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Vivek Lakhanpal

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I am Software Engineer with proficiency in Flash related technologies.

Vivek Lakhanpal

September 22

Modularization of Flex Applications

I was asked for some days to give an online public session on http://www.WiZiQ.com/public/ related to Flex technology. Although I know I am not a good teacher but I thought why not share some knowledge. It might be of some help to beginners who just entered or are entering Flex development.

So after thinking for few days i come up with a topic "Modularization of Flex Applications". Flash apps being heavy in content animation/graphics are always the contender for modularization be it in old Flash days when we use to create separate swf files and load them dynamically or now in Flex by creating modules, which creates separate swf files that can be loaded dynamically at run-time.

I am posting the link of the session, which you can join if you are a beginner in Flex. Sorry for posting it a bit late. But there's still more then 24hrs to go.






July 25

Flash player with ExternalInterface call and it’s use inside form tag

This article is an update to the previous one i have written i.e. picking up domain name….
It’s a new problem i noticed while using ExternalInterface in flash file and embedding that swf file in asp.net web pages and within form tags

The problem starts when we have our flash player (with External Interface call) embedded inside a form tag that is mostly in ASP.net web pages which use runat server controls. Most of IE version 6 and IE 7 starts giving error:’try { flashplayer.SetReturnValue(__flash__toXML(window.location.hostname.toString()) ); } catch (e) { flashplayer.SetReturnValue(”"); }’ or ‘flash player id undefined’
Looking at various websites and finally on livedocs I was able to find the solution/workaround to the problem: Just add following line after your flash file embed code in which you are using any ExternalInterface call.

window.[flashplayer id used in embed code] = document.getElementById(['flash player id used in embed code']).

This will add a window level pointer to the movie so that it can be referenced directly using id/name. As this is only required in case of IE you can put condition for it’s execution only in case of IE.

June 27

Flash embed tag for spaces.live.com

Few days back I tried to paste some of my flash presentations from one of the community website (www.authorstream.com), which provides embed tags you can paste in your blogs. It didn’t work.

In spaces.live.com blog you can paste your video or flash embed tag using “Embed videos” at the bottom of message editor. I simply copied the code provided by the website and pasted it in pop up input box which I received after clicking on “Embed videos” button. When I clicked save button I received following error: “The embed code you've entered is not supported by Spaces. Only Flash video players are allowed.” After some analysis I came to know that spaces.live.com only allow embed code of the whole provided object code or auto generated flash embed code. So when I put flash embed code in the provided input box it just strip of the object part of the code and retain only embed part of the code. Now type value must be present in the embed code for it to be worked in spaces i.e. type="application/x-shockwave-flash" otherwise you will get above mentioned error. After I updated the code and put type in embed code it worked fine.

June 23

authorSTREAM has just added a new feature

Here is a new feature from authorSTREAM.

Actually it's not a new feature; it's an extension or shall i say enhancement to the existing feature, which is used to convert a user's presentations (only specific presentations) to video and make them available to download as mp4 or for podcast.

Being in a developing country, the Internet speed is terrible sometimes or it's a bit costly compared to US and European countries (although the situation has changed in the last few months). So like everyone i also wanted that my content should be viewable/viewed by as many people around the world as it can be.

So if you have your content as video, everyone knows the authority of YouTube and the visibility it brings to your work. But downloading it from one website and then uploading it to another was a bit of a pain--both time-wise and cost-wise. So this new extension from authorSTREAM is a very nice offering, which solves some problems of people like me. You can directly transfer your content to YouTube and enjoy the publicity.

The presentation below by TechGuy describes how you can move your video content to YouTube directly from authorSTREAM.:
        


The above presentation as video on Youtube:
       





June 15

Picking up the domain name where your flash file/player has been hosted

This problem was bugging me for a long time and I was not able to find the solution until recently when I dug into few internet blogs again for sometime and was able to crack the problem. Actually this was a request that came up to me last year for tracking the IPs or domain name where our flash application/player is blogged or embedded. The only solution then I was thinking of was _root._url. But that was of no use as the flash player was being picked from our website and it was returning the URL of our website then the website where it was embedded. I even thought of getURL but it was not useful in this solution. I never worked with ExternalInterface much at that time and never thought it will be of any use as such for me as I thought its functionality is almost like getURL so it will be same as getURL. So I never dug deep into ExternalInterface at that time and I just thought whenever we try to send some variable to through sendAndLoadVar to our domain for tracking the visit count why not try to read the request header. Maybe request header will have the domain information in http-referrer or somewhere. But when we tried to dig deep into that we found that it's the client ip information which we receive in the request header not the domain information so that solution was too ruled out. This year again when I was approached for the solution I thought do some more search & research. I came across this blog of abdul qabiz; there in one thread I found some useful information and came across a mention of another website Flex Pasta. There I found the solution to my problem that I can useExternalInterface to get this domain information and many other information variables like port or URL parameters. So here I found the solution. I created a small code snippet to test it and see how it’s working on a different domain; I created 2 text fields on stage in AS2 file:
ActionScript 2:

import flash.external.ExternalInterface;

