zembly is deadpooled – 2.5 yrs of effort went in vain :(

I got a bad news this morning that zembly is shutting down their service from 30th next. that’s a very bad news because zembly was a nice service for developers. They’d started their business from june 2007, provided exciting APIs to developers to develop mashups on top of popular services like Facebook, MySpace, Flickr and so forth. I’ve seen another popular service like this , appJet, went down this year. Now it’s extremely frustrating that such types of services are shutting down. Why? most probably they’ve failed to secure funding, or may be they’ve some fight in their board of directors, or whatever, who knows and who cares.

But the point is, what happen to developers who has developed their app using services like zembly or appJet? all their efforts to learn these new technology, new tools and to develop some really cool applications using these services just became useless all at a sudden. That’s pathetic, and thats an utter lack-of-respect to your own developers community. These developers are your everything. They were your everything. If these developers didn’t put their efforts for you zembly, you will never survive a quarter, may be six months.

I really dont understand, If you dont have the guts to run your product thats fine. I have no problem with that. But before saying “All our service will be unavailable from blah blah blah” and “We are sorry and blah blah blah” , come on – show a minimal respect to your developer community. After 2.5 years of run, its not a small community after all. And grow up kiddo, before shutting down your company, at least make your project open source – as a sign of minimal respect and loyalty to the developers community who kept you running for so long.

I am sorry for Zembly But I am more sorry for the developer community.

Getting HP-1020 Laserjet Printer working on Snow Leopard

Since upgrading to snow leopard from leopard, this was the biggest problem and most frustrating thing for me. My HP Laser-jet 1020 stopped working. I’ve downloaded all possible updates from apple and none works. My good old printer just became a piece of brick (lol, yeah really)

So how did I finally get it running? almost 10-20 hours of googling+downloading+trial and error+cursing and drinking a lot of coffee, open source stuffs saved my day – here you go .

#1 – download foomatic-RIP from here http://www.linuxfoundation.org/collaborate/workgroups/openprinting/macosx/foomatic (choose the snow leopard package)
#2 – download ghostscript from http://www.linuxfoundation.org/collaborate/workgroups/openprinting/macosx/foomatic )choose snow leopard package)
#3 – download foo2zjs from here http://mac.softpedia.com/progDownload/foo2zjs-Download-33222.html

#4 Ok, now install GhostScript First, then Install Foomatic-RIP. Just perform a default install. no extra thingy – nothing

#5 Now install foo2zjs package. while installing, it will ask for admin access. Then it will open a shell window and display you a list of firmware to choose from. You will find HP-1020 listed on #7 – so type “7″ and hit enter. Now if it asks you whether you want to delete the installation file, choose “yes”.

#6 Now open the “helper” folder inside this foo2zjs package and copy the load_LaserJet_firmware_v4 file to anywhere else. We need this file later.

#7 Connect HP-1020 in USb port and Add the printer from your printer preference panel.

#8 Now double click on load_LaserJet_firmware_v4 file that you have copied earlier and run it

Ok, now you have a working HP-1020 in your snow leopard. Until HP or Apple releases a patch, this is the only way to get it working. Well, dont forget to send me a cup of coffee for saving you from buying a new printer – lol!

Using new PECL Memcached extension for storing session data

Many of you already know that managing session is a critical task for web applications, specially when you want to avoid I/O hop and also a significant load over your database by writing a custom session handler. Beside that, if your application makes use of multiple web servers behind a proxy, then its more than a critical job to share and manage session data among these servers effectively. This is why a central session manager is very important for your application to scale. In this article I am going to show you how you can use the latest Memcached extension (developed by Andrei Zmievski and his team) to isolate the session storage from web servers. I will show you how to compile the extension and use it.

Step1: Install Memcached Server
If you are using Debian its just plain simple

apt-get install memcached

Step 2: Run memcached instances
Lets run two instances of memcached in same machine (well, this article is just for demonstrating you how you can get things done. In the production environment, you can deploy as many memcached instances as you want in different servers in same network)

memcached -d -l 127.0.0.1 -p 11211 -u <username> -m 16
memcached -d -l 127.0.0.1 -p 11212 -u <username> -m 16

Above commands will run two instances of memcached listening on port number 11211 and 11212, same IP 127.0.0.1. Each of them get an allocation of 16 MB of memory (on RAM).

