue this command:

tar cfz blah.tar.gz *.db

The z option compresses.

listing the contents

To see a list of the files within a tarball, issue the following command:

tar -tzf blah.tar.gz

The -t provides a list. the -z indicates that the tarball is compressed. The -f identifies the tarball.
Here's an example:

# tar -tzf makeworld.991126.tgz 
etc/
etc/protocols
etc/aliases
etc/services
etc/hosts

Swipe JS a very useful tool for native-like swiping

2011-12-28T15:36:00.001+02:00

Swipe JS brings content sliding to the mobile web to preserve space and allow for new types of interaction. Many mobile web sliders currently exist but few embody all the rules a slider like this should follow.

1:1 touch movement

1:1 movement, as described above, is about tracking the position of the touch and moving the content exactly how the touch interacts. This interaction is very common in native apps.

Resistant bounds

When Swipe is at the left-most position, sliding any more left will increase the resistance to slide, making it obvious that you have reached the end. This detection/resistance occurs at both left and right bounds.

Rotation/resize adjustment

When a user rotates their device (in turn resizing the browser window), the slider resets to make sure the sliding elements are the right size. This is only necessary for sliders without declared widths.

Variable width containers

Swipe allows you to set a width to the container, which designates the width of each slide element. This is important if you do not want a full width slider (the default).

Scroll prevention

Scroll prevention is one of the most overlooked pieces of mobile sliders. Swipe detects if you’re trying to scroll down the page or slide content left to right.

Library agnostic

Swipe doesn’t rely on any library. Trust me this is a good thing. All you have to do is pass in the container element, set some parameters, and BOOM goes the dynamite– you're all set. You may choose to pass the element to Swipe with a library, but it’s not necessary.

Securing Seedbox (or normal folders)

2011-08-26T15:10:00.001+02:00

Pretty simple, you create a password file, then put the conf file in apache then restart apache.

First make the password file, you want to put it somewhere else other than in your webserver directory, like in /var/lib/apache2 or /etc/apache2/ or something
The first command with the -c will create the file, put it in a dir, give it a name, assign the realm, then give a username. After you hit enter it'll prompt you for a password. All of these can be changed as you like so long as you remember them for the .conf file after

Code:

    htdigest -c /etc/apache2/rtorrent.password.digest rtorrent username

If you want other users to log in too you can add them to that same file with this:

Code:

    htdigest /etc/apache2/rtorrent.password.digest rtorrent username

Second, go into the config folder for your distro, myne was /etc/apache2/conf.d/

Code:

     nano httpd.conf

and paste the following code, then change the following lines as required:

AuthName "rtorrent"
AuthUserFile /etc/apache2/rtorrent.password.digest

Code:

    <LocationMatch .*/pl/stream/[0-9]+/[0-9]+>
        Allow from all
    </LocationMatch>

    <Directory "/srv/www/htdocs/rutorrent" >

AuthType           Digest
AuthName           "rtorrent"
AuthUserFile       /etc/apache2/rtorrent.password.digest
Require            valid-user
BrowserMatch       "MSIE"      AuthDigestEnableQueryStringHack=On
Order              allow,deny
Satisfy            any
</Directory>

Third and last: restart apache

Code:

/etc/init.d/apache2 restart

Showing Or Saving An Image Retrieved Via cURL

2011-03-07T01:58:00.002+02:00

As a developer cURL can be a very handy for numerous reasons. In my case I have used it for my plugin Twitter Stream, but here we are going to look at a little tip I stumbled across while playing with cURL.

cURL is used to make a connection to an external source to retrieve the content at the source. What most people new to cURL don’t realize is that it can be used to retrieve any content, including images.

Display An Image In Browser After Retrieval Via cURL

Let’s take a look at an example of displaying a image in browser after using cURL to grab it.

