This looks like a rail system that comes premade. There are many brands, you might try googling some of them. The posts appear to be metal. The wrap on the top appears to be metal as well. Good luck.

The posts and top look like aluminum or whatever type of metal they use with composite decks...the deck itself is a composite deck (like Trex) so look into the materials commonly used for composite decks and you'll find your answer.

This Fiberon product is similar

Davidsonville porch · More Info