Step 3: Install the PECL Memcached extension.
Lets install the new PECL memcached extension in your web server. This new extension depends on libmemcached. You can grab the latest distribution of libmemcached from https://launchpad.net/libmemcached and compile it in your own machine. Make sure you have the dependencies met.

wget http://launchpad.net/libmemcached/1.0/0.34/+download/libmemcached-0.34.tar.gz
tar -zxvf libmemcached-0.34.tar.gz
cd libmemcached-0.34
./configure
make && make install

Considering everything went fine, lets install the PECL memcached extension

pecl install memcached

If everything goes fine, you should see the output similar like this

Build process completed successfully
Installing '/usr/lib/php5/20060613/memcached.so'
install ok: channel://pecl.php.net/memcached-1.0.0
configuration option "php_ini" is not set to php.ini location
You should add "extension=memcached.so" to php.ini

Make sure that memcached.so is placed in your PHP extension_dir folder (here /usr/lib/php5/20060613). Add the line “extension=memcached.so” in your php.ini and restart your web server.

To make sure, everything’s done and working – run a phpinfo() and check the output. There should be a “memcached” sesction which will look like the following one.

Memcached PECL Extension

Now we need to make change in our php.ini to register Memcached as a session handler and set the necessary properties there. Open your php.ini and add the following two lines. If you find any similar line un-commented, comment them out first.

session.save_handler=memcached
session.save_path="127.0.0.1:11211, 127.0.0.1:11212"

Restart your web server. And …… you are done! – Now all your session data will be saved and served from these memcached servers. No matter whenever you need to extend your setup by adding extra web servers, all user data and session data will remain valid and served from a central location. No I/O issue, no huge write load on DB servers.

RackSpace Cloud Server Client Library for PHP

We, the developers at Leevio are currently developing an open source group collaboration application. We are using RackSpace Cloud servers since the very beginning of the development and we will also deploy in on rack space cloud.

As a part of our study we’d found that RackSpace provides excellent API to manage your cloud services. Unfortunately there are no language binding library released yet (for Cloud Server). But they’ve mentioned that they are developing one for python.

So we have spend our time for last two days and developed a PHP client library to use RackSpace cloud server API from inside a PHP application.

This client library is released under New BSD license. And is available to download/svn-checkout from it’s project page at http://code.google.com/p/phprackcloud/

There is plenty of documentation and example included. The code is mostly self explanatory. Please dont forget to check the Wiki page to get some idea on how to use this library and how far you can go. We have covered all available methods by RackSpace cloud server in our client library.

Happy clouding.

Project Page and Download: http://code.google.com/p/phprackcloud

Using iPaper API to convert office documents to flash movie on the fly :)

Embedding documents in web applications is a challenging work. Because you need to convert these documents into flash movie and only then you can embed them in your web applications. There are many converters available out their for use. Some of them are proprietary, Some of them comes for free. There are command line tools as well as web services also to perform these conversions and make your life easier. In this post I am going to introduce you to IPaper, an excellent service from Scribd. Using IPaper API you can upload and convert your documents to flash movie on the fly, and then you can embed them using Scribd’s excellent document viewer. Scribd offers a collection of client libraries and fortunately, we have a PHP lib in that collection.

