Computing | Ady's Blog

Let Apache Compress Your Website

Website speed is one of the most important factor to make people like to visit more. In 2008, I wrote Compressing WordPress Output and this is done by adding one line to index.php

The problem with that approach is that when you upgrade WordPress you have to manually add the line into index.php, and the technique does not improve loading time for administration pages.

Compressing is done on the fly by Apache, and it helps improve loading time because your browser receives smaller files. While some browsers were broken (they do not know how to handle compressed content), today’s browsers are much more efficient.

If your webhost allows you to add your own .htaccess then you can use this technique. Please note that you can do this for any type of website, not limited to WordPress.

<ifmodule mod_deflate.c>
     AddOutputFilterByType DEFLATE text/text text/html text/plain text/xml text/css application/x-javascript application/javascript
</ifmodule>

As simple as that. The directive above will ask Apache to compress text, html, xml, css, and javascript files before sending them to the browser. We don’t compress images because we don’t save much on image compression plus it will be too stressful for Apache.

You can use Firebug or Chrome to actually verify whether your content is now zipped. You might have to clear your browser cache first otherwise the files will not be requested from the server. You should look for the content-encoding header and it should say “gzip”. To satisfy yourself, you might want to capture the size of the page (there should be a column for that) before and after you add the directives into .htaccess and you should be able to see a significant reduction in size.

If you don’t see gzip then the possibilities are either your webhost does not allow .htaccess or mod_deflate is not installed on the server. To see whether or not mod_deflate is installed on the server you can remove the 1st and 3rd line in .htaccess and refresh the page. If it’s not installed then you will see an error.

For Joomla! users, there’s an easier way to do it in the Global Configuration section:

Simple eh?

For WordPress, one might argue that they can change the parameter gzipcompression in the semi hidden configuration page http://www.yourblog.com/wp-admin/options.php but I tried it in WordPress 3.2.1 and it did not work. I read in WordPress forums, they removed this feature because Apache can handle it much better.

Go ahead and try it out. Your visitors will be thankful.

Sparrow and Shortmail

I’ve been pushing the limits of my mid-2010 13″ MacBook Pro lately, running all sort of applications and leaving them running. There has been occasions where the machine will freeze while it struggles to schedule the CPU time to all of the applications.

I use a lot of email, and by a lot I don’t mean 10 emails per day. No joke. The features of Apple Mail 5.0 are actually enough for my daily use but it does feel a little bit sluggish with 5 IMAP accounts.

Recently, I signed up to Shortmail via my Twitter account. The idea is nice. 500 characters max per email, straight to the point.

While casually browsing through my Twitter stream last night I saw people talking about setting up Sparrow to access Shortmail and sending attachments via Dropbox.

I was thinking, Shortmail is short, Sparrow is light. Combining them together should be nice… and since all of my email accounts are now running via IMAP, why not give Sparrow a try with Shortmail before using it for serious communications.

I downloaded Sparrow through the website to try it out, instead of buying it from the Mac App Store for $9.99

I was pleased that it only asked for my email address and password so I entered my Shortmail account details. It was nice. Shortmail’s logo was displayed on the screen. But it took ten minutes to sync my 3 messages. I don’t know what it was doing and I’m not sure whether the waiting time is caused by Shortmail servers or Sparrow itself.

One thing I hate the most is how markup is displayed in the preview lines in Sparrow. It’s not in Facebook’s email but markup are there for the first 2 emails.

I can understand if there are glitches in Shortmail as it’s still fresh but I don’t expect glitches from Sparrow. I wonder how long it would take for it to sync my gigs of emails from other email accounts. I can’t even imagine and I can’t afford to waste so much time.

Looks likes it’s going to be a while before I am convinced to try Sparrow again. I am glad I didn’t rush to buy the app for $9.99 in the Mac App Store. For now, I’m leaving it to AppZapper to cleanup!

Update 16 December 2011 11:15 AM GMT+8

Less than an hour ago, I received a shortmail from Shortmail telling me that they are working on a new version of their IMAP service that should make a difference. This is great news for those who prefer using Shortmail service via regular email clients. From @Shortmail‘s timeline I can see that they are responding to many users about improving the IMAP service.

