As of today, a valid email by definition is defined by these below RFCs

• RFC 5321,
• RFC 5322,
• RFC 4291,
• RFC 5952 new,
• RFC1123,
• RFC3696 (especially the errata).
• Let me also point out some RFCs that are less relevant, even thought they are frequently cited: RFC 822 (obsoleted by RFC 5322), RFC 2822 (obsoleted by RFC 5322) and RFC1035 (updated by RFC1123).

Few things I’ve noticed and would be interesting to note.

• A Plus sign is perfectly valid in a email. Thus markishh+blogging@gmail.com is a perfectly valid email. Moreover, email clients like gmail use the second portion i.e next to plus as ‘label’ for the incoming messages from them. I really have not tested what happens if it has two plus signs.
• The maximum length of a valid email is 254 characters. It comes from the maximum length of a SMTP transaction is 256 characters including the two angled brackets
• Regexp can’t be used to validate email 100 %. It can test the basics to an extend.
• Special characters can be used in a valid email, it they are enclosed in double quotes. Thus “markish#@test”@markish.in is a valid email. But remember they can’t be escaped by a backslash like what most of us believe.

Ok Now, let’s see how email can validated to a much better extend. Email validation can be done at client end as well as server side. Client side you can implement any regexp that would satisfy. Something like below would help

• ^[_a-z0-9-]+(\.[_a-z0-9-]+)*@[a-z0-9-]+(\.[a-z0-9-]+)*(\.[a-z]{2,3})$
• ^[a-zA-Z0-9_.-]+@[a-zA-Z0-9-]+.[a-zA-Z0-9-.]+$

In the server side, I’d suggest is_email.php a parser / validator developed by Dominic Sayers as a perfect fit. You can download this from here

Once you download the PHP version from here, just include the same in your project. Some thing like below code snippet would do the trick of validation. It’s the best known validator for email as per the existing RFC standards.

Simple Usage

require_once 'is_email.php';
$email="markishh@gmail.com";
if (is_email($email)){
	echo "$email is a valid email address";
 }else{
 	echo "$email is invalid";
 }

The above is very simple and straight forward usage of the script. is_email function returns a Boolean which can be validated against. The class also supports an extended result for the email we supply.

Extended Usage / Testing

require_once 'is_email.php';
$email = 'markishh@gmail.co';
$result = is_email($email, true, E_WARNING);
if ($result === ISEMAIL_VALID) {
	echo "$email is a valid email address";
} else if ($result < ISEMAIL_ERROR) {
	echo "Warning! $email may not be a real email address (result code $result)";
} else {
	echo "$email is not a valid email address (result code $result)";
}

The extended results gives you the SMTP level results as well. This is a very handy as well as simple script that can be added to your existing projects as well.  I hope someone would find it useful and interesting.

@ Credits to Dominic Sayers for developing such a complete validator.

Download link again : http://code.google.com/p/isemail/downloads/list

The validity of the data present in the cache depends on the implementation logic and hugely depends on the nature of the application itself. For example, In an online store, the cache data containing the list of products available in the store can be valid for even 2 hours as there is very less chance of a product being added every 2 hours. But the cache data holding the availability (stock) of products can be valid for probably 2 minutes ( assuming , it’s a real online store where business happens) as the availability keeps changing.

Today we’d talk about one of the techniques in output caching – Record set caching. It’s one of the straight forward approach, that can be implemented. In layman terms, The record-set after a complicated query would be stored separately so that, the future requests can be served from the temporary storage instead of running the time consuming complicated query again every time.

To start with, Let us consider an example. A page delivering search results in JSON format from a product catalogue accepting a search query. Let us put down the algorithm to implement this

Step 1 : Check if a valid cache data exists in cache
Step 2 : If Yes read, the cache data and serve it to the user / client
Step 3 : If No, Read it from the DB and serve the user.
Step 4 : Update / Create the valid cache data with the one got in step 3

Let’s get into coding rightaway..