Scribd API can convert numbers of document types including the followings

* Adobe PDF (.pdf)
* Adobe PostScript (.ps)
* Microsoft Word (.doc, .docx)
* Microsoft PowerPoint (.ppt, .pps, .pptx)
* Microsoft Excel (.xls, xlsx)
* OpenOffice Text Document (.odt, .sxw)
* OpenOffice Presentation Document (.odp, .sxi)
* OpenOffice Spreadsheet (.ods, .sxc)
* All OpenDocument formats
* Plain text (.txt)
* Rich text format (.rtf)

To use IPaper API, you need to create a developer account in ScribD and get your API key and secret key. Also, download the PHP client library from http://www.scribd.com/developers/libraries

You are ready to go once you get your Scribd api key and secret key. You can upload different types of files to scribd server and of course you can make them private or publicly accessible. After successful upload and conversion you will receive a doc_id and access_key from Scribd web service. Using those data you can embed your document in your web app. Lets have a look. In the following code examples, you may find the getEmbedUrl() and getEmbedCode() functions handy. You can also use SWFObject for quick embedding

<?php
include_once("scribd.php");

$UpdloadData = createIPaper("gpl.pdf","pdf","public");
$EmbedUrl = getEmbedUrl($UpdloadData);
echo $EmbedUrl;
$EmbedCode = getEmbedCode($UpdloadData);
echo $EmbedCode;

function createIPaper($File, $FileType, $Access="private")
{
    $scribd_api_key = "<your API key>";
    $scribd_secret = "<your Secret key>";

    if (empty($FileType))
    throw new Exception("Filetype cannot be empty");
    $Scribd = new Scribd($scribd_api_key,$scribd_secret);

    $UploadData = $Scribd->upload($File,$FileType,$Access,1);
    return $UploadData;
}

function getEmbedUrl($UploadData)
{
    if($UploadData){
        $EmbedUrl = "http://d1.scribdassets.com/ScribdViewer.swf?document_id={$UploadData['doc_id']}&access_key={$UploadData['access_key']}&page=1&version=1&viewMode=list";
        return $EmbedUrl;
    }
}

function getEmbedCode($UploadData, $Width=450, $Height=500)
{
    $EmbedCode = <<<EOD
<object codebase="http://download.macromedia.com/pub/shockwave/cabs/flash/swflash.cab#version=9,0,0,0"
    id="doc_512761847372423" name="doc_512761847372423"
    classid="clsid:d27cdb6e-ae6d-11cf-96b8-444553540000"
    align="middle"
    height="{$Height}"
    width="{$Width}" >
<param name="movie" value="http://d1.scribdassets.com/ScribdViewer.swf?document_id={$UploadData['doc_id']}&access_key={$UploadData['access_key']}&page=1&version=1&viewMode=list">
<param name="quality" value="high">
<param name="play" value="true">
<param name="loop" value="true">
<param name="scale" value="showall">
<param name="wmode" value="opaque">
<param name="devicefont" value="false">
<param name="bgcolor" value="#ffffff">
<param name="menu" value="true">
<param name="allowFullScreen" value="true">
<param name="allowScriptAccess" value="always">
<param name="salign" value="">
<param name="mode" value="list">
<embed src="http://d1.scribdassets.com/ScribdViewer.swf?document_id={$UploadData['doc_id']}&access_key={$UploadData['access_key']}&page=1&version=1&viewMode=list"
    quality="high"
    pluginspage="http://www.macromedia.com/go/getflashplayer"
    play="true"
    loop="true"
    scale="showall"
    wmode="opaque"
    devicefont="false"
    bgcolor="#ffffff"
    name="doc_512761847372423_object"
    menu="true"
    allowfullscreen="true"
    allowscriptaccess="always"
    salign=""
    type="application/x-shockwave-flash"
    align="middle"
    mode="list"
    height="{$Height}"
    width="{$Width}">
</embed>
</object>
EOD;
    return $EmbedCode;
}
?>

and here is how it will look after embedding

View this document on Scribd

download the source code from here http://www.box.net/shared/5dav7hnkm9

By the way, IPaper PHP client library has some cool methods like uploadFromUrl() – Check them out )

Stay in touch, In next post I will show you how to use some other exciting tools which you can use and host in your own server . that will be fun to host your own service like this

Thanks to Rana for helping me out with iPaper.

jQuery:hooking form submit and making it ajax request

modern javascript frameworks are big blessings to every front end developer. they made our life so much easier so that we can sleep more and become fat day by day – i am a big fan of jQuery and mootools.