Keep up the good work! By the way, my Shortmail address is romantikaname [at] shortmail [dot] com

Thanks for the shortmail! This is nice, and it shows that you are serious about what you do!

For the record, I was more disappointed with Sparrow displaying ugly markup on the preview pane.

Compiling flip on Mac OS X

I was looking for a simple utility that will work like dos2unix tool on Linux to convert endlines from DOS to UNIX. I was scraping some contents from a server running .NET and those ugly ^M characters appeared in vim.

I found this https://ccrma.stanford.edu/~craig/utility/flip/, downloaded the PPC binary and used it happily for a while.

That is until I upgraded to Lion. I am not an expert in Mac OS X yet, but since Lion took away Rosetta and PPC codes away I got this:

Launch of "flip" failed: the PowerPC architecture is no longer supported.

The “file” utility gave me this:

flip: Mach-O executable ppc

Since I have the old Xcode installed on my machine, I thought I’d try and build it since the source code (a single .cpp file) is provided at the URL above.

Here’s how I was able to build it:

g++ -ansi -O3 -o flip flip.cpp \
-I/Developer/SDKs/MacOSX10.6.sdk/usr/include/c++/4.2.1 \
-I/Developer/SDKs/MacOSX10.6.sdk/usr/include \
-I/Developer/SDKs/MacOSX10.6.sdk/usr/include/c++/4.2.1/x86_64-apple-darwin10 \
-L/Developer/SDKs/MacOSX10.6.sdk/usr/lib && strip flip

The three -I provided it with the include paths, and the -L provided the libraries for the binary to link to. To run the compilers, you need to add them to your PATH: /Developer/usr/bin

Now flip runs well:

Usage: ./flip [-t|-u|-d|-m] filename[s]
   Converts ASCII files between Unix, MS-DOS/Windows, or Macintosh newline formats
 
   Options: 
      -u  =  convert file(s) to Unix newline format (newline)
      -d  =  convert file(s) to MS-DOS/Windows newline format (linefeed + newline)
      -m  =  convert file(s) to Macintosh newline format (linefeed)
      -t  =  display current file type, no file modifications

And “file” recognizes it as:

flip: Mach-O 64-bit executable x86_64

If you have the new Xcode 4.1 (the one that Apple just released for free in App Store), you might need to change certain paths. You’ll have to look at the errors and adjust your parameters.

I am not sure whether my development tool paths were removed as a result of Lion upgrade, but I am currently downloading Xcode 4.1 to the machine. Let’s see whether it’ll automatically set the INCLUDE, LIB, and add the development tools into my PATH.

If it does, then compiling might even be as easy as:

g++ -ansi -O3 -o flip flip.cpp && strip flip

Good luck!

Shrinking VirtualBox Disk Images

On my MacBook Pro with minimal disk size (250GB) I had to install VirtualBox in order to run any kind of Windows, for emergency cases. I was able to install Windows Server 2008 in a 20GB dynamically expanding virtual disk image (VDI).

A couple of months back I also made a clone of my HP NX9010 hard disk, a Seagate Momentus 80GB drive using the dd utility and attach it to the same virtual machine. I don’t have a lot of time at hand so this will enable me to selectively back up the files on that drive, when I have some free time. I use that old laptop to play videos for my child.

After some time, the Windows Server 2008 VDI grew up to 11GB and the Momentus VDI stayed at 74GB because dd was copying it bit by bit. I needed to free up more space. My target was the Momentus VDI because it’s huge and I have already deleted (backed up) a lot of files in it.

As their name suggest, they are dynamically expanding so they will not shrink themselves. In VMware, you can easily stumble upon the “shrink” button in the tool. In VirtualBox, we need to use the command line utility VBoxManage.

It’s as simple as:

VBoxManage modifyhd Seagate\ Momentus\ 80GB.vdi --compact

*VBoxManage is run on the host machine, while the virtual machine is powered off (not suspended).

Running it without any preparation work will shrink the VDI a bit, too insignificant to even notice.

And so I used SDelete to zero all the unused space on the VDI, and ran VBoxManage again. SDelete needs to be run inside the virtual machine while it’s running.

sdelete -c d:

I managed to get the 74GB VDI to shrink to 23GB. Now that’s a significant reduction in size.

