How to automatically transfer a file when two androids are in the same vicinity?

Question

Im working on an app that asks the user to input 5 words. I would like the app to notify the user if someone in the same vicinity has any words that match with the user. I was wondering whats the best way to go about this. Im not sure about bluetooth because I believe it requires the user to manualy make a connection with the other user. I was thinking of maybe uploading the users gps location and comparing it with other users. To be honest I have no idea how to go about this. Thanks for the help!!!

Answer 1

Have all devices communicate their location and "words" to a shared webservice. The webservice can then report back whether their are matches in the vicinity. Don't get distracted by fancy nfc/wifi/bt ideas if you don't need to :)