I'm Vipul From India we do not have any real time data providers free giving market data for nse stocks but yahoo gives live data but u have to log in with your yahoo id and password to get stemming data .
can any one code in program which can help me log in to yahoo and fetch data and send it to ninja trader as external data feed which i can use for my datafeed to view charts
No, that won't give real time prices.
From what I know their is no Yahoo Finance API to grab their market data in realtime, so no solution I think. You can take a look at https://code.google.com/p/yahoo-finance-managed/wiki/YahooFinanceAPIs , but that won't help for realtime.
I used to use Yahoo to get stock options prices, but I was doing a snapshot every 5 minutes (that was in Perl, a long time ago, now you can do that in JSON).
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