01	//The cURL stuff...
02	$ch = curl_init();

03	curl_setopt($ch, CURLOPT_URL, 'http://wallpapers.celeborama.net/wp-content/uploads/2010/02/Cheryl_Cole_Rainbow_Glow_1440x900.jpg');
04	curl_setopt($ch, CURLOPT_HEADER, 0);

05	curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
06	curl_setopt($ch, CURLOPT_BINARYTRANSFER,1);

07	$picture = curl_exec($ch);
08	curl_close($ch);

09	//Display the image in the browser
10	header('Content-type: image/jpeg');

11	echo $picture;

Yes, believe it or not it is actually that simple. Example of cURL grabbing an image and it being displayed in browser.

Let’s also go through what is going on a little. First we initialize cURL, we set the URL, then we tell it we don’t want the header information. We tell it we want to return the information, and we also state we want the transfer to be binary. We then execute it & store the result in a variable, and close/destroy the cURL connection/handler.

Finally we tell the browser that the content we are going to hand it is a jpeg image. You could of course use a MIME type grabbed from the image. Then we echo the binary information inside the variable, that is then interpreted as an image thanks to the content type.

Saving An Image Retrieved Via cURL

Let’s take a look at how to save the image instead of sending it to the browser.

1	//cURL code is exactly the same as before...
2	//Save image...

3	$fh = fopen('filename.jpg', 'x');
4	fwrite($fh, $picture);

5	fclose($fh);

A little more complicated that the previous example, but if you are familiar with PHP file operations it’s still very simple. I can’t really give an example for this one, as you won’t be able to see the result. Trust me though, it works.

Let’s go through this one a little too. The cURL section is exactly the same as before so we don’t need to cover that. First we use fopen to create a file handler & tell PHP what file to write too. xtells PHP to create the file if it doesn’t exist, but to error out if it does already exist. Then we usefwrite to write the raw binary data held in the variable $picture to the file. We then close & destroy the file handler by using fclose.

Possible Uses

One of the main reasons to use cURL to save or display a remote image is that some servers/hosts have allow_url_fopen turned off. This means functions like fopen can’t open files held on external servers.

You could go into the whole copyright issue of displaying other people’s images etc, but I’m not going to get started on my thoughts about that. Just be careful with this kind of script & use it with care.

I hope you have enjoyed this tutorial. If you have any questions or comments please don’t hesitate to leave them below.

Piping Output from One Command to Another

2011-03-03T02:21:00.000+02:00

Piping allows the user to do several fantastic thing by combining utilities. I will cover only very basic uses for piping. I most commonly use the pipe command, |, to pipe text that is output from one command through the grep command to search for text.

Examples:

See if a program, centericq, is running:$ ps ax | grep centericq
25824 pts/2 S 0:18 centericq
Count the number of files in a directory (nl counts things):$ ls | nl
1 #.emacs#
2 BitchX
3 Outcast double cd.lst
4 bm.shader
5 bmtexturesbase.pk3
If my memory serves using RPM to check if a package is installed:$ rpm -qa | grep package_name
A more advance example:$ cat /etc/passwd | awk -F: '{print $1 "\t" $6}' | sort > ./users
This sequence takes the information if the file passwd, pipes it to awk, which takes the first and sixth fields (the user name and home directory respectively), pipes these fields separated by a tab ("\t") to sort, which sorts the list alphabetically, and puts it into a file called users.

PHP POST Upload File Using CURL

2011-03-02T16:50:00.000+02:00

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<?php 
 
 
$data = array ( 
                'type' => 'direct', 
                'userfile[]' => '@c:\Apache Server Doc Folder\picture.jpg', 
                'private' => '0', ); 
 
 
$curl = curl_init(); 
curl_setopt($curl, CURLOPT_URL, "http://www.url.com/upload.php"); 
curl_setopt($curl, CURLOPT_VERBOSE, true); 
curl_setopt($curl, CURLOPT_POST, true); 
curl_setopt($curl, CURLOPT_RETURNTRANSFER, true); 
curl_setopt($curl, CURLOPT_FOLLOWLOCATION, true); 
curl_setopt($curl, CURLOPT_POSTFIELDS, $data); 
$result = curl_exec($curl); 
curl_close($curl); 
 
?>