Building Led light which work on 230V supply
No, just a rectifier and capacitor isn't enough.  You need something that will set the correct current through the diodes, or else they are liable to burn out.  That's especially the case if you suffer from voltage fluctuations.

The best solution is to use a proper LED driver.

The cheap alternative is a suitably high voltage capacitor to produce a "capacitive dropper".  If using a capacitive dropper, assume that any part of the circuit may be live and take appropriate precautions.