Source code

$mcdir = "cache/";
$mcache_validity=10;
$mfnam = $mcdir . "ch_" . $search_data ."_file.txt";
$mread_from_cache = false;
if (file_exists($mfnam)) {
	$mctime = (filectime($mfnam));
	$mtime_offset = time() - $mctime;
	if ($mtime_offset < $mcache_validity * 60) {
		$mread_from_cache = true;
	}
}

In the above code snippet , we just check if there is a valid cache data available. The logic behind is to have a separate file to store the result-set for individual search strings. I’ve set the validity of the cache data to 10 minutes. The next step would be based on the decision made in step-1

Source code

if (!$mread_from_cache) {
    $msql = "select product_id,product_name,product_img,product_desc,product_rate
            from product_master where product_name like '%$search_data%'
            where flag_dele=0";
    $mres = mysql_query($msql);
    $mresult = array();
    while ($mdata = mysql_fetch_object($mres)) {
        $mresult[] = $mdata;
    }
    $cacheData = readCache($mfnam);
    (md5(serialize($cacheData)) == md5(serialize($data))) ? $data = $cacheData : writeCache($data, $mfnam);
}else{
    $mresult = readCache($mfnam);
}
echo json_encode($mresult);
flush();

In the above code, we based on the value of ‘$mread_from_cache‘ , either read from the database or from the cache data. I’ve got a simple query for illustration. It may not be the case in an application. Here we have used two user defined function, one to write and other to read from the cache. The below is the code for them.

Source code

function writeCache($data, $cacheFile='default_cache.txt') {
    if (!$fp = fopen($cacheFile, 'w')) {
        trigger_error('Error opening cache file');
        exit();
    }
    if (!flock($fp, LOCK_EX)) {
        trigger_error('Unable to lock file');
        exit();
    }
    if (!fwrite($fp, serialize($data))) {
        trigger_error('Error writing to cache file');
        exit();
    }
    flock($fp, LOCK_UN);
    fclose($fp);
}
 
function readCache($cacheFile) {
    if (!file_exists($cacheFile)) {
        return '';
    }
    return unserialize(file_get_contents($cacheFile));
}

This is a very basic implementation of record set caching. This can be improved based on the application demand and other load factors. We’ve taken a more procedural approach in this code. In the next article I’d talk about handling the same in a more object oriented approach.

Do share your comments and suggestions.

Today morning, I had a look at the new UI finally. It looks new and fresh. Below are the few notable features.

Two column layout

Twitter Home page

The home page now has the two column layout. The left pane has the usual stuff – the chain of tweets. The right pane / details pane is the new one. Twitter also recognizes the type of content your tweet has. It’s pretty intelligent now! Click on a tweet in the left column, and the detail pane has lot of options for the same and it allows interaction with the content of that tweet as well. What is displayed in the detail pane depends on the nature of the tweet:

• Videos: If the tweet contains a link to a video from sites such as YouTube, Vimeo and USTREAM, that video plays in the detail pane. This is cool feature but never know how much load twitter can handle on this. Already we’re used to “Twitter over capacity” screen…
• Maps: If the tweet is a check-in via services such as foursquare, the detail pane displays a map.
• Pictures: If the tweet includes a link to a picture posted using services such as Flickr, DailyBooth, Twitpic and DeviantArt, that image appears in the detail pane.
• Hashtags: If you click on a hashtag within a tweet, the detail pane conveys up-to-the-moment search results.
• Products: A tweet containing a link to a product on Etsy or other select eCommerce sites will cause a product image to display in the detail pane. I feel twitter is going to build some revenue model around this.
• Replies: A small icon appears in tweets whenever one Twitterer responds to another. Click the arrow and the prior conversation is presented within the detail pane.

Twitter Detail Pane

Better Profile Overview

With lot of space on the right pane, Twitter has made use of it by putting images of your ‘followers’ and ‘following’ ( 7 each) and Listed and favorites. Still lot of space is available. Hopefully, they may come out with google like ‘ads’ on the right pane in the near future…

What is Missing ?

All said and done, I’s expecting bit more from Twitter this time. The following are missing or I missed noticing them.

• Revenue Model: This is the major topic of debate from the day one Twitter become popular. I’s expecting something would be rolled out with this atleaset. But still it’s missing big time. The right pane / detail pane is the place which may be used as placeholder for sponsored ads in near future.

• Performance: Again I don’t see any great improvement in loading time and performance of the site as a whole.

• Priority: With Google introducing Priority Inbox, and twitter identifying the content of the tweet, I’s expecting something like priority in the tweets.

• More than Text: I’s expecting Twitter to allow image / video uploads directly from Twitter web Interface like Google Buzz and Yahoo MeMe. May be Twitter still wants to keep them simple and smart..!

Glitches

The new user interface is still having lot of issues and cross browser compatibility issues. The background images / themes the users have been using would become void and need to be changed immediately.