try{
txtDomain.text = ExternalInterface.call("window.location.hostname.toString");
}catch (myError:Error) {
txtError.text = ("error: "+myError);
}
So it worked locally for me. But when I hosted this file on one website and pasted embed code in one blog, I got null as the value in the textfield. Then I tried to look into the Adobe help docs; there I found that if any error occurred it will return null. So I just tried to do some checkup on the Internet and then I found that allowScriptAccess must always be set as always; then only it will return the value. So I am again stuck in the middle! I will be able to return the track of only those blogs, which will allow me to embed the code with allowscriptaccess as always but due to security threats many of the major blogs have already changed it; they have set it's value as never so you can't embed any third party swf file into these blogs with allowscriptaccess tag with value other then never. So does that mean you can't get domain name track backs from these blogs? I tried to do try catch as you see in the above code but nothing was returned in AS2 other then null. So I read one comment in the Abdul Qabiz blog that he got a security error back in try catch and in that string he got where it was occurred along with the swf file path. I tried that in ActionScript3/CS3 file something like this:
import flash.external.ExternalInterface;

var loc:*;
try{
loc = ExternalInterface.call("window.location.href.toString");
}catch (e:SecurityError) {
test.text = ("error caught: "+e);
}
txtDomain.text = String(loc);
I mentioned the variable type of loc as "*" because I read a comment from senocular on Flashkit that the variable returned by ExternalInterface.call is of type "*". When I tried to assign that value to textfield it gave me an error: TypeError: Error #2007: Parameter text must be non-null. So there I have to typecast the variable as String to remove the error. Now when I published the file and tried that with 'allowscriptaccess' set to 'never' in embed code, I got a flash player error alert popup which said that the following swf can't access the following html file in which it is embedded. Now as html page is hosted on the domain for which I was looking i.e. I can parse out the domain name from that error but an alert is not something a visitor likes to see. I put that call in try catch and got the error trace which has domain name in html page reference in catch block. Similarly if you want to do it in Flex application you can do it something like:
import flash.external.ExternalInterface;

private var dom:*;
private function init():void{
try{
dom = ExternalInterface.call("window.location.hostname.toString");
}catch(e:SecurityError){
dom = "error: " + e.toString();
}
}
Init method can be called up on creation complete event of application. Another problem which I came across this whole process was that during my tracing I noticed that although I can trace up external interface call in Firefox and Safari but Internet Explorer was not responding to the call. When I dug upon it a bit I found on one of the forums that specifying the flash file id along with classid in Object tag is a must to make sure your ExternalInterface call go through and return you a value. For e.g.<object classid='clsid:d27cdb6e-ae6d-11cf-96b8-444553540000' id='player' width='481' height='402' >


March 10

Some hard facts...


* You can't tell which way the train went by looking at the tracks.

* There is absolutely no substitute for a genuine lack of preparation.

* Happiness is merely the remission of pain.

* Nostalgia isn't what it used to be.

* Sometimes too much drink is not enough.

* The facts, although interesting, are irrelevant.

* Someone who thinks logically is a nice contrast to the real world.

* Things are more like they are today than they ever were before.

* Everything should be made as simple as possible, but no simpler.

* Friends may come and go, but enemies accumulate.

* I have seen the truth and it doesn't make as much sense as you think.

* Suicide is the most sincere form of self-criticism.

* If you think there is good in everybody, you haven't met everybody.

* All things being equal, fat people use more soap.

* If you can smile when things go wrong, you have someone in mind to blame.

* One-seventh of your life is spent on Monday.

* By the time you make ends meet, they move the ends.

* Not one shred of evidence supports the notion that life is serious.

* The more you run over a dead squirrel, the flatter it gets.

* There is always one more imbecile than you counted on.

* This is as bad as it can get -- but don't count on it.

* Never wrestle a pig. You both get dirty and the pig likes it.

* The trouble with life is, you're halfway through it before you realize it's a do-it-yourself thing.

* The first rats off of the sinking ship are the best swimmers.
December 24

Answer these Questions

1. If all the nations in the world are in debt (I am not joking. even US has got debts), where did all the money go? (Weird)

2. When dog food is new and improved tasting, who tests it? (To be given a thought)

3. Who copyrighted the copyright symbol? (Who Knows?)

4. Can you cry under water? (Let me try)

5. Why do people say, "Youve been working like a dog" when dogs just sit around all day? (I think they meant something else)

6. Why are the numbers on a calculator and a phone reversed?

7. Do fish ever get thirsty? (Let me ask and tell)

8. Can you get cornered in a round room?

9. What does OK actually mean? (OK, I don't know)

10. Why do birds not fall out of trees when they sleep? (Tonight I will stay and watch)

11. If corn oil is made from corn, and vegetable oil is made from vegetables, then what is baby oil made from? (No comments)

12. What should one call a male ladybird? (No comments)

13. If a person suffered from amnesia and then was cured would they remember that they forgot? (Can somebody help?)

14. Why is it called a "building" when it is already built? (Strange isn't it)

15. If you were traveling at the speed of sound and you turned on your radio would you be able to hear it? (Got to think scientifically)

16. If you're traveling at the speed of light and you turn your headlights on, what happens? (I don't have a change to try)

17. Why is it called a TV set when there's only one? (Nice one)

18. If a person owns a piece of land do they own it all the way down to the core of the earth?
December 05

Attitude is Everything

With a Positive attitude you can do everything and anything in this world.

  

 
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