beginnings of new relay: shows persistence

Mostly comments, it's where I'll start to think about the API for a
web-app version of the relay. The server itself ought to exist
already.

xwords4/newrelay/nr.py

@@ -0,0 +1,61 @@
+#!/usr/bin/env python3
+
+import json, shelve
+
+"""This will be a prototype of a simple store-and-forward message
+passing server. Target clients are peer-to-peer apps like turn-based
+games and maybe chat apps. It's expected that they depend on the
+server for nothing but message passing and any group-formation that it
+depends on (e.g three devices agreeing to participate in a single game
+of Fish, a process that gets them a token that can be used to address
+messages that are part of that game.) Clients can use this server as
+one of several means of communicating, depending on it to deliver
+messages e.g. when the devices are out of range of bluetooth.
+
+"""
+
+# register: a device is meant to call this once to get from the server
+# an identifier that will identify it from then on. Other APIs will
+# require this identifier.
+#
+# @param clientID: a String the client can optionally provide to link
+# this registration to an earlier one. For example, if a client app
+# wants state to survive a hard reset of the device but there are IDs
+# like serial numbers or a user's email address that will survive that
+# process, such an id could be used.
+def register(req, clientID = None):
+    shelf = openShelf()
+    obj = {'deviceID' : shelf['nextID']}
+    shelf['nextID'] += 1
+    shelf.close()
+    return json.dumps(obj)
+
+# Associate attributes with a device that can be used for indirectly
+# related purposes. The one I have in mind is GCM (Google Cloud
+# Messaging), where the device provides a server an ID that the server
+# can use to ask google's servers to forward a push message to the
+# device.
+def setAttr(req, deviceID, attrKey, attrValue):
+    pass
+
+# joinRoom: called when a device wants to start a new game to which
+# other devices will also connect. Returns a gameID that internally
+# refers to the game joined and the device's position in it.
+# @param
+def joinRoom(deviceID, room, lang, nTotal, nHere = 1, position = 0):
+    pass
+
+def forward(req, deviceID, msg, roomID, positions):
+    pass
+
+def openShelf():
+    shelf = shelve.open("/tmp/nr.shelf")
+    if not 'nextID' in shelf: shelf['nextID'] = 0;
+    return shelf
+
+def main():
+    pass
+
+##############################################################################
+if __name__ == '__main__':
+    main()