Some quick tips

Find and replace text within all files within a directory

find PATH_TO_DIRECTORY -type f | xargs perl -pi -e 's/SEARCH_KEYWORD/REPLACE_KEYWORD/g'

Find a text in files in a directory and subdirectories

find PATH_TO_DIRECTORY -exec grep -l 'SEARCH_KEYWORD' {} \;

Find all modified file in last few days within a directory (exclude some sub-directory for e.g. CVS)
Create 2 files as below under DIRECTORY (e.g. find all modified files between 1st July 2011 and 31st July 2011)

touch -t 201107010000.01 FILE_1 /* 2011[year]07[month]01[day] */
touch -t 201107312359.59 FILE_2 /* 2011[year]07[month]31[day] */
find PATH_TO_DIRECTORY -type f -newer FILE_1 ! -newer FILE_2 -exec ls -ogh {} \; | grep -vw 'EXCLUDE_SUB_DIRECTORY' | cut -f4,5,6 -d' '

Batch resize image using ImageMagick

cd PATH_TO_IMAGE_DIRECTORY
mogrify -resize WIDTHxHEIGHT *
mogrify -resize WIDTHxHEIGHT -quality 80 * (to reduce quality)

Copy directory structure without the files

find * -type d -exec mkdir PATH_TO_DIRECTORY/\{\} \;

Webpage screen capturing using khtml2png

Recently, we were working on one PHP project, where we required to have "webpage screen capturing" functionality. I googled on net and found some tools... some window based, some paid... obviously I was looking for *FREE* tool :). As we are working on Lamp (Linux, Apache, MySQL & PHP), I was wondering if I get some Linux based tool.

One solution I found was, using html2ps and then ps2png/ps2jpg/ps2gif to convert it to image. Then ImageMagicK for image manipulation. Somehow I stuck with some weird memory related errors, some package conflicts, some formatting issues etc. So, after spending one day on nothing; I dropped this solution.

Then I tried khtml2png (http://khtml2png.sourceforge.net) and after some r&d, it worked for us.

Some points to remember...
- You need to have VPS/dedicated hosting to setup these tools. On shared hosting, its not possible to install due to various restrictions by hosting providers.

- This tool requires, some libraries and tools: g++, KDE 3.x, kdelibs for KDE 3.x, zlib (zlib1g-dev) and cmake

- This tool uses KDE (K Desktop Environment), that means whenever you use khtml2png tool, it will open one window for *a while* at time of capturing webpage screenshot. We can remove this by using "Xvfb". We will see how to install and configure it later.

- These links will be helpful, if you are planning to develop web application with webpage screen capturing using khtml2png
http://khtml2png.sourceforge.net/index.php?page=faq
http://www.mysql-apache-php.com/website_screenshot.htm

Here is step by step guide to install various dependencies and packages. (I installed these tools on Fedora7 & RHEL5 successfully)

I used "yum" command to install and auto-configure these tools. If "yum" is not available on your machine, get if from http://yum.baseurl.org/ and install it.

Step:1

 yum install ImageMagick

 yum install Xvfb

 yum install gcc gcc-c++ automake autoconf nano zlib zlib-devel

 yum groupinstall "X Window System" "KDE (K Desktop Environment)"

 yum install kdelibs kdelibs-devel

 yum install Xvfb xorg xorg-x11-font* 

Step:2 Install *cmake*
Go to share directory by typing command

cd /usr/local/share/

or any preferred directory where you want to download package. (check http://www.cmake.org for latest "cmake" version)

 wget http://www.cmake.org/files/v2.8/cmake-2.8.1.tar.gz
     
 tar -xzvf cmake-2.8.1.tar.gz

 cd cmake-2.8.1

 ./bootstrap

 make

 make install

Step:3 Download & Install *khtml2png* on your server as per instructions in this link.
http://khtml2png.sourceforge.net/index.php?page=download

Step:4 Check if *khtml2png* is working

 /usr/local/bin/khtml2png2 'http://www.yahoo.com' yahoo.png 

(this will capture yahoo homepage in yahoo.png)

Step:5 Install *khtmld* (a daemon which will be required to run khtml2png in background)
http://wiki.goatpr0n.de/projects/khtmld

I faced couple of problems while setting up *khtmld*, but it got solved by reading suggestions from above link.

I installed above all tools as *root* user.

