Archive for the ‘Software/Code’ Category

Handling Bouncing Email with VERP and PHP

Wednesday, February 18th, 2009

If you’re planning to make your own mailing list software from scratch, bouncing messages will be one of the cases that you’ll have to handle. Fortunately, the magnificent D.J. Bernstein came up with VERP.

VERP stands for Variable Envelope Return Path. Bernstein, original author of qmail, djbdns and daemontools among others, has the technique published on his site.

In summary, this is what you need to do for VERP:

  • Create a catch-all or variable mailbox
  • Set the return path in a format that the recepient address is still readable
  • Fetch all email with formatted to your return path
  • Process your bounced message

The following is an example return path for a mailing list called foo:
foo-admin-john.smith=example.com@yourdomain.com

To set the return path with PHP’s mail function, pass the return path in the additional_parameters like the following:
mail('john.smith@example.com', 'Hello, world!', 'How are you doing today?', '', '-ffoo-admin-john.smith=example.com@yourdomain.com');

Below is an example for fetching bounced messages with VERP from a POP mailbox with PHP’s IMAP extension.


<?php
$mailbox = imap_open('{mail.yourdomain.com/pop3}', 'foo-admin', 'password');
$mailbox_info = imap_check($mailbox);
for($i = 1; $i <= $mailbox_info->Nmsgs; $i++)
{
  $msg_overview = imap_fetch_overview($mailbox, $i);
  $rcpt = $msg[0]->to;
  if(substr($rcpt, 0, 9) == 'foo-admin')
  {
    $target = substr($rcpt, 10); // exclude 'foo-admin='
    $target = substr($target, 0, -15); // exclude '@yourdomain.com'
    $target = str_replace('=', '@', $target); // revert '=' to '@'
    processBouncedEmail($target); // do whatever you want from here
    imap_delete($mailbox, $i); // you can delete the bounce message too
  }
}
imap_expunge($mailbox); // deletes messages marked with imap_delete()
imap_close($mailbox); // close the mailbox :)
?>

That’s how simple it is. I thought it was complicated too.

Another KDE Convert Here

Sunday, January 18th, 2009

Although I use Fedora on my laptop, Ubuntu has always been my recommendation for those who want to try Linux. A friend told me that he switched from KDE and shared tales of how it greatly improved. This led me to randomly blurt out to another friend to try out Kubuntu.

To cut the story short, I made the switch from XFCE to KDE too. It’s quite responsive on my aging laptop and their compositing is surprisingly easy on resources.

Free Image Hosting at www.ImageShack.us

Installation is easy (for Red Hat, Fedora and other derivatives):

# yum -y groupinstall KDE

Twittipy 0.2

Friday, September 19th, 2008

I’m on a very brief break and hacked on my Twitter notifier for a couple of minutes. To tell you the truth, a couple of bugs have been ironed out a week after I posted the first version. It has been working so well, I didn’t bother playing around with the code.

Twittipy now prompts for your username and password. If you want it to save to the config file, just uncomment some of the lines. I’m not comfortable with the password saved in a file and I haven’t thought of a way to encrypt them. By the way, Pidgin saves passwords in plain text too. The login prompt is old code from a wxPython experiment some time ago (and it ain’t pretty).

After you get authenticated, an icon will appear in your system tray. To exit Twittipy, right-click on the icon.

Download it here.

Install Wine 1.1.4 on Fedora 9 + Google Chrome Comments

Sunday, September 14th, 2008

I love Wine! No offense to the GIMP folks but I still use Photoshop 7 and when I found out that it now works out of the box with Wine, it gained my trust. Here’s how to install Wine 1.1.4 on Fedora 9.