Happening behind the Embedded Video

Twitter new user interface promises ‘Easier Interaction’ and ‘More Discovery’. While any change in interface can cause complaints from long-time users, I believe the new Twitter will meet with strong user acceptance. As the new design is rolled out, users have the opportunity to accept it or return to the original design, but I think many will embrace the intuitive new functionality. Share your views and comments on Twitter new UI here.

Bleezer is developed in Java and hence is platform independent. It’s neat and pretty. Though not colourful like MS word xxx, It serves the purpose calmly. It’s available at http://alchemii.net/bleezer/ It supports all the major blog engines – Blogger, WordPress (a special thanks from my side… ), typepad, drupal.

Once you download, you have to run the bleezer.jar in the archive. Make sure to change it’s permission to allow execution as a program. You should have Java already installed in your machine. Just launch it, you are in the new world of blogging in Ubuntu.

Just edit the preferences, add an account in the dialogue as shown below

The features I like in this are

• Enabling me to save the Posts as drafts
• Support for multiple accounts, so that it’s the one point of my blogging
• Gives support for adding tags to the Posts
• It provides a normal view along with the HTML view in tabs
• It provides preview as well – quite easy to see what you post
• Fairly decent WYSIWYG editor.
• Supports editing of published Posts as well

I’d say Bleezer worth a try. Comments welcome

I wanted this site ( single page) to load faster without any complications. I’ve just put the IP of the visitor and a small JS to copy the IP to your clipboard.

Snapshot of ItismyIP.com

I think,  I’m far better this time in choosing my domain name..I’ve seen around 100 hits already in a day without much doing from my side. So I added my adsense today to it.. Hope it gives me back the 10 USD within this year.

I know there are ‘n’ number of popular sites giving this service. But I’m thinking of something different that would help me have my share of traffic. Any suggestions welcome in this regard…!

Have a look here and do share your comments..

I added one more switch to my script ‘S’. It accepts the keywords and searches the YouTube for related videos. Now my scripts usage is like

This helps a lot for me now. Just I trigger something like

C:\Videos> Cscript yt_dl.vbs S 10 Sachin Warne

It downloads 10 videos related to Sachin & Warne from the YouTube.

Hope this improvement helps. The only limitation (atleast that I’ve noticed) is it can download the maximum number of 20 related videos. Please do share your comments.

The modified version can be downloaded here.

    You need to be online to watch a video from YouTube. It also supports buffering. That’s the video can be buffered when connected to the internet and watched offline. (This has helped me to watch so many videos when I’m not connected). But the pain part is if you close the browser, the buffered content is lost. You again have to connect to internet to watch the same video clip.

    Why not we download it and have it offline? I googled and found some websites that provide this service. You tell them the video you need, they give you the download link after sometime. You can download it. But you get this service at the cost of advertisements and annoying popups. There is a plug-in available for Firefox users. Still IE users don’t have any options. All I wanted was to download many video clips in a single shot. The only option was to code myself!

    I chose VBscript as I don’t need any more software installation necessary for this to run. Almost all the Windows comes with the scripting support. Hence I can run my VBscript anywhere even in the Cyber-cafes. It supports two switches currently. Either I can directly supply the list of URLs of videos I want when I’m calling it or I can provide a text file with list of URLs. Something like

When you call the script with ‘U’ switch you can provide the URLs directly. Something like

YT_DL.VBS U http://www.youtube.com/watch?v=kMYw8SodMWQ, http://www.youtube.com/watch?v=hRMyR8BJ74A

When you call the script with ‘F’ switch you can just provide a path to text file which contains the list of URLs

    YT_DL.VBS F url_list.txt

    The main advantage of the script is that you can just create a list of videos you want and put in a text file and pass it on to the script with ‘F’ switch. It downloads and saves them in the same folder with the title of the videos as the file names. You are done with a single command. No waiting, No popup and it can run on your background. You need not even bother about it.

    Please note, when you running this script for the first time, you will (most probably) get an error message stating, “msxml3.dll: Access is denied”. Don’t worry, it’s a security catch. You need to add http://youtube.com to your list of trusted sites. For this go to the ‘Internet options àSecurity tabà select Trusted and click the ‘Sites..’ button. There you add http://youtube.com. Now run your script. You won’t have any issues.