in this post i am going to show you how you can hook a normal form submission process, regardless of it’s method GET or POST, and convert it into an ajax request. the whole process will work dynamically. it will parse form input elements, make a JSON array from them and make an ajax request to the appropriate action url. after that, it will invoke the user supplied callback function.

problem 1: parsing form elements was a small challenge. you can do it in various way (by traversing or serialize or using css selectors). i choose to use serializer routines. jQuery has builtin support for two types of serializing , one is $(form).serialize() and another is $(form).serializeArray(). lets have a look at the output of both of them for the following form

<form id="f1" action='some target' method='POST'>
<input type ="textbox" id='username' name ='username' value='me'/>
<input type ="checkbox" value=1 id='guests' name ='guests'/>
</form>

now lets check the output by both serialize() and serializeArray() method

alert ($('#f1').serialize());
//output is "username=me&guests=1"

alert($('#f1').serializeArray()
//output is [{object},{object}]

are you scared seeing this [object] output of serializeArray()? well dont panic. serializeArray() returns a JSON structure. you can still investigate using toSource() method

alert($('#f1').serializeArray().toSource()
//output is [{"username":"me"},{"guests":"1"}]

but that will not be usable to send in our AJAX request. we need a JSON array key/value pair (or you can use the output of serialize() function too to send as data in ajax request, the serilizeForm part is completely optional )

lets create a new function called serializeForm which will create JSON key/value pair out of serializeArray() and do the rest of the work.

$.fn.serializeForm = function()
{
    data = {};
    url = this.attr("action");
    items = this.serializeArray();
    $.each(items,function(i,item)
    {
        data[item['name']]=item['value'];
    }
    );
    return data;
}

now lets hook the normal submit process of the form using the following hook

function submitHook(form, callback)
{
    $(form).submit(function(e){
        items = {};
        items = $(form).serializeForm();
        url = $(form).attr("action");
        if(""==url)
        {
            alert("Cannot submit form. No action specified");
            return false;
        }
        callback = callback?callback:function(){};
        $.post(url,items,callback);
        return false;
    });
}

now you can just hook the form simply by this

ourCallback = function (data)
{
   alert(data);
}

submitHook($('#f1'),ourCallback);

happy jQuerying

hosting source code and projects for free – compare the available options

when you work as an individual (or even a small team/company), it often requires you to host your project files, source code (using svn/git/mercurial) for free, discuss with people and definitely to use some issue trackers, task list managers. fortunately there are some cool options available out there. some of them comes for free with paid plans as well, some of them have no free plans. some comes with minimal but very essential features and some of them are feature bloated.

i am going to share my comment about some of these applications for you so that you can choose the best that fits for you. and btw, i’m mentioning only those which comes with free plans

1. springloops : this is my most favorite one. springloops comes with both free and paid plans. free plan is enough to manage a small team because they support unlimited peoples in each project. and even in free account in spring loops, you can create up to three active projects. so whenever you are done on any project – just close that project or suspend and open another one. springloops has excellent deployment support. and it can notify or invoke a callback url once after each commit. and that feature is very very useful if you want to take action after “post commit” (which is called a web hook).

and you can create numbers of accounts with under same email address.

pros: excellent source code browser, deployment, support for subversion, nice todo list, 100 MB of space to host your files and source code, integration with basecamp and unlimited number of peoples
cons: no issue tracker, no support for git

2. unfuddle : another neat and cool project hosting service which i’ve been using for a long time. unlike springloops unfuddle has also support for git, storage is even higher by 100 MB more. unfuddle has really cool bug tracker, wiki pages, todo list manager and built in support for iCal and rss feed. but the most frustrating thing with unfuddle free plan is that only 1 active project and 2 people is allowed. this is mainly one of the reasons why I am sticking with springloops. and unfuddle also has no support for managing deployments but i really find that a minor issue.

pros: support for both svn and git, 200 MB of storage, todo list, bug tracker, wiki pages and iCal+feed support.
cons: no support for managing deployment, only 1 active project and 2 people is supported in free plan.

