Achmad Z's Archives

Do you having trouble on Polynomial Functions, binomial theorem or rational function? I believe some of you having trouble on this precalculus topics, then you need someone that having expertise on precalculus help. If you're a college student you might need calculus help on such topics as integral or differential equation or maybe definite integers.
Based on your grade, if you're having trouble on precalculus or calculus topics, you may try free precalculus help or free calculus help out there. Some paid tutor might provide you with free course so you can decide their quality based on how they help you solving your problem on study. You may also consider to use expert calculus tutor to help you by one on one tutoring about your problem. Having someone to tutor you about precalculus or calculus topics is a good idea but you must make sure that the tutorial is at the pace as your learning speed. Before asking help from expert calculus tutor, make sure the tutor have a good reputation to address your problem correctly and can adapt various matter that his student faced.

You know, yesterday maybe was the worst day for my neighbor. He lost his motorcycle. Seems quite impossible because it happen very quickly (not less than 5 minutes) on about 7pm and it happened in front of the house!
This circumstances remind my job as a programmer, webmaster and system administrator. I'm so working a lot on my server and codes security so none of them has hole and bugs. Of course nobody's perfect, sometime we miss something and some-bad-guy take advantage on it. From my neighbor experience, I realize that not only my internet home that need security, my real world home also need security, I must reconsider my home security.
Well, I think I can use the concept to secure my internet home to my real world home, I need home security system. First thing first is to know your own home comprehensively inside out. Take a review on it and write a note about it. Then next step is knowing your neighborhood, take a look around your home at some radius.
After you have a notes about your home inside out, it's time for making decision 'do you want to secure your home by yourself or have some expert to do it?' If you plan to hire someone to secure your home, make sure you pass the note that you've written although professional home security system provider will make their own. There's another aspect that you also need to consider. You can't always watching your own home security, i.e. there's a time you leave your home to go to your office. That's why you need to chose the best home security surveillance system. Just like your internet server, you need some kind of 'watch dog' to alarm you if something suspicious happen on your home.
That's a little tips on real-world home security based on a way I concern on my internet-based home security.

This post will be in Bahasa Indonesia, so, if you didn't speak Bahasa Indonesia, better leave this post.

Lagi males nulis pakai bahasa inggris.. pakai bahasa indonesia saja lah..
Tadi sore dikasih tahu Om Agus kalo header Youtube yang buat download Youtube sudah berubah, makanya Yt.Devzed gak jalan lagi.
Kembali ke coding dah.. Aku ga mau ambil risiko kalo ntar Youtube ganti header lagi, bisa capek ngupdate downloadernya.. akhirnya coba2 pake cURL langsung sambil mengandalkan CURLOPT_FOLLOWLOCATION.. eh ternyata bisa..
ya udah deh sekarang gak pake nge cek headernya dulu kalo mau grabbing...
semoga dengan cara seperti ini kodenya jadi lebih awet..
Yo wes.. ngono wae ahh..

Today (2009-07-27) my payment status is still in PIP, let's see how fast the status changed into "issued".

Update:
- D day+1 : still in PIP

No site is perfect, even the giant Google.
I found one dead link on Google Adsense payment history page. See this payment history page screenshot:


You see that "Payment schedule demo (Flash)" link? When I click on it, look what I got:


Maybe Google Adsense team didn't notice that.

This problem happened to me after I was doing 'yum update' on my server. Apparently updating ffmpeg to latest version causing trouble on loading ffmpeg-php.
In my case, some library has been updated, for example /usr/lib/libavformat.so.51 become /usr/lib/libavformat.so.52. ffmpeg-php compiled with old/previous ffmpeg version will fail to load because it looks for /usr/lib/libavformat.so.51 not /usr/lib/libavformat.so.52. So, we must recompile ffmpeg-php so it will load the new library.
Re-compiling ffmpeg-php does not easy like it seems (on my case). After 'phpize', when trying to './configure', I got error message:
configure: error: ffmpeg headers not found. Make sure ffmpeg is compiled as shared libraries using the --enable-shared option
I know that my ffmpeg is compiled using --enable-shared option:

FFmpeg version 0.5, Copyright (c) 2000-2009 Fabrice Bellard, et al.
  configuration: --prefix=/usr --libdir=/usr/lib --shlibdir=/usr/lib --mandir=/usr/share/man --incdir=/usr/include/ffmpeg --disable-static --enable-libamr-nb --enable-libamr-wb --enable-libdirac --enable-libfaac --enable-libfaad --enable-libmp3lame --enable-libtheora --enable-libx264 --enable-gpl --enable-nonfree --enable-postproc --enable-pthreads --enable-shared --enable-swscale --enable-x11grab
  libavutil     49.15. 0 / 49.15. 0
  libavcodec    52.20. 0 / 52.20. 0
  libavformat   52.31. 0 / 52.31. 0
  libavdevice   52. 1. 0 / 52. 1. 0
  libswscale     0. 7. 1 /  0. 7. 1
  libpostproc   51. 2. 0 / 51. 2. 0
  built on Jul  9 2009 02:14:04, gcc: 4.1.2 20080704 (Red Hat 4.1.2-44)
FFmpeg 0.5
libavutil     49.15. 0 / 49.15. 0
libavcodec    52.20. 0 / 52.20. 0
libavformat   52.31. 0 / 52.31. 0
libavdevice   52. 1. 0 / 52. 1. 0
libswscale     0. 7. 1 /  0. 7. 1
libpostproc   51. 2. 0 / 51. 2. 0

So, the only culprit is 'ffmpeg headers not found' message, seems funny because I already install ffmpeg-devel.
After googling, I get a rather silly solution -- but it works -- :

copy all .h files inside /usr/inlude/ffmpeg/libavcodec, /usr/inlude/ffmpeg/libavdevice, /usr/inlude/ffmpeg/libavformat, /usr/inlude/ffmpeg/libavutil, /usr/inlude/ffmpeg/libpostproc and /usr/inlude/ffmpeg/libswscale into /usr/include/ffmpeg

that simple, your './confgure' will work as usual and can be continued to 'make&&make install'
Now you'll have latest ffmpeg-php that load correct library.

I come up with this idea after realizing that downloading on my Youtube online video downloader and converter doesn't support download accelerator (only one part/thread) and doesn't support resuming paused download. Personally I didn't like this because my internet connection is not dedicated and not too fast (well, it's common on my country).
I'm using PHP to serve the converted file to users. I think there must be something that can solve the issue. I know it can be done because Indowebster.com use this kind of technique. After looking at the header that Indowebster send to user, I bump into some strange header: X-Accel-Redirect. Maybe this is the key to overcome my problem.
I'm Googling a bit then realize that X-Accel-Redirect header is belong to Nginx where my VPS is using Apache as the web server. Googling again a bit deeper, found one Apache header that compatible with Nginx X-Accel-Redirect that is X-Sendfile. The installation is very easy on CentOS 5:

• install the package: # yum install mod_xsendfile
• restart Apache: # /etc/init.d/httpd restart

You can check whether the module is loaded or not using phpinfo();

If you're using other distros than CentOS, make sure your Apache .conf files consist this following lines:

LoadModule xsendfile_module modules/mod_xsendfile.so
XSendFile on
XSendFileAllowAbove off

don't forget to restart Apache.

Using mod_xsendfile (X-Sendfile) on PHP
You can find some PHP example on Apache mod_xsendfile page. On my Youtube online video downloader and converter, I'm using this code (just some part of it) :

//code snippet ....

$mp3name =md5($v) . $ext;
$location="./tmp/" . $mp3name;
$type ="application/octet-stream";
$fname =$title . $ext;

header ('Content-Description: File Transfer');
header ("Content-Type: $type");
header ('Content-Disposition: attachment; filename="' . $fname . '"');
header ('Content-Transfer-Encoding: binary');
header ('Expires: 0');
header ('Cache-Control: must-revalidate, post-check=0, pre-check=0');
header ('Pragma: public');
header ("X-Sendfile: " . $location);
?>

Now, my Youtube downloader is supporting download accelerator and paused download can be resumed.
This is download screenshot before applying Apache mod_xsendfile (X-Sendfile) -- only one thread/part and NO resume capability :


And this is screenshot after applying Apache mod_xsendfile (X-Sendfile) -- multi-part downloading and resume capability :


Yeah, more power for leechers! LOL!

Limitation on my Youtube Online Converter
Well, still, it has limitation like the grabbing process (before conversion) is still slow like-a-hell. in some case, after conversion done, you're redirected to homepage rather than download page. If this happen to you, you just need to redownload it again (enter the youtube URL and click 'convert' again).
There's another limitation: the conversion result file will be automatically deleted after 12 hours.
Enjoy the service!

In my previous post, I've written tutorial how to enable mod_rewrite and .htaccess on XAMPP for Windows. In this tutorial, we will make our XAMPP more like common *NIX web server by enabling php-cURL extension.

Actually it's incredibly easy, follow this step:

• edit c:\xampp\php\php.ini
• Look for this line:

;extension=php_curl.dll

• remove that ";", then save the file
  
• restart Apache (using XAMPP control center or Windows services.msc or command line)
  
• check your phpinfo() whether cURL is enabled or not, if it's successfully enabled, you can see on this screenshot: