Need a way to publish a level to game and generate a code to go with it. Can you help?

OK, so I was thinking of making a level uploading system. But you see the problem is idk really know how this system would work. I was thinking of using subscribe async and Messaging Service but I realized the problem would be that yes, it would upload and be on all servers but if no-one was on any server every single level would be wiped. Also if you were to upload a level and a new server was created they would have no levels. So what I need is a way to get a randomly generated code and have a level attached to it and when you type that code it will give you a level. You need to be able to have create a level and then it will be on the game forever. So like when you type in "ACODE" it will return a table of numbers like 000100101110100101001001000. So yeah plz help!