Still, I was greedy. I wanted to know whether fragmentation has any effect on the shrink-ability of the VDI. So I went into the virtual machine, ran defrag, ran sdelete, then I executed VBoxManage to compact the VDI.

Below was my final result. From 74GB to 5.1GB I was fully satisfied. I was also able to shrink the 11GB VDI that contains the OS to 9.7GB.

If you have questions/suggestions/feedback, please leave a comment.

Good Bye MyBlogLog

I have just received an email from Yahoo! announcing the end of MyBlogLog service. It’s going to be discontinued effective May 24, 2011. Nice of Yahoo! to give us some time before terminating it for good.

However the link for help pages redirected me to this page: http://help.yahoo.com/l/us/yahoo/ysm/ll/featured/index.html, which I think is a mistake because it’s for “Local Featured Listings”.

Nevertheless, we thank you Yahoo! for a great service.

Google Authenticator Rocks

OK, “Google Authenticator” is actually the name of the smartphone apps provided by Google. What is it all about? It’s two factor authentication similar to the ones banks use to authenticate users to log in or to perform transactions. Corporate users might also have the same security method using smart card or RSA SecurID to log in to machines or connect to VPN.

The basic idea is simple, you will need your password and the code provided by the apps so that if your password is compromised the malicious user will not be able to log into your account. Plus, you’ll always have your phone with you so you will have this code when you need it.

Here’s how the app looks like on the iPhone:

The code changes in a few seconds (there’s a timer pie on the left that moves to show how long will the code will stay).

This 6 digit code, will be asked when you log in to Google services from the web browser. Don’t worry it will not be every time if you select it to remember trusted machines. It’ll be remembered for 30 days and after that I think it will be asked again (I have just started using it today so I am just guessing the behavior).

Before you Begin

If you use Google services in various places such as in mobile applications (e.g. Google Mobile App), desktop applications (e.g. Google Talk), and other places where two factor verifications aren’t coded yet, you will need some time to set up application specific passwords for each of them so that they will still work. More on this below.

How To Start

It’s easy to activate. One will need to navigate to https://www.google.com/accounts/SmSAuthconfig and follow the on screen instruction.

Official step by step instruction from Google is available here.

It’s a very simple and quick process. Once activated, all other applications not using two factor authentication will automatically be denied access (login fails) and they need to use the application specific password discussed below.

What if I lose my smart phone?

Google thought of everything. Upon signing up, you will be receiving 10 emergency codes to keep safe. These codes need to be kept securely, but accessible, for example in your wallet. Each of them can only be used one time.

You’ll also have the option use a backup phone number for an emergency code to be sent to you via SMS or an automated voice service. Cool eh?

Application Specific Passwords

While setting up two factor authentication takes maybe 2 or 3 minutes, entering application specific passwords may take some time. They each are 12 characters in length. They are used for applications such as Thunderbird, Outlook, mobile mail, GTalk, IM+ mobile app, etc. and the list is endless.

But it’s not that painful, compared to the security it provides (says a paranoid man).

For pictures from other devices (BlackBerry and Android) please head here: TechCrunch: Google Rolls Out Two-Factor Authentication For Everyone. You Should Use It.

So what about you? Are you jumping on the bandwagon? You should. Tell me your experience below.

Mac OS X: Modifying Stubborn Files Transferred From Windows

This is related to the previous post, where I had a lot of checked out Subversion working copies in my disk. They came from a Windows machine I used before I bought myself a Mac.

For your information, in a Subversion working copy, there will always be a hidden folder named .svn in each directory, and a bunch of files in them. Many files in there are read-only on Windows, and on UNIX or Mac systems they have read permissions set (-r–r–r–). They are supposed to be that way and only a Subversion client can work on them.

When attempting to update my working directory, my Subversion client refused to update the files because it can’t write to .svn/entries

Tested on: Snow Leopard 10.6.6
Known to work as early as: Tiger 10.4.x

The issue is not related to permissions or even Subversion. For some kind of unknown reasons, when read-only files are transferred from Windows, there is a special flag set on Mac OS X – the user immutable flag. When this happens, you will be receiving these:

$ chmod u+w entries 
chmod: Unable to change file mode on entries: Operation not permitted

As root:

$ sudo chmod u+w entries
Password:
chmod: Unable to change file mode on entries: Operation not permitted

However, root can delete the files. But I don’t want the files to be deleted. I merely wanted to update (and later add new and modified files to the repository) my working copy.