3. beanstalk : beanstalk is another very cute looking subversion hosting solution. beanstalk free plan comes with 100 MB of storage space for hosting your source code, 3 active users ad only 1 repository. btw, beanstalk has web hook suport only for paid plans.

pros: nice interface, daily backup, email/rss notification and guest access, integration with many external project hosting and issue tracking solutions.
cons: only 1 repository, only 3 active people. deployment and web hook only for paid accounts

4. goplan : goplan has no support for version controlling and it is more like a project management solution, and it has a very nice interface. goplan supports 3 concurrent projects but 2 people (and i hate that) and 2 collaborators. it gives you 100 MB of storage space. goplan comes with excellent todo list manager, time tracker, discussion board, file versioning and activity stream.

pros: time tracking, discussion board, calendar, plain file storage, todo list
cons: no source code version control (i really wish they will add it)

5. huddle : huddle is another alternative of goplan (project hosting) with no support for version controlling. but huddle comes with some amazing features like free voice conferencing, whiteboard and editing documents online. huddle is feature rich but i really didn’t like their interface that much. whereas others are focusing on a small audience, huddle tried to be solution for everyone. but i still like the ones who are focusing on small audience, because it helps them to be niche. btw, huddle free plan comes with 1 GB of storage.

pros: task list manager, meeting, discussion, file sharing, online file editing, whiteboard, 1GB of storage space.
cons: no source code version control (i really wish they will add it), and “not so cool” interface

some other solutions you can check out xp-dev, bounty source, assembla (was one of my favorite when they had free plans) and projectlocker, github (free for only open source projects) sourceforge and the google code (sourceforge and google code are only for open source projects)

converting standard wordpress into a SQLite powered multi user blogging platform

wordpress is one of the very popular blogging platforms which is not only free but also released as a open source project. officially wordpress runs only on mysql. so if you want to run it with SQLite, you will not find any official support for that. but fortunately justin addie has written an excellent plugin (pdo for wordpress) which will work as an adapter just between the wordpress DAL and mysql. this plugin hooks all the SQL queries which are sent to execute on mysql by wordpress, convert those into PDO compatible statements and then execute them. currently PDO for WordPress is written to work smoothly with mysql and sqlite.

on the other hand, WPMU (wordpress mu or multi-user) is another version of wordpress which uses the core wp with some modifications and convert any single user wordpress blog into a multi user blogging platform. in this blog post i will show you how you can convert a general installation of wordpress into multi user blogging platform (like WPMU, but fully featured) and take advantage of SQLite – so let the fun begin.

step 1: check if your domain support wildcard A record. if so, then create a “*” A record and point it to your server. if it works, now you can point http://.. to your server – that is very much required. alo please check that in your webserver it has “pdo” and “pdo_sqlite” php extensions enabled. you can check that using phpinfo(); – needless to say, you need PHP5

step 2: install wordpress

step 3: install pdo for wordpress
download the pdo_for_wordpress plugin. inside it you will find one file named “db.php” and a folder named “pdo”.
put the db.php inside “wp-content” directory
now put the “pdo” folder inside “wp-content” directory

open wp-config.php
find the following line

define('DB_COLLATE', '');

add the following line just below that line

define('DB_TYPE', 'sqlite');

step 4: create a directory named “userdb” anywhere in your server, make sure to give it write access. in this example we’ve created one as /opt/userdb – DONT FORGET TO ASSIGN WRITE PERMISSION to this “userdb” directory.

step 5: now we will be modifying that “db.php” which we had copied into “wp-content” folder.

find the line in db.php where it says

define ('FQDBDIR', ABSPATH .'/wp-content/database/');
define ('FQDB', FQDBDIR .'MyBlog.sqlite');

now change those lines as below

define ('FQDBDIR', '/opt/userdb/');
define ('FQDB', FQDBDIR ."{$_SERVER['SERVER_NAME']}.sqlite");

and tada – you are done. now point your browser to any subdomain under your domain and it will comeup with registration page. register some blog and check it out (at the bottom of this post you can find the link of a live demo)

now you can extract some themes in the wp-content/themes folder or some plug-ins into wp-content/plugins folder. all users will be able to choose only from those pre installed themes and plugins, and everyones data and configuration will remain separate from others, as everyone is running from their own database. set only “read” access to “wp-content/themes” and “wp-content/plugins” folders to avoid any security loophole.

happy blogging.