  1. Check if you have wine installed.
    $ rpm -qa | grep wine
  2. Uninstall the old version.
    $ sudo yum -y remove wine
  3. Download the latest build from Koji. The following is the i386 build.
    $ wget http://koji.fedoraproject.org/packages/wine/1.1.4/1.fc9/i386/wine-twain-1.1.4-1.fc9.i386.rpm \
    http://koji.fedoraproject.org/packages/wine/1.1.4/1.fc9/i386/wine-capi-1.1.4-1.fc9.i386.rpm \
    http://koji.fedoraproject.org/packages/wine/1.1.4/1.fc9/src/wine-1.1.4-1.fc9.src.rpm \
    http://koji.fedoraproject.org/packages/wine/1.1.4/1.fc9/i386/wine-jack-1.1.4-1.fc9.i386.rpm \
    http://koji.fedoraproject.org/packages/wine/1.1.4/1.fc9/i386/wine-nas-1.1.4-1.fc9.i386.rpm \
    http://koji.fedoraproject.org/packages/wine/1.1.4/1.fc9/i386/wine-core-1.1.4-1.fc9.i386.rpm \
    http://koji.fedoraproject.org/packages/wine/1.1.4/1.fc9/i386/wine-ldap-1.1.4-1.fc9.i386.rpm \
    http://koji.fedoraproject.org/packages/wine/1.1.4/1.fc9/i386/wine-cms-1.1.4-1.fc9.i386.rpm \
    http://koji.fedoraproject.org/packages/wine/1.1.4/1.fc9/i386/wine-cms-1.1.4-1.fc9.i386.rpm \
    http://koji.fedoraproject.org/packages/wine/1.1.4/1.fc9/i386/wine-tools-1.1.4-1.fc9.i386.rpm \
    http://koji.fedoraproject.org/packages/wine/1.1.4/1.fc9/i386/wine-desktop-1.1.4-1.fc9.i386.rpm \

    http://koji.fedoraproject.org/packages/wine/1.1.4/1.fc9/i386/wine-esd-1.1.4-1.fc9.i386.rpm

  4. Install the RPMs.
    $ sudo rpm -Uvh wine-*
  5. Confirm installation.
    $ rpm -qa | grep wine

I upgraded to the lastest version of Wine just to get Google Chrome running on Linux even if I already read that it’s slow and SSL support is absent. I followed this guide.

I almost got it running but it was really slow (see screenshot below). I also have V8 compiled but when I tried to play around with it, I didn’t know what to do even with the interactive console.

Screenshot

My invaluable thoughts on Chrome:

  • I think it’s great that it uses Webkit. Not really sure if it’s faster than Gecko but at least testing with Webkit is more fun now.
  • You can drag a tab in and out of the window. That’s cool but I couldn’t pin the window to stay on top.
  • The developer tools are almost as great as those provided by Firefox extensions (i.e. Firebug).

Pidgin: Invisible Buddies + Some Thinking

Friday, July 11th, 2008

Pidgin: Invisible Buddies

This is me amused with little things.

On a side-note, I think it’s about time to get a new laptop. It’s not that my current laptop needs more juice. It works just fine for my needs and brought me great fortune in the past 4 years from college requirements to enterprise software.

Fedora 7 just reached its end of life and I get this OCD that I have outdated software. With the urge to upgrade but no place to backup my files (strange, all of my drives are full), I think a new laptop is the answer.

An extra hard disk would be a lot cheaper but I’m weighing the extra convenience that I’ll get with a more modern laptop. For instance, if I had a newer wireless card with 802.11g (yes, my laptop is 802.11b!), I’ll be using drivers with WPA support and higher transfer rates. With a DVD combo drive (vs a CD-ROM drive), better RAM, graphics card, and processor, makes me convinced that it’s, err, about time.

I’ll be getting an HP/Compaq because all of our laptops at home that carry the same brand are still alive. Also, it won’t be anything fancy. Just a boring normal laptop and it won’t be a tablet like I wished before. The TX2000 and TX2500 are available locally though.

There will be one busy weekend soon.