The simple solution to this is to use the chflags command to unset the user immutable flag:

$ chflags -R nouchg *

As simple as that, and you will be able to operate on the files again. In my case, my “svn update” operation went as smooth as silk.

Remember, the permissions of the file does not even matter. Even if it’s world-writable -rwxrwxrwx

For the record, I transferred the file via a USB drive (NTFS file system), and I have received reports that this is the same case if you transfer from a file share (Samba or Windows File Sharing).

I hope this saved you some time.

Starting Subversion Service on Demand in Mac OS X

Since I moved to a new home I didn’t let my Linux servers run 24/7 so that I can save on electricity bills. It’s not so much about moving homes but it’s about the tariff increase. My 500W and 400W power supplies can easily reach the max usage of around 300W each which translates to around 432kWh per month, costing me around RM123.55 (source: TNB Tariff). Money that can be better spent for my gadgets, craft items for my wife, or toys for my kid.

The last time my Subversion repositories were used, was in Feb 2009. Since the repositories are just files, I can easily transfer them to my Mac to use locally. For me, file history and ability to revert changes are more important that using the repository as backup. My Mac is backed up using Time Machine anyway so I am pretty much safe. I am obsessed with file history and proper branching in source code, sometimes I think I have a mild version of OCD. Seriously.

OK, now on to the technical part. I am unsure on how my machine is pre-installed with CollabNet’s version, but you can install it on your Mac using one of the available packages listed in Apache’s official Subversion packages list.

Tested on: Snow Leopard 10.6.6
Known to work as early as: Tiger 10.4.x

My version:

svn, version 1.6.5 (r38866)
   compiled Jun 24 2010, 17:16:45
 
Copyright (C) 2000-2009 CollabNet.
Subversion is open source software, see http://subversion.tigris.org/
This product includes software developed by CollabNet (http://www.Collab.Net/).

Please take note that the method I am going to show here is to allow access to Subversion as a service via the network. I like to prepare for future use for example allowing access from other machines. You can always opt for local file based access, http, https, and svn+ssh (and you will not need to do the steps below).

On Mac, you can have services launched as a permanent process or on demand using launchd – System wide and per-user daemon/agent manager.

In this discussion we will be running svnserve on demand, similar to running services via inetd on Linux.

It is fairly straightforward. You need to create a .plist file similar to the one below. I named mine org.apache.subversion.svnserv.plist

< ?xml version="1.0" encoding="UTF-8"?>
< !DOCTYPE plist PUBLIC "-//Apple Computer//DTD PLIST 1.0//EN" 
"http://www.apple.com/DTDs/PropertyList-1.0.dtd"> 
<plist version="1.0">
<dict>
    <key>Debug</key>
    <false />
    <key>Disabled</key>
    <false />
    <key>GroupName</key>
    <string>staff</string>
    <key>Label</key>
    <string>org.apache.subversion.svnserv</string>
    <key>OnDemand</key>
    <true />
    <key>Program</key>
    <string>/usr/bin/svnserve</string>
    <key>ProgramArguments</key>
    <array>
        <string>svnserve</string>
        <string>--inetd</string>
        <string>--root=/Users/adyromantika/SVNRepository</string>
    </array>
    <key>ServiceDescription</key>
    <string>SVN Code Version Management</string>
    <key>Sockets</key>
    </dict><dict>
        <key>Listeners</key>
        </dict><dict>
            <key>SockFamily</key>
            <string>IPv4</string>
            <key>SockServiceName</key>
            <string>svn</string>
            <key>SockType</key>
            <string>stream</string>
        </dict>
    <key>Umask</key>
    <integer>2</integer>
    <key>UserName</key>
    <string>adyromantika</string>
    <key>inetdCompatibility</key>
    <dict>
        <key>Wait</key>
        <false />
    </dict>
</plist>

Things that need to be changed:

Line 17: /usr/bin/svnserve needs to be changed to reflect your local installation.
Line 22 needs to be changed to use your own repository root. This is not the name of the folder with “conf”, “db”, etc. folders but one folder up, so that your svnserve can serve multiple repositories.
Line 11 is where you need to put the group name you want the svnserve process to run as. As you can see, I am lazy so I used the default group “staff”.
Line 41 is where you need to put the username of you want the svnserve process to run as. I used my own user id which is not the best security practice but as I mentioned earlier, I am lazy.