[note - i've checked it against latest wordpress 2.8.4 and it runs okay]

To check out a live example of a running wordpress 2.8.4 on SQLite – click on http://anything.twistats.com/wp/ – and to create your own – just go to this url http://<any_subdomain>.twistats.com/wp and register your one . You can select from six pre installed themes too

removing empty elements from an array, the php way :)

removing empty elements from array is most likely a very common task for everyday programming. different people work on it differently. some runs N times loop and some other tries by finding offset and then by unsetting that. let me show you some common approach of doing it and possibly the best way too , needless to say, in a php way – most of the time such a microsecond does not matter, but well, its still good to find out the best solution

first of all, lets write a function which will create a random array with empty elements

function generateRandomArray($count=10000)
{
    $array = range(0,($count-1));
    for($i = 0;$i<1000;$i++)
    {
        $offset = mt_rand(0,$count);
        $array[$offset] = "";
    }
    return $array;
}

now lets see some different approaches to get it done.
probably most common approach

$array = generateRandomArray();
$len = count($array);
$start = microtime(true);
for ($i=0;$i< $len;$i++)
{
    if(""==$array[$i]) unset($array[$i]);
}
$end = microtime(true);
echo ($end-$start);

you can see the output varies from 0.13-0.14 seconds for an array with 10000 elements in a 2.66 ghz core 2duo machine running mac osx 10.5.8 with 4GB ram.

here is another better approach using array_diff()

$array = generateRandomArray();
$start=  microtime(true);
$empty_elements = array("");
$array = array_diff($array,$empty_elements);
$end = microtime(true);
echo ($end-$start);

this one takes 0.052-0.059 seconds and surely is a significant improvement over the last one

here is another improved version using array_filter()

$array = generateRandomArray();
$start=  microtime(true);
$array = array_filter($array);
$end = microtime(true);
echo ($end-$start);

it takes like 0.002 seconds to complete – pretty good one, eh? (thanks damdec, for reminding about it)

and this is the last one which was my favorite one using array_keys() taking advantage of the optional search_values parameter

$array = generateRandomArray();
$start=  microtime(true);
$empty_elements = array_keys($array,"");
foreach ($empty_elements as $e)
unset($array[$e]);
$end = microtime(true);
echo ($end-$start);

this is an amazing improvement over the previous solutions, it takes only around 0.0008 – 0.0009 seconds for an array of 10000 elements.

i hope you enjoyed this post with micro benchmarks – happy phping

some very useful apps for mac osx, free as well :)

i am a big time fan of mac osx. if you think there are no free+useful app for mac, you are quite wrong. here is my personal favorite list of some free and very useful apps which i use everyday.

CyberDuck: it is my most favorite FTP and SFTP client, and its really very cool. Well, you can use it as a WebDAV and S3 client too. Its open source and you can check it out from here

ALunch: if you use your dock very frequently and are really tired to reconfigure it again and again, alunch is a very nice sticky app launcher for you. it’s organiser is simply awesome and you can arrange all your applications in a a well categorized manner easily. its very nice and one of my very favorites. Check it out from here

iStat Pro and Menus: though it has a name “pro” but it comes for free. it is an awesome device monitoring tool and supplies you very essential information about your mac device, like bandwidth consumption (both eth and bt) temperature, fan RPM, memory usage, cpu usage and it supplies each of these with details. download it from here – btw, forgot to tell you that you can install it in your iphone and ipod touch too!

Chicken of VNC: it is a nice VNC client for mac. if you have multiple macs in your home or you want to use it as a generic VNC client to your other machines, from you mac – it is the perfect tool. open source and free – check it out from here

Caffeine: it is another very useful and handy when you really dont want your screen to black out (heh heh). it sits on your top bar with a icon of coffee cup, and once you click on it the machine will stay active for 30 minutes (configurable). no screensaver, no dimming – its show time . check it out from here