Monday, January 09, 2006

cURL -- A tool limited by imagination

A stock ticker is a piece of code which keeps you updated with the latest(as and when) stock quotations of various companies at the stock exchange. Technically to build this one needs the following tools --

  1. XML
  2. RSS
  3. cURL
  4. sed,awk,grep and simple shell scripting knowledge.

1. XML
Need to know just this concepts elements.

2. RSS (Really Simple Syndicate) -- it is really simple.
As I understand this, there is a link like "http://www.xanadb.com/ticker/YHOO" which provides RSS feed for stocks(YHOO- for yahoo, MSFT-microsoft).
Now observe the xml format carefully. All rss feeds essentially have these 3 elements
title,descrption,link.
An RSS reader is one which makes sense of this rss feed.

So to build the stock ticker here is the design
a) Get the contents of "http://www.xanadb.com/ticker/YHOO" in a variable.
b) Just find the “title” tag. Trash the rest.
c) Find the number and thats it.

3. cURL

Now to achieve step (a) mentioned above we have to use a tool which gets us the contents of the page in a variable or a file.

cURL is shipped freely with most of the Linux installations.

Catch hold of one and execute this

curl "http://www.xanadb.com/ticker/YHOO"

Now go through the manual in case you are using proxies, SSL protected site, etc etc etc.

Now the power is all yours. Just think all the stuff possible with this tool and have i told you this. Its a MIT product.

4. sed,grep and other scripting techniques

Here after its child's play and the scripting skills.

curl "http://www.xanadb.com/ticker/YHOO" | grep title | sed s/title//g

I havent tried the above on a machine , but hope you got an idea as to how the attempt is being made to get the stock quote.

Conclusion

No matter how hard web designers may try to force you to surf their sites interactively, there will always be free tools to help automate the process, thus enriching our overall Net experience.
A deliberate attempt has been made only to answer the "How" part of the tools and not the "What" part of them, as they are available in the links suggested.

Next in Line

PODCAST -- what the hell is this

3 comments:

Murali said...
This comment has been removed by a blog administrator.
Murali said...

Oops sorry acronym mistake right at the end..... reposting my corrected comment


A Pod Cast is wrt an apple iPod. Its the iPod equivalent of radio channels that u have like 91 FM etc etc just that its not radio transmission to ur iPod. You log on to the web and connect ur iPod and open up iTunes (the software that comes with iPod). Then u can receive any kinda content that people post on the web, some being paid services and others free. Apparently there are podcasts coming out in languages like konkani, gujarati etc etc enabling ppl in the US to sit and listen to stuff created by their brethren in their native places, hence the sudden boom in its popularity.

HTH ( All this info might not be extremely, pin point accurate )

Shantanu said...

Million Dollar Question is

"How do I make podcast work to my advantage"