Now that it’s done, copy the file to /Library/LaunchDaemons/ and run the command:

sudo launchctl load /Library/LaunchDaemons/org.apache.subversion.svnserv.plist

You are all set. Please note that since it’s launched on demand, you will not see the svnserve process running unless you are connected to the repository. You can simply use telnet to verify you get some kind of response:

adymac:~ adyromantika$ telnet localhost 3690
Trying 127.0.0.1...
Connected to localhost.
Escape character is '^]'.
( success ( 2 2 ( ) ( edit-pipeline svndiff1 absent-entries commit-revprops depth log-revprops partial-replay ) ) )

If you don’t get a response or “Unable to connect to remote host” you may want to check the file /etc/services and see whether these two lines are commented:

svn     3690/udp    # Subversion
svn     3690/tcp    # Subversion

Good luck. If you are having issues please comment below and I will try my best to help.

Google Instant, Anyone?

I saw quite a significant number of tweets mentioning Google Instant, and decided to check it out. Some people might already be aware of it or heard of it before but I am outdated, that I am willing to admit.

First, I went to the Official Google Blog where I saw Search: now faster than the speed of type.

Next, I tried it myself on Google homepage. It’s really impressive.

google-instant

However, if you use a flaky connection like my Maxis Broadband you might see this:

google-instant-off

It says “Google Instant is off due to connection speed. Press Enter to search”. It’ll behave like normal search.

Which also means that it can be turned off.

The prediction feature is quite nicely programmed too. Notice that its suggestions included the word “mac” because I am on a Mac. Not surprising since this is easily detected by the browser’s user agent string.

I bet the prediction considers many other factors too, including Geo-location.

I find it interesting that I can see this now, since in its tweet Google mentioned that “Google Instant is rolling out to people w/ Instant-capable browsers in France, Germany, Italy, Russia, Spain, U.K. & U.S.”

So the next time you see it, don’t be surprised!

… and tell me how you like it!

Maxis Transparent Proxy is Causing Problems to Developers

I had to transfer 2 WordPress blogs to another hosting provider last night, as the free one is going to expire today. It should be as easy as:

Transfer the files
Transfer the database
Change DNS servers in registry to the new DNS servers
Configure the new hosting location

In a few hours after the DNS propagation is finished I should be able to point to the new site. If not, I should be able to use the host file /etc/hosts to point to the new server and make sure it works well.

I’ve had the trouble with Maxis transparent proxy before when it was blurting out random errors to random sites.

Today, even when OpenDNS is already updated with the new IP (DNS propagation has finished), the transparent proxy is still outdated and points to the old server.

maxis-transparent-proxy-troubling-developers

I am sure if I call Maxis or even use its MaxisListens Twitter account, they will not even understand the concept of DNS.

The thing with transparent proxy is, as long as it’s HTTP traffic it will be going through it (not HTTPS), and it does not matter if I use a host file.

Oh well. I guess I can’t test this quickly right now except by using an anonymous proxy or connecting to an external VPN. Who appreciates time these days?

BTW, making modifications in domainregistry.my was very fun and it took me more than 30 minutes to modify one domain.

SMTP Smart Host Setup for Postfix in Snow Leopard

PHP does not have any SMTP authentication mechanism in its configuration, and most developer opt for PEAR packages to perform email sending via custom ports and SMTP authentication.

I am one of those who will avoid using external packages as much as possible unless really necessary, and of course because I wanted a quick solution to my problem (or an excuse to be lazy).

By default, PHP sets SMTP as localhost and port 25. Under normal circumstances, this should be no issue as the built in Postfix will just connect to the destination server and delivers the mail. However, if your ISP blocks outgoing packets to port 25, the mail will go nowhere.

1. Enabling Postfix on Snow Leopard

Postfix is not enabled by default. You may choose to run it by default on system startup.