    Once downloaded, you can play those .FLV files using FLV players available over the web for free. You can download one from here. Hope you find this script useful. You can use it and modify it in the way you want. If you have any issues or suggestions, please let me know. Have fun and do share your comments here.

The script can be downloaded here.

    Here it depicts the total gross and net sales value of the organization for different category of product and services (ERP & SERVICE here) for different quarters of the year. Let’s say the ERP system of this organization exposes and API that gives this data in some XML format. For example check this XML. Something like below

    Now we’ve the charting APIs from Google (what they don’t provide man….. J ). It provides a powerful set of APIs with lots of options that can produce different type of charts. Please check the Google Charts for further details on the API. Now we have the different services available – viz Data provider and the Chart creator. It’s now time to Mashup them into a more useful UI. I’ve read the data from the xml using an xml parser and fed the same data to the chart API from Google. What we get is a beautiful graph plotted against our enterprise data.

    It’s quite simple with Mashup. Otherwise, we need to run our charting machine which is a overhead in many ways. The above chart depicts the sales in millions (y axis) and against the various quarters (x-axis). The same data can be plotted against a map to depict the geographical distribution of the sales as I showed in my last post. For creating a Mashup there is no limits. It completely depends on the creativity and the requirement of the situation.     There are N number of services and more number of service providers available over the web. Hence the theoretical limit of Mashups is infinite. Out of Infinite probabilities possible, lies the base and secret for the interactive and efficient UI which form the basics of Web 2.0.

The complete source code of the above example can be downloaded here. For using this, just unzip the archive into your webserver and set the parameters in the conf.mysql.php and use the qsales_table_def.sql file to create the table. To see this in action check this link. Hope this gives a better idea of what a Mashup can do. Share with me your views on this.

Writing any Mashup involves the following steps /actions

• Deciding what to write (choose a topic)
• Deciding the data stores (service providers like Google, Amazon, Yahoo, Hostinfo …etc)
• Look for necessary APIs exposed them

Once you are at this point, you can really ‘Mashup ‘ you data to provide your end user a creative user-interface. Now, I’ll take an example and go through the above steps and finally come up with a Mashup widget. I’d try to create a ‘Geo-IP-Map’. It’d show the end-user position (place) on the map. It can be embedded on any web page. I’ve just embedded it in my own sidebar.

For producing this I need the following data

• The Map’s base data
• The latitude and longitude of users’ present location
• The City / Country / Geographical location of the user
• The IP of the end-user

I’ve given the data in the top-down order. Now let’s decide the data store provider for each of the data required

Now you have the API and the data store ready. Both of the above data stores I’ve used require you to register with them for receiving the API key. This requirement varies with the data providers. Now you have this ready, you can just put things in place and provide a creative UI to your users. I used PHP to code my GEO-IP-Map. I’ve added this Mashup maplet to my own blog. You can see it in action in the sidebar itself. After all it is simple and cool…!

If you are interested in this code, you can download the sample from here. I’m not a PHP programmer, hence you may find this very crude. You can modify it to your taste and convenience. Do keep me posted.

I’ll write more on Mashups in my next post.

    Probably most of us are aware what an Operating System (OS) is and what it mean to the overlying applications. Probably it exposes numerous APIs to interact with the underlying hardware resources. The overlying applications just call the APIs to access the Hardware resources. But for the OS in place there, programming would have been a nightmare even now. A simple explanation would be

    In the above picture, it’s clear that, the user applications just make use of the APIs provided by the OS to get access to whatever resources it want to access. But for this infrastructure, it’s really tough to have even a small application program running and we’d not have the comfort of so many high-level programming languages.

    Now coming back to the original discussion, Mashup or Mashup application make use of the similar infrastructure available over the internet. They make use of the services from different websites / service providers and provide altogether completely different service which is more useful and powerful in the end-user perspective. Something like

    A Mashup application or website may be defined as “An application that consumes the output of more than one service and ‘mash’ them up to provide a new service to the end user”. Let’s discuss a typical example. When we impose the data from http://weather.com over the map data provided by Google maps, we get a altogether rich user interface displaying the weather of a particular region along with the forecasts. Something likehttp://www.weatherbonk.com.

Now Mashups have opened a new set of applications that can provide the end user the flexibility and the benefits of more than one service providers. There are hundreds of Mashups already in place. Mashups can also find a very big market in the Enterprise world as well. In my next post I’ll discuss something interesting Mashups and procedure to create a new Mashup.