edu.drexel.cs544.mcmuc.util.RoomDoesNotExistException
A chat room message action must carry a "from" field, which is a nickname that identifies the sender, and a "body" field that carries the user's input. Messages can also optionally contain a "to" value, for which clients can choose to hide from the user messages not meant for them. Messages can also be optionally encrypted with the public key certificate specified by "key". Using "to" and "key" together allows clients to avoid checking the "key" against their own keystore, as they will know the messages was not directed at them. The possible JSON formats are: {'action':'message','from':'','body':''} {'action':'message','from':'','body':'','to',''} {'action':'message','from':'','body':'','key',''} {'action':'message','from':'','body':'','to','','key',''}