Twittipy: A pynotify and pycurl experiment

Friday, June 27th, 2008

It’s been a drag since Twitter IM went down. I had a very brief “play” time the other night that gave birth to Twittipy. It’s a Twitter notifier written in python with pynotify and pycurl.

Running Twittipy

  1. Create a configuration file in your home directory (~/.twittipy)
  2. Set your Twitter username/email and password in the configuration file.
    Example:
    [general]
    username = johnsmith
    password = unhackable
  3. Make Twittipy executable
    $ chmod u+x twittipy.py
  4. Fire it up!
    $ ./twittipy.py &

Twittipy requires Python 2.5, pycurl and pynotify. If it complains of missing modules, you probably didn’t meet the requirements.

Roadmap

I did some googling and found other stuff to try that could improve Twittipy.

  • Port for other platforms (Windows with pywin32 and KDE via wxPython)
  • Icon at the notification area or system tray (via wxPython)
  • Encrypt or obfuscate password in config file and/or if password is not found in the config file, prompt and store in memory.
  • Make use of the other methods of the Twitter API.

Download it here. There are two more options in the config file, update_interval and last_update. The former defaults to 4 minutes and the latter to the current time.

I’m quite satisfied with it. The notifications of pynotify are less obtrusive than an IM message. There’s one noticeable quirk where a tweet repeats. We’ll fix that for the next release.

Comments are welcome and please check out tweetyPy as well (not mine but also an academic project).

Finch

Wednesday, June 11th, 2008

Pidgin kept crashing when I tried tunneling through a remote machine. After minutes of googling around, I found Finch, a command-line version of Pidgin! It used to be called Gaim-text. Really cool!

Finch

I think about queues all the time.

Thursday, April 24th, 2008

Here’s something to waste your time and bore your brains out.

There are three nodes, say Nodes A, B and C. Node A and C are application servers. Node B is a messenger for nodes A and C. Although Node B is not needed but for reasons I’m not allowed to discuss and would rather not discuss, it has to be there and is the root cause why we have a problem.

Let’s start with an example series of events. A new transaction begins from Node C which sends data to Node B. Node B stores the data in a queue. Node A fetches x items from the queue every y seconds.

After Node A processes the transaction, it begins a new transaction. Node A sends data to Node B only this time, it is no longer stored in a queue. Node B immediately forwards the data to Node C.

On some occasions, Node C starts a new transaction as an acknowledgment from the data that originated from Node A. This transaction is treated as a transaction similar to the first one only that Node A knows that it’s an acknowledgment.

Originally, Node A and Node C communicated to each other directly. The queue didn’t exist. The queue came in to fix a couple of problems but it introduced new ones. Recently, the script in Node A that polls data from Node B died and now it’s catching up with backlog. The script processed data one by one. This showed how slow the main application in Node A is.

I already have a solution in mind and I enjoy writing boring stuff but I’d like to hear other views.

Insert to Asterisk’s Queue Log When a Member Is Called

Friday, April 4th, 2008

Asterisk‘s queue_log can come in handy in many cases (queues in Asterisk can be called ACD). There are systems that go as far as depending solely on the queue_log to operate (including mine).

Every now and then requests requirements for a feature to tell if a call in the queue is being transferred to a queue member (an agent) comes up. I had a workaround that used an AGI script but it didn’t work all the time. I’ve been digging around the source code so that it’s inserted into queue_log instead. After three attempts of hacking one friggin’ line of C code, I finally did it. My sincerest apologies to my COMPRO1 and COMPRO2 professors.

You may get the patch for asterisk-1.4.19 over here.

P.S. I know that watching the queue_log isn’t much of a good idea. I only stole the concept and I wasn’t aware of AMI at that time. Migration plans are on the way.

IM-History: A Godsend

Wednesday, January 9th, 2008

If you don’t want to read my boring testimonial, here’s the link for your convenience: IM-History – “All-in-one IM-History Client Suite”.

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