$ sudo vi /System/Library/LaunchDaemons/org.postfix.master.plist

Add before the closing </dict> tag:

  <key>RunAtLoad</key>
  <true />
  <key>KeepAlive</key>
  <true />

Start Postfix:

sudo launchctl
launchd% start org.postfix.master

You can test by using telnet on port 25 if you speak SMTP protocol.

2. Configuring Postfix to use a Smart Host

A smart host is also called a relay. This means that you need an SMTP account somewhere in the Internet to send the mail for you. With spam problems, open relays are identified in databases and are blocked by destination servers, so this means that legitimate mail servers requires authentication.

I used my Yahoo! SMTP account to help me send my test emails. Yahoo! allows for PLAIN authentication. The not so good thing about this method is that your password is transmitted plain text.

GMail is more secure and requires TLS authentication and this requires postfix to have SSL support but since I need this quick I have no time to research and find out whether it is. (Excuses, excuses).

i. Create a storage file for the password, for example /etc/postfix/relay_passwd

plus.smtp.mail.yahoo.com USERNAME:PASSWORD

ii. Secure the config file

$ sudo chmod 600 /etc/postfix/relay_passwd

iii. Create the hash database for postfix

$ sudo postmap /etc/postfix/relay_passwd

iv. Configure /etc/postfix/main.cf:

relayhost = [plus.smtp.mail.yahoo.com]:587 
smtp_sasl_auth_enable = yes  
smtp_sasl_password_maps = hash:/etc/postfix/relay_passwd  
smtp_sasl_security_options =

v. Restart Postfix

sudo launchctl
launchd% stop org.postfix.master
launchd% start org.postfix.master

You should be all set. Test sending an email from PHP.

BTW, if you’re wondering, if you are a Yahoo! Mail web user, chances are that you don’t have SMTP access. However, I have heard that some countries still do have free SMTP access for now.

Connecting to Exchange using Entourage via Outlook Web Access

I wanted to be able to use my personal laptop to check my work email, so that I don’t have to carry around the 3kg DELL beast all the time. Sure, I can use the Blackberry but typing long emails on it can prove painful especially with fat fingers.

I have VPN access, but Cisco (official) VPN client keeps on and on causing my Snow Leopard to crash (kernel panic). The built in VPN client used to work until some security changes were made to the VPN concentrators.

Googling around I found a helpful hint, to set up my Entourage to connect to my work email via the Internet (not having to connect via VPN).

entourage-exchange

All of the fields are self explanatory, but one field was the problem: “Exchange Server”.

If your organization has a “OWA” or Outlook Web Access, you can try entering <servername>/exchange/<your_full_email> into the field and see whether it works. For example if your OWA is owa.romantika.com and your full email is [email protected] you would use:

owa.romantika.com/exchange/[email protected]

One thing I have not figured out yet, is whether or not my organization has public facing LDAP server (for address lookups). Since this is not a standard configuration, the server names are unpublished anywhere. But since it’s available I guess it’s not against the rule.

Hope this helps. I can now check my emails from my Entourage, but that’s it. No VPN access.

BTW I think you can use the same technique with an installation of Microsoft Outlook too!

Error Compiling djbdns and daemontools

While attempting to compile djbdns 1.05 and daemontools 0.76 on a CentOS 5.5 I received the error:

/usr/bin/ld: errno: TLS definition in /lib/libc.so.6 section .tbss mismatches non-TLS reference in envdir.o

The problem can be eliminated by adding:

-include /usr/include/errno.h

In conf-cc files for each tarball. Don’t forget to install gcc first, if you have a basic installation.

By the way, please remember to follow the installation instruction for daemontools exactly as described or you’ll end up with the software somewhere undesirable. Well, you can change /package to be elsewhere. I stupidly did it on /root as a test so the svcscanboot process was unable to execute programs in the /root directory. They run as unprivileged users.

Although these software felt like really old-school to me, they have very small memory footprint and runs very fast. If you’re also looking into DNS, consider PowerDNS too, as it has very good statistical capabilities.

PHP Debugging on PDT using Xdebug, with PHP packaged in XAMPP

It has been a while since I posted something technical so here goes. This article is meant for someone who has done PHP development before, and already has a web server and a working PHP installation.

