I bought a blueray player and it only connects to Ethernet but I only have wifi....

I assume you have a wireless router. The mac is inconsequential.

1) you can run a cable.
2) you can get powerline adapters. these use the house power wiring to connect, making a bridge. You need 2, and they must be plugged directly into an outlet, not a power strip.
3) you can wireless bridge. Either convert a router OR get a wireless bridge.

You should get a ethernet cable that is long enough and connect it to your modem then into the blu ray player. This shuold allow it to connect to the internet