Once you are done with above steps, lets play with *khtml2png*

How to start?
Run following command to run khtml2png without a visible X session

 Xvfb :2 -screen 0 1024x768x24&
 export DISPLAY=localhost:2.0

(you can put above 2 lines in rc.local so it will start automatically whenever server restarts)

Then start *khtmld* daemon as your webserver user (for me it is *apache*) so that PHP script can have permission to talk with this daemon. (run below command after login as *root* user)

 khtmld -K /usr/local/bin/khtml2png2 -c /etc/khtmldrc --user apache&

"-K /usr/local/bin/khtml2png2" is path to khtml2png2 as by default "khtmld" will look for old "khtml2png" (khtml2png2 is latest version). Find khtml2png2 path using

 whereis khtml2png2

"-c /etc/khtmldrc" is config file path for khtmld (you can create this config file if its not already there)
Sample content for khtmldrc

width=1024
height=768
display=:0.0

Capture image using *khtmld*

echo "http://www.yahoo.com /tmp/yahoo.png" >/tmp/khtmldspool 

(for more details - http://wiki.goatpr0n.de/projects/khtmld)

We have also used ImageMagicK command "convert" (http://www.imagemagick.org/script/convert.php) to trim the image for removing whitespace.

convert /tmp/yahoo.png -fuzz 1% -trim /tmp/new.yahoo.png

Sample PHP code for capturing & displaying PNG image using "khtml2png"

<?php
  ob_clean();
  header("Cache-Control: no-cache");
  header("Pragma: no-cache");
  header("Content-type: image/png");

  $webpage_url= "http://www.yahoo.com";

  $out_put_file = "/tmp/yahoo.png"; //captured screen
  $new_out_put_file = "/tmp/new.yahoo.png"; //whitespace removed

  $cmd = "echo '".$webpage_url." ".$out_put_file."' >/tmp/khtmldspool";
  exec("$cmd");

  // some delay till khtml2png capture screen
  while(!file_exists($out_put_file)) { sleep(3); }

  exec("convert $out_put_file -fuzz 1% -trim $new_out_put_file");
 
  while(!file_exists($new_out_put_file)) { sleep(1); }

  // display image on browser
  echo file_get_contents($new_out_put_file);
        
  unlink($out_put_file);
  unlink($new_out_put_file);
  exit;
?>

Hope this will be helpful.

That's all for now.

Is there a way to change YouTube player skin?

Many of you have tried embedding YouTube video in webpage using EMBED tag. It’s very easy. Just copy the code and paste it in webpage, it will start streaming video. You may think, what’s new here? Yes, you are right there is nothing tricky here. Wait for a while.

Check the second scenario. Let say you want to steam any random video (.flv) other than YouTube video. What options do you have? Either you can use built in flash video player with little customization to match look and feel with your website theme or you can use free open source flash video player (e.g. flowplayer) to stream your video. So, what’s exciting here? Nothing.

Now check the third scenario. Let say you want to steam video provided by YouTube, but want to change video skin to match look and feel with your website? What you will do? Is there any option available to change skin of YouTube player other than default skin?

Yes; it’s possible. You can choose “YouTube Custom Player” if you just want to change background color, name of the player and content of default YouTube player. Or you can user “YouTube Chromeless Player”. You can use either JavaScript APIs or Flash APIs to make your custom player.

See the demo here; cromeless player using JavaScript APIs.

I found some limitation in integrating this APIs
(1) YouTube has provided numerous functions to integrate. But it’s hard to control various events like play, pause, mute, un-mute etc. in design.
(2) The given example support embedding of only one video player at a time. What to do if you have more than one video on a webpage?

I have made a JavaScript class using JavaScript APIs which allows user to overcome both the listed issues.

You can download the class and example code here!

Also, check the demo here of what I have implemented.

If you find any difficulties using this class, please contact me.

Hope you will find this post helpful.

How to get domain name from URL using javascript.

Use following javascript function to get domain name from URL.
function fnGetDomain(url) {
   return url.match(/:\/\/(.[^/]+)/)[1];
}

For ex: <script language="javascript">fnGetDomain("http://mail.google.com/mail/?source=navclient-ff");</script> will return "mail.google.com"

A multi-user blog system in PHP - Bluetrait

Blog systems are now very popular and there are plenty of solutions to implement blogs.

"Bluetrait" allows the one or more users to login and post articles that are stored in a database. Currently it supports storing posts in MySQL and SQLite posts.

It supports post categories, comments, comment spam filtering, generating RSS feeds, trackback handling and plug-in extensions.

Download Here!

Ref: http://www.bluetrait.com

Get the contacts of friends of different e-mail providers and social networks - Open Inviter

Retrieving the contacts of users is often used by social networks and similar sites to get viral by attracting the users' friends.

"Open Inviter" is the solution. It can be use to get the contacts of friends of different e-mail providers and social networks.

It can access the Web services servers of different networks to retrieve the contacts of friends of a given user.

Each network is accessed by the means of plug-in classes. Some plug-ins support sending invitation messages to friends to be added to the user contacts.

Currently it comes with plug-ins that support many networks such as:

* AOL * GMail * GMX.net * Windows Live (Hotmail) * Katamail * Lycos * Mail.com * Mail.ru * Rambler.ru * Rediff * Yahoo! * Yandex * Facebook * Hi5 * LinkedIn * MySpace * Orkut * Twitter

Download Here!

Ref: http://openinviter.com