Traditionally in the old days these are the things that I do to debug my PHP code:

Put in extra echo statements that print variable values. It’s easy to miss them when actually deploying the code to production
Use “here I am” echo statements to identify positions in the script. These are also easy to miss
Modify php.ini to verbosely display every error or warning messages. While this is not a concern on development boxes, it might be a problem on production servers
Using custom self-made loggers or something from PEAR or PHPClasses to have a log file written for debugging purpose. This method takes a toll on the time required to actually go through the log which might contain lots and lots of information

A commercial alternative to Xdebug is Zend Studio Web Debugger. Zend’s solution is quite a bit on the pricy side but it’s also supported out of the box by PDT.

Prerequisites

PHP installation. I use XAMPP since it’s clean and it’s quick to set up. If you like to live on the bleeding edge with all the latest updates you can install PHP properly in your system either by using the installer or the zip package
Eclipse installation. I use Aptana Studio
Web server application such as Apache or IIS. I use Apache.
PDT (PHP Development Tools) as a plugin for Eclipse/Aptana.

The debugger

The procedure to configure the debugger is not that different between Zend Studio Web Debugger or Xdebug. I am going to make an example of using Xdebug here.

While Windows users are able to download Xdebug binary and use it immediately, *NIX users have to compile it. Luckily I found that ASPN provides binaries to use with their Komodo IDE (yes, I am lazy to setup binutils and compilers). The zip file contains extension for PHP 4.4-5.3 (at the moment this article was written).

Download Xdebug binary from the ASPN site mentioned above. Extract it to a temporary folder and choose the version corresponding to your PHP version. (Hint: to find your PHP version you can create a PHP file containing < ?php phpinfo(); ?> and view it through your web server)
Copy xdebug.so to the extensions folder. You can also find out where is your extension folder by looking at the phpinfo output, under header “Core” and Directive “extension_dir”.
Edit php.ini (or create an .ini file in php.d depending on your configuration) to include the following:
[xdebug] zend_extension="/full/path/to/your/extension/dir/as/shown/in/phpinfo/xdebug.so"
[xdebug] zend_extension="/full/path/to/your/extension/dir/as/shown/in/phpinfo/xdebug.so"
Restart your web server and you should be able to see xdebug listed in the phpinfo output

*Note: As you might have realized by now, phpinfo(); can be your best friend. It can also be your worst enemy if you put it in a production server, with a super simple name like phpinfo.php as it contains a lot of sensitive information about the server.

Configuring PDT

There are 3 main settings to focus on, to enable debugging in PDT.

1. PHP Executables

pdt-php-executables

As I mentioned earlier, I am using XAMPP. As long you point this to the working PHP installation corresponding to where you install Xdebug, you’ll be fine.

2. PHP Server & Path Mapping

pdt-php-server

This is where you specify your web server.

pdt-php-server-mapping

Mapping is used to tell the debugger the path of the files accessible via the web server and the corresponding path in your workspace.

3. PHP Debug

pdt-php-debug

The options are self-explanatory. You’ll have to select the Server and Executable that you have configured. The default port for Xdebug is 9000 so if you decide to change your Xdebug port remember to change it here too.

Conclusion

Debugging using an IDE is a great way to save time, and to step into your application. If you have done everything correctly, you may use Eclipse/Aptana to debug your PHP files now (Menu > Run > Debug > Run as…) and you’ll get prompted to switch to the PHP Debug Perspective.

Good luck!

Facebook Glitches

Facebook is an application, so it’s normal that it has glitches and problems.

The first one I saw last week while writing a like button plugin is the incorrect number of likes a like button displays:

It’s obvious there were 4 likes for the post but it randomly displays 2 of my friends. When not logged on, it simply says “2 people like this”.

Next, when creating events the date and time for the events are wrongly displayed on the wall but are correct in the left column box and in the event itself:

Last but not least, there seems to be a privacy glitch. When seeing a friend being tagged in a photo I am able to open the photo but given this error:

Now I am more skeptical of uploading photos that I don’t really want to share with everyone.

I don’t have much time to get into the developers forum, but I can’t seem to find an email address or a function to report such problems to FB.

Do you know how?